Zoran S. Nedeljkovic, MD

• Assistant Professor of Medicine
• Department of Medicine, Section of Cardiology
• Boston University School of Medicine
• Interventional Cardiologist
• Boston Medical Center
• Boston, Massachusetts

Activation of these receptors by the endogenous opioids has physiologic effects weight loss plateau wegovy 14 mg mastercard, including analgesia weight loss journal ideas wegovy 14 mg purchase line, drowsiness weight loss pills visalia ca 14 mg wegovy buy with visa, respiratory depression rapide 60 weight loss pills reviews effective 14 mg wegovy, decreased gastrointestinal motility weight loss pills zymax cheap wegovy 14mg on line, nausea, vomiting, and alterations in the endocrine and autonomic nervous systems. The use of opioid drugs can result in the development of tolerance, physiologic dependence, and addiction. Tolerance leads to a shortened duration of the action of opioids and a decrease in the intensity of the drug action, followed by the need for a higher dose to obtain the same clinical effect. Continuous administration of opioids, therefore, leads to the more rapid onset of tolerance (Anand and Arnold, 1994; Suresh and Anand, 2001). With physiologic dependence, there is a need for further drug administration to prevent withdrawal symptoms (agitation, dysphoria, temperature instability). Addiction is a more severe form of dependence that involves a complex pattern of drug-seeking behavior (Christensen, 2008). Complications of Pregnancy Marijuana use during pregnancy is inconsistently reported to have effects on birth outcomes. The inconsistency likely stems from the fact that marijuana is often used in combination with other substances, thus potentiating the risks for prematurity and low birthweight. Day et al (1991) reported a higher incidence of meconium-stained amniotic fluid and other pregnancy and delivery complications after maternal marijuana use, but subsequent studies have not replicated this finding. Frequent use of marijuana was associated with a small decrement in birthweight in a study that did not control for other illicit drug use (Schempf, 2007). Complications of Pregnancy Obstetric complications associated with maternal use of opioids include a higher incidence of spontaneous abortion, premature delivery, preterm labor, abruptio placentae, chorioamnionitis, impaired fetal growth, and fetal distress. In women who use opioids during pregnancy, the incidence of preterm labor and premature delivery ranges from 25% to 41% (Chiriboga, 1993; Lam et al, 1992; Little et al, 1990). The etiology of these opioid-associated pregnancy complications is multifactorial. Maternal lifestyle, malnutrition, infections, and polydrug effects are likely to result in poor perinatal outcomes, including poor intrauterine growth and prematurity. Because the drug supply is often episodic, the pregnant addict is subject to episodes of withdrawal and overdose, thereby subjecting the fetus to intermittent episodes of hypoxia in utero, hindering growth and raising the risk of spontaneous abortion, stillbirth, fetal distress, and prematurity. For example, heroin (diacetylmorphine) exerts its effects by being metabolized to morphine, as does codeine, which is methylated morphine. Other opioids, such as methadone and oxycodone, are structurally unlike morphine but share its pharmacologic properties, because they stimulate similar opioid receptors. Hulse et al (1997) reported an association with heroin abuse and increased prematurity, low birthweight, and reduced fetal growth. A naturally occurring anesthetic of the tropane family of alkaloids, cocaine is obtained from the Erythroxylon coca plant, which is indigenous to the mountain slopes of Central and South America. The coca leaf has been chewed or made into a stimulant tea by the natives of these areas to decrease fatigue and hunger. The pharmacologic actions of cocaine include inhibition of postsynaptic reuptake of norepinephrine, dopamine, and serotonin neurotransmitters by sympathetic nerve terminals, thus allowing higher concentrations of these neurotransmitters. In adults, cocaine binds strongly to neuronal dopamine reuptake transporters, thereby increasing postsynaptic dopamine at the mesolimbic and mesocortical levels and producing the addictive cycle of euphoria and dysphoria (Malanga and Kosofsky, 1999). Tryptophan uptake is similarly inhibited, altering serotonin pathways with resultant effects on sleep. Cocaine use leads to a sense of well-being, increased energy, increased sexual achievement, and an intense euphoria or "high. In adults, cocaine has been associated with cerebral hemorrhage, cardiac arrest, cardiac arrhythmias, myocardial infarction, intestinal ischemia, and seizures. Chronic use is associated with anorexia, nutritional problems, and paranoid psychosis and can ultimately result in neurotransmitter depletion and a "crash," characterized by lethargy, depression, anxiety, severe insomnia, hyperphagia, and cocaine craving. Two forms of cocaine are commonly used-cocaine hydrochloride and cocaine base, which are either extracted by organic solvents or precipitated as "crack" through the use of ammonia and baking soda). Cocaine hydrochloride is a water-soluble white powder that is used orally, intranasally ("snorting"), or intravenously ("running"). Intravenous users are more likely to have a history of heroin abuse and often use the drug in combination with heroin (known as speedballing). Cocaine hydrochloride decomposes on heating and is, therefore, cocaine converted to the free base for inhalation. Crack, the most widely available form of freebase, is almost pure cocaine; when smoked, it readily enters the bloodstream to produce levels similar to those occurring with intravenous use. Crack smoking appears to be particularly reinforcing and is associated with compulsive use, binges, and acceleration of the addictive process. Cocaine and some of its metabolites readily cross the placenta and achieve pharmacologic levels in the fetus (Schenker et al, 1993). Amniotic fluid may serve as a reservoir for cocaine, and its metabolites and prolong exposure to vasoactive compounds. The extent to which cocaine or its metabolites are responsible for aberrant fetal growth, neurodevelopmental sequelae in exposed infants, and the range of congenital malformations reported in the literature may be less than suggested by uncontrolled case reports early in the cocaine-epidemic era. The confounding effects of increased use of multiple drugs, tobacco, alcohol, nutritional deficits, and decreased use of prenatal care among cocaine users make interpretation of the causal relationships between gestational cocaine exposure and intrauterine growth and subsequent neurobehavioral development difficult (Chiriboga, 1993). These identified confounders might serve to explain the reported effects attributed to cocaine in clinical series (Dempsey et al, 1996), although significant effects on the fetus and newborn have been reported in more recent studies that controlled for many confounders (Bada et al, 2002; Shankaran et al, 2007). Complications of Pregnancy Adverse perinatal outcomes associated with cocaine use are believed to be largely because of the vasoconstrictive effects of cocaine on uterine blood supply (Woods et al, 1987). An increase in maternal mean arterial blood pressure, a decrease in uterine blood flow, and a transient rise in fetal systemic blood pressure after an intravenous cocaine infusion have been described in fetal sheep along with significant fetal hypoxemia associated with changes in uterine blood flow (Moore et al, 1986; Woods et al, 1987). To date, no well-defined cocaine-associated syndrome has been identified, and the teratogenic potential of cocaine remains controversial. Earlier reports had suggested that cocaine-exposed infants had a higher rate of limb reduction anomalies, heart defects, ocular anomalies, intestinal atresia or infarction, and other vascular disruption sequences. However, the preponderance of more recent data from multiple studies has failed to demonstrate higher rates of other congenital anomalies among cocaine-exposed infants (Behnke et al, 2001). Any association between fetal cocaine exposure and malformations is likely to be confounded by higher rates of maternal tobacco, marijuana, or alcohol use among the cocaineexposed groups. Cocaine directly stimulates uterine contractions because of its alpha-adrenergic, prostaglandin, or dopaminergic effects, with resulting greater risk for fetal distress and premature deliveries. Abruptio placentae appears to be related to cocaine only when the drug is used shortly before delivery (Ostrea et al, 1992b). Pregnant women who use cocaine are also at high risk for premature labor, low-birthweight infants, premature rupture of the membranes, and perinatal infections. Overall, because of the higher risks of premature delivery, the frequency of respiratory distress syndrome is greater in cocaine-exposed infants. Cocaine-exposed infants less frequently require surfactant administration and intubation for respiratory distress syndrome; however, the risks of bronchopulmonary dysplasia are similar in infants who have and those who have not been exposed to cocaine during gestation (Hand et al, 2001). The clinical effects and toxicity of these agents are often indistinguishable from those of cocaine. Methamphetamine exposure has direct and indirect effects on the fetus, with increases in maternal blood pressure and restrictions in delivering nutrients and oxygen to the fetus (Smith et al, 2003). Like cocaine, amphetamines are sympathomimetics, and they potentiate the actions of norepinephrine, dopamine, and serotonin. Amphetamines can block reuptake of released neurotransmitters; they can also exert a weaker direct stimulatory action on postsynaptic catecholamine receptors. Complications of Pregnancy the medical and obstetric complications of amphetamine use are similar to those described for cocaine use. Amphetamine toxicity has been described as more intense and prolonged than cocaine toxicity. Visual, auditory, and tactile hallucinations are common, and microvascular damage has been seen in the brains of chronic users. Amphetamine withdrawal is characterized by prolonged periods of hypersomnia, depression, and intense, often violent paranoid psychosis. Methamphetamine use is also associated with an increased incidence of premature delivery and placental abruption. Methamphetamine users who stop using earlier in gestation have rebound weight gain, suggesting that the anorexic effects are limited to continuous use (Smith et al, 2003). Like the pregnancies of cocaine users, the pregnancies of amphetamine users are characterized by poor prenatal care, sexually transmitted diseases, and cardiovascular problems including abruptio placentae and postpartum hemorrhage. The risk of cerebrovascular accidents is lower in pregnant amphetamine users than in pregnant cocaine users, but the mechanism for this difference is not understood. Fetal growth restriction, leading to smaller head circumference and lower birthweight, can result from the vasoconstrictive effects of norepinephrine or other vasoactive amines or from diminished maternal nutrient delivery as a consequence of the anorectic effect of amphetamine. Systemic effects from altered norepinephrine metabolism explain the transient bradycardia and tachycardia reported in exposed infants. Studies have failed to show consistent patterns of malformations in amphetamine-exposed infants, although several studies report cleft lip and cleft palate in association with amphetamine and methamphetamine exposure during early gestation (Plessinger, 1998). Fetal Growth Infants exposed to