Peter E. Andersen, MD

• Professor, Department of Otolaryngology/Head and Neck Surgery
• Professor, Department of Neurosurgery
• Director of Head and Neck Surgery
• Oregon Health and Science University
• Portland, Oregon

When swabs are obtained prostate 90 speman 60 pills order with visa, care must be taken to sample the desired site vigorously to obtain as many cells as possible since mycoplasmas are cellassociated man health 00 days buy speman on line amex. Wooden shaft cotton swabs should be avoided because of potential inhibitory effects mens health 300 workout 2014 cheap speman on line. Specimens should be refrigerated if immediate transporta tion to the laboratory is not possible define androgen hormone discount speman 60 pills line. If specimens must be shipped and/or if the storage time is likely to exceed 24­48 h prior to processing androgen hormone nutrition order genuine speman, the specimen in transport medium with cryoprotectant should ideally be frozen and shipped on dry ice to prevent loss of viability. ThermoFisher transport media are reported by their manufacturer to maintain mycoplasma viability for up to 48 h when stored at 2­8°C. Mollicutes can be stored for long periods in appropriate growth or transport media at -70°C or in liquid nitrogen. Frozen specimens may be shipped with dry ice to a reference laboratory if necessary. When specimens are to be examined, they should be thawed rapidly in a 37°C water bath. In order to maximize yield of mycoplasmas from clinical specimens, serial ten fold dilution in liquid media to 10­3 to remove inhibitors and inoculation of broth dilutions to appropriate agar has been suggested [45,50]. Mycoplasmas of importance for human infections utilize glucose and/or arginine as meta bolic substrates, whereas ureaplasmas utilize urea. The var ious medium formulations designed for their cultivation must provide these substances along with other essential ingredients, including serum as a cholesterol source, yeast extract, and a pH indicator for detection of growth when the substrate is metabolized. These media can also be used to cultivate other fastidious and slow growing species. Detailed description of essential components of growth medium, formulations, instruc tions for preparation of various nonproprietary types, and incubation conditions for different mycoplasmas can be found in other reference texts [45]. Multiple vendors including ThermoFisher and Hardy Diagnostics in the United States market various formula tions of growth media, including 10B broth, A7 and A8 agars for cultivation of M. Since the broth does not contain a pH indicator, it is not possible to detect growth by direct observation of the liquid medium. Some manufacturers will produce customized orders of various sizes for most of their media, with or without inhib itors, or special additives, as desired by the purchaser. Most broths and transport media can be obtained in lyophilized form to prolong shelflife. For laboratories that prefer to prepare their own media, individual media components described in other reference texts [45] can be obtained from various commercial sources. Mycoplasma Experience manufactures and sells a variety of diagnostic products for use in detecting myco plasmas of veterinary importance, primarily marketing their products in the United Kingdom and Europe. However, they also produce their own line of liquid and solid media suitable for use in detecting human myco plasmas and ureaplasmas. Mycoplasma Experience manufactures their own broth formulations containing specific biochemical substrates. Frozen agar supplements that can be added to agar are also available for purchase. Several French companies produce a variety of liquid and solid media for urogenital mycoplasma and urea plasma detection, with many of the same names and for mulations as those sold in the United States. Additionally, there are some kits that can be used for detection as well as presumptive species identification. The diag nostic kits have been marketed primarily in Europe, but some have now been introduced into the United States. Species identification is based on differential inhibition by erythromycin and lincomycin. The kit consists of microplates containing lyophilized growth substrates and antimicrobials. Diagnostic kits typically consist of strips with wells con taining specific dried or lyophilized substrates and inhib itors. Specimens are placed in a suspensiontransport medium that is used to inoculate wells. The detection, identification, and quantitation of organisms are based 200 Manual of Commercial Methods in Clinical Microbiology on the color change of specific wells containing substrates and inhibitors. Descriptions of some of the commercial diagnostic kits along with their manufacturers are provided in Table 12. Some commer cially sold diagnostic products have undergone external validation in comparison to one another and with other nonproprietary products in clinical trials that have been published in peerreviewed journals. Some products included in earlier published evaluations are now sold by different companies than when the original evaluations were performed. Other commercial products from various manufacturers and countries exist, but to our knowledge, have not been subjected to rigorous comparison with stan dard methods of testing. Performance of these kits was gen erally satisfactory, but when quantitation is desired, stan dard methods were better. The overall agreement for 13 total Ureaplasmapositive infants between the two tests was 96%. Therefore, organism identification and purity should be verified by colony morphology on agar plates. Their study showed 100% sensitivity and 94% and 90% specificity, respectively for detection of Ureaplasma spp. Lower rates of organism detection by some commercial kits in comparison to standard methods has been attrib uted to the fact that standard methods usually include rec ommendations for serial dilution of the original specimen to remove inhibitors that may be present. Some of the kits and media such as those described above have a shelf life of several months, making them attractive for use in lab oratories that have only occasional needs for performing mycoplasma cultures, but they are considerably more expensive to purchase than media and reagents prepared inhouse. Commercial products have been designed for use with specimens from the urogenital tract, but some are now recommended for use in detecting ureaplasmas in gastric and/or endotracheal secretions from neonates. The very limited independent evaluations of some of the commercial media suggest that in the hands of expe rienced laboratorians, these media may perform in a satisfactory manner for routine detection of urogenital mycoplasma and ureaplasma infections. Some products have never been evaluated against standard noncommer cial media, so their performance characteristics are largely unknown. The commercial kits for organism detection, quantitation, and identification have also undergone relatively limited comparative studies, but most appear to perform in a generally satisfactory manner. For selfprepared media, as well as readytouse com mercial media, rigorous quality control is crucial for detection of fastidious mollicutes. New lots or batches of broth are considered satisfactory if the numbers of organ isms that grow are within 10 to 100fold of the reference batch. Agar plates should support growth of at least 90% of the colonies that are supported by the reference media. Almost any formulation of mycoplasma growth medium that is prepared correctly can be expected to grow prototype laboratoryadapted strains. The real challenge is the ability to isolate mycoplasmas and ureaplasmas from clinical specimens, hence the need for inclusion of known Table 12. Testing inhibitory properties of media against growth of various other organisms likely present in specimens from nonsterile sites may also be worthwhile to prevent loss of mycoplasmas due to over growth of contaminating organisms. It is also important to watch carefully for the presence of contaminating bacteria that can cause falsepositive results. Laboratories that encounter pinpoint colonies that do not Gram stain should consider the possibility of M. Availability of frozen or freezedried mycoplasma media from commercial sources facilitates such transport or subculture that may be needed on an infrequent basis for lowvolume laboratories that do not offer complete diagnostic service for mycoplasmas. However, serology has many drawbacks including: (i) the fact that it takes several days after infection before measurable anti body is produced; (ii) immunosuppressed persons are often unable to mount an antibody response; its retro spective nature requires acute and convalescent sera for optimum diagnostic accuracy; and (iv) the erratic nature of the humoral immune response in many immunologically normal persons. The prominent historical role of serology is mainly because of the relative lack of sensitivity and time consuming nature of culture, as well as the carrier state that may occur in an unknown percentage of persons in the absence of acute infection. Serology is now becoming less important as rapid molecularbased assays become more widely available for direct detection of acute mycoplasmal infection and the limitations and inaccuracies of many commercial serological assays are becoming more apparent. This approach has the the oretical advantage in that only a single specimen, taken approximately 7­10 days after infection, is required. The presence of IgM is considered most significant in pediatric populations when there have been fewer opportunities for repeated exposures. However, chil dren may produce IgM erratically and the antibodies can persist for several months after an acute infection. Infants younger than 6 months of age may not produce a measurable IgM response [27]. Additionally, adults who have been infected repeatedly over a period of years may not respond to mycoplasma antigens with a brisk IgM response. In these cases, reinfection may lead directly to