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Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There are several protozoan infections that cause relatively benign illness in normal individuals but result in severe disease manifestations in patients with AIDS. These diseases include Pneumocystis carinii pneumonia, CNS toxoplasmosis, cryptosporidiosis, and isosporiasis. Pneumocystis carinii pneumonia (PCP) caused by Pneumocystis carinii, is the most common opportunistic infection in AIDS. It is seen in more than 80% of individuals with this syndrome. Although historically classified as a protozoan, this organism shares many biochemical characteristics with fungi. The onset of PCP may be insidious, and cough and dyspnea are the most common presenting symptoms. Auscultation of the lungs is often unremarkable, but diffuse infiltrates are commonly seen on chest radiographs. The diagnosis of PCP can be confirmed by identifying the organism on specimens obtained by sputum induction or bronchoalveolar lavage. Trimethaprim-sulfamethoxazole is the treatment of choice but is unfortunately associated with leukopenia and rash in many individuals. Both trimethaprim-sulfamethoxazole and aerosolized pentamidine are used prophylactically in patients at high risk for initial or relapsing infection. The appropriate use of these agents has resulted in improved survival for AIDS patients with PCP. Toxoplasmosis, due to Toxoplasma gondii, affects the central nervous system in patients with AIDS. Headache is a common presenting symptom, and both seizures and paresis can occur. A diagnosis of toxoplasmosis is strongly suspected in symptomatic individuals with ringed mass lesions noted on head CT. Patients with this condition are treated with a combination of sulfadiazine, pyrimethamine, and folinic acid. Cryptosporidiosis and isosporiasis are coccidian protozoan diseases that can result in severe, acute, and chronic diarrhea in immunocompromised individuals. Cryptosporidiosis is the more common of the two and is caused by an unknown species of the genus crytosporidium. Isosporiasis is due to infection with Isospora belli. Dehydration and weight loss are a common result of infection with either agent. A definitive diagnosis can be made by examining an acid fast stain of a diarrheal stool specimen and demonstrating oocysts that are specific for each of these organisms. Fluid replacement and general supportive care are essential in the treatment of both of these diseases. Spiramycin is an unproven treatment modality that is often used in patients with cryptosporidiosis. Isosporiasis responds to initial therapy with trimethaprim-sulfamethoxazole, followed by prophylaxis with pyrimethamine. The adoption of safe sexual practices that minimize fecal-oral contamination should decrease the future prevalence of these diseases and other enteric parasitic infections.
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PMID:Parasitic diseases. Diseases associated with acquired immunodeficiency syndrome. 201 33

Coccidial parasites of the genus Isospora cause intestinal disease in several mammalian host species. These protozoal parasites have asexual and sexual stages within intestinal cells of their hosts and produce an environmentally resistant cyst stage, the oocyst. Infections are acquired by the ingestion of infective (sporulated) oocysts in contaminated food or water. Some species of mammalian Isospora have evolved the ability to use paratenic (transport) hosts. In these cases, infections can be acquired by ingestion of an infected paratenic host. Human intestinal isosporiasis is caused by Isospora belli. Symptoms of I. belli infection in immunocompetent patients include diarrhea, steatorrhea, headache, fever, malaise, abdominal pain, vomiting, dehydration, and weight loss, blood is not usually present in the feces. The disease is often chronic, with parasites present in the feces or biopsy specimens for several months to years. Recurrences are common, Symptoms are more severe in AIDS patients, with the diarrhea being more watery. Extraintestinal stages of I. belli have been observed in AIDS patients but not immunocompetent patients. Treatment of I. belli infection with trimethoprim-sulfamethoxazole usually results in a rapid clinical response. Maintenance treatment with trimethoprim-sulfamethoxazole is needed because relapses often occur once treatment is stopped.
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PMID:Biology of Isospora spp. from humans, nonhuman primates, and domestic animals. 899 57