By T. Ortega. Edgewood College. 2019.
Instead buy discount forzest online impotence depression, it remains the same and has brought in the argument of reoxygenation of the tumor cells during frac- tional radiation therapy generic 20 mg forzest otc erectile dysfunction daily medication, provided sufﬁcient time is allowed for this to happen buy generic forzest on line erectile dysfunction medication new zealand. This phenomenon has an important implication in radiation therapy in that even though the proportion of hypoxic cells remains the same, the total number of hypoxic tumor cells will be killed by radiation over time, thus leading to a successful treatment. The mechanism of reoxygenation has been attributed to the fact that as the tumor shrinks in size, surviving cells that were previously deprived of oxygen diffusion due to distal location 244 15. Radiation Biology of the blood vessels ﬁnd themselves closer to the blood supply and so reoxygenate. When cells are treated with these drugs for several days before irradiation with x- or g-rays, cells become highly sensitive to radia- tion. For optimal therapeutic gain in radiotherapy, patients should be treated for a period of time extending over several cell cycles to maximize drug incorporation into the cells. Others Radiosensitizers such as actinomycin D, puromycin, methotrexate, and 5- ﬂuorouracil have been successfully used in combination with radiation to treat cancer. Whether these agents truly increase radiosensitivity or are simply toxic to the cells is still not clear. Investigators have been trying to explore radiosensitizing chemicals to substitute for oxygen that requires the use of a high-pressure technique. Metronidazole (Flagyl), having a structure with high electron affnity, is a good radiosensitizer for hypoxic cells. Another useful radiosensitizer for hypoxic cells is misonidazole, which also has high electron affnity. Mis- onidazole is almost ten times more effective than metronidazole in sensi- tizing hypoxic cells. Another radiosensitizer of this kind is etanidazole, which is less toxic than misonidazole, and has great potential in radio- therapy. These agents protect normal cells from radia- tion damage by combining with free radicals that are produced by radia- tion and would be toxic to normal cells. However, these compounds cause severe adverse reactions such as nausea and vomiting. Experimental evidence showed that Classiﬁcation of Radiation Damage 245 these products concentrate more in normal cells and less in tumor cells. As a result, normal cells are protected better than tumor cells if these agents are administered immediately before the radiation dose is given. Expo- sure of cells to 100 to 1000rad (100 to 1000cGy) causes delay in the G2 phase to M phase transition. An exposure of 1000rad (1000cGy) inhibits the progression of the S phase cells by 30%, whereas the S phase to G2 phase transition is not affected by such an exposure (Prasad, 1995). Classiﬁcation of Radiation Damage Cell death is a measure of extreme radiation damage. All these damages are relevant in clinical radiation therapy as to the effective- ness of treatment. Sublethal damage occurs in mammalian cells, when a radiation dose is given in fractions at different time intervals rather than a single dose. Repair involves the healing of the radiation-induced damage in the time interval between the two fractions of the dose. If the second dose is applied too soon after the ﬁrst application, the damage does not have enough time to repair and the cell will die. In the redistribution process, the cells are desynchronized and sensitized to show increased damage. Following irradiation, the radiosensitive cells will die, and one would expect the proportion of radioresistant cells and hence the surviving fraction to increase. Regeneration is a mechanism of response to depopulation of a cell cohort due to radiation damage, and depends on the types of tissue and their proliferating capacity. Protracting a fractionated dose should be beneﬁcial to normal tissues and somewhat harmful to regenerating tumor cells. Reoxygenation discussed earlier is an effect that makes the hypoxic cells more radiosensitive in the presence of oxygen in fractionated radiotherapy. Sublethal damage repair depends very much on the dose rate and in which stage of the cell cycles the cells are. For example, the testis of male rats is most radiosensitive, whereas the small intestine seems to be less affected by radiation. The repair is signiﬁcant with x-rays and g-rays and almost nonex- istent for neutrons and