cocaine in utero have lower birthweight, smaller birth length, and smaller head circumference (Bada et al, 2002, 2005; Behnke et al, 2001). Cocaine is hypothesized to reduce fetal growth via vasoconstriction of uteroplacental vessels with consequent decreased fetal substrate and oxygen delivery (Schempf, 2007). Several studies have shown a dose-response effect of cocaine exposure on fetal growth. In the Maternal Lifestyle Study, cocaine-exposed infants were 1 week younger in gestational age, and after controlling for confounders, cocaine exposure was associated with decrements in birthweight (151 g), length (0. After adjusting for the effects of birthweight, gestational age, sex, maternal height, maternal weight gain, and other drug use, newborns with a high exposure to cocaine, as measured by radioimmunoassay of cocaine metabolites in maternal hair, had a disproportionately smaller head circumference even for their birthweight, resulting in "head wasting" (Bateman and Chiriboga, 2000). The N-methylated form, methamphetamine (or "crystal"), is increasingly abused because it readily dissolves in water for injection and it sublimates (converts directly from a solid to gas) when smoked (known as ice). The amphetamine isomers have similar clinical effects and can be distinguished only in the laboratory. Cocaine and methamphetamine use occurred together in 13% of the methamphetamine users, and tobacco, alcohol, and marijuana use were also more frequent in the methamphetamine users. Methamphetamine contributed significantly to low birthweight, even after correcting for confounders such as low socioeconomic status, gestational age, and tobacco exposure. Urine toxicology testing was initially believed to be the best approach, and the universal approach was used in many busy labor and delivery units, particularly in urban centers. This law requires each state (as a condition of receiving federal funds under the Child Abuse Prevention and Treatment Act) to develop policies and procedures designed "to address the needs of infants born and identified as being affected by illegal substance abuse or withdrawal symptoms resulting from prenatal drug exposure. Each state was expected to develop their own guidelines for identification of at-risk pregnancies. The opinion stated that "as a result of intensive research in addiction over the past decade, evidence-based recommendations have been consolidated into a protocol for universal screening questions, brief intervention and referral to treatment. Therefore a history of drug and alcohol use should be routinely included in the initial contact with every pregnant patient. To be effective, the history taking must be nonjudgmental and must occur in the context of other lifestyle questions. When a positive history of use is obtained, intervention should begin immediately. The person taking the history should be prepared to offer preliminary counseling on risk reduction and concrete referrals for treatment programs, although access to drug programs is often restricted, inadequate, or delayed. Although the screening questionnaire approach works well for women who seek prenatal care, it is not useful for the significantly higher percentage of substance-using pregnant women who do not seek or actively avoid prenatal care. For these women, it is more helpful to identify maternal risk indicators for perinatal substance abuse at the time of delivery. Use of one of the screening questionnaires in addition to drug testing increases the likelihood of identifying at-risk pregnancies and neonates, allowing for earlier referral for treatment or specialized interventions. If risk indicators suggest perinatal substance abuse, then consideration should be given to newborn drug testing. For urine testing, there is a poor correlation between maternal and newborn tests. The earliest newborn urine will contain the highest concentration of substances, but the first urination may be missed and urine output in the first day is often scant. However, some drug metabolites such as cocaine are present for 4 to 5 days, and marijuana metabolites may persist for weeks. The disadvantages of newborn urine drug testing are that it primarily reflects substance exposure during the preceding 1 to 3 days, and alcohol is nearly impossible to detect. Meconium drug testing (at term) reflects substance exposure during the second half of gestation, has a high sensitivity for opioids and cocaine, and can assess for more drugs than urine testing. The cost is similar to newborn urine testing, but it generally takes longer to obtain results. Other newborn drug tests include hair-which is costly and has a high sensitivity for cocaine, amphetamines, and opioids but not for marijuana-and umbilical cord segments, which is an evolving technology that is not widely available (Kuschel, 2007). Methadone maintenance programs associated with comprehensive medical and psychosocial services for the pregnant woman are of additional benefit. Methadone maintenance has been shown to be associated with higher birthweight in some but not all studies (Brown et al, 1998; Kandall and Doberczak, 1999). Detoxification of a pregnant heroin user is infrequently attempted, because maternal drug withdrawal is believed to be associated with subsequent fetal withdrawal, fetal asphyxia, and spontaneous abortions (Barr and Jones, 1994). Dashe et al (1998) reported on a small study of opioid-using pregnant women undergoing safe maternal detoxification. Close to 60% of the women completed detoxification, but almost 30% resumed opioid use. McCarthy et al (1999) showed that women who reduced their methadone dose during pregnancy had infants with higher birthweights than a control group who continued on the same or increased methadone dose throughout pregnancy. In the United States, most pregnant, narcotic-addicted women are treated with daily methadone rather than a program of detoxification. In the Netherlands, women enrolled in a methadone program had higher rates of prenatal care, which were associated with higher birthweights and reduced prematurity in the offspring (Soepatmi, 1994). Others have shown that higher methadone doses are associated with improved head circumference and increased gestational age at delivery (Hagopian et al, 1996).

The rates of rare complications of meningitis or neurologic impairment from local anesthetic toxicity with the use of a spinal catheter may be somewhat higher than the other neuraxial techniques weight loss pills history generic wegovy 14 mg with visa, but they remain unknown weight loss kickboxing discount wegovy 14 mg buy online. Some data suggest that leaving the spinal catheter in place for 24 hours decreases the risk of postdural puncture headache (Ayad et al weight loss resistance purchase wegovy 14mg on-line, 2003; Cohen et al weight loss retreat wegovy 14 mg purchase, 1994) weight loss pills banned in usa 14mg wegovy purchase with amex. Before delivery of the baby, the primary anesthetic for the incision and delivery is the induction agent, because there is little time for uptake and distribution of the inhaled agents into the mother or fetus (Dwyer et al, 1995). Induction Agents Anesthesiologists use a variety of agents to rapidly induce unconsciousness. Each agent represents a different biochemical class, and each has specific advantages and cardiovascular effects. Sodium thiopental is a highly lipid-soluble, proteinbound barbiturate that can cause decreased cardiac output and hypotension and rapidly crosses the placenta. Historically, it was the most common induction agent for cesarean section under general anesthesia. However, doses of 8 mg/kg can result in neonatal depression (Finster et al, 1972), and higher doses may require cardiorespiratory supportive techniques until the neonate can excrete the drug. The lack of neonatal effects is unclear, but may be caused by first-pass metabolism by the neonatal liver, rapid redistribution into maternal vascular-rich tissue beds, additional dilution by the fetal circulation, and higher fetal brain water content. Propofol is a diisopropylphenol that is available as a 1% aqueous solution in an oil-in-water emulsion containing soybean oil, glycerol, and egg lecithin. Unlike thiopental, propofol is preservative free and must be drawn up only hours before use. Other differences are that propofol decreases the incidence of nausea and vomiting, and it is currently not a controlled substance. Propofol has not been demonstrated to be superior to thiopental in maternal or neonatal outcome. Propofol administration has no significant effect on neonatal behavior scores with induction doses of 2. Etomidate contains a carboxylated imidazole ring that provides water solubility in acidic solutions and lipid solubility at physiologic pH. Like thiopental, etomidate has a rapid onset of action because of its high lipid solubility, it rapidly crosses the placenta, and redistribution results in a relatively short duration of action. However, local infiltration is useful in rare circumstances, such as acute fetal distress without an available anesthesia provider. The major risks for maternal morbidity are pulmonary aspiration and failed intubation. Appropriate airway examination, preparation for unanticipated events, and familiarity with techniques and the algorithm for difficult intubation (American Society of Anesthesiologists Task Force on Management of the Difficult Airway, 2003) are critical for providing a safe general anesthetic. The trachea is intubated with a cuffed endotracheal tube, and a surgical incision is made after confirmation of tracheal intubation and adequate ventilation. Anesthesia is maintained by administering a combination of inhaled nitrous oxide and a potent inhaled halogenated agent. Ketamine, a structural analogue to phencyclidine, is more lipid soluble and less protein bound than thiopental. It is an analgesic, hypnotic, and amnestic with minimal respiratory depressive effects. Ketamine is biotransformed in the liver to active metabolites, such as norketamine. In contrast to thiopental, sympathomimetic characteristics of ketamine increase arterial pressure, heart rate, and cardiac output through central stimulation of the sympathetic nervous system, making it an ideal choice for a patient in hemodynamic compromise. Doses that are higher than those appropriate for induction of general anesthesia (1 mg/kg) can increase uterine tone, reducing uterine arterial perfusion. No neonatal depression is noted with typical induction doses (Little et al, 1972). Nitrous Oxide Inhaled nitrous oxide is often used as part of maintenance for general anesthesia, because of its minimal effects on maternal hemodynamics and uterine tone. As a sole agent, it is insufficient to provide an appropriate level of anesthesia for an operative procedure. Additional information about nitrous oxide is found in the previous section under Inhalation Analgesia. Inhaled Halogenated Anesthetics Isoflurane, sevoflurane, desflurane, and halothane are all halogenated hydrocarbons that differ in chemical composition, physical properties, biotransformation, potencies, and rates of uptake and elimination. In clinical use, specialized vaporizers deliver these volatile liquid agents, so that the inhaled concentrations can be carefully titrated by anesthesiologists because of the relatively profound cardiovascular effects and potential for uterine muscle relaxation. These agents are important components of general anesthesia for cesarean section, but readily cross the placenta. Without the use of these agents, the incidence of maternal recall of intraoperative events is unacceptably high (Schultetus et al, 1986; Tunstall, 1979). Placental transfer of inhalation