Coccidioidomycosis

Introduction 

-Coccidioidomycosis is caused by dimorphic soil-dwelling fungi of the genus Coccidioides

-it is endemic in the arid regions of the southwestern United States, Central America, and South America

-Coccidioides grow in nature as a mold composed of barrel-shaped arthroconidia

-Infection occurs after inhalation of arthroconidia which will develop into large multinucleated spherical structures called spherules, which undergo division to release endospores 

Symptoms & Signs 

-Infection is usually self-limited in 60% of individuals 

-In the symptomatic, it takes the following clinical manifestations 

Valley fever, San Joaquin Valley fever, or desert rheumatism: the most common presentation; influenza-like or pneumonia like illness; fever, night sweats, profound fatigue, cough, headache, malaise, pleuritic chest pain, arthralgia, peripheral eosinophilia, hilar or mediastinal lymphadenopathy

Coccidioidal CNS disease: headache, fever, altered mental status, typically basilar meningitis, cranial nerve deficits 

Coccidioidal Skin Disease: most common form of disseminated disease, classic lesions seen on the nasolabial fold and sternoclavicular area, appears as papules, nodules, or verrucous plaques, ulcers, draining sinuses, abscesses, maculopapular rash (toxic erythema), erythema nodosum typically over the lower extremities, erythema multiforme, usually in a necklace distribution 

Coccidioidal joint disease: Joint pains and swellings often of the knees and ankles 

Diagnosis 

Microscopy: Large spherules containing endospores 

Culture: White to tan cottony colony formation, barrel-shaped arthroconidia
Serology: the mainstay of diagnosis, two serologic assays are used: The tube precipitin-reacting antigen detects IgM antibodies; The complement-fixing (CF) antigen detects IgG antibodies

Imaging: Patchy, nodular, lobar pulmonary infiltrates, hilar lymphadenopathy, mediastinal lymphadenopathy 

Treatment 

Mild disease: No treatment Severe disease: Amphotericin b, itraconazole, fluconazole, voriconazole, posaconazole

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