Jonathan Adler, M.D., FAAEM

• Assistant in Emergency Medicine,
• Massachusetts General Hospital
• Instructor in Medicine,
• Harvard Medical School
• Boston, MA

The higher the ingestion of food anxiety symptoms pdf order 5 mg emsam mastercard, the lower the blood alcohol level anxiety icd 9 purchase emsam 5 mg with amex, since the food can absorb some alcohol anxiety symptoms diarrhea emsam 5 mg buy lowest price. The assessment is performed regularly to identify when withdrawal systems appear and track the severity of withdrawal systems until withdrawal symptoms are absent anxiety symptoms and signs buy emsam line. Blood Glucose Glucose is the source of energy for cells and is transported into cells by insulin anxiety 37 weeks cheap 5 mg emsam with visa. As blood glucose levels rise following ingestion of food, the pancreas releases insulin to move the glucose from blood into cells. Insulin and other diabetes medications are withheld until the test is administered. Rationale for the Test · Screen for · Diabetes · Hypoglycemia · Assessment of the treatment for diabetes Nursing Implications · Assess if the patient · Is ill. Blood Type Test Blood is identified by an antigen on the surface of red blood cells. Red blood cells may have the Rh antigen attached to them, sometimes called the Rh factor, and is determined by the Rh test. It is now understood that these blood types contain antibodies that can cause a transfusion reaction. Blood Urea Nitrogen Ammonia is formed when bacteria in the intestines break down protein. Ammonia is then converted by the liver into the waste product urea, which is excreted by the kidneys in urine. The various types of chemistry screens are called Chem 20, Chem 12, Chem 7, and so on, where the number represents the number of blood components examined in the test. Cholesterol and Triglycerides Tests Cholesterol is produced in the liver and is used for cell growth and hormone production. Excess cholesterol in the blood forms plaque on the side of blood vessels that can lead to cardiovascular disorders. The cholesterol and triglycerides tests profile lipoproteins to measure components of cholesterol. Cold Agglutinins Agglutinins are antibodies that cause red blood cells to aggregate forming a clump called Rouleaux formation at low temperatures as an immune reaction to an infection. High levels of agglutinins can impede blood flow to the extremities when exposed to cold, resulting in tissue damage unless the extremity is warmed. The higher the second number of the ratio, the greater the number of antibodies in the blood sample. The mean corpuscular hemoglobin result indicates the same disorders as high and low mean corpuscular volume. The level of C-peptide is considered equal to the amount of insulin, indicating the amount of insulin made by the pancreas. The C-peptide test measures the level of C-peptide in blood and is used to differentiate between types 1 and 2 diabetes. The healthcare provider may order a C-peptide stimulation test to differentiate between types 1 and 2 diabetes. C-reactive protein attaches to damaged cells or microorganism enhancing phagocytosis in the destruction of the microorganism or damaged cell. The healthcare provider will order other tests to identify the source of the inflammation. Creatinine and Creatinine Clearance Creatine phosphate provides energy to skeletal muscles. Creatine is metabolized into creatinine and is carried in blood to the kidneys for filtering and excretion in urine. If kidneys are malfunctioning, creatinine levels in the blood increase and creatinine levels in urine decrease. There are three types of creatinine tests: · Blood creatinine level test: this test measures the level of creatinine in blood. Fetal kidney function is assessed by testing the level of creatinine in amniotic fluid. The healthcare provider may order the glomerular filtration rate test to determine kidney function. D-xylose Absorption Test D-xylose is a simple sugar that is absorbed by the intestines. A urine test is less accurate than the blood D-xylose absorption test for patients younger than 12 years of age. Nursing Implications · the patient should avoid fruits, jams, pastries, and jellies 1 day before administration of the test. Ferritin Ferritin is a protein found in bone marrow, liver, skeletal muscles, and the spleen that binds to iron. The ferritin test measures the level of ferritin in blood to determine the amount of iron in the body. Folic Acid Folic acid is a type of vitamin B that is necessary for cell development and maintenance. Women who are planning to become pregnant should increase the intake of folic acid to reduce the risk of spina bifida, and cleft lip and palate. Gastrin Gastrin is a hormone produced by the G cells of the stomach lining when food enters the stomach. Glycohemoglobin Glucose binds to hemoglobin in red blood cells, which has a life span of 120 days. Once metabolized, iron binds to the transferrin protein, which transports iron to bone marrow and other tissues. Rationale for the Test · Screen for · Nutritional status of the patient · Iron deficiency anemia · Hemochromatosis · Assess treatment of iron deficiency anemia. Nursing Implications · Assess if the patient · Has taken iron supplements 12 hours before the test is administered · Has taken vitamin B12 supplements 2 days before the test · Is sleep deprived · Is stressed · Has received a blood transfusion 4 months prior to the test · Is taking estrogen, birth control pills, Chloromycetin, aspirin, corticotrophin, and St. Lactic Acid Muscle cells convert glucose into lactic acid and use lactic acid for energy when oxygen levels are low during strain of heart failure, exercise, shock, and sepsis. Liver disorders can result in lactic acidosis because of a high level of lactic acid in the blood. The most common form of lead is inorganic lead that is not metabolized in the liver. Lead that is absorbed and not excreted is found in blood, bones/teeth (94%), and liver, kidneys, lungs, brain, spleen, muscle, and heart. Lead affects growth and development if lead-tainted water, paint chip, food, or dust is ingested or if lead is in contact with the skin. Children are more susceptible to lead poisoning because increased levels of lead in blood interfere with neural and brain development. Children who are in early development are at risk for permanent growth impairment if they ingest lead. The lead mobilization urine test is performed during chelation therapy to assess if the therapy is removing lead in urine. Lead levels above 10 mcg/dL on two occasions typically must be reported, so the source of the lead can be found. Employees with a level higher than 45 mcg/dL should be seen by their healthcare providers. Level of lipase in the blood increases when the pancreatic duct is blocked or there is damage to the pancreas. The healthcare provider may order the amylase test at the same time as the lipase test. Rationale for the Test · Screen for · Pancreatic disease · Pancreatitis · Cystic fibrosis · Assess treatment for · Pancreatitis · Cystic fibrosis Nursing Implications · Assess if the patient has · Eaten or drunk, except water, 12 hours before the test is administered. Partial Thromboplastin Time When bleeding occurs, 12 blood clotting factors cause blood to coagulate to stop the bleeding in a process called hemostasis. Coagulation of blood is affected by a cascade of blood clotting factors where one factor activates other factors. A clotting factor may be absent or have a decreased or increased level changing the way blood clotting factors function. In addition, clotting inhibitors such as heparin and warfarin can reduce the effectiveness of clotting factors. Thromboplastin is a plasma protein from platelets and damaged endothelium cells of blood vessels that converts prothrombin to thrombin. Some medications such as aspirin and antihistamines affect the results of the test. Patients who experience serious bleeding problems when taking heparin are likely to be administered protamine sulfate by slow infusion. There are new medications such as apixaban (Eliquis); dabigatran (Pradaxa); edoxban (Savaysa); and rivaroxaban (Xarelto) that perform similar to warfarin (Coumadin) but do not have a narrow therapeutic range and therefore do not require regular dose adjustments based on blood tests. Nursing Implications · Assess · Prescription and nonprescription medications taken by the patient. Reticulocyte Count Reticulocyte is an immature red blood cell that is released by bone marrow and develops into a mature red blood cell in 2 days. The reticulocyte count test determines the amount of reticulocyte in a blood sample. Nursing Implications · Assess if the patient · Is undergoing radiation therapy · Is pregnant · Has had a blood transfusion in the previous week · Has undergone a prostate biopsy in the past 8 weeks · Is taking Bactrim, Septra, corticotrophin, Imuran, levodopa, Chloromycetin, methotrexate, or Cosmegen Understanding the Results · the reticulocyte test results are available in 1 day. Vitamin B12 attaches to the intrinsic factor produced by the parietal cells in the stomach. The intrinsic factor protects vitamin B12 from intestinal bacteria and enables absorption of vitamin B12 by the intestines. There are two parts to the Schilling test: · Part 1: the patient ingests vitamin B12 that is radioactively tagged. Up to 25% of the ingested vitamin B12 will normally be detected in the 24-hour urine sample. Rationale for the Test · Screen for · Absorption of vitamin B12 · Production of the intrinsic factor Nursing Implications · Assess if the patient · Is pregnant · Properly collected the 24-hour urine sample · Is taking Mycitracin, Dilantin, or colchicine · Has kidney disease · Used a laxative prior to administration of the test · Has had a radioactive scan 2 weeks prior to the test Understanding the Results · the Schilling test results are available quickly. Rouleaux settles quicker than erythrocytes, therefore the increased sedimentation rate indicates that the patient has inflammation. Serum Osmolality Serum osmolality is the number of particles of substances that are dissolved in blood serum (liquid portion of blood). A decrease in fluid results in an increase in serum osmolality-there is less fluid in the blood. An increase in fluid results in a decrease in serum osmolality-there is more fluid in the blood. The result of the urine test is compared with the serum osmolality to estimate kidney function. Nursing Implications · Assess if the patient · Has ingested alcohol, since this can affect the test results · Recently received a blood transfusion Understanding the Results · Test results are available in 4 hours. Total Serum Protein the total serum protein test assesses the levels of albumin, globulin, and total protein in a blood sample. It is continuously metabolized into amino acids, which are used to make enzymes, hormones, and new proteins. Albumin is also important for tissue growth and healing because it carries water, sodium, potassium, calcium, hormones, fatty acids; bilirubin, thyroxine and medicine to tissues. Alpha globulins inhibit an enzyme that digests protein and an enzyme that is involved in coagulation. As a result more protein is available to the body and blood can freely distribute globulins throughout the body. Beta globulin binds with iron and transports iron throughout the body and is involved in targeting foreign material so the foreign material can be destructed by the immune system. Gamma globulins are antibodies called immunoglobulins and consist of IgG antibodies to bacteria and viruses; IgE protects against parasites and triggers the histamine response to allergens; IgM is the first response to infection; IgD function is not understood; and IgA protects body surface and found in mucous membranes; blood, saliva, and tears. A test for total serum protein reports separate values for total protein, albumin, and globulin. A toxicology test typically identifies if the drug is present but not the level of the drug. Uric acid is produced when purine found in wine, beer, liver, anchovies, mackerel, and dried beans is metabolized. Uric acid is excreted by the kidneys through the urine and a small amount in stool. Summary Hematology clinical laboratory tests examine blood and its components to assess for signs of disease. A sample of blood can be collected from a vein, a finger, or from the heel, depending on the amount of the blood sample that is required for the test. The clinical laboratory then measures the sample and compares the results to a range of values that the clinical laboratory has determined to be normal. A test result that is outside the normal range is assessed by the healthcare provider to determine if it is a significant sign of a disease. A high level of blood glucose signals the pancreas to secrete insulin, which assists glucose to cross cell membranes where glucose is used for energy. Glucagon is a hormone that signals the liver, muscles, and other organs to release stored glucose into the blood, resulting in an increase in blood glucose levels. The balance between insulin and glucagon secretions maintains a narrow range of blood glucose. However, diseases such as diabetes can cause an imbalance, resulting in high levels of blood glucose (hyperglycemia) or lower levels of blood glucose (hypoglycemia) that cannot be brought into range naturally. Estimate the sugar content of the breakfast and subtract that amount from the test results. C-reactive protein is leaked from damaged cells shortly after cells are injured increasing the amount of C-reactive protein in blood. A low level of C-reactive protein indicates that the liver is responding to reduce the inflammation process. C-reactive protein attaches to damaged cells or microorganism enhancing phagocytosis in the destruction of the microorganism or damaged cell shortly after cells are injured. C-reactive protein attaches to the liver causing an increase of white blood cells in blood to enhance phagocytosis in the destruction of the microorganism or damaged cell shortly after cells are injured.

