CAUSES : The cryptococcus fungus is ubiquitous. Person to person transmission is rare.
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DIFFERENTIAL DIAGNOSIS
β’ In CNS disease - toxoplasmosis, lymphoma, AIDS dementia complex, progressive multifocal leukoencephalopathy, herpes encephalitis, other fungal disease
β’ In pulmonary disease - tuberculosis, Pneumocystis, histoplasmosis, coccidioidomycosis, Kaposi sarcoma,
lymphoma
β’ In disseminated disease - tuberculosis, histoplasmosis, lymphoma, coccidioidomycosis
3. CUTANEOUS CRYPTOCOCCOSIS MIMICS
- COMEDO
- BASAL CELL CARCINOMA
- SARCOIDOSIS
- MOLLUSCUM CONTAGIOSUM
4. BONY CRYPTOCOCCOSIS MIMICS
- TUBERCULOSIS
OTHER TESTS :
* CSF - DIRECT SMEAR SHOWS YEAST CELLS, LOW GLUCOSE, HIGH PROTEIN & LYMPHOCYTOSIS.
* CAPSULAR ANTIGEN - POSITIVE BY LATEX AGGLUTINATION TEST
* ENZYME IMMUNOASSAY FOR CRYPTOCOCCAL ANTIGEN
β’ Serum cryptococcal antigen (if positive, search for dissemination, perform L.P.)
β’ CSF cryptococcal antigen (positive in 95% of cultureproven positive cases)
β’ India ink preparation of CSF (50% positive in non-AIDS patients; 80% (bronchoalveolar lavage) positive in AIDS patients)
β’ Culture of CSF, sputum, blood, urine
SPECIAL TESTS: Lumbar puncture in cryptococcal meningitis: Imperative to check opening pressure initially (may repeat if clinical deterioration). Significantly increased intracranial pressure associated with poor prognosis.
- In non-AIDS patients - elevated opening pressure, elevated CSF protein, decreased glucose and lymphocytic pleocytosis.
- In AIDS patients - abnormal CSF findings in 40% of patients. high opening
pressure > 200 mm water in 70% of patients.
IMAGING :
β’ In cryptococcal meningitis - CT of brain is negative unless focal cryptococcomas present
β’ In pulmonary cryptococcosis - chest x-ray may show infiltrates, nodules, mass lesions (with rare cavitation), miliary spread, hilar adenopathy (10%), pleural effusions (less than 5%)
DIAGNOSTIC PROCEDURES : Biopsies of skin lesions may be diagnostic