4
Diagnosis
Dissemination
Î Hematogenous spread beyond the lungs normally occurs within weeks
to several months following infection.
• Exceptions to this estimate are immunosuppressed patients with more remote
prior exposure or patients who have previously been treated with an antifungal
drug for primary pulmonary infection in whom relapses occurred up to 4 years
after treatment had been stopped.
ÎThe signs and symptoms of disseminated coccidioidal lesions vary widely
depending upon their location. Importantly, pulmonary symptoms or
radiographic abnormalities may be minimal or completely absent.
Î Although patients with deficiencies in cellular immunity are especially
susceptible to severe coccidioidomycosis including dissemination,
most patients with coccidioidal lesions outside of the lungs have no
identified immune deficiencies.
Serological Testing
Î Enzyme immunoassays (EIAs) for anticoccidioidal immunoglobulin M
(IgM) and immunoglobulin G (IgG) are commercially available.
Î When done to evaluate a clinical illness, any positive test result for
anticoccidioidal antibodies is usually associated with a recent or
active coccidioidal infection, in contrast with serologic tests for many
other types of infection where diagnostic IgG antibodies often are
detectable for life.
Î An important limitation of all coccidioidal serologic tests is that
they may be negative and even persistently negative despite an early
coccidioidal infection being present.
Î EIA is often used for initial screening because of its increased
sensitivity. However, if not confirmed by the more specific but less
sensitive immunodiffusion test, the diagnosis is less certain. Repeat
testing is often useful to resolve this uncertainty.
Î Patients who have already developed extrapulmonary coccidioidal
lesions nearly always exhibit anticoccidioidal antibodies in their
serum, regardless of whether tested by EIA, immunodiffusion or
complement fixation titration. Severely immunosuppressed patients
may be exceptions to this rule.
