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69 Cards in this Set
- Front
- Back
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What are 3 fungi that cause pneumonia?
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-Histoplasma capsulatum
-Coccidioides immitis -Blastomyces dermatidis |
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What type of fungus is Histoplasmosis?
Where is it found? How is it transmitted? How is it NOT transmitted? |
Dimorphic (mold/yeast)
Found in soil - ohio Transmitted by inhaling bird and bat droppings Not transmitted person-to-person |
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What is the characteristic morphology of histoplasmosis?
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Narrow based budding
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What is the pathogenesis of histoplasmosis similar to?
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TB
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What type of symptoms are seen in Primary pulmonary histoplasmosis?
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-Usually asymptomatic
-May see fever/chills/myalgia, nonproductive cough |
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What is the usual treatment for primary pulmonary histoplasmosis?
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Self-limiting
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What are the steps seen in primary pulmonary histoplasmosis?
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1. Yeast taken up by alveolar macrophages
2. Enter lymphatics, disseminate 3. Granulomas form, central necrosis develops |
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What happens to the lesions in primary pulmonary histoplasmosis?
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-Healing
-Fibrosis -Calcification -May cavitate |
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What is chronic histoplasmosis similar to?
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Secondary TB
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Where are the granulomatous lesions in chronic histoplasmosis found?
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Apical lung lobes
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What are the 3 common drugs used to treat cavitary lesions in chronic histoplasmosis?
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-Itraconazole
-Fluconazole -Amphotericin B |
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What allows for progressive disseminated histoplasmosis to develop? Where is it predominantly seen in the body?
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-Immunocompromised states
-See in primarily extrapulmonary sites |
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What are the clinical signs seen in progressive disseminated histoplasmosis?
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-Severe fever/chills, productive cough, etc
-Diarrhea, anemia, purpura, lymph node/spleenomegaly |
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Why is progressive disseminated histoplasmosis ba?
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Because it has a high rate of mortality causing death within weeks
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How is progressive disseminated histoplasmosis treated?
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Aggressively with Amphotericin B
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Where can organisms be isolated from in disseminated histoplasmosis?
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-Alveolar macrophages
-All over in free tissue |
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What are the best methods for diagnosing H. capsulatum?
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-H/P
-CXR -Tissue ID with special stains -Serology -Direct immunoflourescence |
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What other diphasic fungus can cause pulmonary infections?
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Coccidioides immitis
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What morphology does Coccioides immitis have in the environment? In humans?
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Environment = arthroconidia
Humans = spherules |
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How is it spread?
How is it not spread? |
By inhaling the arthroconidia from dust
Not by person-to-person |
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How does Coccidiomycosis develop?
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The arthroconidia block phagolysosomal fusion in macrophages
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How many patients are infected in endemic areas? (San joaquin) Why?
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80% or more!
-Patients are usually asymptomatic |
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What % of patients with coccidiomycosis have lung lesions?
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10%
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What is the characteristic morphhology seen in patient samples for coccidiodes?
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-Thick walled non-budding spherules
-Spherules contain endospores |
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What type of lung tissue morphology is seen in coccidiomycosis?
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-Acute inflammation
-Granulomatous inflammation -Central necrosis |
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How often is disseminated disease seen in coccidiomycosis?
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Rarely - only in immunocompromised
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How is uncomplicated coccidiomycosis treated?
How is disseminated disease treated? |
Noncomplicated: self limiting
Disseminated: Amphotericin B, antifungals |
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What other dimorphic fungus causes lung infections?
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Blastomyces dermatiditis
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In what form is environmental Blastomyces seen as?
In human hosts? |
Environment: mycelial form (mold)
Humans: yeast |
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Where is Blastomyces dermatiditis found?
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In soil in WISCONSIN!! and other midwest areas, and countries..
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What is the hallmark morphology seen in yeast Blastomycosis in humans?
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-Broad based budding
-Multiple nuclei |
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How does Blastomycosis compare to the other noncomplicated lung infections caused by yeasts?
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More acute
-Sudden onset -Fever/chills/productive cough etc |
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What type of blastomycosis is MOST common?
