CAUSES Coccidioides immitis , a soil fungus
especially adapted to arid conditions. Liberated spores are inhaled when soil is disturbed: digging, construction sites, archaeological sites, dust storms, spelunking (exploring caves).
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DIFFERENTIAL DIAGNOSIS
β’ Pneumonia, all etiologies
β’ Lung carcinoma
β’ Sarcoidosis
β’ Histoplasmosis, other fungi
β’ Lung abscess
β’ TB
β’ Lymphoma
β’ Meningitis
β’ Plus all other causes of cough, fever, fatigue
β’ Old granulomas can be mistaken for tumors
β’ Skin test turns positive at 3 weeks to 3 months; may remain positive indefinitely; applying skin test will not interfere with serologies. Skin test is currently not being manufactured and it is unclear when it will be available
again.
β’ Serology - immunodiffusion measures precipitin antibodies (IgM) rise within 2 weeks and fall after 2 months; complement fi xation antibodies (IgG) rise at
1-3 months; patients with mild symptoms may never develop detectable serology
β’ May have elevated sedimentation rate and peripheral eosinophilia
β’ Culture of sputum, wound exudate, joint aspirate; unlikely to grow fungus in urine, blood, pleural fluid
SPECIAL TESTS : Biopsy of affected tissue, e.g., lung nodule, skin lesion
IMAGING : Chest x-ray findings include - normal, infiltrate(s), nodule(s), cavity, adenopathy mediastinal or hilar, pleural effusion
DIAGNOSTIC PROCEDURES : If unable to establish diagnosis from skin testing and serologies
- bronchoscopy, fine-needle biopsy, open lung biopsy, pleural biopsy, bone/skin/node biopsy, CSF stain, serology, culture