Evaluation of the cervical spine to avoid worsening an existing injury and stabilization if necessary 4 anxiety symptoms 8-10 purchase emsam 5 mg online. Consider a staged approach if panfacial fractures are present to allow for reimaging and re-assessment anxiety symptoms gagging 5 mg emsam purchase mastercard. Blood products may be considered if extensive fractures requiring complex anxiety symptoms shivering purchase emsam no prescription, lengthy approaches are required anxiety symptoms 8 year old boy generic emsam 5 mg on-line. Patients should be counseled on postoperative care including pain management anxiety symptoms adults discount emsam generic, dietary and activity restrictions, and possible need for secondary revision procedures. General: these procedures are routinely performed under general anesthesia with the patient orotracheally or nasotracheally intubated. Often, swelling limited to the face does not impact airway dynamics significantly and is manageable without the use of a tracheosotomy. The decision to manage the occlusion is typically the key variable when considering oral versus another route of intubation. Technical skill using internal fixation techniques such as plate and screw systems 5. Detailed understanding of normal occlusion and common pre-existing malocclusions 6. Experience with surgery in the region including cranioorbital, peri-orbital, oral cavity, and oropharynx 7. Access and ability to work with other surgeons to address common concomitant injuries to the brain, eye, and dentition 186 A Operative Risks 1. A, A wavy line or sine-wave incision is made with the incision placed more posterior for better aesthetics. Another option can include a posterior-auricular incision for even better aesthetics when access to the joint is less important. B, the dissection is carried deep to the superficial layer of the superficial temporal fascia until about 1 cm above the arch within the temporal adipose tissue pad. Dissecting deep to this layer helps avoid injury to the facial nerve, particularly the frontal branch. When combined with a dissection that proceeds along the nasal bones and anterior orbital rims, 360 degrees of the orbit can be visualized when using this approach. The following surgical technique section includes steps common to cranio-orbital and midface fracture treatment procedures followed by particular steps that are specific to each individual procedure. I do not favor submental intubation approaches, and I avoid tracheostomy when possible. Multiple options for eyelid incisions are shown including the transconjunctival, subcilliary, midlid, and infraorbital incision. For simple fractures, an arterial line is often not needed and transfusion is rare. However, for extensive facial fractures with many approaches, these monitoring methods and blood products may be helpful. Staged procedures can also allow for additional imaging and adjustments of the three-dimensional position of segments if extensive fractures are present. In the central region, the flap is advanced anteriorly just superficial to the periosteum up to the supraorbital ridge. Osteotomes can be used to mobilize the bone housing the supraorbital neurovascular bundle to gain more flap mobility. If detached from their normal insertions, then a small fragment of bone can almost always be identified. Endoscopic repairs of small leaks can be considered if an open approach is not needed. Rarely, internal endoscopic balloon techniques can be effective for a localized fracture that is intruded. Appropriate three-dimensional positioning of the zygoma, superior orbital rims, and nasal bones is critical to providing the appropriate width, height, and projection of the face. The positioning of the maxilla often depends upon the position of the upper facial skeleton. Trans-nasal wiring secured to a contralateral plate is helpful in achieving proper dimensions. The arch is dissected out separately as needed, making the incision approximately 1 cm superior to the arch into the deep layer of the superficial fascia or adipose tissue pad. The skin may be closed with staples, running 4-0 monofilament or 4-0 resorbable braided suture. Often, limited approaches give a limited view of the adequacy of reduction in three dimensions. After reduction, if the defect is small and not in a critical area where volume loss can occur, then a reconstruction of the floor may not be necessary. Critical areas where volume loss may occur include the bulge in the floor of the orbit and the medial bulge of the medial wall. D, A transcranial approach was required via bicoronal incision and bifrontal craniotomy with removal of the posterior wall of the frontal sinus. E­J, Split-thickness cranial vault bone was used for reconstruction of the orbits and other areas. K, the patient had a pre-existing malocclusion consisting of an open bite, which was recognized due to developmental mammelons on the incisors and a pre-injury plan for orthognathic surgery. L­M, Despite an elevated intracranial pressure, the patient recovered with the need for only minor nasal cartilage revision and rhinoplasty due to lacerations associated with the nose. A, A young male who sustained a left fist to the face resulting in a fractured zygoma with medial displacement. B, the computed tomography scan shows the typical displacement that requires three-dimensional repositioning via multiple incisions. Brow, intra-oral, and transconjunctival incisions are often used to position and fixate fractures such as these. The isolated zygomatic arch fracture is typically found in two or more fragments, requiring a repair that is more of a flat surface than an actual arch. Lower-lid approaches such as the deep fornix trans-conjunctival with or without inferior lateral cantholysis, subcilliary, or lid crease incisions can be used depending upon the need for access, existing lacerations, or preferences. Very small plates and screws are used to avoid a high profile that is palpable through the thin tissues around the eye. Larger defects benefit from more support with materials that retain a specific shape, such as porous polyethylene with imbedded mesh. These are best reconstructed with preformed or customized reconstructive