Tags: Hepatitis

Trematodes

Essentials of Diagnosis Blood flukes: demonstration of eggs in feces, urine, or rectal biopsy Liver flukes: demonstration of eggs in feces Intestinal flukes: demonstration of adult worms or eggs in feces Lung flukes: demonstration of eggs in sputum or feces All trematode species that are parasitic for humans are digenetic. Sexual reproduction in the adult fluke is followed by asexual multiplication in the larval stage. Most species of adult trematodes have an oral and ventral sucker. The life cycles of trematodes that are important human pathogens are similar among all five major species. Eggs are excreted in the feces of the host, hatch in fresh water, and require a primary host …

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American Trypanosomiasis (Chagas’ Disease)

Essentials of Diagnosis • Epidemiologic factors: time spent in an endemic zone; poor housing conditions, eg, mud or thatched housing; exposure to reduviid insect vector • History and physical exam: Romana’s sign (swollen periorbital mucosal tissues after ocular inoculation); chagoma (skin nodule at the site of acute inoculation); in the chronic phase, congestive heart failure, dysphagia or regurgitation, and constipation • Laboratory exam: 1. Acute Chagas’: trypomastigotes revealed by Giemsa smear of blood or buffy coat; culture of affected tissues, ie, the inoculation site; serologic enzyme immunoassay and enzyme-linked immunosorbent assay (ELISA); xenodiagnosis if available 2. Chronic Chagas’: radiological studies show congestive heart failure, megacolon, or megaesophagus; ECG shows right bundle …

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Cryptosporidium, Cyclospora, & Isospora Species & Microsporidia

Within the last decade, the AIDS epidemic has heightened awareness of several gastrointestinal spore-forming protozoan pathogens. The genera Cryptosporidium, Isospora, and Cyclospora are members of the subclass Coccidia and phylum Apicomplexa; the microsporidia are a group of organisms belonging to the phylum Microspora. The spectrum of disease caused by these protozoans goes beyond gastrointestinal manifestations, and the significance of these protozoan infections is becoming increasingly appreciated in both immunocompromised and immunocompetent hosts. CRYPTOSPORIDIUM Essentials of Diagnosis • Key signs and symptoms include dehydration with watery diarrhea of variable quantity. • Waterborne transmission is the most common mode of oocyst transmission. • Patients at risk for person-to-person transmission include household contacts, sexual …

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Cryptosporidium: Clinical Syndromes

Enteric cryptosporidiosis is the most common clinical presentation in patient populations. In addition, immunocompromised patients may present with cholecystitis or respiratory infections attributed to C parvum (Box 1). Asymptomatic infection has also been reported. 1. ENTERIC CRYPTOSPORIDIOSIS Clinical Findings A. Signs and Symptoms. An average of 5-7 days passes from oocyst ingestion to symptom onset. Symptoms are similar in both immunocompetent and immunocompromised patients but are prolonged and considerably more severe in compromised patients. Patients complain of watery diarrhea in variable quantities of = 25 L/day leading to significant dehydration. Abdominal cramps, malaise, low-grade fever, and anorexia are frequently reported. Nausea, vomiting, myalgia, headache, and weight loss may also occur. Symptoms …

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Toxoplasma Gondii

General Considerations A. Epidemiology. Toxoplasma gondii infection, or toxoplasmosis, is a zoonosis (the definitive hosts are members of the cat family). The two most common routes of infection in humans are by oral ingestion of the parasite and by transplacental (congenital) transmission to the fetus. Ingestion of undercooked or raw meat that contains cysts or of water or food contaminated with oocysts results in acute infection. In humans, the prevalence of toxoplasmosis increases with age. There are also considerable geographic differences in prevalence rates (eg, 10% in Palo Alto, CA; 15% in Boston, MA; 30% in Birmingham, AL; 70% in France; = 90% in El Salvador). Differences in the epidemiology of …

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Non-falciparum Malaria (P Vivax, P Ovale, P Malariae)

Clinical Findings A. Signs and Symptoms. Patients with nonfalciparum malaria invariably develop fever and chills that may become cyclic. Initially, patients experience chills, which are followed by fever (Box 1). Patients with malaria often manifest many nonspecific symptoms such as weakness, malaise, headache, and myalgias. As the disease progresses, signs of anemia, such as pale conjunctiva, may be seen. Splenomegaly and mild hepatomegaly may also be present. After hours of fever, defervescence occurs with marked diaphoresis. Patients are weakened and exhausted from the severity of the disease. In established infections caused by P vivax and P ovale, a periodicity may occur approximately every 48 h. P vivax and P ovale infections …

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Extrapulmonary P Carinii Infections

Extrapulmonary P carinii infections occur in < 3% of patients and must be diagnosed with histopathologic samples. Primary prophylaxis for PCP with pentamidine may confer a higher risk for extrapulmonary infection. Symptoms of extrapulmonary involvement are nonspecific, usually consisting of fevers, chills, and sweats. Although any area of the body may be involved, splenomegaly with cysts and thyroiditis are most common. Diagnosis The practice of diagnosing PCP morphologically by traditional staining methods (silver methenamine and toluidine blue) of induced sputum samples in HIV-infected individuals has fallen out of favor. Although relatively simple and inexpensive, staining of sputum samples induced by hypertonic saline inhalation is clearly dependent on operator and laboratory experience, …

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Candida Vulvovaginitis

Clinical Findings A. Signs and Symptoms. Risk factors for Candida infection of the vagina include pregnancy, oral contraceptive use, diabetes mellitus, HIV infection, and antimicrobial therapy, although the majority of infections occur in the absence of these risks. Typical complaints are vulvar pruritus and vaginal discharge (Box 1), although a wide range of symptoms exists. Pruritus, the most common complaint, is often intense, and the discharge, classically described as cottage cheese-like, may range from a thin, white, scant discharge to homogeneously thick. Odor, if present, is mild. Other symptoms may include vulvar burning, external dysuria, vaginal irritation and soreness, and dyspareunia. Symptoms may peak the week prior to menses and wane …

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Rocky Mountain Spotted Fever (RMSF)

Essentials of Diagnosis Key symptoms and signs: abrupt onset of high fevers, headaches, myalgias, malaise, and a flu-like illness 3-12 days after tick bite; rash (80-90% of patients, initially maculopapular, then petechial, classically involving the palms and soles). Predisposing factors: tick exposure (April through September), pet owners, animal handlers, and outdoor activities. Commonest geographic location of infection: rural. Confirmatory serology via IFA. PCR with blood or skin biopsy: sensitive and specific but not widely available. General Considerations RMSF is caused by Rickettsia rickettsii and is an acute tick-borne illness occurring during seasonal tick activity. The disease is characterized by acute onset of fever, headache, and a rash of the extremities spreading …

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Ehrlichia Infection (Ehrlichiosis)

Essentials of Diagnosis Key symptoms and signs: abrupt onset of high fever, headache, myalgias, chills 8-9 days after tick bite; rash (36% of human monocytic ehrlichiosis [HME] patients; only 2% of human granulocytic ehrlichiosis [HGE] patients); central nervous system involvement (20-25% of patients). Predisposing factors: tick and rural exposure (April through September). Presentation: most present as flu-like illness. Key laboratory features: thrombocytopenia, leukopenia, and elevated liver transaminases. Diagnosis: confirmed by a fourfold or greater rise in titers with an IFA. General Considerations Human ehrlichiosis was first recognized in the United States in 1986 as a life threatening tick-borne illness similar to Rocky Mountain spotted fever (RMSF), but with a much lower …

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