an IgG response; so the absence of a positive IgM test does not rule out an acute infection. A single IgG measurement is also not advisable due to the presence of a high background of IgG antibodies in many healthy persons and its persistence after clinical resolution of infection. When convalescent sera were tested, the number of IgGpositive specimens rose to 82% [40]. This same study also found that only 14 of 27 (52%) acutephase sera tested positive by various IgM assays, rising to 88% when convalescent sera were tested. In view of these considerations, it is advisable to test simultaneously for both IgM and IgG in paired spec imens collected 2­3 weeks apart for the most accurate diagnosis of recent or current M. A fourfold or greater rise in anti body titer indicates a current or recent infection [49]. IgA antibodies are produced early in the course of disease, rise quickly to peak levels, and decrease earlier than IgM or IgG. In theory, a single early specimen could detect an acute infection even after multiple reinfections. Further research into IgA responses in adult and pediatric populations and assessment of antibody levels in other body fluids such as urine is warranted. They are IgM antibodies to the Iantigen of erythrocytes, and are detected by agglutination of type O, Rhnegative erythrocytes at 4°C. They are produced 1­2 weeks after initial infection, and persist for several weeks. A positive test result is not specific for mycoplasmal infec tion since other bacteria, viruses, or even collagen vascular 12. However, mycoplasmas are much more anti genically complex than viruses, leading to nonspecific reactions. Therefore, one cannot differentiate between antibody classes using this technique, and recent infection in adults who may have minimal IgM response may be missed. Numerous publications have appeared since the early 1980s describing a number of different techniques for measuring antibody response to M. However, in most instances it is not as accurate a test as some of the newer assay formats, considering its lack of antibody class distinction and tendency for crossreactivity with other microorganisms. More recent studies evaluating commercial kits have merely compared one method or product versus another. Results and conclusions from some studies were based upon assay of a single acutephase serum sample, while others have used paired specimens. Often, there was no clearcut designation of what constituted a true infec tion, so comparisons and extrapolations from multiple studies becomes rather complex and not always feasible. Many additional commercial assays are available in various European and Asian countries. These kits have been studied in comparison to other methods and have been shown to provide accurate, quantitative serologic data [2,17]. The antigencoated particles are incu bated with test serum, and if the serum contains specific antibodies, the particles agglutinate, resulting in a visible reaction. Antibodies bound to the solidphase antigen are visualized by using enzymelabeled conjugates directed against the primary antibody and substrate read in a spectrophotometer. The amount of conjugate reacting is proportional to the levels of antibody present. A permeable membrane or filter paper is impregnated with antigen to which serum is added, followed by addition of antihuman IgG or IgM enzyme conjugate. If specific antibodies are present, the particles agglutinate, resulting in a visible reaction. Specific antibody is detected in dilutions of test serum after staining with antihuman IgM or IgG fluorochrome conjugate. They are amenable to a variety of assay conditions, detect very small amounts of antibody, and can be made isotypespecific. Crude multiantigen preparations, purified proteins, capture approaches, purified glycolipids, and synthetic peptides have all been used as targets. A positive test is indicated by development of a blue color in both of the upper reaction ports. Although the manufacturers and some investigators have endorsed the use of a single assay by this product for diagnosis of acute M. It is apparent that problems exist with essentially all of the serological tests that have undergone comparative evalua tions. For others that have not undergone such comparisons, nothing is known about their diagnostic accuracies beyond what the manufacturer states in package inserts. Beersma and coworkers [7] published a comprehensive European study, evaluating 12 commercial M. However, if invasive extragenital dis ease occurs, elevation of antibody titers is often apparent. No single sero logic test has proven satisfactory in identification of genital mycoplasmal infections and most assays for M. However, this does not preclude the potential for crossreacting antibodies arising from a genital infection with this organism. No commercial serologic kits for detection of antibodies to urogenital mycoplasmas are produced and sold commercially in the United States. No external clinical evaluations have been reported for these products at the time of this writing and serologic approach to diagnosis is not recommended for genital mycoplasmas at present. However, it is not satisfactory for detection of fastidious and/or extremely slowgrowing organisms such as M.

In mice inoculated with virus prostate 5k run cheap speman 60 pills on-line, clinical signs and characteristic pathological lesions are often indicative of virus growth prostate cancer biopsy 60 pills speman order amex, but additional laboratory tests such as serology mens health 042013 chomikuj proven speman 60 pills, immunofluorescence prostate cancer natural treatment order speman with american express, and immunohistochemistry must also be performed for a definitive diagnosis prostate cancer 9 on gleason scale buy 60 pills speman mastercard. Natural host animals may also be used to isolate viruses when other methods fail to produce results. An antigen is coated onto a solidphase surface, the test serum and an enzymelabeled antibody specific for the coated antigen are added together, and they compete for binding to the immobilized antigen. The color developed (by adding a chromogenic enzyme substrate) is inversely proportional to the amount of viral antibody present in the test serum. The assay is typi cally inexpensive, sensitive, and rapid, and a diagnosis can usually be made within hours. A large number of sam ples can be processed in a single run in a fully automated fashion using an automated plate washer and reader. Alternatively, a standard dilution of a serum sample is mixed with serial dilutions of the test virus. The serum­virus mixtures are then inoculated onto monolayers of susceptible cell cul tures, and the inoculated cells are monitored for evidence of virus infection. Therefore, for viruses that do not replicate in cell cultures, antiviralneutralizing anti bodies can be detected by inoculating the in vitro serum­ virus mixtures into live animals or embryonated eggs for evidence of virus infection. However, the in vivo neutral ization approach is expensive and timeconsuming, and is of little practical value. Viral antigen prepara tions are placed in a central agar well, and positive control Table 19. Commercial Methods in Clinical Veterinary Microbiology 353 and test sera are placed in peripheral wells. Precipitin lines are formed when the diffusing viral antibodies meet and react at optimal conditions with the diffusing viral antigen on the agar plate. The test serum is diluted serially in 96well plates and incu bated with a standard amount of virus. If the test serum contains viral anti body, the antigenspecific viral antibody forms immune complexes with the viral antigen. An immunofluorescence assay can also be used to detect viral antigens if a known specific viral antibody is available (see below). Western immunoblot analysis can detect viral anti bodies in serum specific to a viral protein. The presence of an antibody­antigen complex is demonstrated by adding an enzyme, chemi luminescent, or radioisotopelabeled secondary anti body. Western immunoblot analysis is often used as a confirmatory test to verify the results of serological assays. This assay has been used for detection of viral antibodies of many viruses such as equine lentivirus [20], bovine immunodeficiency virus [188], African horse sickness virus [17], and bovine leukemia virus [71]. With a known specific viral antibody, Western blot analysis can also be used to detect virus antigens in clinical samples. This technology utilizes multiple microspheres (up to 100 sets) and each one is conjugated to a differ ent antigen for uniform detection of multiple antibodies in a small sample volume. Commercial assays using this technology have been introduced for chickens (Biovet Inc. Each veterinary diagnostic laboratory usu ally has its inhouse immunofluorescence assay procedures for each virus. Viral antigenspecific antibody is coated to a solidphase surface (usually a 96well plate), and the clinical specimen containing viral antigen is then added. After addition of an enzymelabeled antibody, a chromogenic enzyme substrate is added for color development. The color developed is proportional to the amount of viral antigen present in the specimen. Many clinical materials, such as frozen tissue sections, cell smears, or monolayers, are appropriate for this assay, but fresh clinical samples are the best. The digoxygenin system is particularly attractive because nonspecific background can be minimized. However, the specific viral genomic frag ments to be labeled as probes have to be generated in the research or diagnostic laboratories for each virus of interest. The antibodycoated latex beads are stable, and the results can be read by eye or can be measured photometrically within 30 min. This assay is tradition ally used to detect the presence of viral antigen in feces of many veterinary viruses such as porcine rotavirus [145], bovinerotavirus [51,113], and canine parvovirus [15]. Total nucleic acids extracted from clinical sam ples are immobilized, denatured, and hybridized with a radioisotope, chemiluminescent, or