implants. Some surgeons place a small drain in the floor of the orbit to avoid the formation of a hematoma. When reducing these fractures, it is important to mobilize them back to the proper projection. Ifmultiple facial fractures have occurred and the maxilla is in several fragments, then the mandible is usually reconstructed to its original three-dimensional form. This allows for proper closure later and a good vascular pedicle to anterior maxillary segments. It is often helpful to expose the anterior nasal floor and interior piriform rim to help align the segments for fixation. Plating is not recommended in the palatal region, as the tissue is thin in most areas causing plates and screws to become exposed and/or infected. A, the classic clinical appearance of an emergent trap door fracture in a young girl with entrapment. B, A coronal computed tomography scan shows entrapment of periorbita and inferior rectus. C, Navigation and mirroring technology can be used to help position an orbital implant into a defect once the periorbita has been released. The anterior and lateral views of the Le Fort midface fracture classification are shown highlighting the involvement of the various structures of the midface. Custom splints can be made of acrylic using dental models, but they can also be fashioned quickly from perforated thermoplastic splint material. As such, plating systems are often used at the four anterior buttresses of the maxilla to provide fixation. Many surgeons use an outside-in approach, by which the mandible and upper cranio-orbital skeleton are reconstructed prior to the maxilla when pan-facial fractures occur. Dissecting the coronal incision too superficial in the anterior area of the superficial temporal fascia layers may cause frontal nerve branch weakness. Dissecting the coronal incision too deep in the anterior area of the superficial temporal fascia layers into the muscle, causing muscle wasting and a lateral aesthetic defect in the temporal region. Complete reconstruction of the eyelid suspension system, resulting in a rounded appearance to the eyelid 5. Incomplete repositioning of the canthi resulting in traumatic telecanthus or poorly suspended eyelids 6. Failure to integrate dento-alveolar fracture treatment with the repositioning of the maxilla and/or mandible when reestablishing the occlusion 8. Failure to refer to a dental specialist for dental injuries either during the initial reconstructive phase or soon thereafter Common Errors in Technique 1. Drains are placed to bulb suction in the scalp and can be removed when fluid collection has decreased markedly. For patients who have had maxillary fractures, a smooth liquid diet is used for at least several weeks. In patients with solid fixation, soft food can be introduced within several weeks. Antibiotics for 7 days postoperative (optional) Facial sutures may be removed at 5 to 7 days when resorbable sutures are not used. Patients with minimally displaced fractures and a stable occlusion without mobility of the maxilla can be placed on a liquid diet to avoid an operation if they are unable to tolerate it medically or wish to avoid a procedure. Data in this area are not strong enough to make definitive statements regarding which incision may be best. Much of the data are self-reported and have inherent bias associated with the study designs. That being said, many surgeons quote an eyelid scarring complication rate such as ectropion, lid lag, or entropion at slightly over 10%. Disruption of the orbital septum, orbicularis oculi, levators, or canthal system usually creates some lid contour irregularity. Postoperative nasal/oral bleeding may stop spontaneously if mild or with oxymetazoline spray for nasal bleeding. Cerebrospinal fluid leak due to a persistent fistula or breach at the cranial base into the sinonasal region. Many small leaks can be repaired using an endoscopic approach with or without navigation. Others may require an open approach with pericranial flap placement or other techniques to block the leak. In some cases, a lumbar drain can be placed to change differential pressure for very small leaks. The outcome data on this approach are not clear, but it is occasionally employed as a conservative measure. This may cause the emergent need for decompression at the bedside and/or in the operating room with a lateral canthotomy and release of the hematoma. Secondary reconstruction may be needed to gain adequate coverage of the globe and cornea if this is severe. Enophthalmos due to incomplete reconstruction of the floor or wall of the orbit 6. Malunions discovered late may require osteotomies, orthognathic surgery, and/or orthodontic therapy to resolve imbalances in the occlusion. Malunions of the zygoma can be masked with an onlay implant or more ideally treated with a zygomatic repositioning osteotomy. Nonunions of the midface are very rare but most often occur at the lower Le Fort level and involve the occlusion. Infections can occur and usually require antibiotics and sometimes drainage procedures. Plates and screws should be replaced during active healing or removed if the infection occurs after initial healing. Editorial Comment the keys to achieving superior results with complex facial fractures are as follows: 1. Adequately diagnose, prepare, and then execute approaches to those fractures with proper instrumentation available. Achieve a high level of proficiency with plates and screws and the techniques involved in fixation of the bones. Adequately reconstruct the volume and architecture of the orbit accurately after significant fractures. Complex maxillary fractures: role of buttress reconstruction and immediate bone grafts. Midface fractures: advantages of immediate extended open reduction and bone grafting. A comparative study of different approaches in the treatment of orbital trauma: an experience based on 274 cases. Early complications from frontal sinus fractures include all of the following, except a. All the following are viable immobilization techniques for mobile maxillary fractures, except a. Traction on the inferior rectus is thought to activate the oculocardiac reflex (bradycardia, hypotension, and vomiting) and could theoretically be fatal.

