EXAM #2: PULMONARY FUNGAL INFECTIONS Flashcards
What is the most common endemic fungal infection in the US?
Histoplasmosis
*Along the Ohio/Mississippi rivers
What activities are Histplasmosis associated with?
1) Cave exploring
2) Excavation
3) Construction
4) Demolition
What type of organism is histoplasmosis?
Dimorphic fungus
Mold in the cold and a yeast in the heat
What cells does histoplasmosis infect?
Macrophages (alveolar)
*Mycelial infects and then yeast conversion occurs in the macrophage
Where does Histoplasmosis “live?”
- Soil
- Bird and bat droppings
How is histoplasmosis transmitted?
Inhalation
Describe the clinical course of histoplasmosis.
1) Inhalation and phagocytosis of histoplasma in alveolar macrophages
2) Hematogenous dissemination
3) Cell-mediated containment
*Infection is typically asymptomatic and causes granulomas i.e. residual nodules in the lung and spleen.
In symptomatic cases of histoplasmosis, what do patients complain of?
Subacute non-specific respiratory symptoms, often cough or flu-like sx.
What are the physical exam findings associated with histoplasmosis?
Rales and possible consolidation
What are the CXR findings associated with histoplasmosis?
- Hilar and mediastinal lymphadenopathy
- Calcified granulomas
What disease must you differentiate between prior to treatment of histoplasmosis?
Sarcoidosis
If you give a patient with histoplasmosis (not sarcoidosis) high dose steroids, you may kill them
In what patient populations is chronic pulmonary histoplasmosis most common?
Patients with underlying COPD
What are some of the clinical syndromes associated with histoplasmosis?
1) Broncholithiasis
2) Mediastinal granuloma
3) Fibrosing mediastinitis (precipitates SVC syndrome)
4) Pericarditis
5) RA
What skin findings are associated with histoplasmosis?
1) Erythema nodosum
2) Erythema multiforme
How is histoplasmosis diagnosed?
1) Antigen detection from blood, urine, or BAL fluid
2) Serology w/
- Complement fixation
- Immunodiffusion
How does the treatment plan for moderate to severe histoplasmosis differ from mild-moderate?
Moderate- severe:
1) Amphotericin B (2 weeks) followed by
2) Itraconazole
Mild-moderate:
- Itraconazole only
What type of organism is Coccdioides?
Dimorphic fungus
*Mold in the cold, yeast in the heat
What are the two organisms that fall under the label of coccidioides? Where are these species endemic?
- C. immitis= CA
- C. posadasii= other SW states
Describe the morphological features of coccidioides outside the body, and inside the body.
Outside= barrel-shaped arthroconidia
Inside= large spherule containing endospores
How is Coccidioides transmitted?
Inhalation of spores from dust exposure
*Think archaeological excavation and desert military maneuvers
What is the most typical clinically significant manifestation of coccidioides called?
San Joaquin Valley Fever w/
- Pneumonia
- Fatigue
- Arthralgias
What is the primary manifestation of pulmonary coccidioides?
Community acquired pneumonia with erythema nodosum and erythema multiforme
What organs/systems can disseminated coccidioides affect?
1) Skin or subcutaneous soft tissue
2) Meninges
3) Skeleton
How is coccidioides diagnosed?
Serological testing w/
- Immunodiffusion
- Precipitin antibodies
- Complement fixation
- ELISA
What types of coccidioides infection requires treatment? How is it treated?
1) Infections not affecting the CNS= itraconazole
2) Reticulonodular pneumonia or CNS manfiestations= amphotericin B
What organism causes Blastomycosis?
Blastomyces dermatitidis
*Again, dimorphic fungi i.e. mold in the cold and a yeast in the heat
What is the mnemonic to remember how Blastomycosis appears on wet smear?
Broad-based-budding
How is Blastomycosis transmitted?
Inhalation of spores from moist soil
Where is Blastomycosis endemic?
- Southeastern and south-central states that border the Mississippi and Ohio River basins
- Great Lakes
- Small portion of New York and Canada
What is Blastomycosis associated with?
Wooded areas and soil with decaying vegetation
What is the mnemonic to remember the organs/ systems involved in Blatomycosis infection?
BLAS
- Bone
- Lung (pneumonia)
- And Skin
How are the cutaneous lesions associated with Blastomycosis described?
Verrucous lesion with irregular borders
M*may mimic squamous cell carcinoma.
How does Blastomycosis treatment differ from Histoplasmosis?
Most patients with Blastomycosis require treatment
How is Blastomycosis treated?
1) Amphotericin B
2) Itraconazole
What type of organism is Pneumocystis jirovecii?
Pneumocystis jirovecii is an opportunistic fungi
What patient population is classically associated with Pneumocystis pneumonia (PCP)?
HIV+ with CD4 counts under 200
How is PCP diagnosed?
Silver stain of:
- Induced sputum
- Bronchoalveolar lavage
- Lung biopsy
Describe the appearance of PCP on CXR.
Diffuse, bilateral infiltrates extending from the perihilar region described as “ground-glass.”
Ground glass appearance is also seen on CT scan
How is PCP treated?
TMP-SMX
*Maybe with inhaled Pentmadine
What are alternative medications to TMP-SMX for PCP treatment?
- Dapsone
- Atovaquone