enzymelabeled singlestrand viral nucleic acid probe. After washing away the unbound probe, the membrane is exposed to a film for autoradiography or, in the case of an enzymelabeled probe, the signal of bound probes in the membrane is measured by color development with a substrate. Dot blot hybridization has been used to detect nucleic acids of many viruses such as porcine and bovine enteric coro navirus [150], infectious bursal disease virus [56], bovine rotavirus [118], swine encephalomyocarditis virus [104], feline infectious peritonitis virus [97], and avian reovi ruses [93]. Traditionally, 32P was used to label probes by methods such as nick translation and endlabeling. However, a specific viral genomic fragment or a synthetic oligonu cleotide for each virus of interest has to be generated in a research or diagnostic laboratory for labeling as probes. Because of the extreme sensitivity, care must be taken to avoid carryover or crosscontamination, which could lead to falsepositive results. This method allows for distinction between virus replicating in the this sues and circulating virus. A definitive or differential diagnosis can often be made on the basis of the restriction fragment patterns. This method has become affordable and rapid in recent years and is now more frequently used in veterinary diag nostic laboratories to determine virus characteristics and sequence changes. This section will focus primarily on reagents and systems designed specifically for bacterial identification. Many bacteria isolated from animals are identical to or are of the same genus as those that cause disease in humans. However, there are few commercial bacte rial identification systems capable of adequately iden tifying most veterinaryspecific pathogens because the number of veterinaryspecific pathogens is inadequate to generate the large databases needed for their accurate identification. Furthermore, the cost to develop systems needed to identify the relatively few hostspecific bacteria that are isolated in clinical veterinary laboratories is relatively high. Therefore, systems developed for isola tion of bacteria from human clinical specimens are often used for the identification of bacteria from animal spec imens. For a detailed discussion of rapid kits and instru ments used in bacteriology, please refer to other chapters in this text. This section will focus on reviews of studies that have evaluated the application of available systems for identification of bacteria isolated from animal specimens. Knowledge of the animal species and body site from which a bacterial isolate originated is an important key in the identification process. Although most state animal diagnostic laboratories and teaching hospital laboratories will use automated systems and kits for identification, many veterinary diagnostic laboratories still use con ventional macrotube biochemical tests [128]. The cost of rapid identification systems compared to the cost of mac rotube biochemicals may prohibit the use of the former in smaller veterinary laboratories. However, most veterinary diagnostic laboratories will also maintain the conven tional macrotube tests because, as mentioned above, kit and automated systems usually lack data from a sufficient number of animal isolates to generate accurate biocodes within their databases [1,27,139]. Many studies have evaluated the miniaturized biochemical test systems and semiautomated systems for their ability to identify iso lates of veterinary origin. Following laser desorption, these molecules are ionized and analyzed by mass spectrometry to generate a spectrum (proteomic fingerprint) that is used to identify the bacterial species. However, the initial cost of the equipment is likely to place this technology outside the realm of many veteri nary laboratories. The authors felt that the poor performance of the system in the identification of the staphylococci could be attributed to the low number of veterinaryspecific strains in the database. No recent updates of the Vitek system for 360 Manual of Commercial Methods in Clinical Microbiology identification of staphylococci from animals have been reported. After 18 h of incubation in test plates, 85% of the bacteria were correctly identified to the species level. The systems were most accurate for identifications at the species level for Escherichia coli, Klebsiella spp. As with previous studies, both sys tems had difficulty identifying Pasteurella/Actinobacillus and nonfermentative bacilli other than Pseudomonas aeruginosa. However, the same authors found that the two systems were similar and acceptable (>90% categorical agreement) in susceptibility testing of over 3700 Gram negative isolates of veterinary origin [158]. In comparison to agar disk diffusion, the Sensititre system has been shown to be moderately to highly accurate in determining the susceptibility of Gramnegative and Grampositive pathogens responsible for bovine mastitis [138]. In conclusion, none of the commercial bacterial identification systems, either microbiochemical, semi automated, or automated appear to be capable of identi fying the diverse array of bacteria that may be encountered in a clinical veterinary setting. Many of these systems can be helpful in the identification process when used in conjunction with supplemental tests to identify a particular species. A bacterial identification with a relatively low degree of confidence should alert the veterinary bacteri ologist to perform ancillary tests. Although it is possible to generate new bacterial identification codes with some commercial systems, comparative tests of automated sys tems and kits designed for the human market are less com monly being tested in veterinary laboratories as inhouse molecular tests become more common. This diverse group includes the genera Actinobacillus, Pasteurella, Haemophilus, Mannheimia, and Bordetella, among others. This system was determined to be 62% accurate in identifying this group of organ isms. However, if the unique bio codes that were generated by the study were added to the system database, 85. Although the identification kit did not include this organism in its data base, five unique biocodes were generated. The authors concluded that the system could be used to identify this pathogen if these biocodes were added to the database. Again, studies of older systems, many of which are no longer in produc tion, were overall inaccurate at identification of staphy lococci [68,81,130,175,176]. A major reason attributed to the inaccuracy of these systems was the inability to adequately identify isolates more specific to animal specimens. The efficacy of commercial miniaturized biochemical systems to identify streptococci from animal specimens has also been examined. The success of this system to identify the isolates to species level was highly variable (71. Several Streptococcus species were particularly difficult to iden tify, including Streptococcus uberis. Although this organism is not currently in the data base of the system, 62 strains from bovine milk samples were tested, and four unique biocodes for this organism were generated. The rapid latex agglutination kits designed to identify streptococci from human specimens are also applicable for the identification of streptococci from animals. These kits include reagents for identification of groups C and G streptococci, which are commonly isolated from horses and dogs, respectively. Isolates of groups A, B, D, and F are also occasionally isolated from animal specimens. Once the bacteria are isolated in pure culture, these kits are very accurate for group typing of streptococci. With the additional tests recommended by the man ufacturer, the system correctly identified 81% of isolates to the genus level. The majority of the errors that were incurred were a result of biocodes not appearing within the codebook of the system. Although none of the numerical codes generated were in the current database, there were no discrepant results in 12 of 18 tests. After storage at -80°C for 40 days there was no substantial loss of viability com pared to baseline cultures for any of the species except P. Although storage in the trans port swab medium was considered useful if freezing of the specimen was necessary, tests were not carried out with freezing the specimen at -20°C, which is likely to be more common. In addition to being an important nosocomial pathogen in humans, Clostridium difficile is also the most common cause of neonatal diarrhea in piglets in the United States and can cause disease in other animal species. The authors concluded that the performance of all the assays was unacceptable as a single test and recommended that a twostep algorithm be used. Their ability to identify seven species of mycoplasma isolated from swine (Mycoplasma hyosynoviae, Mycoplasma argi nini, Mycoplasma solivarium, Mycoplasma hyorhinis, Mycoplasma flocculare, Mycoplasma hyopneumoniae, and Acholeplasma laidlawii) based on generated enzyme pro files was evaluated [74]. The standard for paratuberculosis diagnosis has been solid medium culture methods, which have been reviewed by Whipple et al. Therefore, culture of the agent is 100% specific, but is only about 50% sensitive [152]. Drawbacks are the probe is less sensitive than culture (limit of sensitivity is 104 M. However, the sensitivity of any antibody mediated test depends on the time course of the infection. Infections due to mycobacteria can also be identified by the skin reaction elicited following inoculation of the skin with an extract of the bacteria, and is due to the cell mediated immune response that follows mycobacterial infection. However, skin testing is not recommended for the diagnosis of paratuberculosis, due to low specificity. Mycobacterium bovis is the etiological agent of tuber culosis in cattle, and this pathogen is still a concern in domestic animals and for wildlife. Rapid serological antibody detection tests are available from Chembio Diagnostic Systems, Inc. Both appear to be useful in diagnosis of tuberculosis in elk, reindeer, and whitetailed deer.

