Infectious Disease
Endemic Mycoses & Other Fungal Infections
Infectious Disease

Endemic Mycoses & Other Fungal Infections

Histoplasma, Coccidioides, Blastomyces, Cryptococcus, Aspergillus, Candida, Sporothrix.

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Endemic dimorphic fungi

FungusRegionReservoirFeaturesDiagnosisTreatment
Histoplasma capsulatumOhio + Mississippi River valleysBird/bat droppings (caves)Flu-like + pulmonary nodules; immunocompromised: disseminated (hepatosplenomegaly, pancytopenia, oral ulcers); intracellular yeast in macrophagesUrine antigen, serology, biopsyItraconazole; amphotericin if severe/disseminated
Coccidioides immitisSW US (Arizona, S. California), MexicoSoil after rain/dust storms'Valley fever' = pulm + erythema nodosum + arthralgias; can disseminate to skin/bone/meninges (esp. AA/Filipino, pregnant)Serology, spherules on biopsyFluconazole or itraconazole; ampho for severe/meningitis
Blastomyces dermatitidisMississippi + Ohio Valleys + Great LakesDecaying wood, soilPulmonary + skin (verrucous ulcers), bone, GU; broad-based budding yeastBiopsy/cultureItraconazole; ampho for severe
ParacoccidioidesLatin AmericaSoilPulm + mucocutaneous oral ulcers; 'captain's wheel' yeastBiopsyItraconazole; ampho if severe
Sporothrix schenckiiWorldwide (rose gardener)Soil/thorny plantsLinear ulcers along lymphatics from scratch ('rose gardener')CultureItraconazole

Opportunistic & yeast infections

FungusPatientFeaturesTreatment
Cryptococcus neoformansHIV (CD4<100), immunocompromisedMeningitis (headache + AMS + ↑opening pressure); India ink shows encapsulated yeast; serum/CSF cryptococcal antigenAmphotericin B + flucytosine 2 weeks → fluconazole consolidation/maintenance
Aspergillus fumigatusNeutropenic / transplantInvasive: pulm with halo/air crescent sign; angioinvasion. Aspergilloma (fungal ball in old cavity). ABPA (asthma + brown sputum)Voriconazole (invasive); aspergilloma observe; ABPA steroids ± itraconazole
Mucormycosis (Rhizopus)DKA + ferric overload (deferoxamine)Black necrotic eschar in nose/sinus → invades orbit/brain; non-septate hyphaeEmergent surgical debridement + amphotericin B
Pneumocystis jiroveciiHIV CD4<200, steroidsBilateral interstitial infiltrates + hypoxia + ↑LDHTMP-SMX + steroids if PaO₂<70 or A-a>35
Candida albicansDiabetes, abx, immunocompromised, IV linesOral thrush, esophagitis (white plaques on EGD), vulvovaginitis, candidemiaFluconazole (uncomplicated); echinocandin (severe/candidemia)

High-yield pearls

  • Histoplasmosis: bird/bat poop + Mississippi/Ohio — pancytopenia in HIV
  • Coccidioides: 'cocci in California' + erythema nodosum
  • Blastomyces: BROAD-based budding; verrucous skin lesions
  • Sporothrix: 'rose gardener's disease' — linear lymphangitic spread
  • Cryptococcus + HIV: India ink + cryptococcal antigen; treat serial LPs for ↑OP
  • Mucor in DKA: emergent surgery + ampho; deferoxamine + iron overload also risk
  • Aspergillus halo sign / air crescent / fungal ball in old cavity
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