0521779407-C03 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 20:54
Coccidioides Immitis 365tests
Laboratory
■Early respiratory: normal, except for increased ESR or eosinophilia
■CSF examination (meningitis):
➣Elevated CSF pressure
➣Elevated WBC count, protein
➣Depressed glucose
➣Eosinophils may be prominent
■Microbiology – culture
➣Cultures highly infectious to lab personnel – treat with great care,
always warn lab if cocci is suspected
➣Usually grows well after 5–7 d of incubation
■Serology
➣Mainstay for outpatient diagnosis – most highly specific for active
infection, one negative test does not exclude diagnosis
➣Complement-fixing antibodies – blood or other body fluids (esp
CSF). 1:16 or greater usually treated as positive, but significant
inter-lab variability. Serial determinations by same lab most
useful; any+titer in CSF significant
➣Tube preciptin antibodies – 90% have TP antibodies at some time
in first 3 weeks of symptoms, <5% at 7 mo after self-limited illness
➣Immunodiffusion – IDTP or IDCF detects above antibodies using
alternative technique – at least as sensitive
➣ELISA – IgM or IgG Ab – highly sensitive, but occ. false positives,
especially with IgM ELISA. Usually confirm a positive ELISA with
IDTP, IDCF or CF before considering truly positive.
■Skin testing
➣DTH quite specific, but remains positive for life (thus, most useful
in epidemiology)
■Histopathology
➣Direct examination of sputum secretions or tissue
Imaging (CXR)
■Early respiratory: unilateral infiltrates, hilar adenopathy, effusions
■Fulminant: diffuse infiltrate (ARDS-like)
■Pulmonary nodules and cavities appear on CXR if they are present
differential diagnosis
■Distinguish from other fungal infections of the lung (Histo, Crypto-
coccus, Aspergillus).
■Distinguish from mycobacterial diseases of the lung, other chronic
pneumonias.