a-particles. For example, the survival of the HeLa cells increased after irradiation, when the cells were treated with excess thymidine or hydro- xyurea for a period of 4hr. Stochastic and Deterministic Effects Two categories of radiation effects on biological systems are encountered: stochastic and deterministic. Stochastic effects are the biological effects that occur randomly, the probability of which increases with increasing dose without a threshold. Radiation-induced hereditary effects and cancer inci- dences are examples of stochastic effects. The assumption of no threshold is made on the belief that radiation damage to a few cells or a single cell could theoretically induce the genetic disorder or cancer, and the severity of the disease will be the same, if it ever occurs. Acute Effects of Total Body Irradiation 247 The deterministic or nonstochastic effects are induced by high radiation doses and the severity of the damages, rather than their probability of occurrence, increases with the dose. Cataracts, skin erythema, sterility, and ﬁbrosis are examples of deterministic effects induced by high radiation doses. Acute Effects of Total Body Irradiation Different tissues of the body respond differently to radiation, due to varying degrees of radiosensitivity. When an adult subject is irradiated over the entire body, various syndromes are manifested depending on the dose applied. The effects of radiation are characterized by the survival time of the species and various stages of acute syndromes following the total- body irradiation. Cell survival time varies with mammal species depending on the indi- vidual radiosensitivity. Acute radiation syndromes appear in four stages: prodromal, latent, manifest illness, and recovery or death. A minimum of 200 to 300rad (200 to 300cGy) is required for all four stages to be seen and can cause death. In the prodromal stage, major symptoms are nausea, vomiting, and diarrhea and they occur in the early phase, lasting for only a short period of time depending on the dose. In the latent stage, biological damage slowly builds up without manifestation of any syndromes, again lasting for hours to weeks, depend- ing on the dose. During the manifest illness stage, radiation syndromes appear as a result of the damage to the organs involved after the latent period, and the subject becomes ill. Hemopoietic Syndrome Hemopoietic or bone marrow syndromes appear at a total body dose of 250 to 500rad (250 to 500cGy) following irradiation. Also, the number of lymphocytes are greatly depressed, whereby the immune system of the body is sup- pressed.
Such people tend to perceive deafness as participants order forzest 20mg online erectile dysfunction drugs medications, three (2%) did say they would consider having a burden or disadvantage buy forzest 20 mg visa erectile dysfunction doctor boston, and one they were inclined to view as prenatal diagnosis with selective termination of a hearing foe- a struggle to live with order cheap forzest on line erectile dysfunction causes cancer. Despite the negative picture created about tus, since they preferred to have deaf children (39,40). Culturally reaction is somewhat extreme, and it is difﬁcult to say whether, Deaf participants are particularly optimistic about their situation in reality, anyone would choose such a course of action. How- and feel that being deaf is not a disability and also not something ever, what this does demonstrate is the extent of the feelings of that genetic technology needs to interfere with. This shows that Deaf cultural solidarity that some Deaf people have, and also deafness is not a condition that is clearly detrimental. Indeed to be hearing in this instance would be a disad- of deafness, for example, by population carrier screening, vantage. This ﬁts in with previous literature already genetic testing added onto the Newborn Hearing Screening documented that shows some deaf parents prefer to have deaf Programme or mass-scale availability of prenatal testing for children (14,18,39,40,55,56). All such people are directly affected by such programmes and have valuable insight to offer about the potential impact of this. Summary proﬁle of parents Appropriate and effective clinical services for deaf people can be developed as long as health professionals take the time interested in prenatal testing to learn about the diversity of cultural attitudes held by differ- for deafness ent people affected by deafness (66). Genetic counselling ser- vices require a specialist knowledge of deafness, Deaf culture, The author has also documented the