Pulmonary Fungal Infection 1 Flashcards
When are Coccidioides most infectious and what do they form in order to become infection?
Dry summer form hyphae with alternating arthrospores
How are coccidioides spread
Formation of arthroconidia in the summer months–carried by wind and inhaled by humans
Who are the people most susceptible to coccidioides?
Snow birds moving to Southwest US
Where is coccidioides endemic?
Southwestern US
When coccidioides enters the terminal bronchiole of a patient what occurs
Changes form:
Spherules–highly resistant to eradication by immune sys
Thick, doubly-refractive wall
Filled with endospores
Wall ruptures to release endospores–new spherules
Are spherules and endospores seen with coccidioides pathogenesis infectious?
NO–no human to human spread
What is required in order for a patient to develop serious pneumonia or dangerous dissemination when infected by coccidioides?
Must be a high dose or the patient must be immunosuppressed
What occurs during the acute phase of a coccidioide infection?
Innate immunity–marcophages attempt to clear the infection and are often successful
When the innate immune system is inadequate for clearance of coccidioides, what occurs?
Chronic phase–lymphocytes and histiocytes initiate granuloma and giant cell formation
Many patient are asymptomatic or develop non-specific flu-like symptoms 60%
What are the symptomatic diseases that occur with coccidioides infection?
Valley fever or desert rheumatism
- Fever
- Arthralgias
- Erythema nodosum–shins (side effect of immune response–so its working)
- Erythema multiforme–rash on entire body
- Chest pain
What is most likely to occur if a patient is immunosuppressed and gets an coccidioides infection?
Disseminated infection–both intracellular travel in macrophages and hematogenous spread
What risk factors make pts more susceptible to disseminated infection from a coccidioides infection?
Advanced age Immunocompromise Late-stage pregnancy Occupational high-level exposure BLACK or FILIPINO race--this is an actual racial bias and not based on socioeconomic status
What are the primary sites of disseminated infection from a coccidioides infection?
Bones and meninges
When do most coccidioid infections occur?
Summer or autumn
Will a patient with a disseminated coccidioides infection (immunosuppressed) have a positive or negative PPD and what is used with the PPD test?
Negative
PPD with coccidioidin or spherulin
When erythema nudosum (adults)/ multiforme (peds) or arthralgias occurs with a coccidioides infection, what does this indicate
This is a HSR–meaning the immune system is working properly
Red, tender nodules on exterior surfaces –such as lower legs
Delayed cell-mediated HSR to the fungal antigens
RISK of dissemination is LOW
Where does a coccidioides infection disseminate to and what is found on PE?
Meninges–syms similar to bac meningitis but onset is slow
Bone–osteomyelitis
Skin or lymph nodes–soft tissue abscesses, hematogenously seeded
Syms:
- Night sweats
- Dyspnea
- Fever
- Weight loss
Biopsy of coccidioides
Exam for spherules
How should coccidiodes be cultured
On sabouraud’s agar at 25C
Its a cottony white mold composed of hyphae with arthrospores–INFECTIOUS
What is found within the CSF with a coccidiodes infection?
Lymphocytic pleocytosis Elevated protein Hypoglycorrhachia--low glucose Eosinophilia IgG
What a predisposed complications of coccidioides infection that must be treated even with mild disease
Severe immunosuppression DM Black/Fillipino Cardiopulmonary dz Pregnancy
Persisting lung lesions or disseminated coccidioides infection should be treated with?
Amphotericin B and long-term itraconazole
Minimum of 6 months therapy
Meningitis caused by coccidioides infection should be treated with?
Fluconazole–gets through BBB
Is histoplasma thermally dimorphic?
Yes–mold in soil, yeast in tissue–real budding yeast