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Nontraumatic Hemorrhage and Vascular Lesions 264 may nonetheless be confusing anxiety symptoms vomiting buy emsam 5 mg overnight delivery, as normal-flowing but deoxygenated venous blood also appears hypointense anxiety natural treatment discount emsam 5 mg buy on line. The medullary veins enlarge and contain desaturated hemoglobin; thus anxiety symptoms 24 hours day emsam 5 mg fast delivery, they are seen on T2* sequences as prominent linear hypointensities entering the subependymal veins at right angles (9-36C) anxiety grounding cheap emsam online. Intrasinus thrombi usually appear as elongated cigar-shaped nonenhancing filling defects on axial T1 C+ (924D) anxiety 5 4 3-2-1 emsam 5 mg fast delivery. As the transverse sinuses often have hypoplastic segments, a "flow gap" must be interpreted with caution (see below). As the intrasinus thrombus organizes, the clot begins to exhibit T1 shortening and becomes progressively hyperintense. T2* can be misleading, as clot signal gradually approaches that of normal sinuses. Note area of less prominent blooming that is now approaching signal intensity of the white matter. As blood has resorbed and largely disappeared, there is little or no T2* "blooming. Any residual clot may be reduced to a thin, almost inapparent isointense collection within the thick, strongly enhancing duraarachnoid. Delayed emptying often makes the cortical veins appear as if they are "hanging in space" (9-27D). Numerous tortuous, corkscrew vessels in the parenchyma and sulci also enhance intensely. Approximately 10% of patients report sudden onset of a "thunderclap" headache that clinically mimics aneurysmal subarachnoid hemorrhage. Symptoms such as focal neurologic deficits, seizures, and impaired consciousness are less common than with dural sinus or deep vein thrombosis. Corticalsubcortical hyperintensities consistent with vasogenic edema are common associated findings. With a sensitivity of more than 95%, they are by far the best imaging sequences for detecting thrombosed cortical veins. A well-delineated tubular hypointensity with "blooming" of hemoglobin degradation products within the clot is observed at all stages of evolution, persisting for weeks. Patchy or petechial hemorrhages in the underlying cortex and subcortical white matter are common, as is associated convexal subarachnoid hemorrhage. Note venous congestion with edema, and engorgement of white matter medullary veins. In addition to clot in the sinus, thrombus extends into one or more cortical veins (9-17). If the anastomotic vein of Trolard is dominant, its occlusion may result in lobar hemorrhage. Transverse sinus occlusion that extends into a dominant vein of Labbé often causes extensive posterior temporal and anterior parietal hemorrhage (9-18) (9-19). Most patients present with headache (80%) followed by rapid neurologic deterioration and impaired consciousness (70%). Venous congestion in the medullary and subependymal veins is also hypointense due to slow flow and hemoglobin deoxygenation (9-36C). Arterial strokes caused by artery of Percheron thrombosis or "top of the basilar" occlusion often affect both thalami. Venous Anatomy and Occlusions Cavernous Sinus Thrombosis/Thrombophlebitis Cavernous thrombosis/thrombophlebitis is the most common form of septic cerebral venous sinus thrombosis, a rare but potentially lethal condition with significant morbidity and high mortality. If it occurs in conjunction with sinus infection, it is termed cavernous sinus thrombophlebitis (937). Nontraumatic Hemorrhage and Vascular Lesions 272 ophthalmoplegia, and visual loss is present in 80-100% of cases. Venous Occlusion Mimics We conclude this chapter on venous anatomy and occlusions with a brief discussion of conditions that can mimic-or obscure-venous thrombosis. Sinus Variants the major differential diagnosis of cerebral venous thrombosis is a congenital anatomic variation. Septations or trabeculations are fibrotic bands looking like linear filling defects in sinuses. This causes the appearance of a hyperdense sinus relative to the brain parenchyma. However, the intracranial arteries in patients with high hematocrits are also similarly hyperdense. Unmyelinated Brain Infants and young children often have higher hematocrits than adults, with relatively lower density of their unmyelinated brains. High-attenuation blood vessels and low-attenuation brain make all vascular structures (including dural sinuses and cortical veins) seem relatively hyperdense to dural sinus. Diffuse cerebral edema with decreased attenuation of the cerebral hemispheres makes the dura and all the intracranial vessels-both veins and arteries-appear relatively hyperdense compared with the low-density brain. Nontraumatic Hemorrhage and Vascular Lesions 276 Selected References Normal Venous Anatomy and Drainage Patterns Cheng Y et al: Normal anatomy and variations in the confluence of sinuses using digital subtraction angiography. Because diseases such as atherosclerosis are so prevalent, evaluating the craniocervical vessels for vasculopathy is one of the major indications for neuroimaging. In this article, we discuss diseases of the craniocervical arteries, first laying a foundation with normal gross and imaging anatomy of the aortic arch and great vessels. We then address the topic of atherosclerosis, starting with a general discussion of atherogenesis. The section on atherosclerosis concludes with a consideration of arteriolosclerosis. While arteriolosclerosis is by far the most common cause of small vessel vascular disease, nonatherogenic microvasculopathies such as amyloid angiopathy can have devastating clinical consequences. Normal Anatomy of the Extracranial Arteries Aortic Arch and Great Vessels Cervical Carotid Arteries Atherosclerosis Atherogenesis and Atherosclerosis Extracranial Atherosclerosis Intracranial Atherosclerosis Arteriolosclerosis Nonatheromatous Vascular Diseases Nonatherosclerotic Aging Phenotypes Fibromuscular Dysplasia Dissection Vasoconstriction Syndromes Vasculitis and Vasculitides Other Macro- and Microvasculopathies 277 277 279 281 281 284 289 293 295 295 295 299 302 303 306 Normal Anatomy of the Extracranial Arteries Aortic Arch and Great Vessels the aorta has four major segments: the ascending aorta, transverse aorta (mostly consisting of the aortic arch), aortic isthmus, and descending aorta. The trachea, left recurrent laryngeal nerve, esophagus, thoracic duct, and vertebral column lie behind the arch. The pulmonary bifurcation, ligamentum arteriosum, and left recurrent laryngeal nerve all lie below the arch. Three thoracic aorta "lumps and bumps" are normal anatomic variants that should not be mistaken for pathology. Both the aortic isthmus and spindle typically disappear after two postnatal months but can persist into adulthood. A ductus diverticulum is a focal bulge along the anteromedial aspect of the aortic isthmus and is seen in 10% of adults. A smaller slipstream actually reverses direction in the bulb, temporarily slowing and stagnating before reestablishing normal antegrade laminar flow with the central slipstream. The maxillary artery divides into its