Modification of therapy may result in a direct cost saving to the hospital [23 androgen hormone synthesis purchase cheap speman line,26] and lower mortality rates [23] man health care in urdu purchase speman with mastercard. Thus prostate 30cc order speman 60 pills on-line, automated systems have the potential to offer improved patient care in addition to labor savings androgen hormone sensitivity order speman online now, standardization of testing mens health protein buy speman 60 pills on line, reproducibility, and data management. Along with the advantages of automated systems, the purchaser should also be mindful of the limitations of each system. It has been common practice with commercial systems over the past two decades that following the pub lication and identification of a selective limitation with a pathogen and corresponding antimicrobial agent in an in vitro test panel, the manufacturer often voluntarily removes the panel from the market. In this chapter, each of the four current automated 416 Manual of Commercial Methods in Clinical Microbiology Table 22. The Vitek 2 measures changes in turbidity over time (growth curve), comparing a growth control well with wells containing various drug concentrations. The Vitek 2 instrument replaced the prior less automated Vitek 1 (Vitek Legacy) instrument over the period 1999­2010. In addition, three Vitek 2 Compact instruments are available with test card capacities of 15, 30, and 60 cards. The Vitek 2 system contains computer software to also deduce the susceptibility results for selected Gram positive bacteria (Staphylococcus spp. The Vitek 2 system incorporates test setup and sample veri fication with a Smart Carrier component. Optical reading of cards is performed every 15 min in the Vitek 2, with a multichannel fluorometer and photometer to record fluorescence, turbidity, and colorimetric signals. Susceptibility results are reported in 4­18 h, depending on the organism and susceptibility parameters. In a study of susceptibility testing of entero cocci, the Vitek 2 was evaluated with 150 clinical isolates of enterococci, which included vanA, vanB, and vanC strains and six species of enterococci [29]. The essential agreement results for ampicillin, vancomycin, teicoplanin, and highlevel gentamicin resistance were 93, 95, 97, and 97%, respectively. Among the seven antimicrobial agents tested, the Vitek 2 exhibited one very major error for teicoplanin, no major errors to any of the antimicrobials tested, and seven minor errors for teico planin. Results are obtained after 15 to 18 h by turbidimetric readings of overnight conventional panels and after 4. The Synergies plus Negative 96well panels were configured with 36 wells containing fluorogenic substrates for rapid organism identification (2. Since the rapid panels were no longer available at the time of writing this chapter, only the conven tional panels are listed in Table 22. The optional LabPro Alert System software incorporates the detection of unusual resistance results and incorporates institutionspecific infection prevention guidance into footnotes or comments for physician review. An evaluation of the MicroScan WalkAway system was conducted by Rittenhouse et al. The challenge panel included 17 enterococci and 15 staphylococci that were nonsusceptible to linezolid. Susceptibility results are determined in the Phoenix system by utilizing a resazurinbased redox dye as well as kinetic measurements of turbidity to detect bacterial growth in the presence of an antimi crobial agent. The panels are automatically incubated for up to 18 h, and the results are read and reported. Compared to a doubledisk diffusion reference method to detect inducible clindamycin resistance, the Phoenix showed a sensitivity of 100% and specificity of 99. In comparison to a broth microdilution reference method, the categorical agreement of the Phoenix panels ranged from 92 to 100% with one exception for viridians streptococci and penicillin, which was 87%. The overall categorical agreement of the Phoenix panel with the 13 antimicrobial agents studied was 99. Panel configurations are available for Gram positive and Gramnegative bacteria and are listed in Table 22. Antimicrobial susceptibility testing panels for diagnostic use employ a proprietary substrate (nonfluorescent) in the media used to suspend the bacterial isolate and perform panel inoculation. The panels were read by a Sensititre SensiTouch 422 Manual of Commercial Methods in Clinical Microbiology reader. The categorical agreement for antimicrobial agents with S, I, and R results ranged from 87. No significant major errors and 0% very major errors were encountered in the study. MicroScan AutoScan 4 In addition to the automated WalkAway plus system, MicroScan has a semiautomated instrument, the AutoScan 4. The panels are either inoculated manually or inocu lated with the MicroScan Renok instrument, which is designed for the hydration and inoculation of all types of MicroScan panels. After inoculation, the panels are manually loaded one at a time into the AutoScan 4 and read automatically. The AutoScan 4 has been used typically in smaller laboratories with a lower testing volume or has been used for the testing of supplemental antimicrobial agents. The choice of a test system may be influenced by the laboratory budget and available personnel. However, the upgrading of a manual system to a semiautomated or automated system may also depend on the need to handle a larger volume of tests and/or the need to provide rapid computerassisted reports. A computerassisted manual system provides the observer with a touch screen, keypad, or light pen to enter and record results. When the OptiRead is utilized, a fluorogenic substrate is added to the bacterial inoculum. Panels are incubated offline for 18 h and then loaded one at a time onto the Sensititre OptiRead instrument, where bacterial growth is detected by the presence of fluorescence. In the same study, 5233 Grampositive bacteria were evaluated and the overall category agreement was 98. Sensititre JustOne strips for the supplemental testing of a single antimicrobial agent are also available from Thermo Scientific. The agarbased methods traditionally have been set up and read manually, but within the past two decades, semiautomated commercial readers have been introduced to facilitate the rapid reading and recording of both the gradient diffusion and disk diffusion methods. Up to six Etest strips 424 Manual of Commercial Methods in Clinical Microbiology may be placed in the radial fashion on the inoculated plate. The plates are incubated overnight, and an elliptical zone of growth inhibition due to the antibiotic gradient formed in the agar is visualized. In an evaluation of vanco mycin susceptibility results for enterococci, Tenover and colleagues reported no very major or major errors with the Etest method [68]. The Etest yielded an essential agreement (within ±1 dilution) of 100% and a category agreement of 90. The overall categorical agreement of the Etest with the 13 antimicrobial agents studied was 99. Disks are also available from these manufacturers in Europe and also from i2a (Intelligence Artificielle Applications, Montpellier, France). Up to 12 commercial disks are placed on the inoculated agar surface and incubated at 35°C for 16­24 h. The disk diffu sion method, which has been used for over four decades, does not require