respiratory tract fungal Flashcards
Describe the cause of Zygomycoses (mucormycosis)
Caused by Zygomycetes (Rhizopus, Absidia, Mucur)
- NON-septate hyphae
- sporangia bearing sporangiospores
describe Rhinocerebral zygomycosis
- most common form of zygomycosis
- occurs mostly in diabetic patients
- originates in sinuses following inhalation of spores
Symptoms: - initial = nasal congestion, blood-tinged rhinorrhea, tender sinuses, headache and fever.
- progresses = facial edema and visual disturbances, progression to brain results in altered mental status
describe the diagnosis of zygomycosis
- observation of hyphal elements and culture confirmation
- tissue section hyphae are often observed in blood vessels, frequently braning at right angels
describe the treatment of zygomycosis
Amphotericin B
Describe the cause of Candidiasis
Caused by the genus Candida
- -> most infections caused by C. Albicans
- exist as yeast (normal flora), pseudohyphal (tissue invasion), and hyphal (tissue invasion) forms
- white lesions/membranes are composed of yeast and pseudohyphal forms
describe Oral Candidiasis (Thrush)
- Often seen in infants, AIDS patient, Adults undergoing steroid/antibiotic treatment.
Symptoms: diffuse erythema and white patches on surface of buccal mucosa, throat, tongue, gums
–> plaques can be scraped or wiped away revealing a raw, erythematous, lesion
Describe the diagnosis and treatment of Oral candidiasis (thrush)
Diagnosis:
- diagnosis acheived by direct observation of symptoms.
Treatment:
- oral formulations (mouth washes or lozenges) of Nystatin and azole compounds.
Describe systemic Mycoses
Diverse group of clinical presentations
- Not opportunistic fungi (affects healthy individuals)
- Acquired by inhalation of fungal elements (hyphae or spores)
Describe the types of fungi causing Systemic mycoses
Histoplasma capsulatum
blastomyces dermatitidis
paracoccidioides brasiliensis
Coccidioides immitis = dimorphic fungi (yeast during infection)
Cryptococcus neoformans = encapsulated yeast in both environment and man
C. neoformans
Describe Histoplasmosis
Caused by Dimorphic fungus HISTOPLASMA CAPSULATUM
- found in soil containing bird/bat droppings
- Infection acquired by inhalation of micro- or macroconidia from environment
Describe the clinical symptoms of Histoplasmosis
- Inhaled fungal spores are phagocytosed by pulmonary macrophages and convert to their yeast form
- organism can replicate within macrophages and spread through the lymphatic and reticuloendothelial system
describe pulmonary histoplasmosis
A mild flu-like illness with a dry cough, fever, and fatique
- develops several weeks after exposure and improves within 2-3 weeks
- most infections resolve WITHOUT antifungal intervation
- calcification of pulmonary lesions is common
- pulmonary infiltrate and chest pain are more common in severe infections
