Flashcards in Fungal respiratory infections Deck (49):
Which fungal pathogens are associated with the sinuses?
Which fungal pathogens are associated with the lungs?
1. Histoplasma 2. Blastomyces 3. Paracoccidioides 4. Coccidioides 5. Cryptococcus
Which fungal pathogens are associated with the lungs of immunocompromised patients?
1. Pneumocystis 2. Aspergillus
What are predisposing factors to zygomycete infection?
1. Immunosuppresion 2. Diabetes 3. Burns
What are the properties of zygomycetes?
1. Non-septate hyphae 2. Sporangia bearing sporangiophores
What are the clinical symptoms of rhinocerebral zygomycosis?
1. Most common form of zygomycosis 2. Primarily in diabetic patients 3. Infection originates in sinuses 4. Extends to neighboring tissues 5. Initial symptoms look like standard sinus congestion 6. Can progress to periorbital area, brain
What is the diagnosis for zygomycoses (mucormycosis)?
1. Broad aseptate hyphae in blood vessels 2. Hyphae branch at 90 degrees
What is the treatment for zygomycoses (mucormycosis)?
How does candida present in normal flora?
How does candida present in tissue?
What is the clinical presentation for oral candidiasis?
1. Diffuse erythema and white patches on surface of buccal mucosa, throat, tongue, gums 2. Plaques can be scraped or wiped to reveal raw erythematous lesion 3. White lesions are composed of yeast and pseudohyphal forms of C. albicans
What is the treatment for oral candidiasis?
Oral formulations of nystatin and azole compounds
What are the properties of systemic mycoses?
1. Initially present as respiratory illness 2. Not opportunistic 3. Acquired by inhalation 4. Dimorphic forms are regional, C. neoformans is worldwide 5. All dimorphic except for C. neoformans (encapsulated yeast)
What pathogens are responsible for systemic mycoses?
1. Histoplasma capsulatum 2. Blastomyces dermatitidis 3. Paracoccidioides brasiliensis 4. Coccidioides immitis
What are the characteristics of histoplasmosis?
1. Endemic to Mississippi river valley and Ohio river valley 2. Caused by histoplasma capsulatum 3. Found in soil (bird and bat droppings) 4. Infection via inhalation of micro or macroconidia
What is the clinical syndrome of histoplasmosis?
1. Inhaled fungal spores are phagocytized by pulmonary macrophages and convert to their yeast form 2. Replicates within macrophages 3. Usually asymptomatic (95%)
What are the properties of histoplasmosis?
1. Mild flu like illness with dry cough, fever, fatigue 2. Develops several weeks after exposure 3. Improves in 2-3 weeks 4. Self limiting 5. Calcifications of pulmonary lesions common
What are the properties of chronic pulmonary and dissenminated histoplasmosis?
1. Typically in immunocompromised individuals 2. More life threatening than normal histoplasmosis 3. Fever, night sweats, anorexia, fatigue, respiratory symptoms 4. Hepatomegaly, splenomegaly, lymphadenopathy possible
What is the diagnosis for histoplasmosis?
1. Direct observation (difficult due to small size) 2. Culture (takes a long time) 3. Serology (detect Ab or Ag)
What is the treatment for histoplasmosis?
1. Amphotericin B for pulmonary and disseminated 2. AIDS patients: lifelong suppressive therapy with azoles
How can B dermatitidis be differentiated from H. capsulatum?
1. Size of yeast 2. Thickness of wall
What are the characteristics of blastomyces dermatitidis?
1. Dimorphic2. Yeast in tissues
What are the properties of blastomycosis?
1. Primarily pulmonary disease 2. Transmission via inhalation 3. Yeast survive in macrophages 4. Mostly asymptomatic
What are the clinical symptoms of blastomycosis?
1. Acute - cough, fever, chills, arthralgia, myalgia 2. Chronic pulmonary - cough, fever, night sweats, sputum production 3. Disseminated - skin lesion, bone infection, prostate involvement
What is the diagnosis for blastomycosis?