instrumentation and therefore has the lowest reagent cost of performing susceptibility testing. Other potential advantages of this method include the flexibility to test new antimicrobial agents and the ability to detect resistant subpopulations of organisms. Disadvantages of the disk diffusion method are that it provides only qualitative S, I, R results, and it may not reliably detect intermediate or resistant categories for select antimicrobial agent and pathogen combinations [41]. A total of 368 clinical isolates, including 241 Gramnegative rods and 127 Staphylococcus spp. Chromogenic agars are formulated such that the organism to be identified accumulates and then enzymatically hydrolyzes a carbohydrate substrate complex, in the presence or absence of one or more selective agents. The list may not be inclusive, as there may be additional manufac turers and additional chromogenic media either available or in development in countries outside of the United States. Prior to inoculation onto the chromogenic media, swabs were individually incubated overnight in a selective enriched broth of brain heart infusion with 7% NaCl and 4 mg/mL oxacillin. The review showed that use of an enrichment broth prior to plating increased the sensitivity of the chromogenic media and that incubation beyond 24 h decreased specificity due to overgrowth of contaminating flora. The same study also tested both chromogenic agars against Enterobacteriaceae strains with defined mechanisms of resistance to lactam agents. The lower specificities (falsepositives) were mostly due to the growth of AmpCproducing Enterobacteriaceae, mainly Enterobacter spp. Girlich and colleagues tested 131 Enterobacteriaceae with reduced susceptibility to carbapenems against three chromogenic media [30]. Instrument (time to results) Cepheid GeneXpert System (1 h) BioFire Film Array (1 h) Verigene Sample Processor Verigene Reader (2. The test concludes with a highresolution meltcurve analysis, and the entire assay time is about 1 h. In the FilmArray analysis there were a total of 67 mecA results for Staphylococcus spp. An aliquot of each positive blood culture is placed into a nucleic acid extrac tion tray and inserted into the Verigene Sample Processor. The extracted nucleic acid is then automatically transferred into a test cartridge and hybridized to complementary nucleic acid capture probes immobilized on a glass micro array slide. The nucleic acid target sequence is detected using a second hybridization with a gold nanoparticle conjugated detection probe. The reading of the array is conducted in the Verigene Reader and the entire assay time is about 2. Also, there have been a few rapid commercial molecular test systems that have been impactful for earlier targeted patient therapy, but have been restricted to the detection of known antimicrobial resistance determinants from positive blood cultures. The pri mary approach has been the direct detection of modifica tions of the antibiotic molecule itself causing a mass shift due to bacterial degradative enzymes, such as hydrolysis of a lactam ring [10,33,48,66]. The method is facilitated by the use of nucleic acid dyes that only permeate dead bacteria, and the proportion of dying cells after exposure to an antibiotic can be rapidly assessed [65,72]. Vibrating cantilevers containing bacterial cells is another new methodology that has been studied for the detection of antimicrobial resistance [31,44,72]. Cantilevers are structures that are anchored at one end, and these devices can be constructed with small fluidic pathways that allow bacterial passage. Following exposure to an antibiotic, the density of bacteria changes and this can be measured in cantilevers that vibrate continuously. In this system, magnetic beads coated with bacterial antibodies are incubated with a bacterial broth suspension and then exposed to a revolving magnetic field to detect the change in the frequency of rotation of the beads with and without the addition of antimicrobial agents. The hanging drop approach has the advantage of substan tially reducing the test volume and reducing the time to result [63]. A recent study evaluated a realtime automated optical screen ing method based on timelapse imaging of multiple bacteria­antimicrobial agent combinations [28]. After a process of electrostatic immobili zation of live bacterial cells, test solutions with and without antimicrobial agents were added to individual channels of the cassette, and microscopic darkfield images of progeny clones were analyzed as timelapse images. The image analysis software was then able to generate growth probability scores based on the rate of a progenitor cell growing into a clone of daughter cells. The method of automated microscopy using accelerated population analysis profiles was also able to differentiate heterogeneous vancomycin intermediate S. In the future, new test systems that are capable of performing rapid detection of the cumulative effects on bacterial cells due to multiple mechanisms of resistance (heteroresistance) will correlate more closely with the present phenotypic growthdependent measurements of resistance, and these types of tests may have the opportu nities to be the next generation systems for antimicrobial susceptibility testing. An additional challenge will be the development of extensive databases to support the next generation systems. Clinical evaluation of the FilmArray blood culture identification panel in identification of bacteria and yeasts from positive blood culture bot tles. Comparison of the Etest to agar dilution, broth microdilution, and agar diffusion susceptibility testing techniques by using a special challenge set of bacteria. Clinical and financial benefits of rapid bacterial identification and antimicrobial suscepti bility testing. Using matrixassisted laser desorption ionizationtime of flight mass spectrometry to detect carbapenem resistance within 1 to 2. Comparison of B Phoenix and bioMérieux Vitek 2 automated systems for the detection of macrolide­lincosamide­streptogramin B resistance among clinical isolates of Staphylococcus. Multiplex identification of Grampositive bacteria and resistance determinants directly from positive blood culture broths: evaluation of an automated microarraybased nucleic acid test. Chip calorimetry for fast and reliable evaluation of bactericidal and bacteriostatic treatments of biofilms. Validation of the automated reading and incubation system with Sensititre plates for antimicro bial susceptibility testing. Matrix assisted laser desorption ionizationtime of flight mass spectrom etry: a fundamental shift in the routine practice of clinical microbiology. Methods for Antimicrobial Dilution and Disk Susceptibility Testing for Infrequently Isolated or Fastidious Bacteria, 2nd edn. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically, 9th edn. Automated and Manual Systems for Antimicrobial Susceptibility Testing of Bacteria 431 23 Doern G. Clinical impact of rapid in vitro susceptibility testing and bacterial identification. Analysis of the comparative workflow and performance charac teristics of the Vitek 2 and Phoenix Systems. The clinical impact of automated suscepti bility reporting using a computer interface. Multilaboratory study of the Biomic automated wellreading instrument versus MicroScan WalkAway for reading MicroScan antimicrobial susceptibility and identification panels.

