Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
|
What are the endemic fungi in the US?
|
- Blastomycosis
- Histoplasmosis - Coccidioidomycosis |
|
|
Which fungal infection is endemic in WI?
|
Blastomycosis
|
|
|
Which fungal infection is endemic in parts of CA, AZ, NM, and TX?
|
Coccidiodomycosis
|
|
|
Which fungal infection is endemic in the SE?
|
Histoplasmosis
|
|
|
What areas is Histoplasmosis commonly found?
|
Areas frequented by birds (they are the carriers and spread the fungus with their droppings)
|
|
|
What is the life cycle of Histoplasmosis?
|
- Grows as mycelium
- Spread by birds and bats in their droppings - Parts of fungi break off and are inhaled - Pieces are ingested by macrophages in human ("intracellular organism") |
|
|
What are the forms of Histoplasma?
|
Dimorphic
- Hyphae - Macroconidia - Microconidia |
|
What is this a chest xray of?
|
Pulmonary Histoplasmosis
- Multiple calcified lesions - Probably had the disease a while back - Disseminated infiltrates to both sides of lungs * This is not diagnostic on its own, but with appropriate history |
|
What does this show?
|
Histoplasma in Yeast form in tissue (no longer a mycelium in tissue) = dimorphic
|
|
|
How can you assess if someone has been exposed to Histoplasma?
|
Histoplasmin hypersensitivity skin test (analogous to a TB skin test)
|
|
|
If you have a positive Histoplasmin hypersensitivity skin test, what does that mean?
|
You have been exposed to Histoplasma, but it doesn't say whether you have an active infection
|
|
|
What are the clinical features of Histoplasmosis?
|
- Multiple calcified lesions in lungs
- Granulomas in lungs - Fibrosing mediastinitis (may lead to pericarditis or pleuritis) which can restrict great vessels and cardiac movement |
|
|
Who gets localized granulomas during a Histoplasmosis infection?
|
- Patients with an intact immune system
- If you are immune compromised you are less likely to get a localized granulomatous infection, but rather have a dispersed infection |
|
|
When does Fibrosing Mediastinitis occur? What causes it?
|
Exaggerated inflammatory response to healed Histoplasma lesions
|
|
|
What is the sequence of events in Histoplasmosis?
|
- Primary infection
- Lesion heals - Secondary infection - Fibrosis - Obstruction of SVC - Cor pulmonale (PA obstruction) - Mitral Stenosis (PV obstruction) |
|
|
What is the life cycle of Blastomyces?
|
- Starts as mycelium in environment (can be introduced by wood slivers)
- Inhaled and turns into yeast (dimorphic) - Also seen in dogs but it doesn't spread from dogs to humans (even though this picture suggests otherwise) |
|
|
What does Blastomyces look like in the human?
|
- Yeast form budding
- Extracellular because it is too big to be ingested by macrophage |
|
What do these x-rays show?
|
Pulmonary Blastomycosis
- Moderate (L) - diffuse background infiltrates - Severe (R) - patchy infiltrates, this would definitely be symptomatic |
|
|
What are the clinical features of Blastomycosis?
|
- Pulmonary Blastomycosis
- Cutaneous Blastomycosis |
|
Which fungal infection could be found in this environment?
|
Coccidiodes
- Certain soils and precipitation patterns |
|
|
What is the life cycle of Coccidioides?
|
- Organism grows as mycelium
- Breaks off into little pieces that break off at connections (arthrospores) - They retain "furry" pieces of cytoplasm that help them float through wind - Inhaled by humans and form spherules that burst to release endospores |
|
What fungal infection is this?
|
Coccidioides Arthroconidia
|
|
What does this EM show?
|
Coccidioides spherules - they burst and release endospores
|
|
What does this image show?
|
Coccidioides spherules - they burst and release endospores
|
|
|
How do you stain Coccidioides?
|
- Periodic Acid-Schiff
- KOH+ Calcofluor - Methenamine Silver |
|
|
How do you determine if someone has been exposed to Coccidioides?
|
Coccidioidin hypersensitivity skin test
|
|
|
What are the clinical features of Coccidioidomycosis?
|
Valley Fever
- Pulmonary Coccidioidomycosis - early and late cavitation - Coccidioidomycosis Pneumonia |
|
What does this chest x-ray show?
|
Cavitation in pulmonary Coccidioidomycosis
|
|
Case: 38 yo MKE man developed low grade fever, myalgias, and non-productive cough. Crackles over R posterior chest. Patient had no travel hx, no animal exposure, no HIV risk, worked clearing land for transmission lines.
Given oral erythromycin empirically w/o effect. Condition worsened to fevers, night sweats, and 15 lb weight loss. CXR shows densely consolidated RUL w/o pleural effusion. *What is the differential diagnosis? |
- Blastomycosis
- TB - Malignancy |
|
|
Case: 38 yo MKE man developed low grade fever, myalgias, and non-productive cough. Crackles over R posterior chest. Patient had no travel hx, no animal exposure, no HIV risk, worked clearing land for transmission lines.
