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Flashcards in Endemic mycoses Deck (20):
1

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)

2

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

3

Mycology of coccidioidomycosis

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

4

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

5

Diagnosis of coccidioidomycosis

Biopsy is best, DNA probe, maybe ABs

6

Therapy for coccidioidomycosis

Amphoteirriicin B (for worst case), fuconazole, Itraconazole

7

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

8

Mycology of histoplasmosis

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

9

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)

10

Diagnosis of histoplasmosis

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

11

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

12

Complications of histoplasmosis

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

13

Disseminated histoplasmosis

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

14

Therapy for histoplasmosis

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

15

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

16

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

17

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

18

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

19

Therapy of blastomycosis

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

20

Important reminders when dealing with endemic mycoses

You need to ask about travel history a lot!