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Any patient with such a rash requires urgent investigation and the involvement of senior 22 Chapter 3: Emergency dermatology colleagues prostate zoloft buy cheap speman 60 pills on line. Note prostate cancer metastasis to bone order speman with paypal, too prostate cancer foods purchase speman 60 pills amex, that a strong clinical suspicion of bacterial meningitis is one situation in which immediate treatment of disease takes precedence over investigations mens health hrithik roshan buy speman 60 pills on-line. Surgical debridement (which sometimes means amputation of part/ all of a limb) is always indicated radiation oncology in prostate cancer munich buy generic speman, combined with postoperative highdose intravenous antibiotics. A typical history consists of preceding malaise and fever in a patient known to have atopic dermatitis, followed by a widespread vesicular rash that quickly breaks down to leave eroded areas. Patients can become systemically unwell, and a small number of cases develop a viraemia and/or meningoencephalitis. Management is hospitalbased and involves general supportive measures, such as intravenous fluids and antipyretics, but definitive treatment is with intravenous antiviral therapy in the toxic patient (it is reasonable to use oral aciclovir in the afebrile patient). It is common practice to give broadspectrum antibiotic cover to stop superimposed bacterial infection. Crucially, if there is any evidence of ocular involvement, early ophthalmological review is essential. Necrotizing fasciitis Necrotizing fasciitis is an extremely dangerous condition that can be very difficult to diagnose, as sometimes very little can be seen from a surface inspection. There are two forms of the condition: type 1 is caused by aerobic and anaerobic bacteria and is often seen postoperatively; type 2 is caused by a group A streptococcus and can arise spontaneously in healthy individuals. In both cases, the infection spreads beyond the subcutis into underlying fascia and muscle; this is deeper than simple cellulitis infection and, contrary to popular belief, the two are not a continuum. Clinically affected areas are usually disproportionately painful compared with the other findings (although occasionally the area may become anaesthetic). The patient may also be much more toxic than apparently justified by the clinical signs. One sign that may be extremely useful in identifying this condition is the presence of crepitus or visible evidence of gas on a plain Xray (both of which indicate a gasforming organism in the soft tissues). Excruciating pain with no obvious cause, with or without crepitus or subcutaneous gas pockets on a plain Xray, requires the involvement of senior colleagues because urgent surgical intervention is essential. Intravenous antibiotics used alone are Angioedema (and anaphylaxis) Angioedema is usually a type I hypersensitivity reaction characterized by swelling of the dermis, subcutaneous tissues and mucosae. Triggers can be allergic or nonallergic, but the final pathway in both cases is the release of inflammatory mediators, such as histamine, from mast cells, causing fluid to Chapter 3: Emergency dermatology 23 Table 3. A similar process occurs in urticaria, but here only superficial vessels in the upper dermis are affected. The same picture can also result from non immunoglobulin E (IgE)mediated reactions. The key issue in managing a patient with angioedema is to assess the airway and ensure that it remains patent. It must also be pointed out that skin and mucosal changes are subtle/absent in 20% of reactions. Most importantly, given the lifethreatening nature of angioedema and anaphylaxis, while carrying out your initial assessment and management, it is imperative to involve senior doctors (including an anaesthetist) so that they are aware of the problem and will be able to help, especially if initial management is unsuccessful. It is a blistering disorder caused by the haematogenous dissemination of exfoliative toxins that cleave desmoglein 1, which are produced by some types of staphylococci. Treatment is with intravenous antibiotics and general supportive measures such as intravenous fluids and good nursing and nutritional care. Final word Dermatological emergencies need early identification and prompt management by experts, and nobody will expect junior doctors to manage these complicated conditions on their own. However, basic knowledge of these disorders will enable them to initiate swift and appropriate action, and it is speed of intervention that proves lifesaving in most cases. Occasionally, other bacteria are implicated in cellulitis ­ Haemophilus influenzae is an important cause of facial cellulitis in children, often in associa tion with ipsilateral otitis media or a sinus infection. In immunocompromised individuals, a variety of bacteria may be responsible for cellulitis. Cellulitis frequently occurs on the legs, but other parts of the body may be affected ­ the face is a com mon site for erysipelas. The organisms may gain entry into the skin via minor abrasions, or fissures between the toes associated with tinea pedis, and leg ulcers pro vide a portal of entry in many cases. A frequent predis posing factor is oedema of the legs, and cellulitis is a common condition in elderly people, who often have leg oedema of cardiac, venous or lymphatic origin. The skin is tight and shiny, blister forma tion and areas of skin necrosis may occur. It is rarely bilateral and, if both legs are red and swollen, especially in the absence of a fever and malaise, consid eration should be given to other diagnostic possibilities, such as lipodermatosclerosis (see Chapter 17). In presumed streptococcal cellulitis penicillin +/- flucloxacillin is generally recommended, initially given intravenously. This disorder achieved notoriety a few Dermatology Lecture Notes, Eleventh Edition. Mild folliculitis can be treated with a topical anti bacterial agent, but if it is extensive, a systemic antibi otic may be required. Once the necrotic central core has been discharged, the lesion gradually resolves. In some patients, boils are a recurrent problem, but this is rarely associated with a significant underlying dis order. Such individuals may be nasal or perineal car riers of staphylococci, and organisms are transferred on the digits to various parts of the body. Patients suffering from recurrent boils should have swabs taken from the nose for culture, and if found to be carrying staphylococci should be treated with a topical antibacterial such as mupirocin, applied to the nostrils. Some patients have recurrent episodes of cellulitis, each episode damaging lymphatics and leading to fur ther oedema. Carbuncle A carbuncle is a deep infection of a group of adjacent hair follicles with S. Initially, the lesion is a domeshaped area of tender erythema, but after a few days suppuration begins and pus is discharged from multiple follicular orifices. Carbuncles are usually encountered in middleaged and elderly men, and are associated with diabetes and debility. Staphylococcal infection Folliculitis Infection of the superficial part of a hair follicle with Staphylococcus aureus produces a small pustule on an erythematous base, centred on the follicle. The crusts eventually separate to leave areas of erythema, which fade without scarring. These rupture very easily (indeed, there may be none visible) to leave exudation and crusting, and the stratum corneum peels back at the edges of the lesions. Streptococcal impetigo may be associated with post streptococcal acute glomerulonephritis. Impetigo may occur as a secondary phenomenon in atopic eczema, scabies and head louse infection. In localized infection, treatment with a topical antibiotic such as mupirocin will suffice, but in more extensive infection, treatment with a systemic antibiotic such as flucloxacillin or erythromycin is indicated. Erythrasma Caused by a Grampositive organism, Coryne bacterium minutissimum, erythrasma occurs in inter triginous areas ­ axillae, groins and submammary regions. However, the most common site is the toe web spaces, where it produces a macerated scaling appear ance identical to that caused by fungal infection. Chapter 4: Bacterial and viral infections 27 Scrofuloderma Scrofuloderma results from involvement of the skin overlying a tuberculous focus, usually a lymph node, most commonly in the neck. Lupus vulgaris the majority of lesions of lupus vulgaris occur on the head and neck. The natural course is gradual peripheral extension, and in many cases this is extremely slow, occurring over a period of years. Lupus vulgaris is a destructive process, and the cartilage of the nose and ears may be severely damaged. There is a risk of the development of squamous cell carcinoma in the scar tissue of longstanding lupus vulgaris. Warty tuberculosis Warty tuberculosis occurs as a result of direct inoc ulation of tubercle bacilli into the skin of someone previously infected, who has a high degree of immunity. It is commoner on the lower legs and feet but may develop on the buttocks and thighs as a result of sitting on ground contaminated by infected sputum. These are terribly rare and probably result from haematog enous dissemination of bacilli in individuals with a moderate or high degree of immunity. This usually presents as a solitary nodule, caused by inoculation of Mycobacterium marinum into the skin via an abrasion sustained while swimming or while cleaning out an aquarium ­ often after the demise of the fish contained therein. Leprosy has a wide distribution throughout the world, with most cases occurring in the tropics and subtropics, but population movements mean that the disease may be