distal branches within the pterygopalatine fossa. It loops anteroinferiorly, then courses superiorly to supply the tongue, oral cavity, and submandibular gland. The facial artery arises just above the lingual artery, curving around the mandible before it passes anterosuperiorly to supply the face, palate, lips, and cheek. The occipital artery courses posterosuperiorly between the skull base and C1 to supply the scalp, upper cervical musculature, and posterior fossa meninges. The superficial temporal artery runs superiorly behind the mandibular condyle and loops over the zygoma to supply the scalp. Its first major branch is the middle meningeal artery, which runs superiorly and enters the calvaria through the foramen spinosum to supply the cranial meninges. After giving off the middle meningeal artery, the maxillary artery courses anteromedially in the masticator space and then loops into the pterygopalatine fossa, where it terminates by dividing into branches that supply the deep face, paranasal sinuses, and nose. These anastomoses (summarized in the box below) both provide an important pathway for collateral blood flow and pose a potential risk for intracranial embolization during neurointerventional procedures. We begin our discussion with an overview of the etiology, biology, and pathology of atherogenesis. Atherogenesis and Atherosclerosis Terminology the term "atherosclerosis" was originally coined to describe progressive "hardening" or "sclerosis" of blood vessels. The term "atheroma" (Greek for porridge) designates the material deposited on or within vessel walls. Atherosclerosis is the most common pathologic process affecting large elastic arteries. Atherosclerosis is a complex, slowly developing process that begins in the early teenage years and progresses over decades. Its causes are multifactorial but appear to be a combination of lipid retention, oxidation, and modification, which in turn incites chronic inflammation. Plasma lipids, connective tissue fibers, and inflammatory cells accumulate at susceptible sites in arterial walls, forming focal atherosclerotic plaques. Monocyte accumulation and macrophage differentiation are also induced as part of the inflammatory process. Neoangiogenesis is closely associated with plaque progression and is likely the primary source of intraplaque hemorrhage. Angiogenic factors cause vasa vasorum proliferation, formation of immature vessels, and loss of capillary basement membranes. Red blood cells leak into the plaque, inducing further inflammation and increasing the risk of plaque ulceration and rupture. However, the rate at which plaques develop is faster in patients with genetic predisposition and acquired risk factors, such as hypertension, smoking, type 2 diabetes, and obesity. The entire vasculature is exposed to similar environmental and genetic influences. The unusual flow patterns generated by this unique geometry result in increased particle residence time and low, oscillating wall shear stresses in the outer wall of the carotid bulb. This may account for the unusually high prevalence of atheromas at this particular location. The first detectable lesion is lipid deposition in the intima, seen as yellowish "fatty streaks. Uncomplicated stable plaques-the basic lesions of atherosclerosis-consist of cellular material (smooth muscle cells, monocytes, and macrophages), lipid (both intracellular and extracellular deposits), and an overlying fibrous cap (composed of collagen, elastic fibers, and proteoglycans). The intima covering a stable plaque is thickened, but its exterior surface remains intact, without disruption or ulceration. As a necrotic core of lipid-laden foam cells, cellular debris, and cholesterol gradually accumulates under the elevated fibrous cap, the cap thins and becomes prone to rupture ("vulnerable" plaque) (10-9). Proliferating small blood vessels also develop around the periphery of the necrotic core. Neovascularization can lead to subintimal hemorrhage with rapid expansion, which increases pressure inside the plaque, promotes increasing lipid deposition, and enlarges the necrotic core, further weakening the overlying fibrous cap. Plaque ulceration occurs when the fibrous cap weakens and ruptures through the intima, releasing necrotic debris (10-10). Slowly swirling blood within the ulcerated denuded endothelium first allows platelets and fibrin to aggregate. An intermittent Bernoulli effect then pulls the aggregates into the rapidly flowing main artery slipstream, causing arterioarterial embolization to distal intracranial vessels. Although atherogenesis actually begins in the mid-teens, most patients with symptomatic lesions are middle-aged or elderly. However, atherosclerosis is increasingly common in younger patients, contributing to the rising prevalence of strokes in patients younger than 45 years. Treatment options include prevention, medical therapy (lipid-lowering regimens), and surgery or endovascular therapy (see below). Each technique has its advocates, advantages, disadvantages, cost considerations, and special "use case" scenarios. In-depth analysis and comparison of the many available vascular imaging modalities are beyond the scope of this book. Aortic emboli involve the left brain in 80% of cases and show a distinct predilection for the vertebrobasilar circulation. This striking geographic distribution is consistent with thromboemboli arising from ulcerated plaques in the descending aorta that are then swept by retrograde flow into left-sided arch vessels. Arch atherosclerosis is a documented independent risk factor for stroke, found on imaging studies in 10-20% of patients with acute ischemic infarcts and 25% of fatal strokes at autopsy. Ulcerated aortic plaques are present at autopsy in 60% of patients who died from cerebral infarction of unknown etiology. The aortic arch and proximal descending aorta should be visualized together with the extracranial and intracranial vasculature. Intravenous contrast is necessary to define the presence of mural thrombus, determine plaque extent, and evaluate the aortic wall for complications such as ulceration, aneurysm, and dissection. Complete imaging evaluation of patients with thromboembolic infarcts in the brain should include investigation of the aortic arch. Carotid Bifurcation/Internal Carotid Arteries Between 20-30% of all ischemic infarcts are caused by carotid artery stenosis (10-12). Therefore, determining the degree of carotid stenosis on imaging studies is now both routine and required. Carotid stenosis is classified as moderate (50-69%), severe (7093%), and "preocclusive" or critical (94-99%) (10-13) (10-15). Rupture of an "at-risk" plaque with a large necrotic core under a thin fibrous cap is responsible for the majority of acute thrombi. Smooth plaques and extensive coalescent calcifications are associated with decreased risk of plaque rupture. Large atherosclerotic plaques may demonstrate one or more subintimal low-density foci. Both findings carry increased risk of plaque rupture and concomitant distal embolization. Ulcerations-seen as irregularly shaped contrast-filled outpouchings from the lumen-are detected with 95% sensitivity and 99% specificity.

