| Disease/Syndrome |
Histoplasmosis |
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| Category |
Infection, Occupational |
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| Acute/Chronic |
Subacute |
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| Synonyms |
Histoplasma capsulatum infection |
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| Biomedical References |
Search PubMed |
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| Comments |
Infection is common, but chronic disease is rare. The five forms of the disease are asymptomatic, acute respiratory, acute disseminated, chronic disseminated, and chronic pulmonary. Most cases of histoplasmosis are detected as incidental radiographic findings such as enlarged mediastinal or hilar lymph nodes and pulmonary nodules. A high-dose exposure can cause an acute respiratory disease within 2 weeks of exposure. Complications of acute infection include arthralgias, erythema multiforme, erythema nodosum, mediastinal adenitis, pleural effusions, pericarditis, and uveitis. In severe cases, acute infection can precipitate respiratory failure. Chronic pulmonary disease resembles pulmonary tuberculosis with cavitation; it is found in patients with pre-existing emphysema. Immunocompromised patients are susceptible to the disseminated forms of histoplasmosis with the following complications: mucosal and skin lesions; hepatosplenomegaly and generalized lymphadenopathy; adrenal insufficiency; endocarditis; and infections of the GI tract, CNS, and bone marrow. Laboratory evidence of dissemination includes anemia, leukopenia, thrombocytopenia, and elevated hepatic transaminases. In acute and subacute pulmonary histoplasmosis, testing for antigens in urine and bronchoalveolar lavage fluid (BALF) makes the diagnosis in about 75% of the cases. The usefulness of serology is limited because the results remain positive for years after initial infection. BALF should also be cultured and stained (Diff-Quick, Giemsa, and GMS). [CCDM, p. 273-5; Merck Manual, p. 915, 1533; ID, p. 2220-1; Wheat JL et al. Pulmonary Histoplasmosis Syndromes: Recognition, Diagnosis, and Management. Seminars in Respiratory and Critical Care Medicine.2004;25:129-43; Guerrant, p. 294-6; eMedicine: Alhameed FM. Histoplasmosis, Thoracic; Hagood JS. Histoplasmosis] Over 90% of histoplasmosis cases are subclinical. In an acute primary infection 7-10 days after exposure, the main findings are fever, headache, nonproductive cough, chest pain, rales, patchy infiltrates, and hilar adenopathy. About 6% of patients have acute pericarditis. Most cases of progressive disseminated histoplasmosis occur in immunosuppressed patients. Diarrhea, abdominal pain, and ulcers of GI tract are common; ulcers of the skin, mouth, and throat are also found. [PPID, p. 3012-3025] |
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| Latency/Incubation |
3 days to 2.5 weeks |
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| Diagnostic |
Stain; Culture; Serology; Antigen detection; |
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| ICD-9 Code |
115.0 |
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| Effective Antimicrobics |
Yes |
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| Scope |
Endemic in areas of N. and S. America--the Ohio and Mississippi River valleys in the US; Cases reported in Asia and Europe; [ID, p. 2219] |
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| Reference Link |
CDC - Histoplasmosis |
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| X-Ray |
eMedicine - Histoplasmosis, Thoracic : Article by Fahad M Alhameed, MD, FRCPC |
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| Related Information in Haz-Map |
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| Symptoms/Findings |
Symptoms/Findings associated with this disease:
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| Job Tasks |
High risk job tasks associated with this disease:
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