Coccidioidomycosis is caused by
the dimorphic fungus Coccidioides immitis.
The organism is thick-walled, mature, spherules containing endospores.
Spherules rupture liberating endospores into surrounding tissue.
chronic, necrotizing lesions that clinically & pathologically resembles
High risk groups are
African-Americans and Asians, pregnant women during the third trimester, and
immunocompromised persons. Construction or agricultural workers, and
archeologists who are exposed to dust are also at risk.
Epidemiology: Endemic in
the south-western United States, parts of Mexico and South America.
Reservoir : Soil in semiarid
Mode of infection: Inhalation
of airborne arthroconidia (barrel shaped infectious units) from
contaminated soil. The contaminated soil may be disturbed
following excavation or after a natural disaster like dust storm or
earthquake. Arthroconidia mature to form endospore containing
A- 60% of air born infections are
B- 40% cases are symptomatic.
Lung: Primary pulmonary
coccidioidmycosis are acute disease with influenza-like symptoms associated
with suppurative or granulomatous pneumonitis with abundant organisms.
Initially, there is a solitary area of consolidation, sometimes diffuse
pneumonic consolidation or multiple foci of consolidation is seen.
Cavitation is the most common
complication, which may communicate with bronchial tree.
Hilar lymph nodes may or may not be involved.
Disseminated lesions (0.5-1%of patients) by hematogemous route are seen in meninges,
skin, soft tissue, bones, adrenals,
Central nervous system is affected in 50% patients with disseminated lesion
. Coccidial meningitis is a chronic lesion with insidious onset .
Granulomatous and suppurative lesions are noted affecting basilar process
and sometimes brain parenchyma and spinal cord. Hydrochephalus is a
infection is very rare following inoculation of organisms at sites of
trauma. In disseminated disease the skin lesions takes the form of verrucous
plaques (nasolabial fold), granulomatous papules and nodules usually on the
head. Subcutaneous abscesses or pustular lesions & sinus tracts are also
. Usually kenee, ankle and wrist joints are involved.
osteomyelitis. Long bones as well as bones of hands, feet, pelvis and skull
may be involved.
Other organs involved include:
gastrointestinal tract, genito-urinary tract, pericardium and peritoneum
In tissue the
inflammatory reaction is both purulent and granulomatous. Endospores
incite a polymorphonuclear response. As the endospores mature into
spherules, the acute reaction is replaced by lymphocytes, plasma cells,
epithelioid cells and giant cells.
Image link (Dr Tsutsumi):
Images: Link (Dr Rosen):
Caseative pulmonary granuloma (resemble Tuberculosis); Epithelioid cells and
giants cells may be noted ; Organisms are present within the
granuloma ; Mature spherule with endospores ;
Hyphae may be present
in the pulmonary cavities ;
Often associated with
microabscess formation ; Most
of the lesions are healed by fibrosis & calcification.
Non caseating granuloma in the upper and mid-
dermis; Thick walled spherules within the granuloma ; Early
lesions and subcutaneous abscesses demonstrate abundant neutrophil
polymorphs ; Some lymphocytes, histiocytes and eosinophils are also
1. Skin test ;
2. Serodiagnosis ;
3. Immunoflourescence- confirmatory.