agents is rapid because these are nonionized, highly lipid-soluble substances of low molecular weight. The concentrations of these agents in the fetus depend directly on the concentration and duration of anesthetic in the mother. Clinicians often confuse the use of general anesthesia and the terms fetal distress and depressed neonate. A depressed fetus will likely become a depressed neonate, and general anesthesia may be used because it is the most rapidly acting anesthetic to allow cesarean delivery. A Cochrane review of 16 studies comparing neuraxial blockade versus general anesthesia in otherwise uncomplicated cesarean deliveries found that "no significant difference was seen in terms of neonatal Apgar scores of six or less and of four or less at one and five minutes and need for neonatal resuscitation" (Afolabi et al, 2006). The authors concluded that there was no evidence to show that neuraxial anesthesia was superior to general anesthesia for neonatal outcome. Recent experimental animal studies have demonstrated neuronal apoptosis in the developing brain when a variety of agents are administered to induce and maintain general anesthesia (Istaphanous and Loepke, 2009; Loepke and Soriano, 2008). Implications for the fetus and neonate from brief anesthetic exposures are currently unknown because of a lack of human studies and difficulties extrapolating animal study methodology to humans. The induction­delivery interval is not as important in neonatal outcome as the uterine incision­delivery interval, during which uterine blood flow may be compromised and fetal asphyxia may occur. A long induction­delivery time may result in a neonate who is lightly anesthetized but not asphyxiated. If excessive concentrations of anesthetic are given for inordinately long times, neonatal anesthesia, evidenced by flaccidity, cardiorespiratory depression, and decreased tone, can be anticipated (Moya, 1966). It cannot be overemphasized that if the neonatal depression is caused by transfer of anesthetic drugs, the infant is merely lightly anesthetized and should respond easily to basic treatment measures. Treatment should include and focus on effective ventilation; cardiopulmonary resuscitation is rarely necessary. For these reasons, it is critical that clinicians experienced with neonatal ventilation are present at operative deliveries under general anesthesia in which the time from skin incision to delivery may be longer. A discussion of the operative and anesthetic plan by the neonatologist, obstetrician, and anesthesiologist is crucial for optimizing the outcome of neonates in these situations. Neuromuscular Blocking Agents Succinylcholine remains the skeletal muscle relaxant of choice for obstetric anesthesia, because of its rapid onset and short duration of action. Side effects include increased maternal potassium levels, myalgias, and succinylcholine is a known trigger agent for malignant hyperthermia in susceptible individuals. If the hydrolytic enzyme is present either in low concentrations (Shnider, 1965) or in a genetically determined atypical form (Baraka, 1975), prolonged maternal or neonatal respiratory depression secondary to muscular paralysis can occur. Rocuronium is a rapid-acting, nondepolarizing neuromuscular blocker that is an acceptable alternative to succinylcholine. It provides adequate intubating conditions in approximately 90 seconds at doses of 0. Unlike succinylcholine, it has a much longer duration of action, decreasing maternal safety in the event the anesthesiologist is unable to intubate or ventilate the patient. It has the benefit of not being a triggering agent of malignant hyperthermia or elevating serum potassium levels. During the operation, nondepolarizing neuromuscular blocking agents can be titrated to improve operating conditions. This placental impermeability is only relative, however, and neonatal neuromuscular blockade can occur when large doses are given (Older and Harris, 1968). The diagnosis of neonatal depression secondary to neuromuscular blockade can be made on the basis of the maternal history. The paralyzed neonate has normal cardiovascular function and good color, but lacks spontaneous ventilatory movements, has muscle flaccidity, and shows no reflex responses. The anesthesiologist can place a nerve stimulator on the neonate and demonstrate the classic signs of neuromuscular blockade (Ali and Savarese, 1976). Treatment consists of ventilatory support until the neonate excretes the drug, up to 48 hours. Reversal of nondepolarizing relaxants with cholinesterase inhibitors may be attempted. Its purpose is to allow the pediatrician and neonatologist a better understanding of the decisions and concerns of the anesthesiologist and the implications of his or her interventions. To provide the best care for mother and child, excellent communication is required between the obstetrician, pediatrician, anesthesiologist, and nurse. Only by facilitating these lines of communication and obtaining input from each discipline can patient care and safety become optimized. American Society of Anesthesiologists Task Force on Obstetric Anesthesia: Practice guidelines for obstetric anesthesia: an updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia, Anesthesiology 106:843-863, 2007. Marucci M, Cinnella G, Perchiazzi G, et al: Patient-requested neuraxial analgesia for labor: impact on rates of cesarean and instrumental vaginal delivery, Anesthesiology 106:1035-1045, 2007. This effort was the result of an early vision by a group of scientists that with advances in technology and sequence analysis this task could be achieved (Watson and Cook-Deegan, 1991). The central goal was to provide a reference sequence of the human genome that could serve as a framework on which to better understand disease pathogenesis. There have been numerous spin-offs from the technology and analytic platforms developed. A wide range of other organisms have now had their genomes sequenced from pathogenic viruses to complex plants and animals. These sequences provide insights into disease pathogenesis that are infectious or immunologic and open new doors to therapies. The nature of how a gene is defined has been substantially altered by these insights, so that the gene is now recognized as a far more complex structure with elements dispersed sometimes 1 million nucleotides or more from the protein coding components classically thought of as "the gene" (Gerstein et al, 2007). Understanding the genetic relationships between individuals of different ancestral origins has led to the current effort to describe genetic variation across the human species as an essential aspect of understanding predisposition to or resistance from disease. Because the identification that carriers of sickle cell trait had increased resistance to malaria, or the identification of genetic factors conferring persistence of lactose tolerance into adult life as a mechanism associated with the advantages of dairy farming (Bersaglieri et al, 2004), it has been evident that individual genetic variation is an important contributor to health and disease. The hemoglobin system has provided an evolving paradigm for our understanding of the molecular nature of genetic disease beginning in the 1940s (Neel, 1949; Pauling et al, 1949) and onward to serving as a model for gene therapy in the modern era. Finally, as part of the social and legal component, the work has led to legislation in the United States and abroad that is designed to protect individuals from discrimination based on their genetic background. One early outcome of these meetings and the recognized need to convert research findings to clinical utility was creation of Mendelian Inheritance in Man by Victor McKusicks, which has now evolved into Online Mendelian Inheritance in Man ( The international effort continues with many individual countries now focusing on genome efforts that are specifically relevant to their own high-risk medical conditions. This spirit of open access has, in turn, led to a stronger community ethic for the sharing of scientific and medical data that may be a legacy that will exceed the value of the sequence itself. There have been many technical and analytic advances that have enabled the sequence, and more recently its variation, to be understood and applied. Currently these advances extend to the characterization of hundreds of thousands of genetic variants on large populations of individuals. This chapter will provide some detail on the various aspects of the Human Genome Project that are of current relevance. This same time interval has seen the identification, treatment, and in some cases prevention of a wide range of disorders that have a strong genetic component (including Rh incompatibility and phenylketonuria) and a variety of other neonatal biochemical disorders and the hemoglobinopathies. Discussed in Chapters 3 and 27 are the details of the current state of our knowledge of these important advances in prenatal and neonatal screening. It now seems apparent that the past focus on adding one disease at a time to the armamentarium of those that can be studied and treated using genetic tools will soon give way to a comprehensive analysis available at the level of the individual genome. Much of the current effort in human genome work is devoted toward individualized medicine, in which physicians will have the ability to treat not just a disease but a specific person with a disease and to account for their genetic and environmental variation in response to therapy or risks associated with prevention. Motulsky (1957) recognized this pharmacogenetic (or pharmacogenomic when applied globally) approach in the early days of human genetic study as being essential to understanding the significant variation in response to therapeutic agents or toxins. Pharmacogenetics is already being applied clinically to identify patients at risk for toxic reactions to some chemotherapeutic agents as well as antiinfectious compounds. Individualization of diet and nutritional approaches is also on the immediate horizon, and it seems likely that over the next few years there will be in place high-throughput genotyping platforms that will provide comprehensive information to the pediatrician and neonatologist for providing direct alterations and care beginning in early infancy. These individualized genomewide profiles are already available to early adopters and are creating new models for how physicians will anticipate health care needs and outcomes for their patients. The history of the Human Genome Project, both its scientific and social basis, has been published widely in review articles and books. Its central conceit arose in the middle 1980s, when it became apparent that technology was advancing so that an undertaking could at least be considered (Watson and Cook-Deegan, 1991). By the early 1990s there were formal projects devoted to its implementation in academic settings. The combination of academic and commercial interests led to a competition that in the end provided the stimulus to develop large-scale, high-throughput methodologies and the analysis tools that in 2001 enabled the project to reach one of its primary goals ahead of some of even the most aggressive predictions for when a complete human sequence might be in place (Lander et al, 2001; Venter et al, 2001). These successes and their resulting technologies and algorithmic advances were based on trials in less complex organisms. The next decades will be, in part, devoted to developing and understanding how these conserved sequences play a role in human health and disease. A few current features will be discussed, with many more evolving almost daily in the primary literature.