Pathology Four general stages are recognized in the evolution of a cerebral abscess: (1) focal suppurative encephalitis/early cerebritis anxiety symptoms - urgency and frequent urination buy emsam 5 mg mastercard, (2) focal suppurative encephalitis/late cerebritis anxiety symptoms for teens emsam 5 mg buy without a prescription, (3) early encapsulation anxiety ulcer emsam 5 mg buy otc, and (4) late encapsulation anxiety 100 symptoms order 5 mg emsam overnight delivery. Each has its own distinctive pathologic appearance anxiety and depression association of america emsam 5 mg order fast delivery, which in turn determines the imaging findings. Sometimes also called the "early cerebritis" stage of abscess formation, in this earliest stage, suppurative infection is focal but not yet localized (12-29). An unencapsulated, edematous, hyperemic mass of leukocytes and bacteria is present for 1-3 days after the initial infection (12-30). The next stage of abscess formation is also called "late cerebritis" and begins 2-3 days after the initial infection (12-31). Patchy necrotic foci within the suppurative mass form, enlarge, and then coalesce into a confluent necrotic mass. By days 5-7, a necrotic core is surrounded by a poorly organized, irregular rim of granulation tissue consisting of inflammatory cells, macrophages, and fibroblasts. Proliferating fibroblasts deposit reticulin around the outer rim of the abscess cavity. The abscess wall is now composed of an inner rim of granulation tissue at the edge of the necrotic center (12-34) and an outer rim of multiple concentric layers of fibroblasts and collagen (12-35). The necrotic core liquefies completely by 7-10 days, and newly formed capillaries around the mass become prominent. The "late capsule" stage begins several weeks following infection and may last for several months. Collagen deposition further thickens the wall, and the surrounding vasogenic edema disappears. The wall eventually contains densely packed reticulin and is lined by sparse macrophages. Congenital, Acquired Pyogenic, and Acquired Viral Infections Clinical Issues Demographics. Brain abscesses occur at all ages but are most common in patients between the third and fourth decades. Headache, seizure, and focal neurologic deficits are the typical presenting symptoms. Rapid diagnosis, stereotactic surgery, and appropriate medical treatment have reduced mortality to 2-4%. Intense but somewhat irregular rim enhancement is present on T1 C+ images (12-33B). The rims of abscesses are usually thin, complete, smooth, and 355 Imaging General Features. Imaging findings evolve with time and are related to the stage of abscess development. A poorly marginated cortical/subcortical hypodense mass is the most common finding (12-32A). Well-defined double-layered wall surrounds a central core of necrosis, inflammatory debris. A "double rim" sign demonstrating two concentric rims, the outer hypointense and the inner hyperintense relative to cavity contents, is seen in 75% of cases (12-37A). T1 C+ sequences show a strongly enhancing rim (1224) (12-37B) that is thinnest on its deepest (ventricular) side and "blooms" on T2*. With treatment, the abscess cavity gradually collapses while the capsule thickens even as the overall mass diminishes in size. The shrinking abscess often assumes a "crenulated" appearance, much like a deflated balloon (1239A). Contrast enhancement in the resolving abscess may persist for months, long after clinical symptoms have resolved (1239). Early cerebritis is so poorly defined that it can be difficult to characterize and can mimic many lesions, including cerebral ischemia or neoplasm. Follow-up scan at the end of treatment shows a small residual enhancing nodule with almost complete resolution of the surrounding edema. Infection, Inflammation, and Demyelinating Diseases 358 Once a ring develops around the necrotic center, the differential diagnosis is basically that of a generic ring-enhancing mass. Less common entities that can appear as a ring-enhancing mass include demyelinating disease, in which the ring is usually incomplete and "open" toward the cortex. Ventriculitis also occurs as a complication of meningitis and neurosurgical procedures such as external ventricular drainage. Recognition and prompt intervention are necessary to treat this highly lethal condition. Terminology Ventriculitis is also called ependymitis, pyocephalus, and (less commonly) ventricular empyema. Etiology Infection of the ventricular ependyma most often occurs when a pyogenic abscess ruptures through its thin, medial capsule into the adjacent ventricle. A reduction of 1 mm between the ventricle and brain abscess increases the rupture rate by 10%. Nosocomial meningitis/ventriculitis is a rare but potentially devastating complication following neurosurgical interventions. The most common pathogens causing ventriculitis are Staphylococcus, Streptococcus, and Enterobacter. Ependymal enhancement without intraventricular debris and pus is a nonspecific finding on imaging studies. Mild, thin, linear enhancement of the periventricular and ependymal veins is normal, especially around the frontal horns, septi pellucidi, and atria of the lateral ventricles. Germinoma and metastasis from an extracranial primary neoplasm can both cause irregular ependymal thickening and enhancement. Recent studies estimate that intraventricular rupture occurs in up to 35% of brain abscesses. In general, headaches are more severe and are accompanied by signs of meningeal irritation. Image-guided stereotactic aspiration is the simplest, safest method to obtain pus for culture and to decompress the abscess cavity. The combination of third-generation cephalosporins and metronidazole is the mainstay of initial empirical antimicrobial treatment. Despite aggressive medical and surgical management, many patients do poorly and succumb to the disease. Early diagnosis and prompt treatment are essential to maximize neurologic recovery. Terminology Empyemas are pus collections that can occur in either the subdural or epidural space. Empyemas in infants and young children are most commonly secondary to bacterial meningitis. In older children and adults, over two-thirds of empyemas occur as extension of