attitudes of parents of deaf and the role that genetics has played within history (67). It is children towards many different aspects relating to the deafness also imperative that communication and language differences in the family (11). Training in Deaf Awareness would be valuable ﬁle of the type of person who may choose to have prenatal for any health professional wanting to work in this area. In summary, deaf parents of deaf children who were interested in prenatal diagnosis for deafness (because they wanted to avoid passing deafness on) were more Acknowledgements likely to prefer to have hearing children, see their deaf children as disadvantaged, feel an actual burden of having a child who is I would like to acknowledge the input of Prof Jenny Hewison deaf, and want a cure for deafness in their child. Even though it is ents interested in prenatal diagnosis for deafness were more nearly 10 years since we worked together I am still inﬂuenced likely to consider termination for deafness as acceptable, to ﬁnd by their wisdom. For example, if parents were able to see their child as ease: a British Study of families attending a genetic counseling ser- advantaged or less of a burden, or if they felt that communica- vice. Attitudes of deaf people and their families towards issues surrounding genetics 171 3. Aetiologic diagnosis in hearing-impaired children - chological Implications of the New Human Genetics. Parents’ attitudes towards genetic testing and the gene mutations—molecular and audiological ﬁndings. Aetiology of bilateral sensorineural hearing impairment Acad Sci 1991; 630:236–239. Opposition from deaf groups to the cochlear born Hearing Screening Programme, London, 3rd Sept, 2002. Am J Hum Genet “Delivering genetic information sensitively across culture” Nurs 1998; 63:1175–1180. More recently, Zoll (7) has suggested that genetic language disorders A communication disorder is an inability to understand and/or may be linked to a gene localised at 7q31. For the majority of Dyslexia, also a language problem, is known to be inherited communication disorders, we do not understand the cause. Phonological language disorders, also, have been shown know that many result from hearing impairment, intellectual to be more common among children whose parents had such disabilities, cerebral palsy, mental retardation, and cleft lip disorders than among controls (10). The presence of a genetic component of a disease can be dif- Over the past 10 years, there has been considerable progress ﬁcult to identify. Evidence supporting a genetic component in human genetics, and the mechanisms by which genetic includes familial clustering of cases, increased incidences of con- defects can cause speech, language, hearing, cognitive, and sanguineous mating (i. Later, she and her dren or siblings of affected individuals, and concurrence of iden- colleagues showed that stuttering is concordant in more than tical twins with the disorder. Ingham (3) reported that at least 75% of cases of stuttering speculate that there is a genetic contribution to the aetiology. However, it must be realised that there are several nongenetic Shprintzen (4) considered that virtually all instances of reasons why a disease phenotype, causally unrelated to a genetic human disability and disease have a genetic component, even if predisposition, can be seen recurrently in the same family. He was referring nongenetic familial aetiologies should be taken into account primarily to craniofacial anomalies, but his comment applies when postulating a genetic contribution to a particular disorder. Members of a family are frequently exposed to the same It is well known that clefts of the lip with or without clefts environmental insults. This may lead to recurrent manifestation of the palate may be of genetic origin or may be produced by of the same condition. A poor or rich educational environment environmental factors or chromosomal anomalies. The often multifactorial or, as many geneticists believe, caused by a combined effects of such factors as age, sex, education, parental single mutant gene with allelic restriction (5). Medical conditions such as diabetes, lupus ery- yet, no concrete evidence of a connection between genes or thematosus, and phenylketonuria can all result in sequelae that some combination of genes and grammatical abilities, but that can give the appearance of a genetic relationship. However, before learning can begin, children must be Dialects and language-related difﬁculties, despite recurrence in ready to learn; that is, they must be biologically, socially, and