The cardiac anomalies associated with the 22q11 deletion syndrome are variable weight loss pills boots buy wegovy with paypal, but usually involve the outflow tract and the derivatives of the branchial arch arteries weight loss pills 2014 uk order wegovy australia. Other manifestations weight loss orlando purchase line wegovy, which may be present in the newborn period weight loss 8 months buy wegovy pills in toronto, include petechiae and bruises weight loss fruit cheap wegovy line, bloody diarrhea, and hemorrhage after procedures. Children with the 22q11 deletion syndrome also exhibit a higher incidence of receptive-expressive language difficulties, cognitive impairment, and behavioral problems including psychotic illness (Jolin et al, 2009; Scambler, 2000). In the nursery, identification of infants with congenital conotruncal abnormalities or unexplained, persistent hypocalcemia should prompt consideration of this syndrome. Thymic implants can partially correct the immunologic deficits (Markert et al, 2007). For example, in developing countries, immunization during pregnancy with tetanus toxoid is a cost-effective method for preventing neonatal tetanus and for providing up to 10 years of protection for infants (Gill, 1991; Schofield, 1986; Vandelaer, 2003). The benefits are substantial for both mother and infant from induction before or during pregnancy of maternal IgG antibody that can be transferred to the fetus and protect both the fetus and mother against postpartum morbidity and mortality (Healy and Baker, 2006; Insel et al, 1994; Linder and Ohel, 1994). However, immunization during pregnancy is biologically distinct from immunization of nonpregnant individuals. Vaccine epitopes can be shared with vital fetal or placental tissues; therefore vaccination can lead to unanticipated maternal or fetal morbidity. Maternal immunization can induce an antibody response in the fetus, as has been demonstrated with tetanus toxoid (Gill et al, 1983) and thereby induce potentially undesirable immunologic side effects. Nevertheless, the increase in availability of potentially protective, transplacentally transferred IgG through active maternal vaccination prompted the Institute of Medicine to recommend the establishment of a program of active immunization to control early-onset and late-onset group B streptococcal disease in both infants and mothers (Institute of Medicine and National Academy of Sciences, 1985). Efforts to develop safe, effective vaccines for protection from group B streptococcal infections have encountered the same difficulties with immunogenicity and safety observed in the development of other vaccines that induce protection from polysaccharide-encapsulated organisms (Baker et al, 1988; Noya and Baker, 1992). The availability of conjugate vaccines, which include group B streptococcal polysaccharide antigens covalently linked either to tetanus toxoid or to a protein in the membrane of group B streptococci (beta C protein) (Madoff et al, 1994; Wessels et al, 1993; Yang et al, 2007) have shown some promise. The indications for active vaccination during pregnancy rest on assessment of maternal risk of exposure, the maternalfetal-neonatal risk of disease, and the risk from the immunizing agents. In general, immunization with live viral vaccines during pregnancy is not recommended (Box 36-1). Preferably, immunizations with live viral vaccines are performed before pregnancy occurs. However, rare instances may occur in which live viral vaccine administration is indicated. For example, if a pregnant woman travels to an area of high risk for yellow fever, administration of that vaccine might be indicated because of the susceptibility of the mother and the fetus, the probability of exposure, and the risk of the mother and fetus from the disease. More common examples in the United States include influenza and polio virus vaccination. If a chronic maternal medical condition would be adversely affected by influenza, active immunization may be indicated during pregnancy. Similarly, if imminent exposure to live polio virus in an unprotected woman is anticipated, live oral polio virus vaccine may be used during pregnancy. If immunization can be completed before the anticipated exposure, inactivated polio virus vaccine can be given. A summary of recommendations for immunizations during pregnancy is provided in Box 36-1. For the pediatrician, maternal immunization represents an important preventive intervention. Breastfeeding does not adversely affect immunization, and inactivated or killed vaccines pose no special risk for mothers who are breastfeeding or for their infants. The benefit of decreasing the risks of development of hepatocellular carcinoma, cirrhosis, and chronic active hepatitis from perinatal transmission of hepatitis B through prenatal screening and active and passive immunization of the infant is substantial (Arevalo and Washington, 1998). The implications of maternal vaccination during pregnancy for preterm infants have not been studied. The anthrax attacks of September 2001 have raised the possibility of the need for preexposure or postexposure immunization programs that may include pregnant women. Currently available data tend to suggest that the anthrax vaccine licensed since 1970 in the United States has no detrimental effects on pregnancy and does not increase adverse birth outcomes, although caution is advised when administering this vaccine during the first trimester (Inglesby, 2002; Ryan et al, 2008; Wiesen and Littell, 2002). A second infectious agent that might be used in a bioterrorist attack is variola virus (smallpox). Although eradicated in 1977, this virus remains a concern because of its lethality, especially in pregnancy (Enserink, 2002; Suarez and Hankins, 2002). Pregnancy is a contraindication to smallpox immunization (Wharton et al, 2003); however, if an intentional release of smallpox virus should occur, pregnant women should be immunized because of their high risk of mortality if unprotected (Suarez and Hankins, 2002). The recommendations of the American Academy of Pediatrics for immunization of infants can be found at aapredbook. For the preterm infant, different clinical approaches to immunization are used by practitioners, including decreasing the dose of immunogen, postponing the first immunization until a corrected age of 2 months, or waiting for an arbitrary weight to be achieved by the infant. However, the American Academy of Pediatrics recommends administering full-dose diphtheria, tetanus, and pertussis immunization beginning at 2 months of age. This recommendation has been endorsed by the Committee on Infectious Diseases of the American Academy of Pediatrics. Only single-antigen hepatitis B vaccines should be used for the birth dose (Mast et al, 2005). Special efforts should be made to complete the hepatitis B vaccination schedule within 6 to 9 months in populations of infants with high rates of childhood hepatitis B infection (Peter, 1994). Agency for Toxic Substances and Disease Registry raised concern about the possibility that administration of thimerosal-containing vaccines, including the hepatitis B vaccines, might lead to exposure to mercury that exceeded federal guidelines (Clark et al, 2001). Guidelines for hepatitis immunization of infants have been developed for implementation for term and preterm infants. Short-term and long-term neonatal immunologic protection after fetal exposure to maternally administered vaccines against anthrax or smallpox, the mass use of which might be prompted by a bioterrorist attack, has not been studied. Similarly, guidelines for neonatal immunization against these agents are not currently available. Before the eradication of smallpox, smallpox vaccine was routinely administered to older infants and children. For postexposure prophylaxis in newborn infants, both chemotherapy (amoxicillin, ciprofloxacin, or doxycycline) and immunization should be considered. Clinicians faced with decisions concerning immunization strategies for pregnant women and newborn infants after a bioterrorist attack should consult the Web site for the Centers for Disease Control and Prevention ( Koga K, Mor G: Toll-like receptors at the maternal-fetal interface in normal pregnancy and pregnancy disorders, Am J Reprod Immunol 63:587-600, 2010. Levy O: Innate immunity of the newborn: basic mechanisma and clinical correlates, Nat Rev Immunol 7:379-390, 2007. Mor G, Cardenas I: the immune system in pregnancy: a unique complexity, Am J Reprod Immunol 63:425-433, 2010. PrabhuDas M, Adkins B, Gans H, et al: Challenges in infant immunity: implications for responses to infection and vaccines, Nat Immunol 12:189-194, 