Coccidioidomycosis and paracoccidioidomycosis

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Summary of Coccidioidomycosis and paracoccidioidomycosis

Coccidioides is a genus of dimorphic ascomycetes in the family Onygenaceae. Infected patients present with an acute respiratory illness characterized by fever, cough, and pleuritic pain. Skin manifestations, such as erythema nodosum, are also common. Coccidioides infection can cause a severe and difficult to-treat meningitis in AIDS and other immunocompromised patients.

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Coccidioidomycosis and paracoccidioidomycosis

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COCCIDIOIDES SPP. osms.it/coccidioides ▫ Metalloproteinase: inhibits phagocytosis ▫ Alteration of pulmonary surfactant proteins PATHOLOGY & CAUSES ▪ Coccidioidomycosis ▫ Systemic fungal infection caused by Coccidioides immitis, C. posadasii; usually manifests as acute pneumonia ▪ AKA San Joaquin Valley Fever/“desert rheumatism” (associated with arthralgia) ▪ Arthroconidium inhalation → conversion to spherules → activation of T-lymphocytes → production of cytokines → inﬂammation → acute pneumonia ▫ In infected tissue, spherules grow, septate → release endospores → infection spreads ▪ Immune response ▫ Mainly mediated by Th1 cells ▫ Interleukin 17, TNF alpha, interferongamma ▪ Incubation period: 1–4 weeks ▪ Common sites of infection: lungs, skin, bones, CNS ▪ High prevalence areas: arid, dry regions in U.S. (e.g. California, Southwest), Mexico, Central America, South America Coccidioides spp. ▪ Size: 20–70μm ▪ Dimorphism ▫ Mold form: found in soil ▫ Yeast form: parasitic ▪ Produces arthroconidia (barrel-shaped, multinucleated spores) ▫ Production stimulated by human sex hormones ▫ Arthroconidia convert to spherules (2–5μm; in infected tissues) ▪ Infectious particles: arthroconidia ▪ Virulence ▫ Enzyme with elastase activity: ↑ infection, inﬂammation ▫ Cell surface glycoprotein with adhesin activity 560 OSMOSIS.ORG Clinical syndromes ▪ Acute pneumonia ▪ Dermatologic lesions ▫ Wart-like lesions on face ▫ Erythema nodosum/multiforme ▪ Osteomyelitis ▪ Meningitis RISK FACTORS ▪ Outdoor occupations; recreational exposure to soil (e.g. gardening, camping); immunosuppression; recent travel to endemic areas; comorbid conditions COMPLICATIONS ▪ Adult respiratory distress syndrome; fatal multilobar pneumonia; pyopneumothorax; meningitis; chronicity SIGNS & SYMPTOMS ▪ ▪ ▪ ▪ ▪ Mostly mild/asymptomatic Non-speciﬁc: fever, malaise Cough, pleuritic pain, hemoptysis, arthralgia Erythema nodosum/multiforme Wart-like lesions on face (e.g. nasolabial folds) DIAGNOSIS DIAGNOSTIC IMAGING X-ray ▪ Pneumonia ▫ Parenchymal inﬁltrates, thin-walled cavities ▪ Osteomyelitis ▫ Osteolytic bone lesions

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Coccidioidomycosis and paracoccidioidomycosis

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Histologically, coccidioides can be seen under a microscope using a stain.

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A 28-year-old man presents to the emergency room with new-onset dyspnea. He reports having had several sexual partners over the past decade, using barrier protection only sparingly during this time. His CD4 count was found to be 120/mm³. He recently emigrated from Uruguay to New York City three months ago and reports no additional travel. Physical examination shows hepatomegaly along with lymphadenopathy and the presence of several purple papules scattered across his face. Bronchial lavage reveals round yeast with multiple buds. Which of the following is the most likely causative agent?

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