a family, may be due to a shared cultural (rather than genetic) psychologically mature enough to undertake the task. Differences in habits and abuse of drugs or alcohol As Kies reported (22), linguists do not agree on exactly may result in a phenotype that can be misconstrued as being of how biological factors affect language learning, but most agree genetic origin. Foetal alcohol syndrome shows a constellation with Lenneberg (23) that human beings possess a capacity to of features that may include a characteristic facial appearance; learn language that is speciﬁc to this species and no other. Lenneberg also suggested that language might be expected from By chance, two members of a family may develop the same the evolutionary process that humans have undergone, and that condition with no underlying genetic or environmental predis- the basis for language might be transmitted genetically. Also, some members of a family may acquire a condi- As part of genetically endowed language abilities, tion for reasons completely unrelated to other members of the Lenneberg (24) hypothesized a “critical period” during which family. A “phenocopy” is an individual with a phenotype simi- language learning proceeds with unmatched ease. A child’s lar to other members of a family but with a different aetiology early years are especially crucial for language development (11). However, some stochastic events may be inﬂuenced to because that is the period before the two hemispheres of the some degree by a genetic predisposition (12). As Mendel (13) ﬁrst delineated the methods by which genetic partial proof of this, Lenneberg discussed cases in which chil- factors are transmitted and ﬁrst discovered the basis of heredity dren in bilingual communities were able to learn two languages in his studies of peas. Although most communicative disorders ﬂuently and without obvious signs of effort before the age of appear to have a complex inheritance pattern, a select group of about 12. However, learning a second language after the age of communicative disorders has inheritance patterns that directly 12 becomes enormously difﬁcult for most people. Similarly, many neurolinguists have argued that children’s brains are biologically too immature to comprehend several grammatical concepts commonly used in languages around the world. Concepts such as plurals, auxiliary verbs, inﬂectional end- Language development ings, and temporal words will develop in all languages in stages. One of the earliest scientiﬁc studies to record the language The fact that those stages of language development are “identi- development of a child was that by a German biologist cal” and “predictable” in all languages further suggests that there Tiedemann in 1787 (14). He was interested in starting a col- are strong biological preconditions for learning language. The concept of a sentence is the main guiding principle in Interest in language development intensiﬁed with the publica- a child’s attempts to organize and interpret the linguistic evi- tion of Darwin’s theory of evolution, and Darwin (15) himself dence that ﬂuent speakers make available to him. These ideas contributed to the study of language development in children, are a part of the “nativist” position discussed later.
Institut für Medizinische Physik cheap 20mg forzest with mastercard purchase erectile dysfunction pump, Universität Wien purchase 20mg forzest overnight delivery impotence in a sentence, Währingerstrasse 13 generic 20mg forzest visa erectile dysfunction groups in mi, A-1090 Vienna, Austria Ochi, H. Division of Nuclear Medicine, Osaka City University Medical School, 1-5-7, Asahimachi, Abenoku, Osaka 545, Japan Orellana, P. Laboratorio de Medicina Nuclear, Hospital Clínico, Pontificia Universidad Católica de Chile, Marcoleta 347, Santiago, Chile Oren, V. Division of Nuclear Medicine, Department of Radiology, Siriraj Hospital, Faculty of Medicine, Mahidol University, Bangkok-noi, Bangkok 10700, Thailand Rajeswaran, S. Department of Nuclear Medicine, Martyr Rajaie Cardiovascular Centre, The University of Medical Sciences of Iran, Vali-asr Avenue, Tehran, Islamic Republic of Iran Rodriguez Perez, J. Kohly, Playa, La Habana, Cuba Saidin bt Hj, Dahlia Department of Nuclear Medicine, Hospital Kuala Lumpur, 50586 Kuala Lumpur, Malaysia Sidibe, S. Service de radiologie et de médecine nucléaire, Hôpital national du point “G” , B. Radioisótopos, Comisión Nacional de Energía Atómica, Avenida del Libertador 8250, Buenos Aires 1429, Argentina Strauss, L. Department of Oncologic Diagnosis and Therapy, German Cancer