Pulmonary Fungi Infections Flashcards
What are the general characteristics of agents causing systemic mycosis?
Inherently virulent; Exhibit biochemical and morphological features enabling evasion of host defenses; Four dimorphic, one grows as yeast
What is the primary focus of infection for agents causing systemic mycosis?
Lungs
What are the characteristics of Histoplasma capsulatum’s parasitic phase?
Small budding yeast found almost exclusively in macrophages; Ovoid yeast form measuring 1.5-2.9um; Mould has both micro and macro conidia
What is the most common disease caused by Histoplasma capsulatum?
Histoplasmosis
What is the African variant of Histoplasma capsulatum?
Histoplasma duboisii
What is the parasitic phase of Histoplasma capsulatum?
Tuberculate macroconidia formed on short, hyaline, undifferentiated conidiophores
What is the habitat of Histoplasma capsulatum?
Soil, especially in areas contaminated with bat and bird droppings
What is the clinical syndrome in an immunocompetent host infected with Histoplasma capsulatum?
Asymptomatic or mild flu-like illness in immunocompetent hosts
What are the clinical syndromes in an immunocompromised host infected with Histoplasma capsulatum?
Disseminated histoplasmosis in immunocompromised hosts; Chronic pulmonary histoplasmosis in chronic obstructive pulmonary disease patients
How is Histoplasma capsulatum diagnosed?
Serology: Complement Fixation Test using histoplasmin and inactivated whole yeast phase; Direct histopathologic examination of infected tissue; Culture: Blood, urine, sputum
What is the treatment for Histoplasma capsulatum infection?
Amphotericin B
What is another name for Blastomyces dermatidis?
Ajellomyces dermatidis
What are the clinical manifestations of Blastomyces dermatidis infection?
Progressive exertional dyspnea, fever, nonproductive cough, chest discomfort
What is the morphology of the yeast phase of Blastomyces dermatidis?
Budding yeast, wide-based attachment between mother and daughter cells
What is the morphology of the mold phase of Blastomyces dermatidis?
Branching septate hyphae with pyriform microconidia
What is the epidemiological distribution of Blastomyces dermatidis?
Mainly limited to North America
How is Blastomyces dermatidis diagnosed?
Culture: Readily grown on conventional media; Histopathologic examination shows spherules in tissue; Serodiagnosis: Tube precipitin and Complement fixation tests
What is the treatment for Blastomyces dermatidis infection?
Amphotericin B
What is another name for Paracoccidioidomycosis?
Lutz-Splendore-Almeida’s disease
What is the morphology of the yeast phase of Paracoccidioidomycosis?
Budding yeast, ship’s wheel appearance
What is the morphology of the mold phase of Paracoccidioidomycosis?
Branching septate hyphae with no typical pattern of sporulation
What is the epidemiology of Paracoccidioidomycosis?
Mainly restricted to Central and South America
What is the clinical syndrome associated with Paracoccidioidomycosis?
Frequently asymptomatic but can become progressive; oral and nasal lesions
How is Paracoccidioidomycosis diagnosed?
KOH preparations, culture, serodiagnosis
What is the treatment for Paracoccidioidomycosis?
Long-term therapy with Amphotericin B; Ketoconazole is also effective
What is another name for Coccidioidomycosis?
San Joaquin Valley fever
What is the morphology of the mold phase of Coccidioidomycosis?
Branching septate hyphae with alternate cell developing into arthroconidia
What is the morphology of the yeast phase of Coccidioidomycosis?
Large spherical structures called spherules filled with endospores
What is the epidemiology of Coccidioidomycosis?
North, Central, and South America
What are the clinical manifestations of Coccidioidomycosis?
Mild febrile to moderately severe pulmonary disease
How is Coccidioidomycosis diagnosed?
Culture, histopathologic examination, serodiagnosis
What is the treatment for Coccidioidomycosis?
Long-term therapy with Amphotericin B; Ketoconazole is a useful alternative
What is another name for Cryptococcosis?
Acidic mucopolysaccharide capsule
What is the morphology of Cryptococcus neoformans?
Pigeon roosts, survives well in dry, alkaline, nitrogen-rich environments
What is the distinctive feature of Cryptococcus neoformans?
Solitary pulmonary nodule; meningitis in immunocompromised
What is the epidemiology of Cryptococcosis?
Inhalation of dessicated yeast cells and small basidiospores into lungs
What are the clinical manifestations of Cryptococcosis?
Definitive diagnosis: Culture, India ink preparation, serodiagnosis
How does Cryptococcus neoformans cause infection?
Pulmonary lesions usually self-limited; Amphotericin B for disseminated disease
How is Cryptococcosis diagnosed?
Nearly all infected in infancy
What is the treatment for Cryptococcosis?
Trophic and cystic forms
What are the two distinct forms of Pneumocystis?
Progressive exertional dyspnea, fever, nonproductive cough, chest discomfort
What are the clinical manifestations of Pneumocystis jirovecii pneumonia (PCP)?
Clinical presentation, blood tests, radiographs suggestive but not diagnostic
How is PCP diagnosed?
Induced sputum, bronchoscopy with bronchoalveolar lavage, transbronchial biopsy
What is the preferred primary prophylaxis for PCP?
Trimethoprim-sulfamethoxazole (TMP-SMX)
What are the alternative options for primary prophylaxis for PCP?
Dapsone, aerosolized pentamidine, atovaquone
What is an adjunctive treatment for PCP?
Corticosteroids
What staining methods are used for the microscopy of Pneumocystis?
Giemsa staining, GMS, Florescence microscopy, Toluidine Blue O, Diff quik
What is shown in lung biopsy using silver stain for Pneumocystis?
Lung biopsy using silver stain to demonstrate Pneumocystis organisms in tissue
What are the risk factors for PCP?
CD4 count <200 cells/µL, prior PCP, oral thrush, recurrent bacterial pneumonia
What has led to a decline in the incidence of PCP in the United States and Western Europe?
Prophylaxis and effective ART, decline in incidence in the United States and Western Europe