2011. Patterson Viral Infections of the Fetus and Newborn Viral infections of the fetus and newborn infant are common and underrecognized. Given the urgency of identifying invasive bacterial disease in the neonate, the identification of viral infections is often relegated to a matter of secondary importance. However, identifying viral infections can also be a matter of great urgency, because antiviral agents are available for many of the most common infections. Accordingly, an appropriately high index of clinical suspicion of a neonatal viral infection can be lifesaving. Moreover, identification of viral disease in the newborn period may be of great prognostic significance, particularly for neurodevelopmental issues. This chapter reviews the epidemiology, pathogenesis, diagnosis, and short- and long-term clinical management of many of the more common viral infections encountered in neonates. One of the great challenges in the evaluation of viral disease in the newborn is the ascertainment of the timing of acquisition of infection. In this chapter, congenital infection is defined as any infection acquired in utero. Perinatal infections are defined as those acquired intrapartum, typically during the labor and delivery process. Postnatal infections are acquired in the post-partum period and are defined as infections acquired after delivery through the first month of life. In some situations, correctly identifying the timing of acquisition of infection can have substantial consequences, not only for the management of the infant, but for the long-term prognosis. There is considerable overlap across categories for some viral infections that can be transmitted at any of these time points, and this will be considered on a pathogen-by-pathogen basis. These manifestations include evidence of intrauterine growth restriction, hydrops fetalis, hepatomegaly, splenomegaly, pneumonitis, bone lesions, rashes, and hematologic abnormalities (Box 37-1). Because the incidence of congenital viral infections is high (Alpert and Plotkin, 1986), it is appropriate for clinicians to have a high index of suspicion in any newborn with signs or symptoms. However, caution should be taken in efforts to lump all neonatal viral infections into a single diagnostic category. Numerous variants of this acronym have been suggested over the past four decades (Ford-Jones and Kellner, 1995; Kinney and Kumar, 1988; Ronel et al, 1995; Tolan, 2008). Such studies can facilitate rapid pathogen-specific diagnosis; therefore the diagnosis of neonatal viral disease should depend on diagnostic virology, not serology. A list of the myriad of viral pathogens that have been reported to cause congenital infection and disease is included in Box 37-2. Viruses listed in declining relative order of importance relative to prenatal, perinatal (intrapartum), and postnatal timing of typical infection. A recent travel history or recent emigration might suggest consideration of some of these more unusual agents. Rather than rely on a large battery of serologic tests, the clinician can usually narrow the differential diagnosis of a suspect neonatal or congenital viral infection with the history and physical examination, followed by the use of focused, specific diagnostic studies. The entity of neonatal herpes is reviewed in the following section, along with current management approaches for this infection. The degree of genetic relatedness of these two viruses is approximately 45%, and the genome structures and morphology of the virion (virus particle) are virtually identical (Kieff et al, 1972). After a number of triggers, including ultraviolet radiation, stress, and immunosuppression, the virus reactivates at the level of the dorsal route ganglia and initiates a cascade of viral transcription that leads to the production of infectious virus, which can traffic via the axon to the cutaneous surface or ocular surface, producing lesions (Toma et al, 2008). Importantly, clinically evident lesions need not be present for person-to-person transmission of infection to susceptible individuals, because asymptomatic or subclinical shedding of virus is well documented, particularly in the setting of genital herpes. Because neuroradiologic studies cannot reliably distinguish these entities, definitive diagnostic virology is necessary. Specific viral pathogens, their basic virology, the clinical manifestations of diseases they cause in the newborn, management strategies, and prospects for prevention are considered on a pathogen-specific basis in the remainder of this chapter. Genital herpes is characterized by blisters, ulcers, or crusts on the genital area, buttocks, or both. Typically, symptomatic disease manifests with a mixture of vesicles, ruptured vesicles with resulting ulcers, and crusted lesions. Systemic flulike symptoms such as headache, fever, and swollen glands can accompany an outbreak of genital herpes, particularly during primary infection. Other symptoms include dysuria, urinary retention, vaginal or penile discharge, genital itching, burning or tingling, and groin sensitivity. Genital lesions vary in number, are painful in nature, and if untreated persist for up to 21 days (Whitley et al, 1998). It has been recognized in recent years that many individuals with genital herpes are asymptomatic and unaware of their status (Wald et al, 2000). Patients with recurrent symptomatic episodes continue to shed virus in between episodes, even after lesions have healed and crusted over (Leone, 2005). In the United States, the reported range of neonatal herpes ranges from 1 in 2500 births to 1 in 8000 births (Corey and Wald, 2009; Kimberlin, 2005; Whitley, 2004). The majority of cases occur in infants born to women who were recently infected, rather than to women with histories of recurrent genital herpes. Primary infection late in pregnancy poses a higher risk of transmission to the infant than do primary infections occurring before or early in pregnancy, suggesting that the evolution of a maternal antibody response confers some measure of protection for the infant (Brown et al, 2003; Caviness et al, 2008a). Primary genital herpes infection in a pregnant mother results in an attack rate of 33% to 50% for her infant, whereas recurrent maternal infection results in a 1% to 3% attack rate (Arvin, 1991; Brown et al, 1997; Prober et al, 1987). Approximately 90% of these women are undiagnosed, because they are asymptomatic or have other subtle symptoms that are incorrectly attributed to other vulvovaginal disorders. Rarely, cases of intrauterine infection have been described; these are often associated with overwhelming primary maternal infection and usually result in fetal demise. On occasion, placentitis is also observed (Baldwin and Whitley, 1989; Chatterjee et al, 2001; Florman et al, 1973; Hutto et al, 1987; Vasileiadis et al, 2003). Neonatal herpes can have devastating long-term consequences, making early recognition of paramount importance. Premature infants appear to be at greater risk, possibly because of reduced transplacental transfer of protective antibody. Approximately 40% to 50% of affected infants are less than 36 weeks in gestational age (Whitley, 1988). These symptoms are followed rapidly by jaundice, hypotension, disseminated intravascular coagulation, apnea, and shock. This form of disease is indistinguishable at its onset from both neonatal enterovirus infection and bacterial sepsis. Localized disease may begin somewhat later, with most cases appearing in the 2nd to 3rd weeks of life. The infants are lethargic, irritable, and tremulous, and seizures are common and difficult to control. Other less common but potentially localized or disseminated findings are keratoconjunctivitis, chorioretinitis, and pneumonitis, which can manifest as a focal infiltrate or as diffuse bilateral disease. Supraglottitis, intracranial hemorrhage, aseptic meningitis, and fulminant liver failure have been described (Abzug and Johnson, 2000; Erdem et al, 2002; Greenes et al, 1995; Kohl, 1994, 1999; Schlesinger and Storch, 1994). Less common presentations of neonatal herpes include hydrops fetalis (Anderson and Abzug, 1999) and laryngitis (Vitale et al, 1993). In disseminated disease, virus is present in blood, conjunctivae, respiratory secretions, and urine; it is also present in the central nervous system in approximately half of patients. When neonatal herpes is suggested, viral cultures of the throat, conjunctiva, blood, stool or rectum, and urine should be obtained, as should scrapings of vesicular, pustular, and ulcerative skin lesions. In the remaining two thirds, infection is presumably via asymptomatic maternal genital tract shedding of virus.