Research Centre, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany Tanaka, E. Section of Nuclear Medicine, Philippine Heart Center, East Avenue, Quezon City 1100, Philippines Uemura, K. Research Institute for Brain and Blood Vessels, 6-10, Senshu-Kubota-Machi, Akita-City 010, Japan Wagner, M. Permanent Mission of the Holy See to the International Organizations in Vienna, Theresianumgasse 33/4, A-1040 Vienna, Austria Wagner, H. Centre of Nuclear Medicine, Department of Radiology, Sâo Paulo University Medical School, Rua Joào Della Manna. Nuclear Medicine Department, Department of Health and Medical Services, Dubai Hospital, P. Box 5050,100-31 Tokyo International N E T H E R L A N D S Martinus Nijhoff International, P. Fatma El-Husseini, professor of pathology for providing some of her pathology figures. Tarek El-Diasty, consultant radiologist, is acknowledged for providing the radiology figures. Doctors in all specialties are facing renal diseases either as isolated disorder or in association with other disease. For these reasons it became mandatory to give more attention for better education of renal diseases especially for young doctors and medical students. It covers most of the items of renal diseases in a simple fashion with sufficient number of illustrations and figures. For those who are seeking for more details, this could be easily obtained from the more comprehensive version of this book entitled "Essentials of Clinical Nephrology". Mohamed Fakhry prize for the most distinguished research in Internal Medicine, Awarded by the Egyptian Academey of Research and Technology, 1987. Renal tubules through the increase in the formation of ammonia and titratable acids (phosphates, sulphates and phenols). Human recombinant erythropoietin is now commercially available for the treatment of anaemia in uraemic patients. The hilum of the kidney which is present medially contains renal artery, vein, lymphatics and pelvis of the ureter. The kidney lies in the paravertebral gutter on the posterior abdominal wall retroperitoneally and opposite the twelfth thoracic down to the third lumbar vertebra. The right kidney is slightly lower than the left (liver effect), lower pole reaches one finger breadth above the iliac crest. It shows the hilum containing the renal vessels and pelvis of the ureter which branches inside the kidney into 2-4 major calyces, each of which in turn branches into several minor calyces. The kidney parenchyma is divided into outer cortex (1 cm thick) and inner medulla. The medulla is formed of 8-18 pyramids which are conical- shaped, with its base at cortico-medullary junction and its apex projects into minor calyces as papillae. The cortex which is granular-looking may extend between pyramids forming columns of Bertini. Medullary rays are striated elements which radiates from the pyramids through the cortex. The first part of the nephron is the glomerulus (renal corpuscle) which lies mainly in the renal cortex, followed by proximal convoluted tubule which also lies mainly in the renal cortex. This is followed by a loop of Henle which is partly in the cortex and partly extends deep into the medulla. Part of the distal convoluted tubule comes into contact with the hilum of the glomerulus and afferent arteriole. Cells in the hilum of the glomerulus and those in distal convoluted tubule and afferent arteriole are modified to form the Juxta glomerular apparatus. Distal convoluted tubule ends into the collecting duct which lies partly in the cortex and partly in the medulla. In the medulla, collecting ducts descend in the pyramids, at the renal papillae collecting ducts unite together to form ducts of Bertini which discharge urine into renal pelvis. The glomerulus (renal corpuscle): The renal corpuscle is formed essentially of two modified structures of different embryonic origins: A. The second is modification of the end of the afferent arteriole, which divides into several primary branches. Each capillary is lined with basement membrane, lined from inside by endothelial cells and from outside by epithelial cells which lie on the capillary basement membrane by foot process (so it is called podocyte). Glomerular capillaries are lined by basement membrane which is covered from inside with endothelial cells and from outside by epithelial cells (podocytes). It is located mainly at the hilum of the glomerulus, and extends between capillary loops. Its main function is to support the capillary tuft, also, it may have a phagocytic function and contractile function. Phagocytic property of the mesangium helps in clearing