Given oral erythromycin empirically w/o effect. Condition worsened to fevers, night sweats, and 15 lb weight loss. CXR shows densely consolidated RUL w/o pleural effusion. *How can you rule out TB? |
Quantaferon test / TB test - only tells you if they have been exposed but not diagnostic of current infection)
Acid-fast stain on sputum |
|
Case: 38 yo MKE man developed low grade fever, myalgias, and non-productive cough. Crackles over R posterior chest. Patient had no travel hx, no animal exposure, no HIV risk, worked clearing land for transmission lines.
Given oral erythromycin empirically w/o effect. Condition worsened to fevers, night sweats, and 15 lb weight loss. CXR shows densely consolidated RUL w/o pleural effusion. *Med student notices this tender 2cm nodule on his leg. What do you do? |
Get nodule biopsied and sent to clinical laboratory, get KOH prep
|
|
Case: 38 yo MKE man developed low grade fever, myalgias, and non-productive cough. Crackles over R posterior chest. Patient had no travel hx, no animal exposure, no HIV risk, worked clearing land for transmission lines.
Given oral erythromycin empirically w/o effect. Condition worsened to fevers, night sweats, and 15 lb weight loss. CXR shows densely consolidated RUL w/o pleural effusion. *This is what KOH prep shows on skin biopsy of 2cm nodule. What is the agent? |
Blastomyces
|
|
|
How do you treat patient diagnosed w/ Blastomycosis?
|
6 month course of Itraconazole
|
|
|
Case: 38 yo MKE man developed low grade fever, myalgias, and non-productive cough. Crackles over R posterior chest. Patient had no travel hx, no animal exposure, no HIV risk, worked clearing land for transmission lines.
Given oral erythromycin empirically w/o effect. Condition worsened to fevers, night sweats, and 15 lb weight loss. CXR shows densely consolidated RUL w/o pleural effusion. *Pulmonary disease caused by Blastomyces is usually benign. Why was it treated w/ Itraconazole? |
Treated empirically because it kept getting worse and had disseminated to the skin
|
|
|
What is the mechanism of action of Itraconazole that makes it the preferred drug?
|
Targets the cell membranes - blocks ergosterol synthesis (which is specific to fungi)
|
|
|
Case 2: Acute respiratory illness in workers 10 days after excavating at archeological site in Utah/Colorado.
They get a CXR that shows multiple, thin-walled cavities w/ diameter of 2-4 cm and mediastinal lymphadenopathy. *What fungal pathogen do you suspect? |
Coccidioides immitis
|
|
|
Case 2: Acute respiratory illness in workers 10 days after excavating at archeological site in Utah/Colorado.
They get a CXR that shows multiple, thin-walled cavities w/ diameter of 2-4 cm and mediastinal lymphadenopathy. *What bacterial pathogen should you screen for? |
- Francisella tularensis
- Yersinia pestis - Mycoplasma species - Rickettsia reckettsii |
|
|
Case 2: Acute respiratory illness in workers 10 days after excavating at archeological site in Utah/Colorado.
They get a CXR that shows multiple, thin-walled cavities w/ diameter of 2-4 cm and mediastinal lymphadenopathy. *Could a hantavirus or adenovirus be involved? |
Yes
- Vector for hantavirus is rodents - Adenovirus is transmitted by respiratory airborn droplets (they were sleeping in tents so close quarters) |
|
|
Case 2: Acute respiratory illness in workers 10 days after excavating at archeological site in Utah/Colorado.
They get a CXR that shows multiple, thin-walled cavities w/ diameter of 2-4 cm and mediastinal lymphadenopathy. *Viral and bacterial serology and cultures were negative. What endemic mycosis do these people probably have? |
Coccidiodomycosis
|
|
|
Case 2: Acute respiratory illness in workers 10 days after excavating at archeological site in Utah/Colorado.
They get a CXR that shows multiple, thin-walled cavities w/ diameter of 2-4 cm and mediastinal lymphadenopathy. *The workers slept closely together in a tent. Could the infection be transmitted horizontally? |
No - endospores in human are not infectious to other humans
|
|
|
Case 2: Acute respiratory illness in workers 10 days after excavating at archeological site in Utah/Colorado.
They get a CXR that shows multiple, thin-walled cavities w/ diameter of 2-4 cm and mediastinal lymphadenopathy. *Is it necessary to do lung biopsies in these patients? |
No it wouldn't tell us anything we don't already know or suspect. Based on epidemiology and presentation and clustering of cases you probably have enough information as it is.
|
|
What is the likely diagnosis of this?
|
Histomycosis - small intracellular yeast
|
|
What is the likely diagnosis of this?
|
Coccidioides - spherules / endosporse
|
|
What is the likely diagnosis of this?
|
Blastomycosis - large yeast w/ large neck bud
|
|
|
What do histoplasmosis, blastomycosis, and coccidiodomycosis have in commen?
|
- Acquired via respiratory route
- Exhibit dermatological manifestations - Cause disease in immunocompetent people - Endemic to specific geographical regions |