encountered anywhere. Leprosy is a disease of peripheral nerves, but it also affects the skin, and sometimes other tissues such as the eyes, the mucosa of the upper respiratory tract, the bones and the testes. The incubation period is lengthy, probably several years, and it is likely that most patients acquire it in childhood. A low incidence of conjugal leprosy (leprosy acquired from an infected spouse) suggests that adults are relatively non susceptible. The disease is acquired as a result of close physical contact with an infected person, the risk being much greater for contacts of lepromatous cases ­ the nasal discharges of these individuals are the main source of infection in the community. Tuberculoid When cellmediated immunity is well developed, tuberculoid leprosy occurs, in which skin and periph eral nerves are affected. Thickened branches of cutaneous sensory nerves may be palpable in the region of these lesions, and large peripheral nerves may also be palpa ble. If the pos sibility of leprosy enters into the discussion of differential diagnosis in the clinic, the eponymous title should always be used, because the fear of leprosy is so ingrained, even in countries where it is not endemic. Chapter 4: Bacterial and viral infections 29 shows granulomas, and bacilli are not seen. Lepromatous When the cellmediated immune response is poor, the bacilli multiply unchecked and the patient develops lepromatous leprosy. The bacilli spread to involve not only the skin, but also the mucosa of the respiratory tract, the eyes, the testes and the bones. Histology shows diffuse granulomas throughout the dermis, and bacilli are present in large numbers. Viral infections Warts Mr Lely, I desire you would use all your skill to paint my picture truly like me, and not flatter me at all; but remark all these roughnesses, pim ples, warts, and everything as you see me, other wise I will never pay a farthing for it. There is no absolute diagnostic test for leprosy ­ the diag nosis is based on clinical and histological features. Patients with disease at the tuberculoid end of the leprosy spectrum (paucibacillary) are treated with a combination of monthly rifampicin and daily dapsone for 6 months, while those at the lepromatous end (multibacillary) are treated with monthly doses of rifampicin and clofazimine and daily dapsone for 24 months. Preparations containing salicylic acid are often quite effective, and a wart paint should cer tainly be used for at least 3 months before alternative treatment is considered. The agent of choice is liquid nitrogen, which can either be applied directly the leprosy spectrum Tuberculoid · One or two skin lesions only. There are often numerous tiny black dots produced by thrombosed capillaries (not seen in this example). The aim is to achieve complete freezing of the wart and a narrow rim of surrounding skin. This is a painful procedure, and should not be inflicted on children ­ most tiny tots will, sensibly, retreat under the desk protesting loudly at the first sight of the nitrogen evaporating in its container. Multiple warts usually require more than one application, and the optimum interval between treatments is 2­3 weeks. The typical appearance is of a small area of thickened skin, which, when pared away, reveals numerous small black dots produced by thrombosed capillaries. They must be distinguished from calluses and corns, which develop in areas of friction over bony prominences. Calluses are patches of uniformly thickened skin that generally retain normal superfi cial skin markings (which warts do not), and corns have a painful central plug of keratin that does not contain capillaries. Treatment is with wart paints or cryotherapy, after paring down overlying keratin. They often occur in lines, due to inoculation of the virus into scratches and abrasions. Plane warts are extremely difficult to treat effectively, and attempts at treatment may do more harm than good. Chapter 4: Bacterial and viral infections 31 Genital warts (condylomata acuminata) In recent years, the importance of certain types of genital wart viruses in the aetiology of penile and cervical cancer has been recognized, and this has modified attitudes to what was previously considered a minor sexually transmitted inconvenience. If genital warts are seen in a child, the possibility of nonaccidental injury and/or sexual abuse should be considered and appropriate inquiries undertaken. These lesions resolve spontaneously, and in infants and small children are best left alone to do so. However, if parents of small children are anxious, they can be advised to squeeze each lesion between the thumbnails to express the central plug ­ this will often speed their resolution. In older children and adults, mol luscum contagiosum can be treated by cryotherapy. It is usu ally seen in people who bottlefeed lambs and in butchers and abattoir workers who handle the car casses of sheep. The diagnosis can be confirmed by electron Molluscum contagiosum the lesions of molluscum contagiosum are caused by a poxvirus. This lesion is in a typical site; the young woman concerned had been bottlefeeding lambs. Orf lesions resolve spontaneously in 6­8 weeks, but the disease may act as a trigger for erythema multiforme (see Chapter 16). Hand, foot and mouth disease this is not related to foot and mouth disease of sheep and cattle, but is a harmless disease caused by Coxsackie virus infection, usually type A16. Following a primary infection, the virus settles in sensory ganglia, and may be triggered to produce recurrent lesions by a variety of stimuli. However, neither has rigid territorial demarca tion, and lesions anywhere may be caused by either type. Recurrent herpes simplex Recurrent cold sores on the lips (herpes labialis) are common.

Dermatomyositis is an autoimmune inflammatory disease of skin and muscle that may occur in child hood or in adult life prostate cancer 5-alpha reductase inhibitors discount 60 pills speman with amex. There are differences in the man ifestations of the disease in these two age groups androgen hormone qui speman 60 pills buy free shipping. Vasculitis and the late development of calcinosis are features of the childhood disease that are not seen in adults prostate drugs buy 60 pills speman visa. In some adults prostate oncology questions buy 60 pills speman free shipping, dermatomyositis is associated with systemic malignancy prostate ultrasound biopsy procedure cheap speman 60 pills buy line, whereas there is no asso ciation with malignancy in the childhood disease. The main features are the occurrence of recurrent miscarriage, venous throm boses, cerebral infarcts, thrombocytopenia and livedo reticularis and cutaneous necrosis. These clinical abnormalities are associated with the presence of anticardiolipin antibodies and lupus anticoagulant (subsets of antiphospholipid antibodies). Neonatal lupus erythematosus Neonatal lupus is associated with transplacental pas sage of maternal antiRo and antiLa antibodies. Its features include skin lesions, thrombocytopenia, hepatosplenomegaly and complete heart block. Muscles In some cases, there is little evidence of any muscle disease, whereas in others there is profound muscle weakness. Typically, there is symmetrical weakness and wasting of proximal muscle groups, leading to difficulty combing the hair or standing up from a sit ting position. Other systemic features include interstitial pulmo nary fibrosis and cardiac disease (usually manifest as rhythm disturbance or conduction defects). The reported frequency of malignancy in associa tion with adult dermatomyositis varies widely between 160 Chapter 18: Connective tissue diseases series of patients, but the incidence seems to be higher in older individuals. Morphoea Morphea is a disorder of unknown aetiology in which there is sclerosis of the skin. Treatment In dermatomyositis associated with malignancy, there is usually marked improvement when the neo plasm is excised. The mainstay of therapy is oral corticosteroids, often in combination with immunosuppressives such as azathioprine, methotrexate or cyclophos phamide. Where there is severe muscle involve ment, physiotherapy is an important adjunct to drug therapy, in order to minimize contractures. Eventually, usually after many months, the sclerosis resolves, leaving atrophic, hyperpigmented areas. Classification of scleroderma · Morphoea: sclerosis of the skin without systemic involvement. Chapter 18: Connective tissue diseases 161 Linear Linear morphoea usually affects one limb, often extending its full length. In childhood, it can signifi cantly impair the growth of the limb and produce severe flexion deformities of large joints and digits. Frontoparietal (en coup de sabre) Resembling a sabre cut across the scalp and forehead, this type of morphoea is a considerable cosmetic problem. A linear, depressed, sclerotic area extends from the face into the scalp, and is associated with loss of hair along its length. Flexion contractures restrict limb move ment, and if the chest is severely affected, breathing may be impaired. The gastrooesopha geal sphincter mechanism is also impaired, leading to gastrooesophageal reflux, oesophagitis and eventual stricture formation. Atrophy and fibrosis of the smooth muscle of the small bowel lead to impaired peristalsis, and the resultant relative stagnation of small bowel contents predisposes to bacterial overgrowth as colonic bac teria move upstream into the small intestine. Gut bacteria deconjugate bile salts (which are essential for micelle formation), and this leads to fat malab sorption and steatorrhoea. Occasionally, patients present with a picture simulating acute intestinal obstruction. Similar pathology affects the large bowel and leads to the formation