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Flashcards in Endemic mycoses Deck (20):

the meaning of dimorphic as it relates to the endemic mycoses

Can grow as either a test of a mould depending on environment (Yeast at 37 and mould in lab)


Epidemiology of coccidioidomycosis

Endemic to hot dry places in western hemisphere - in US, California, Arizona, N Mexico, Texas. Some in mexico, Central and south america


Mycology of coccidioidomycosis

Exists as mycelium (mould), but when spores inhaled it forms spherule (a multinucleated structure)


Symptoms of coccidioidomycosis

Many have no symptoms or mild URTI. Others have influenza-like illness 3 weeks after exposure (cough, fever, drenching night sweats, pleuritic chest pain, or arthralgia). Often resolves w/o Tx, but can develop severe pneumonia and spread to skin, bone/joints, meningitis


Diagnosis of coccidioidomycosis

Biopsy is best, DNA probe, maybe ABs


Therapy for coccidioidomycosis

Amphoteirriicin B (for worst case), fuconazole, Itraconazole


Epidemiology of histoplasmosis

Most endemic in the Mississippi and Ohio river valleys, Also parts of Australia, Africa, SE Asia, and South America, soil fungus that favours moderate climate & humidity. Found in bird and bat poop enhance growth


Mycology of histoplasmosis

H. capsulatum exists in 2 forms – mycelial phase (present at ambient temperature) and the yeast phase (present at 37ºC or higher)


Pathogenesis of histoplasmosis

Microconidia settle into the alveoli and are engulfed by neutrophils and macrophages; once intracellular mycelia are converted to the yeast form; migrate to lymph nodes and than to distant organs that are rich in macrophages (liver and spleen)


Diagnosis of histoplasmosis

Most have mild flu-like illness. Severity depends on inoculum. Acute and possibly many complications. Fungal stain, or AB (slow)


Acute histoplasmosis

symptoms include fever, chills, non-productive cough, chest pain (substernal related to enlargement of mediastinal/hilar lymph nodes, pleuritic pain is uncommon), malaise, myalgia, etc. CXR findings usually shows hilar/mediastinal lymphadenopathy (LN) or patchy reticulonodular infiltrates. Respiratory failure and death may ensue


Complications of histoplasmosis

Massive enlargement of the mediastinal LNs; Histoplasmoma (lesion forms calcified mass); Fibrosing Mediastinitis (can lead to scarring and airway obstruction)


Disseminated histoplasmosis

acute and chronic progressive disseminated histoplasmosis. Complications – CNS involvement, endocarditis, adrenal involvement. Acute is 100% fatal if untreated


Therapy for histoplasmosis

bad disease use Amphotericin B then itraconazole (itraconazole for mild disease too)


Epidemiology of blastomycosis

States along Ohio and Mississippi river basins (incl Manitoba), States/provinces by great lakes and St Lawrence. Parts of Africa, India, Isreal


Mycology of blastomycosis

Blastomyces dermatitidis – grows as a mycelial form at room temperature and as yeast form at 37C. Inhale conidia, then Conidia that escape the host defenses are rapidly converted to the yeast form – resistant to phagocytosis


Diagnosis of blastomycosis

Non-specific symptoms, usually non-productive cough. Chest Xray: some low things initially. Identify the fungus in smear or culture from tissue or exudates (culture takes 2-4 weeks of incubation). Serology weak


Secondary infections to blastomycosis

Pulmonary infection: like chronic pneumonia; cutaneous: seeding through blood, cause lesions that look like skin cancer or ulcers, no lymphadenopathy; subcutaneous; bone/joint; genitourinary; CNS


Therapy of blastomycosis

All cases need to be treated! Ketoconazole or itraconazole in immunocompetent patients, Amphotericin B for severely immunocompromised


Important reminders when dealing with endemic mycoses

You need to ask about travel history a lot!