The postnatal increase in glomerular function reflects greater cardiac output weight loss pills 375mg 14mg wegovy mastercard, reduced renal vascular resistance weight loss unintentional buy wegovy 14 mg low cost, redistribution of intrarenal blood flow weight loss pills 750 mg purchase wegovy paypal, and changes in intrinsic glomerular basement membrane permeability (Morselli et al weight loss natural remedies wegovy 14 mg purchase with visa, 1980) weight loss pills venom hyperdrive 30 buy wegovy amex. The rate of change of renal function and its susceptibility to hypoxemia, nephrotoxic drugs, and underperfusion prevent accurate predictions of drug elimination rates in newborns, which often must be measured empirically. Large interindividual variation occurs for most of these enzymes and is complicated by inherited differences in activity. The number of exponential terms necessary to adequately describe the kinetic profile of a drug designates the number of compartments involved, recognizing that many more compartments may exist. In fact, the volume of distribution for drugs that are bound extensively in tissues may exceed 1. For drugs exhibiting first-order kinetics, the higher the concentration, the greater the amount removed during an interval of time. The following equations describe the concentration (C) of a drug whose first-order kinetics have a constant rate k (hour-1), at time t, and an initial concentration of C0 achieved after administration of a dose. In differential equation form, the change in C with time is dC = - kC dt the solution to this differential equation gives the exponential form, which describes C at time t: Ct = C0 e - kt If this equation is transformed using the natural logarithm (ln), it results in: ln Ct = ln C0 - kt the last equation fits the equation of a straight line, so that a graph that plots ln Ct versus t has an intercept of ln C0 at t = 0 and a slope of ­k, the rate constant for the change in concentration; this can be used to calculate the half-life and to estimate appropriate dosages. Although rates of change are often described with differential equations, useful concepts at the bedside are emphasized in this section. More detailed mathematical discussions of pharmacokinetics can be found elsewhere (Buxton, 2006; Rowland and Tozer, 2010). These compartments may or may not be equivalent to anatomic or physiologic fluid volumes. In the simplest case, the compartment may correspond to the vascular space and equal the volume of a real body fluid. Large or highly polar molecules can be confined to this central compartment until they are eliminated by excretion or metabolism. Many drugs, however, diffuse reversibly out of the central compartment into tissues or other fluid spaces, generically referred to as peripheral or tissue compartments. Half-life is a first-order kinetic process because the same proportion, 50%, of the drug is removed during equal periods. Half-life can be determined mathematically from the elimination rate constant k as: Natural logarithm 2 0. Drug concentrations measured serially are graphed on semilogarithmic axes, and the best-fit line is determined either visually or by linear regression analysis. In this illustration of first-order kinetics, the concentration decreases 50% (from 800 to 400) during the first hour and decreases another 50% (from 400 to 200) during the second hour. More drug is removed during one half-life at higher concentrations, although the proportion removed remains constant. Two exponential terms are needed to describe the change in concentration over time, as: C = Ae - t + Be - t where k = 0. An initial rapid decrease in concentration is the distribution () phase, often lasting 15 to 45 minutes, which is followed by a sustained slower rate of removal, the elimination () phase. Such biphasic processes are best visualized from semilogarithmic graphs of concentration versus time. When such semilogarithmic graphs show In this equation, the rate constant for distribution is designated to discriminate it from the rate constant for terminal elimination (), where A and B are the time = 0 intercepts for the lines describing distribution and elimination, respectively. The rate constant of distribution () can be determined by plotting the difference between the total amount of drug lost initially and the amount of drug lost through elimination (Greenblatt and Koch-Weser, 1975). The single slope of the distribution phase and of the terminal elimination phase does not imply that distribution or elimination occurs through a single process. The observed rates usually represent the summation of several simultaneous processes, each with differing rates, occurring in various tissues. When the time course of drug elimination is observed for prolonged periods, a third rate of elimination, or phase, may also be observed and is usually attributed to elimination of drug that has reequilibrated from deep tissue compartments back into the plasma. The kinetics of a drug are expressed with the smallest number of compartments that accurately describe its concentration changes over time. Such kinetics can occur when a drug remains entirely within the vascular space or central compartment or when a drug passes rapidly back and forth between the circulation and peripheral sites until it is metabolized or excreted by first-order kinetics. The adjective apparent is used because careful study often shows that distribution occurs even though the kinetic curve has only a single slope. Single-compartment kinetics implies that the drug rapidly and completely distributes homogeneously throughout the body, which rarely occurs clinically. In many pharmacokinetic studies in newborns, blood samples are not obtained early enough to allow calculation of the distribution phase, and the kinetics are described as single-compartment. If sampling begins after the distribution phase, the concentration time points may fit a single-compartment, first-order model, which determines the elimination rate constant (). The kinetics cannot be assumed, however, to fit a single-compartment model from such a limited study. The more clinically limited but accurate approach to kinetic analysis, noncompartmental analysis, makes no assumptions about the number of compartments (Rowland and Tozer, 2010). For drugs exhibiting zero-order kinetics, small increments in dose can cause disproportionately large increments in serum concentration. Certain drugs administered to newborns exhibit zero-order kinetics at therapeutic doses, and concentrations and must be recognized for their potential accumulation (Box 34-2). Estimation of the elimination half-life is generally done using the slope of the log transformed concentration measurements made during the end of a pharmacokinetic study. This relationship can be expressed as: dC dt It is important to understand when zero-order kinetics occurs, how to recognize it, and how it affects drug concentrations. Zero-order kinetics is sometimes referred to as saturation kinetics, because it can occur when excess amounts of drug completely saturate enzymes or transport systems so that they metabolize or transport only a constant amount of drug over time. When drug concentrations are high from a drug overdose or the pathway for elimination is impaired as in renal dysfunction, kinetics = -k Thus noncompartmental pharmacokinetics provides a simple means to assess fundamental pharmacokinetic parameters, which may be useful for dosing patients when detailed knowledge of the complete pharmacokinetic profile is not needed. To determine the kinetics safely, population pharmacokinetic approaches are valuable, particularly because they can accommodate unbalanced study designs for drug sampling. The population approach describes the concentration-versus-time profile for all the patients enrolled in a given study simultaneously, estimating population parameters that describe the general pharmacokinetic profile of the complete study group and patient specific parameters that define the individual patients in the study. For example, one group of 28- to 32-week premature infants might have samples drawn at 1, 4, and 12 hours, whereas another group of 28to 32-week premature infants might be sampled at 0. The concentrations from these two groups of similar patients are then analyzed in aggregate to provide information during both distribution and elimination phases, thus describing the kinetics with a limited volume of blood sampled from each patient. Furthermore, the population approach allows for the investigation of patient covariates of interest that might explain differences seen within the population of patients enrolled in the trial. Typical covariates such as gestational age, gender, and disease conditions can also be assessed for their contribution to differences seen between subjects in a clinical study. These covariates can be helpful for gaining a better understanding of factors that may alter the pharmacokinetics of infants that might otherwise be considered similar. The target site of drug action is usually inaccessible for monitoring concentrations. A specific concentration or range of circulating concentrations is correlated with the effective concentration at the site of action, which provides a "therapeutic" concentration range. The requirements for effective and accurate application of the target drug concentration treatment strategy in adults have been discussed by Spector et al (1988). When applied to newborns, these requirements highlight the special problems of drug therapy in these patients and the special circumstances in which clinical drug concentration monitoring is appropriate. Some of these requirements are as follows: ll An available analytic procedure for accurate measurement of drug concentrations in small volumes of blood ll A wide variation in pharmacokinetics among individuals with the knowledge that population-based kinetics do not accurately predict individual kinetics ll Drug effects are proportional to plasma drug concentrations ll A narrow concentration range between efficacy and toxicity (narrow therapeutic index) ll Constant pharmacologic effect over time, in which tolerance does not develop ll Clinical studies that have determined the therapeutic and toxic drug concentration ranges concentrations are attainment of effective concentrations and avoidance of toxic concentrations. As Kauffman (1981) has indicated, drug concentration ranges are not absolute reflections of effective therapy. Patient response, not a specific drug concentration range, is the endpoint of therapy. Although concentrations of aminoglycoside antibiotics, such as gentamicin, are monitored frequently in newborns, toxicity is rare (McCracken, 1986). Because of the limited evidence of toxicity in newborns, it is more important to measure aminoglycoside concentrations to achieve effective concentrations for treatment of culture-proven infections than to avoid toxicity. In newborns with serious therapeutic problems, measurement of serum drug concentrations should be used to achieve effective concentrations and to avoid toxicity. When the desired concentration range and kinetic parameters are known, doses may be estimated to reach that concentration with single bolus doses or bolus doses followed by continuous infusions. This equation may be used to estimate dosage changes needed to increase or decrease concentration. For the first dose, the starting concentration is zero; afterward, the calculation of distribution volume should use the change () in