of multiple widemouthed pseudodiverticula. In linear morphoea on the limbs, physio therapy is essential to maintain joint motility, and orthopaedic surgery may be necessary. Plastic sur gery can be of considerable cosmetic benefit in fron toparietal morphoea. Pulmonary An inflammatory alveolitis is followed by pulmo nary fibrosis, and disease of small pulmonary arter ies leads to pulmonary hypertension and cor pulmonale. These infarctive changes lead to progressive pulp atrophy and resorption of the underlying terminal phalanges. It is a disorder in which sclerotic changes in the skin occur as one component of a multisystem disorder associated with a vasculopathy of small arteries. Systemic involvement Gastrointestinal Dysphagia is the result of oesophageal involvement. Renal Fibrinoid changes in arteries and arterioles are asso ciated with proteinuria and hypertension. Renal involvement is usually mild, but in some cases it is severe and rapidly progressive, and leads to renal failure. Treatment No therapy is known to alter the overall course of sys temic sclerosis, but many components of the disease may be helped significantly by specific measures. Patients with oesophageal reflux should avoid lying flat, and treatment with proton pump inhibitors may be very effective. Broadspectrum antibiotics are help ful in treating patients with gut bacterial overgrowth and malabsorption. In interstitial pulmonary disease, cyclo phosphamide is effective, and bosentan is of benefit for pulmonary arterial hypertension. Nervous system Neurological involvement is uncommon, but carpal tunnel syndrome and trigeminal neuropathy have been reported. Hepatic There is a significant association between systemic sclerosis and primary biliary cirrhosis. Prognosis Severe pulmonary or renal involvement is a poor prognostic factor, although treatment is improving, but most patients with systemic sclerosis live for many years. Musculoskeletal Arthralgia and arthritis occur in some patients, and myopathy and inflammatory myositis may also occur. A number of other chemicals may induce diseases mimicking sys temic sclerosis, including perchlorethylene and trichlo rethylene (solvents used in dry cleaning) and bleomycin. A disorder similar to systemic sclerosis occurred in 1981 in people poisoned by contaminated rapeseed oil sold as cooking oil in Madrid. Nephrogenic systemic fibrosis this disorder has been described in recent years and occurs in association with renal insufficiency and exposure to gadoliniumbased contrast media. Ill defined, indurated plaques occur on the trunk and limbs, and joint contractures also occur. Pseudoscleroderma Sclerodermalike changes may be seen in a number of unrelated conditions, including porphyria cutanea tarda, carcinoid syndrome and phenylketonuria. Everyone has experienced shortterm, localized itch, and there is a perverse joy in having a really good scratch. Itching may be restricted to one or more sites, or may cover virtually the whole body surface. It may creep about, appearing first on an arm and later on the back, or in more than one site simultaneously. Especially itchy are the eczemas, lichen planus, insect bites and infestations, urticaria and dermatitis herpetiformis. Mechanisms of pruritus We do not clearly understand why skin diseases itch, and we know very little about irritation in otherwise apparently normal skin. The sensation that we call itch is produced, conditioned and appreciated at several levels in the nervous system: stimulus, mediators and receptors, peripheral pathways, central processing and interpretation. A wide variety of stimuli can induce an itch, including a number of chemicals, especially histamine, prostaglandins and some proteinases. However, itch most often occurs without the obvious involvement of any of these, and although histamine can induce itch without producing weals, nonsedative antihistamines have no effect on simple pruritus. Interestingly, many itchprovoking stimuli induce pain if applied at higher intensities, and scratching appears to induce pain and thereby abolish irritation, as do other sensory stimuli. More complex, central mechanisms may also be important in modulating and appreciating pruritus. Itching can definitely be affected by higherlevel brain activity: it is much less apparent when the mind is fully occupied and much worse when boredom sets in. However, in many instances there are considerable secondary skin changes from scratching. Subtle changes are easily obscured by scratching: a classic example of this is scabies (see Chapter 6). A full history and a careful examination of the skin are therefore important in all patients complaining of itching. Many patients who develop this kind of localized itching will admit to coping poorly with stress. Two very important and troublesome forms of localized pruritus are lichen simplex chronicus and prurigo and anogenital pruritus. Prurigo nodules may accompany areas of lichen simplex or appear separately almost anywhere; they are frequently multiple. Treatment this depends upon the cause, but avoiding irritants and using nonsoap cleansers is important in all patients. Treatment Potent topical steroids (sometimes under occlusive bandages) may help, but the problem often recurs. Anogenital pruritus Two very common forms of localized itching (and also the least talked about) are pruritus ani and pruritus vulvae. However, although haemorrhoids and tags are often present, and they may contribute to chronic faecal leakage, their treatment alone does not always relieve the symptoms. The problem is also often dismissed as psychological, but only rarely is this the complete explanation. Attention to irritant factors and symptomatic relief of inflammation is important. A swab for candida should always be taken, and any evidence of infection treated accordingly. Aetiology Pruritus ani is probably largely a lowgrade irritant reaction to faeces, sweat and discharge; sedentary occupations make matters worse. Generalized pruritus Persistent generalized pruritus is extremely unpleasant, and can either affect most of the body surface continuously or involve several different areas. Clinical features Skin changes vary considerably, from nothing to see at all to mild flakiness of the skin with a few scratch marks to a skin covered in excoriations, scars and Chapter 19: Pruritus 167 nodules. Although there may be no identifiable underlying disorder, all patients with generalized irritation should be investigated, because a number of potentially remediable systemic disorders may be responsible. Cancers Lymphoreticular malignancies are particularly prone to cause itching, but pruritus may also occur in association with a variety of carcinomas. Pregnancy (see Chapter 16) Drugs Various agents induce itching, but the mechanisms are poorly understood. Diabetes mellitus You may come across lists quoting diabetes as a cause of itching, but we do not consider it to be so. Psychological factors When everything else has been excluded, psychological factors may be considered. The most common underlying problem is an anxiety neurosis, but patients with monodelusional psychoses such as parasitophobia also itch. These individuals, however, offer their own explanation only too readily (see Chapter 21)! Polycythaemia rubra vera is characteristically associated with itching triggered by bathing. If these tests are negative initially, and if the pruritus persists, repeat at intervals. Irritation may precede the development of other features of cholestatic liver disease, especially in primary biliary cirrhosis. Chronic renal failure Unfortunately, the intractable itch of renal failure is largely unaffected by dialysis. Parathyroidectomy is said to help, but the benefit is shortlived and is hardly justified in most patients. When no apparent underlying reason can be found, a topical steroid and a sedative antihistamine, such as hydroxyzine, may help. Sedative antihistamines often cause excessive drowsiness and confusion, and topical steroids are of limited use. Care has to be taken, however, as these agents can make both the patient and their surroundings very slippery! Increased frequency of washing and the use of harsh soaps and detergents make matters worse, both by removing surface lipids and by acting as direct irritants. The patients (and their carers) are often anxious and miserable, but this is usually secondary to the irritation rather than a primary cause. Robert Urich, actor the skin may be involved directly or indirectly in a number of systemic disease processes, and can provide visible diagnostic clues that may lead to the discovery of internal disease. Cutaneous infection Mucosal candidiasis ­ particularly balanoposthitis and vulvovaginitis ­ and carbuncles occur more frequently in people with diabetes. Endocrine disease Diabetes There are a number of cutaneous manifestations of diabetes (see box). Necrobiosis lipoidica Lesions of necrobiosis lipoidica characteristically occur on the shins, although they may develop elsewhere. Potent topical steroids and intralesional steroid injections are among several treatments suggested for necrobiosis lipoidica, but the results of therapy are not very impressive. Diabetic bullae In this uncommon blistering disorder of people with diabetes, subepidermal bullae occur on the hands and feet. Xanthomas Hyperlipidaemia in uncontrolled diabetes may be associated with the development of multiple small, yellow, eruptive xanthomas. Lipoatrophy Partial or generalized cutaneous lipoatrophy is associated with insulinresistant diabetes. Cheiroarthropathy Cheiroarthropathy is a sclerodermalike thickening of the skin of the hands in people with type 1 diabetes.

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