Fungi Flashcards
Three common fungal causes of acute pneumonia?
- Histoplasma capsulatum
- Coccidioides immitis
- Mucormycosis (rhizopus)
Five common fungal causes of chronic pneumonia syndrome?
- aspergillus
- blasto derm
- coccidioides
- histo
- cryptococcus neoformans
Which 3 fungi are associated with infections in patients with granulocyte dysfunction (neutropenia)?
- aspergillosis
- zygomycosis
- candidiasis
Which 5 fungi are associated with infections in patients with depressed CMI?
- candida (mucosal)
- coccidioidomycosis
- cryptococcus
- histoplasmosis
- pneumocytosis
Most prevalent and most virulent aspergillus species?
- fumigatus
- flavus
Mycology of aspergillus?
- MOLD
- narrow, branching, septate hyphae
Most widely used test for aspergillus detection?
- galactomannan antigen test (immunofluoresence)
Three allergic classifications of aspergillosis?
- extrinsic allergic alveolitis
- extrinsic asthma and allergic bronchopulmonary aspergillosis (ABPA)
- allergic sinusitis
What kind of patient does extrinsic allergic alveolitis with aspergillus occur in?
- farmer or malt work
- non-atopic workers to antigen in moldy hay/grain
What kind of patients does ABPA occur in?
- children, adolescents and young adults with asthma
- allergic response to hyphae without direct tissue invasion
What kind of patient does allergic sinusitis with aspergillus occur in?
- immunocompetent atopic patient with history of repeated bouts of sinus congestion
What kind of patient does saprophytic aspergillosis occur in?
- patients with cavities due to TB, sarcoid, bronchiectasis, pneumoconiosis, CF
- fungal balls –> local hemorrhage
Three major predisposing factors to invasive aspergillosis?
- granulocytopenia
- high dose corticosteroids
- HIV
What is the airborne form of mucormycosis?
sporangiospores (contains lots of individual spores)
Unique, common predisposing factor to mucormycosis?
- DM
Structure of mucomycosis? Diagnosis?
- broad, irregularly wide, non-septate hyphae
- NO serology available
Presentation of pulmonary mucormycosis?
- persistent fever and pulmonary infiltrates refractory to AB Tx
- consolidation involving one or multiple lobes
- endobronchial masses, erosion of bronchi, bronchopleural, and broncocutaneous fistulae and granulomatous mediastinitis
Two AIDS-defining pulmonary illnesses?
- Cryptococcus neoformans
- Pneumocystis jirovecii
What is the morphology of cryptococcus?
- encapsulated yeast (polysaccharide capsule with India Ink)
How does cryptococcus manifest in COPD patients? IC?
- pneumonia with nodular lesions/cavitary disease/pleural effusions
- disseminated disease – meningoencephalitis, cutaneous lesions
Primary predisposing factor to PCP?
- CD4 T cell defect caused by HIV infection
How does PCP usually present? (pneumocystis jirovecii)
- pneumonia
- history of dry cough, fever, dyspnea, difficulty with deep inspiration
- bilateral diffuse infiltrates with ground-glass appearance
- extra-pulmonary infections rare
Histopathology of PCP?
characteristic eosinophilic honeycombed material in alveolar space with H&E
Geographic distribution and morphology of Histoplasma capsulatum?
- Mississippi-Ohio River valleys
- dimorphic
- mold in environment = septate hyphae, large tuberculated conidia and small smooth conidia
- yeast in tissue = small, single bud with narrow septum
Three pulmonary disease manifestations of histo?
- acute primary pulmonary: immunocompetent with heavy inoculum; influenza-like illness, self-limiting (diffuse alveolar infiltration or military pattern that resolves with calcifications)
- chronic cavitary pulmonary: COPD; indolent but progressive respiratory infection (low grade fever, productive cough, dyspnea, night sweats)
- asymptomatic infection: fungemia and dissemination that could reactivate later
How does histo present in the immunocompromised?
dissemination
Diagnosis of histo?
serology, agglutination, complement fixation, immunofluorescence
Morphology of blastomyces dermatiditis? Specific environmental association?
- dimorphic
- mold in environment = septate hyphae, conidia on slender conidiophores
- yeast in tissue = thick walled, budding, WIDE septum
- bodies of water – Mississippi-Missouri River valleys
Four pulmonary manifestations of blastomycosis?
- 70% asymptomatic
- acute or subacute with influenza-like symptoms in immunocompetent patients
- chronic that may progress to dissemination particularly in IC patients
What fungal disease is fulminant with ARDS?
Blastomycosis
What cross-reaction can complicate blastomycosis serology?
- H. capsulatum
What other animal is highly susceptible to blastomycosis?
- canines
- not contagious to humans from dogs
Geographical distribution and morphology of coccidioidomycosis?
- desert southwest and deserts of Central and South America
- dimorphic
- mold in soil = septate hyphae with arthroconidia
- spherules containing endospores in tissues
What fungal disease is associated with erythema nodosum? Implications?
- Coccidioidomycosis
- associated with good prognosis
How does cocci present as a pulmonary disease?
- initial infection = self-limiting
- complications occur in IC – nodules, cavities, progressive pneumonia, pyopneumothorax, bronchopleural fistula
- extra pulmonary disease: skin, soft tissue, osteomyelitis, arthritis, meningitis
Which fungus exists as spherules instead of yeast in tissue?
Cocci