infection from paranasal sinus disease. Infection can erode directly through the thin posterior wall of the frontal sinus, which is half the thickness of the anterior wall (12-42). Infection may also spread indirectly in retrograde fashion through valveless bridging emissary veins. Approximately 20% of empyemas in older children and adults are secondary to otomastoiditis. Rare causes of empyemas include penetrating head trauma, neurosurgical procedures, or hematogenous spread of pathogens from a distant extracranial site. Ependymal enhancement is seen in only 60% of cases and varies from minimal to moderate (12-41A). When present, ependymal enhancement tends to be relatively smooth, thin and linear rather than thick and nodular. They range from small, focal epidural collections (12-42) to Infection, Inflammation, and Demyelinating Diseases 360 extensive subdural infections that spread over most of the cerebral hemisphere and extend into the interhemispheric fissure. Multiple lesions including mixed intra- and extradural collections are seen in 15-20% of cases. Loculated and/or multiple unilateral collections are more common than separate bilateral empyemas. The most common gross appearance of an empyema is an encapsulated, thick, yellowish, purulent collection lying between the dura and the arachnoid. Early empyemas may be unencapsulated collections of cloudy, more fluid-like material. Microscopic features are those of nonspecific inflammatory infiltrate with varying amounts of granulation tissue. Clinical Issues (12-42) Purulent frontal sinusitis with extension into epidural space causes epidural empyema and frontal lobe cerebritis. An adolescent boy with significant headache and fever should elicit a high index of suspicion for sinusitis complications and prompt immediate imaging evaluation. The most common clinical presentation is headache, followed by fever and altered sensorium. The interval between initial infection (usually sinusitis) and onset of the empyema is typically 1-3 weeks. Once established, untreated empyemas can spread quite rapidly, extending from the extraaxial spaces into the subjacent brain. Besides cerebritis and abscess formation, the other major complication of empyema is cortical vein thrombosis with venous ischemia. Surgical drainage and rapid initiation of empiric intravenous antibiotic therapy (initially vancomycin and a third-generation cephalosporin) has been shown to reduce mortality. The extracerebral space is widened, and the underlying sulci are compressed by Congenital, Acquired Pyogenic, and Acquired Viral Infections the collection. The inwardly displaced dura can sometimes be identified as a thin hypointense line between the epidural collection and the underlying brain (12-43). Hyperintensity in the underlying brain parenchyma may be caused by cerebritis or ischemia (either venous or arterial). Empyemas show variable enhancement depending on the amount of granulomatous tissue and inflammation present (12-24). The encapsulating membranes, especially on the outer margin, enhance moderately strongly (12-43B) (12-44B) (12-45C). Congenital, Acquired Pyogenic, and Acquired Viral Infections 363 (12-47A) A 66y man developed headaches and frontal scalp swelling several weeks after resection of an anterior fossa meningioma. Note thin film of intradural fluid between layers of periosteal and meningeal dura. The virus initially gains entry into cells in the nasopharyngeal mucosa, invades sensory lingual branches of the trigeminal nerve, then passes in retrograde fashion into the trigeminal ganglion. It establishes a lifelong latent infection within sensory neurons of the trigeminal ganglion, where it can remain dormant indefinitely. Pathology (12-50B) Axial section in the same case shows petechial hemorrhages in insular cortex of both temporal lobes. The anterior and medial temporal lobes, insular cortex, subfrontal area, and cingulate gyri are most frequently affected (12-50A). Extratemporal, extralimbic Congenital, Acquired Pyogenic, and Acquired Viral Infections involvement occurs but is more common in children compared with adults. Massive tissue necrosis accompanied by numerous petechial hemorrhages and severe edema is typical. Inflammation and tissue destruction are predominantly cortical but may extend into the subcortical white matter. Perivascular lymphocytic cuffing with diffuse neutrophil infiltration into the necrotic parenchyma is typical. It follows a bimodal age distribution, with one-third of all cases occurring between the ages of 6 months and 3 years and one-half seen in patients older than 50. A viral prodrome followed by fever, headache, seizures, behavioral changes, and altered mental status is typical. Nearly two-thirds of survivors have significant neurologic deficits despite antiviral therapy. Hypodensity with mild mass effect in one or both temporal lobes and the insula may be present (12-51A). Infection, Inflammation, and Demyelinating Diseases 366 demonstrate cortical/subcortical hyperintensity with relative sparing of the underlying white matter. Enhancement varies from none (early) to intense gyriform enhancement several days later (12-52D). Primary neoplasms such as diffusely infiltrating astrocytoma usually involve white matter or white matter plus cortex. Acute cerebral ischemia-infarction occurs in a typical vascular distribution, involving both the cortex and white matter. Postictal edema is transient but generally more widespread, often involving most or all of the hemispheric cortex. Temporal lobe confluent hyperintensities with patchy foci of marked hypointensity are consistent with encephalomalacia and chronic hemorrhage. Similar findings were present in the insular cortex and cingulate gyri (not shown). The median interval between transplantation and onset of neurologic symptoms is 3 weeks. Patients typically present with altered mental status, shortterm memory loss, and seizures. Note edema and mass effect, seen as hyperintensity in both cerebellar hemispheres. Postictal hippocampal hyperemia is transient, and extrahippocampal involvement is absent. The most common nonepidemic viral encephalitis, herpes encephalitis, was discussed earlier.

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