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Chronic > acute!
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Where does blastomycosis spread in disseminated disease?
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-Skin
-Bone -Cutaneous (rare) |
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Why does blastomycosis cause disease?
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Macrophages can't ingest it
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What are the cells that respond to blastomyces infections?
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PMNs
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So what type of inflammation is seen in Blastomycosis?
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-Suppurative
-Neutrophilic |
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What do chronic lesions contain in Blastomycosis?
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-Granulomas
-Surrounding neutrophilic inflammation |
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How is Blastomycosis treated?
(severe vs mild) |
Antifungals
-Severe = amphotericin B -Mild = Conazoles |
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4 things that make patients susceptible to lung infections:
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1. AIDS
2. Immunosuppressive chemotx 3. BMT 4. Irradiation |
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How does a lung infection in an immunocompromised patient compare to a normal patient?
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More severe
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What are 4 bacterial causes of lung infection that infect immunocompromised patients more often than normal?
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-Pseudomonas
-Mycobacteria -Legionella -Listeria |
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What are 2 viral causes of lung infection that infect immunocompromised patients more often than normal?
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-CMV
-Herpesvirus |
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What are 5 fungal causes of lung infection that infect immunocompromised patients more often than normal?
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-Pneumocystis carinii
-Aspergillosis -Zygomycosis -Candidiasis -cryptococus neoformans |
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What type of genome does CMV have?
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dsDNA
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What family is CMV in?
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Herpes viruses
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What percentage of the US has serum antibody to CMV?
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50-90% based on soe status
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What are 4 ways that CMV can be transmitted?
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-blood
-solid organ transplant -breast milk -sexual contact |
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How does CMV survive in hosts?
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-Remains latent in WBCs
-Reactivates when cell immunity decreases (immune suppression) |
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What type of infection do we see when CMV infects immunoCOMPETENT people?
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Either Asymptomatic, or a mononucleosis like illness
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What 2 types of patients are we most concerned about regarding CMV? Why?
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-Fetuses - congenital defects
-Immunosuppressed - systemic diseases |
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What immunosuppressed patients are most likely to develop systemic disease from CMV reactivation?
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Those with CD4+ counts <50
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What are the 4 features of systemic CMV disease?
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-Pneumonitis
-Hepatitis -Colitis -Retinitis |
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What 5 main clinical symptoms will an immunosuppressed patient with CMV infection present with?
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-Fever
-Leukopenia -Thrombocytopenia -Nonproductive cough -Shortness of breath |
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What 5 features will be seen on lung biopsy in a CMV pneumonitis?
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HIFEE
-Hyaline membranes -Interstitial mononuclear infiltrate -Focal necrosis -Edema -Exudate |
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In what 3 cell types does CMV cause characteristic cytopathic features?
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-Alveolar macrophages
-Epithelial cells -Endothelial cells |
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What does CMV do to cells? 3 things:
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-Enlarged
-Owl's eyes -Smaller cytoplasmic blue inclusions |
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How is CMV diagnosed?
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-Culture
-Antigen testing -PCR -Tissue biopsy |
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How is CMV treated?
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-Ganciclovir, Foscarnet
-IvIG |
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What ubiquitous fungus is associated with causing pneumonia in immunosuppressed patients?
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Pneumocystis carinii
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How is Pneumocystis carinii transmitted?
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Airborne droplets
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What is a reservoir of Pneumocystis carinii?
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Children with subclinical pulmonary infections
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When does Pneumocystis cause infection?
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When the CD4 count drops below 200
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What does PCP often cause co-infections with?
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CMV
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What is pneumocystis pneumonia like compared to CAP?
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Drier, more indolent, more prone to progress into respiratory failure
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How does Pneumocystis colonize the airways?
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By adhering to Fibronectin on Type I pneumocytes
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What is the pathology that Pneumocystis sets up in the lungs?
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Intra-alveolar proteinaceous exudate
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How is Pneumocystis carinii diagnosed?
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-CXR showing a diffuse pattern
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How is Pneumocystis carinii treated?
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With bactrim
(sulfamethoxazole+trimethoprim) |