the glomerulus from any circulating immune complexes or antigens. The contractile function may help in modulating the renal blood flow and the capillary wall filtration surface. Juxta-glomerular apparatus: Juxta-glomerular apparatus is a specialized structure which is present at the hilum (vascular pole) of the glomerulus (Figure 1. It is composed of four groups of cells which contain granules in their cytoplasm (most probably renin). The epithelioid cells which are modified cells in the wall of the afferent and-to less extent-efferent arterioles. Concentration And Dilution Of Urine: This function is very important to regulate body water and tissue osmolarity. This is maintained despite the wide variation in fluid intake (increased intake decreases osmolarity and vice versa) and load of osmotically active substances e. This can increase to over 1200 mosmol/day in states of severe catabolism as in patients with extensive burns.
Colonization of the anterior nares forzest 20mg discount erectile dysfunction pump as seen on tv, perineum 20mg forzest overnight delivery erectile dysfunction options, or skin buy discount forzest 20 mg on line erectile dysfunction pump implant, particularly if the cutaneous barrier has been disrupted or damaged, may occur shortly after birth and may recur anytime thereafter (1–4). Approximately 20% of individuals always carry one type of strain and are called persistent carriers. Carriage rates are higher than in the general population for injection drug users, persons with insulin-dependent diabetes, patients with dermatological conditions, patients with long-term indwelling intravascular catheters, and those with human immunodeficiency virus infection. Other gram-negative bacilli are found more rarely on the skin, and these include Proteus and Pseudomonas in the toe webs and Enterobacter and Klebsiella on the hands. Antibiotics disturb the balance within commensal flora and leave the surface vulnerable to colonization by exogenous gram-negative bacilli and fungi. The principal fungal flora is lipophilic yeasts of the genus Malassezia, and nonlipophilic yeasts such as Candida spp. Primary skin infections occur in otherwise normal skin and are usually caused by group A streptococci or S. A deficiency in the expression of antimicrobial peptides may account for the susceptibility of patients with atopic dermatitis to skin infection with S. Other factors predisposing to skin infections include vascular insufficiency, disrupted venous or lymphatic drainage, sensory neuropathies, diabetes mellitus, previous cellulitis, foreign bodies, accidental or surgical trauma, burns, poor hygiene, obesity, and immunodeficiencies. Extension into the superficial dermis with involvement of lymphatic is typical of erysipelas, whereas cellulitis is an extension into the subcutaneous tissue. A clinically useful distinction with important management implications subdivides soft tissue infections into nonnecrotizing and necrotizing processes (9). The Center for Drug Evaluation and Research for development of antimicrobial drugs has classified skin and soft tissue infection as uncomplicated or complicated. The uncomplicated category included simple abscesses, impetiginous lesions, furuncles, and cellulitis. Compli- cated category included infection involving the deeper layer or requiring significant surgical intervention. Superficial infection in an anatomical site with a risk of gram-negative pathogen or anaerobes such as the rectal area was also considered to be complicated (10). DiNubile and Lipsky classified skin and soft tissue infections to assist clinician in recognizing uncomplicated and complicated infections (11). Classification can also be based according to the severity of local and systemic signs and symptoms of infection, and the presence and stability of any comorbidities. Class 1 patients have no signs or symptoms of systemic toxicity without any comorbidities and can be managed in an outpatient setting. Class 3 patients have toxic appearance, one unstable comorbidity, or a limb-threatening infection, whereas class 4 patients have sepsis syndrome or serious Table 1 Classification of Skin and Soft Tissue Infection Based on Uncomplicated and Complicated Infections and Systemic Syndromes Uncomplicated Complicated Systemic syndromes Superficial: impetigo, ecthyma Secondary infection of diseased skin Scalded-skin syndrome Deeper: erysipelas, cellulitis Acute wound infections: Traumatic Toxic shock syndrome Hair follicle associated: Bite related Purpura fulminans folliculitis, furunculosis Post operative Abscess: carbuncle, Chronic wound infections: Diabetic foot infections cutaneous abscess Venous stasis ulcer Pressure ulcers Perianal infections Necrotizing fasciitis (type 1 and type 2) Myonecrosis (crepitant and noncrepitant) Source: Adapted in part from Ref. Guidelines developed by the Infectious Disease Society of America are written in references to specific disease entities, mechanism of injury, or host factors (13). Classification of skin and soft tissue infections based on uncomplicated and complicated infections, and systemic syndromes is depicted in Table 1. Here we review causes of skin and soft tissue infection with emphasis on severe skin and soft tissue infection, highlighting the clinical presentation, diagnosis, and approach to management in the critical care setting. There are two clinical presentations: bullous impetigo and nonbullous impetigo, and both begin as a vesicle (14). The group A streptococci responsible for impetigo belong to different M serotypes (2,15–21) from those of strains that produce pharyngitis (1,2,4,6,22) (23,24). They are common in exposed areas such as hands, feet, and legs, and are often associated with traumatic events such as minor skin injury or insect bite. Predisposing factors include warm ambient temperature, humidity, poor hygiene, and crowded conditions. Cutaneous infection with nephritogenic strains (2,15,17–21) of group A streptococci can lead to poststreptococcal glomerular nephritis. For extensive bullous impetigo, treatment with antistaphylococcal agents is selected with consideration of susceptibility testing. A carbuncle is a more extensive process that extends into the subcutaneous fat in areas covered by thick, inelastic skin. Multiple abscesses separated by connective tissue septa develop and drain to the surface along the hair follicle. Infections occur in areas that contain hair follicles such as neck, face, axillae and buttocks, sites predisposed to friction, and perspiration. Predisposing factors include obesity, defects in neutrophil dysfunction, and diabetes mellitus. Bacteremia can occur and result in osteomyelitis, endocarditis, or other metastatic foci. Systemic anti-staphylococcal antibiotics are recommended in the presence of surrounding cellulitis and large abscesses or when there is a systemic inflammatory response present. In typical erysipelas, the area of inflammation is raised above the surrounding skin, and there is a distinct demarcation between involved and normal skin, the affected area has a classic orange peal (peau d’orange) appearance. The induration and sharp margin distinguish it from the deeper tissue infection of cellulitis in which the margins are not raised and merge smoothly with uninvolved areas of the skin (Fig. Erysipelas is almost always caused by group A Streptococcus, though streptococci of groups G, C, and B and rarely S. Formerly, the face was commonly involved, but now up to 85% of cases occur on the legs and feet largely due to lymphatic venous disruptions (25,26). Agents such as erythromycin and the other macrolides are limited by their rates of resistance and the fluoroquinolones are generally less active than the b-lactam antibiotics against b- hemolytic streptococci. It often occurs in the setting of local skin trauma from skin bite, abrasions, surgical wounds, contusions, or other cutaneous lacerations. Specific pathogens are suggested when infections follow exposure to seawater (Vibrio vulnificus) (28,29), freshwater (Aeromonas hydrophila) (30), or aquacultured fish (S. Lymphedema may persist after recovery from cellulitis or erysipelas and predisposes patients to recurrences. Recurrent cellulitis is usually due to group A Streptococcus and other b-hemolytic streptococci. Recurrent cellulitis in an arm may follow impaired lymphatic drainage secondary to neoplasia, radiation, surgery, or prior infection and recurrence in the lower extremity may follow saphenous venous graft or varicose vein stripping. In addition, Severe Skin and Soft Tissue Infections in Critical Care 299 Figure 2 Cellulitis of the left thigh in a alcoholic patient, blood cultures grew group B Streptococcus. Uncommonly, pneumococcal cellulitis occurs on the face or limbs in patients with diabetes mellitus, alcohol abuse, systemic lupus erythematosus, nephritic syndrome, or a hematological cancer (22). Meningococcal cellulitis occurs rarely, although it may affect both children and adults (33). Cellulitis caused by gram-negative organisms usually occurs through a cutaneous source in an immunocompromised patient but can also develop through bacteremia.