1. Observation of distinct yeast forms in sputum or biopsy 2. Long cultivation
What is the treatment for blastomycosis?
1. Amphotericin B 2. Azole compounds for uncomplicated pulmonary
What are the properties of paracoccidioidomycosis?
1. Limited to tropical south and central America 2. Caused by P. brasiliensis 3. High prevalence (90%) in men 4. Dimorphic 5. Ship's wheel and mickey mouse ear morphologies
What are the properties of coccidioides immitis?
1. Dimorphic 2. Arthroconidia easily airborne 3. Following inhalation fungus converts to spherule
What are the properties of spherules in coccidioides immitis?
1. Multinucleated 2. Produces hundreds of single nucleated spores
What are the clinical symptoms of coccidioidomycosis?
1. Asymptomatic 60% of the time 2. Mild to moderate flu like symptoms developing 1-3 weeks after infection 3. Self resolving 4. Chronic form may take years to resolve
What are the properties of disseminated coccidioidomycosis?
1. Rare2. Develops within 1 year of infection 3. Infection of bones, joints, skin, CNS
What are the properties of coccidial meningitis?
1. Develops slowly with increasing headache, fever, stiff neck, other neurological signs 2. Frequently fatal if untreated
What is the diagnosis for coccidioidomycosis?
1. Direct observation for spherule in sputum or biopsy 2. Cultivation 3. Serology
What is the treatment for coccidioidomycosis?
1. Azoles 2. Amphitericin B for disseminated and meningitis
What is the leading form of fungal meningitis?
What are the properties of cryptococcus neoformans?
1. Most common cause of cryptococcosis 2. NOT dimorphic 3. Encapsulated yeast
What are properties of pulmonary cryptococcosis?
1. Asymptomatic or mild, spontaneously resolving flu like sickness 2. Little sputum production 3. Little damage to lung (granuloma or cavitation)
What are properties of disseminated cryptococcosis?
Skin and bone lesions
What is the treatment for cryptococcal meningitis?
1. Long term (6-10 weeks) Amphotericin B + 5-fluorcytosine or fluconazole 2. Relapse is common in AIDS patients may require suppressive therapy
What are properties of pneumocystis jiroveci pneumonia (PCP)?
1. Caused by pneumocystis carinii (jiroveci) 2. Single celled eukaryote 3. Phylogenetically related to fungi 4. Some cellular and metabolic processes similar to protozoa 5. Difficult to grow in lab 6. Highly lethal
What are the clinical symptoms of PCP?
1. Infection via inhalation 2. Usually asymptomatic 3. Symptomatic - dyspnea, nonproductive cough, fever 4. Patient develops interstitial pneumonia with cellular infiltrate (weakness, tachypnea, cyanosis, death)
What is the diagnosis for PCP?
1. Identification in clinical material (lung lavage) 2. Need a special silver stain 3. Need to be looking for it and make special lab request
What is the treatment for PCP?
1. Trimethoprim-sulfamethoxazole - interferes with folate synthesis pathway 2. Prophylaxis in AIDS patients
What are the most common pathogens associated with aspergillosis?
1. A. fumigatus 2. A. flavus
What are the properties of aspergillosis?
1. Not dimorphic - always a filamentous mold 2. Infection via inhalation of conidia 3. Hyphal growth in tissues causes pathology
What are aspergillomas (fungus balls)?
1. Colonization of pre-existing lung lesions 2. Consist of hyphae within a matrix of fibrin and cellular debris 3. Typically unilateral 4. Frequently asymptomatic 5. Hyphal penetration of blood vessels results in hemoptysis
What are the properties of invasive / disseminated / systemic asperigillosis infection?
1. Occurs primarily in patients with leukemia, neutropenia, organ / marrow transplant 2. Frequently fatal 3. Invasion of lung parenchyma following infection 4. Hyphae invade vessel lumen causing thrombosis / infarction / hemorrhage 5. Dissemination from lung to GI, brain, liver, kidney
What is the diagnosis for aspergillosis?
1. Observation of hyphal elements in sputum or biopsy (septate hyphae with 45 degree V shaped branching) 2. Culture confirmation