concentration from the preceding trough to the peak associated with that dose. To reach a desired concentration rapidly, a loading dose can be administered followed by a sustaining infusion. Clinical measurements of drug concentrations usually include both bound and unbound drug, and the active portion is the portion that is unbound (see Distribution, earlier). The two broad indications for monitoring drug where C = concentration, Vd = volume of distribution, and k = rate constant of elimination. Steady state is reached when tissue concentrations are in equilibrium and the amount of drug removed equals the amount of drug infused. As noted during infusions, the length of time required to reach steady-state concentrations depends primarily on the elimination half-life, not the dosing interval. Clearance is proportional to organ blood flow and the intrinsic capacity of organs to metabolize or remove drug from the circulation. Clearance can be measured by the rate of appearance of drug outside the body (similar to urinary creatinine clearance) or by the rate of disappearance of drug from the circulation compared with the circulating concentration. Values for clearance and volume of distribution at different stages of preterm development are available for a few drugs and can be used to estimate the doses needed to achieve and maintain therapeutic concentrations associated with desired clinical responses. Studies of the analgesic fentanyl illustrate the developmental changes in its kinetics and how they can be used to calculate dosages to reach and maintain concentrations associated with effective analgesia. Analgesia has been associated with a serum fentanyl concentration of 1 to 2 ng/mL (Santeiro et al, 1997). If analgesic treatment is initiated with a continuous infusion of fentanyl, five half-lives are needed to reach a steady state. It is important to consider that if drug clearance decreases, the steady state concentration during an infusion will increase proportionally. During repeated administration, the peak and trough levels after each dose increase for a time. Steady-state, or plateau, concentrations are reached when the amount of drug eliminated equals the amount of drug administered during each dosing interval. During repetitive dosing, the steady-state concentrations achieved are related to the half-life, dose, and dosing interval relative to the half-life (Buxton, 2006; Rowland and Tozer, 2010). Several important principles of pharmacokinetics are illustrated in this figure; the mathematics are described in detail elsewhere (Buxton, 2006). Drug concentrations rise and fall with drug administration (absorption) and elimination. For dosing intervals of one half-life, accumulation is 88% complete after the third dose, 94% complete after the fourth dose, and 97% complete after the fifth dose. At steady state, the peak and trough concentrations between doses are the same after each dose. If a drug is administered with a dosing interval equal to one half-life, the steady-state peak and trough concentrations are twofold those reached after the first dose. If the dosing interval is shortened to half of a half-life, the concentration decreases less before the next dose, more total drug is administered per day, and the steady-state peak and trough concentrations are considerably higher (3. In general, the initiation of analgesic treatment and increases in infusion doses of analgesics should begin with a loading dose based on the estimated volume of distribution in the central compartment (circulation) and desired concentration. The use of a loading dose shortens the time to reach higher effective analgesic concentrations, but also increases the likelihood of toxicity, as has been reported with digoxin. Limited data are available regarding the gestational age­ related changes in fentanyl clearance, but two studies show that it increases with advancing gestational age (Koehntop et al, 1986; Santeiro et al, 1997) and with increasing age after birth (Gauntlett et al, 1988; Santeiro et al, 1997). The linear graph of clearance versus gestational age from 38 neonates who began treatment within 47 hours after birth was used to derive mean rates of clearance at different gestational ages, as shown in Table 34-1. Other investigators studied single-dose fentanyl kinetics during anesthesia and found an apparent central volume of distribution of fentanyl in neonates of 1. Note that this distribution volume is smaller than the steady-state volume of distribution of 5. In turn, the apparent steady-state volume of distribution after a single bolus dose of a lipophilic drug is usually smaller than that associated with continuous drug infusions, during which tissues throughout the body become saturated with drug. The steady-state distribution volume for fentanyl during continuous infusions was calculated as 17 L/kg (Santeiro et al, 1997). It should be noted that because fentanyl is highly lipid soluble, it distributes rapidly from the central compartment into the peripheral tissue compartment. This large distribution volume likely reflects the period during the infusion when the drug is leaving the circulation to penetrate peripheral tissues, such as fat. Because it may take 15 to 60 hours to achieve a steady-state concentration (five half-lives) after a fentanyl infusion is begun or the infusion rate is increased, a patient may need repeated bolus doses to maintain effective plasma concentrations in the central compartment. The best approach is to repeat the calculated loading dose until the desired clinical effect is achieved. This also illustrates why, for sedation specifically, dosing should be adjusted to achieve the desired clinical effect. Clearance calculations, however, can guide the starting doses to achieve effective sedation, as illustrated later. This postnatal rise in clearance of fentanyl likely relates either to maturation of cytochrome P450 3A4 (the enzyme responsible for fentanyl metabolism) activity or to increased hepatic blood flow after birth, because fentanyl has a high hepatic extraction rate. For drugs like fentanyl with a high hepatic extraction ratio, the rate-limiting factor in clearance is the flow of blood to the liver (Saarenmaa et al, 2000). Some researchers have observed that increased intraabdominal pressure reduces fentanyl clearance, which is likely caused by reduced hepatic blood flow (Gauntlett et al, 1988; Koehntop et al, 1986). Clinical changes known to increase or decrease fentanyl clearance should be used to adjust starting dosages, but dosing should be adjusted primarily for the desired clinical effect. These models can identify clinical situations and conditions when doses are likely to require modification. Mathematical simulations create theoretical pharmacokinetic profiles for patients after a dose using the range of pharmacokinetic parameters determined from a patient population.

Most cases are ascertained with low carnitine on screening and are usually diagnosed with mutation analysis and the failure of carnitine levels to rise in the postnatal period weight loss motivation pictures buy discount wegovy 14mg online. Most physicians treat the disorder with carnitine to raise Long-Chain 3-Hydroxy Acyl-Coenzyme A Dehydrogenase Deficiency the long-chain 3-hydroxy acyl-CoA dehydrogenase deficiency is associated with acute illness weight loss yoga exercise purchase 14 mg wegovy with visa, fasting-induced hypoglycemia weight loss pills non-prescription safe 14mg wegovy, hypoketosis weight loss meal replacement shakes buy cheap wegovy 14mg on-line, cardiomegaly weight loss pills celebrity use cheap wegovy 14 mg mastercard, and muscle weakness (Roe and Ding, 2001; Stanley et al, 2006). Newborn screening has also ascertained asymptomatic and affected mothers and has altered our perception of this condition and its severity. In addition, largely asymptomatic mothers affected with an organic acidemia and low carnitine levels in the mother and fetus have been detected. This disorder is the only one in which pharmacologic administration of carnitine has dramatic effects on the clinical and laboratory abnormalities. Repletion of plasma carnitine levels is the benchmark by which the efficacy of treatment is judged, but the degree of repletion of tissue levels (skeletal muscle and heart) is inferred but rarely demonstrated. Treatment is successful in the short, intermediate, and longer terms, but no information on the lifespan of these patients who appear healthy is available. In addition, the acute development of ventricular dysrhythmias may be related to accumulation of such species in cardiac tissue. It is often considered to be almost invariably fatal or very serious, but the probability is that more mild cases with reduced but not absent transporter activity have not been found. The other phenotype is caused by a more serious enzyme defect and manifests in early infancy. The first detailed report was of a 3-month-old boy with hypoketotic hypoglycemia, coma, seizures, hepatomegaly, cardiomegaly, cardiac arrhythmias associated with an increase in long-chain acylcarnitine levels in tissues, and the absence of urinary dicarboxylic aciduria. Renal tubular acidosis, which is caused by impaired distal hydrogen ion secretion, has rarely been reported. Characteristic laboratory findings are the absence of dicarboxylic aciduria and high plasma levels of total carnitine and free carnitine; however, the plasma acylcarnitine profile is not abnormal. These patients are now often found by expanded newborn screening because of an abnormal ratio of carnitine to the carnitylated long-chain fatty acids. Normally, acetoacetyl CoA can also be hydrolyzed to acetyl CoA by the mitochondrial acetoacetyl-CoA thiolase. Patients with a deficiency of this thiolase do not have a defect in ketone body synthesis but, rather, metabolic acidosis associated with excess ketosis (Mitchell and Fukao, 2008; Stanley et al, 2006). Severe acute metabolic decompensation has been reported in infants, but there are also asymptomatic adults with the disorder. The episodes are heralded by fasting or increased protein intake, because isoleucine is a precursor Acylcarnitine Translocase Deficiency Acylcarnitine translocase deficiency is an exceedingly rare defect. It was initially reported in a male infant who suffered a cardiac arrest at 36 hours of age in association with fasting stress and ventricular dysrhythmias (Roe and Ding, 2001; Stanley et al, 2006). The continuous nasogastric feeding of a low-fat, high-carbohydrate formula failed to normalize clinical abnormalities, and the patient died at 3 years of age. Therefore this block leads to a defect in distal catabolism of isoleucine and in processing of the precursor of ketone body formation-namely, acetoacetyl-CoA. The characteristic urinary metabolite pattern detected on urine organic acid analysis is the presence of isoleucine metabolites, such as 2-methylacetoacetate, 2-methyl-3-hydroxybutyrate, and triglylglycine. During acute decompensation, lactate and the traditional ketone bodies are detected in excess amounts in the urine. Some older children have been mistakenly identified as having ketotic hypoglycemia because glycine may be elevated in plasma. Deficiency in the mitochondrial acetoacetyl-CoA thiolase can be demonstrated in cultured skin fibroblasts and by mutation analysis. Treatment of acute episodes consists of intravenous glucose and administration of alkali to correct metabolic acidosis, which may be severe. Long-term therapy involves mild protein