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Flashcards in Endemic mycoses Deck (20)
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1
Q

the meaning of dimorphic as it relates to the endemic mycoses

A

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

2
Q

Epidemiology of coccidioidomycosis

A

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

3
Q

Mycology of coccidioidomycosis

A

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

4
Q

Symptoms of coccidioidomycosis

A

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

5
Q

Diagnosis of coccidioidomycosis

A

Biopsy is best, DNA probe, maybe ABs

6
Q

Therapy for coccidioidomycosis

A

Amphoteirriicin B (for worst case), fuconazole, Itraconazole

7
Q

Epidemiology of histoplasmosis

A

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

8
Q

Mycology of histoplasmosis

A

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

9
Q

Pathogenesis of histoplasmosis

A

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)

10
Q

Diagnosis of histoplasmosis

A

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

11
Q

Acute histoplasmosis

A

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

12
Q

Complications of histoplasmosis

A

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

13
Q

Disseminated histoplasmosis

A

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

14
Q

Therapy for histoplasmosis

A

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

15
Q

Epidemiology of blastomycosis

A

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

16
Q

Mycology of blastomycosis

A

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

17
Q

Diagnosis of blastomycosis

A

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

18
Q

Secondary infections to blastomycosis

A

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

19
Q

Therapy of blastomycosis

A

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

20
Q

Important reminders when dealing with endemic mycoses

A

You need to ask about travel history a lot!