restriction, avoidance of fasting, and prompt attention to any intercurrent illness or development of ketonuria. A deficiency of this enzyme represents the most profound defect in ketone body synthesis (Roe and Ding, 2001; Stanley et al, 2006). Approximately one third of patients with this disease are in the first week of life. In this subgroup of patients, the onset is dramatic and the disease is catastrophic, being characterized by vomiting, lethargy, coma, seizures, hepatomegaly, hypoglycemia, little or no ketones in urine, and hyperammonemia. Only small, inappropriate amounts of acetoacetic acid and 3-hydroxybutyric acid may be detected. Treatment of the acute episode consists of administration of intravenous glucose and alkali to correct metabolic acidosis. Some patients treated with protein-restricted diets, but the most important element in long-term care is the avoidance of fasting. The last defect to be discussed in the area of disturbances in ketone body metabolism is the succinyl-CoA 3-ketoacidCoA transferase deficiency (Mitchell and Fukao, 2008; Stanley et al, 2006). In this disease, the ketone bodies, acetoacetic acid, and 3-hydroxybutyric acid are synthesized adequately in the liver, but they cannot be metabolized in the extrahepatic tissues because of the failure of activation of acetoacetate to acetoacetyl CoA by the transferase enzyme. Conversion to a CoA derivative is required for hydrolysis to acetyl CoA for final metabolism in the Krebs citric acid cycle. This disorder is rare, and most of the affected patients in the newborn period do not survive. The hallmark of the disease is persistent ketosis, even after correction of overt metabolic acidosis and the institution of frequent feedings with the avoidance of fasting. Plasma values of acetoacetate and 3-hydroxybutyrate are always mildly to moderately elevated, resulting in intermittent ketonuria. The most important aspect of therapy is the avoidance of fasting, during which acidosis and ketosis can be overwhelming. The gene that encodes this enzyme has been cloned, and several mutations have been detected. Depending on the nature of the enzyme deficiency, lactate, pyruvate, and alanine levels can be elevated in the blood. The ratio of blood lactate to pyruvate (L:P ratio) can be helpful in distinguishing the different types of inborn errors. The first enzymatic step is a decarboxylation reaction catalyzed by a heterodimeric system consisting of the E-1 subunit, encoded by a gene on the X-chromosome, and E-1, which is autosomally encoded as are all the other subunits in this complex. Typically, the L:P ratio is normal and distinguishes it from disorders of the mitochondrial respiratory chain. The diagnosis is rarely known immediately, and the standard intravenous support of high glucose exacerbates the metabolic acidosis and worsens the outlook for the patient. The diagnosis is inferred when all the clinical biochemical data are collated and can be confirmed by an enzymatic deficiency in lymphocytes or cultured skin fibroblasts or by mutation analysis of the E-1 gene in particular. The enzyme assay is difficult in the most experienced hands, and it is difficult to understand the high residual activity that is often recorded. The majority of patients are more indolent on clinical presentation, with developmental delay that may resemble Leigh syndrome, and they may have a modest elevation of lactate, with pyruvate being the most telling biochemical marker of the disease. This group of patients often respond well biochemically to a high-fat and low-carbohydrate diet. Most of the patients are later than the newborn period and have severe progressive neurodegenerative disease. An expanding number of mutations have been identified and provide a basis for prenatal diagnosis. Phosphoenolpyruvate Carboxykinase Deficiency Phosphoenolpyruvate carboxykinase enzyme also functions in gluconeogenesis, and there are two forms in liver, one in the cytosol and the other in the mitochondrial compartment. Patients do not usually come to attention until childhood with hypotonia, failure to thrive, hepatomegaly, lactic acidosis, and hypoglycemia. Although there is no adequate experience in identifying the optimal therapy for these patients, it is reasonable to assume that frequent feedings and avoidance of fasting are important in avoiding severe metabolic imbalance. Mitochondrial Respiratory Chain or Electron Transport Chain Defects Oxidative phosphorylation is the key process performed by the mitochondria of cells. Any inborn error of metabolism that involves the tightly coupled and regulated process of mitochondrial energy metabolism may have profound effects on health and disease, because oxidative phosphorylation is the process by which we convert nutrients into energy. Type A is characterized by lactic acidosis in the newborn period and delayed development. In type B, the catastrophic form of the disorder, the infant is acutely ill, usually in the first week of life, with encephalopathy, severe metabolic acidosis with lactic acidosis, and hyperammonemia (De Meirleir et al, 2006; Munnich et al, 2001; Robinson, 2001). Unlike patients with a type A defect, in whom the blood L:P ratio is normal because both lactate and pyruvate are comparably elevated, patients with the type B defect often have an elevated L:P ratio. The hallmarks of mitochondrial disease are almost always multisystem involvement and unambiguous lactate acidemia or acidosis. Although some debate exists as to whether lactate elevation is present in all mitochondrial disorders that present in life, it is a virtual requirement for such a diagnosis in newborns and early infants. Older and still useful technologies such as muscle biopsy with histologic analysis by light and electron microscopy, mitochondrial complex assay on either fresh (preferred, but infrequently available) or flash-frozen tissue and skin fibroblast studies are still available. In fatal cases, a rapid autopsy and proper preservation of tissue specimens are essential. A less frequent, newly recognized family of disorders are the coenzyme Q biosynthetic disorders, diagnosed reliably only by coenzyme Q10 levels in muscle, and not in plasma. Although the subject of much debate, there is no credible evidence that mitochondrial disease is treatable, with the obvious exception of a small minority caused by coenzyme Q deficiency. Given the inability to identify these patients quickly, it is reasonable to treat acutely ill patients with presumed mitochondrial disorders with high doses of coenzyme Q. Benign Infantile Mitochondrial Myopathy, Cardiomyopathy, or Both Benign infantile mitochondrial myopathy is associated with congenital hypotonia and weakness at birth, feeding difficulties, respiratory difficulties, and lactic acidosis. A developmental switch from the defective fetal gene to the adult form may be responsible for the gradual improvement. It was thought to be the only example of a developmental defect in oxidative phosphorylation that is probably nuclear encoded and in which the treatment is only supportive during the early newborn period to prevent death from respiratory disease. However, a recent study suggests that the etiology may be a maternally inherited, homoplasmic m. The form also associated with cardiomyopathy may be a variant of the benign isolated myopathy and involves striated muscle in both skeletal and cardiac muscle. It manifests in the newborn period with lactic acidosis and a cardiomyopathy that improves during the first year of life. More attention must be paid to these two disease entities, because with early optimal medical care, affected infants may have an excellent prognosis. Lethal Infantile Mitochondrial Disease Infants with lethal infantile mitochondrial disease are severely ill in the first few days or weeks of life or in the extended newborn period. He was delivered by cesarean section because of variable decelerations, and he emerged without meconium staining or passage. An echocardiogram showed concentric right ventricular hypertrophy with elevated right ventricular pressure (70 mm Hg). Initial laboratory studies showed acute metabolic acidosis (blood lactate >18 mmol/L; arterial pH, 6. Metabolic investigations showed persistent arterial lactic acidemia (range, 3 to 11 µmol/L) with increased pyruvate (range, 0. A left quadriceps muscle biopsy was used for histochemical analysis and to prepare a 10% extract for respiratory chain studies. A series of echocardiograms documented biventricular, hypertrophic, nonobstructive cardiomyopathy. The patient died on the seventh hospital day after a sudden episode of hemoglobin desaturation. The right ventricle was found to be thickened and enlarged, with relative sparing of the left side. The pulmonary vasculature of the lungs showed hypertrophy that extended to the most distal vessels. This baby had a fatal syndrome defined clinically by prenatal cardiomyopathy and severe pulmonary hypertension in the newborn period. This case is an example of a mitochondrial metabolic disorder, but without a specific molecular genetic cause. A more extensive evaluation by current methods might or might not have revealed a diagnosis. Death often occurs by 6 months of age and almost always is associated with overwhelming lactic acidosis. Skeletal muscle shows lipid and glycogen accumulation and abnormally shaped mitochondria on electron microscopic examination. Generalized proximal renal tubular dysfunction may occur, leading to the renal Fanconi syndrome. This disease is characterized as a progressive neurodegenerative disorder with severe hypotonia, seizures, extrapyramidal movement disorders, optic atrophy, and defects in automatic ventilation or respiratory control (Finsterer, 2008; Leigh, 1951). There is no effective treatment for this disease, unless the cause is a specific inability to synthesize coenzyme Q10. It is possible that most of the patients with Leigh disease have disturbances in nuclear-encoded genes. Some patients may manifest hypertrophic cardiomyopathy, liver dysfunction, and microcephaly. The neuropathologic lesions include demyelination, gliosis, necrosis, relative neuronal sparing, and capillary proliferation in specific brain lesions. Commonly, elevation in blood lactate is only slight to moderate, as well as intermittent, in this diverse group of patients. The only example of such a mutation manifesting in early infancy is the Pearson syndrome. This disorder is systemic and primarily affects the hematopoietic system and pancreas function.

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References

• Szilagyi DE, Smith RF, Elliott JP, et al: Infection in arterial reconstruction with synthetic grafts, Ann Surg 176:321, 1972.
• Williams DM, Lynch RE, Cartwright GE. Prognostic factors in aplastic anaemia. Clin Haematol 1978;7(3):467-74.
• Nobukuni Y, Mitsubuchi H, Hayashida Y, et al. Heterogeneity of mutations in maple syrup urine disease (MSUD): screening and identification of affection E1a and E1b subunits of the branched-chain a-keto-acid dehydrogenase multienzyme complex. Biochim Biophys Acta 1993;1225:64.
• Pacheco-Galva?n A, Hart SP, Morice AH. Relationship between gastro-oesophageal reflux and airway diseases: the airway reflux paradigm. Arch Bronconeumol 2011; 47: 195-203.
• Ocampo PS. Splenomegaly. In: Pediatric Decision Making. Ed. Berman S. 3rd edn. Mosby-Year Book, St. Louis; 1996.
• Mitchell DG, Hill MC, Hill S et al: Serous carcinoma of the ovary: CT identification of metastatic calcified implants. Radiology 1986; 158:649-652.