Fungal infections - 3

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Fungal infections - 3
2010-07-26 11:27:01
Fungal infections

Fungal infections - 3
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  1. Commensal

    Opportunistic infection in immunocompromised individuals

    superficial and deep of the skin, mucosal, lung, systemic
  2. Dermatophyte infections

    Candida albicans

    candidiasis (thrush); mucosal and systemic
  3. Aspergillus

    lung and systemic

    Nasal and maxillary sinuses
  4. Cryptococcus

    Histoplasma capsulatum
    Lung and brain

    lung, oral
  5. What are the 3 types of responses to fungal infections?
    • 1. minimal - dermatophyte (skin) ringworm, tinea
    • 2. acute - candidiasis
    • 3. granulomatous - histoplasmosis
  6. What is the etiology of histoplasmosis?
    • Histoplasma capsulatum
    • It is a mold in soil, bat/bird guano, yeast in tissue
  7. What is histoplasmosis?
    A disease caused by the fungi histoplasma capsulatum that is spread by inhaling spores --> it is a pulmonary disease. The organism is often found in soil.
  8. What are the clinical features of histoplasmosis?
    • 1. mild, flu-like symtpoms
    • 2. 2-3 weeks after infection, T-cell mediated granulomatous inflammation, antibody is produced several weeks later
    • 3. acute lungs 1%, 2 week duration, calcification of hilar nodes
    • 4. chronic lungs immunosuppressed in elderly
  9. What are oral manifestions of histoplasmosis?
    • - disseminated (diffused) to extrapulmonary sites.
    • - It is rare and found in 2-10% of HIV pts.
    • Oral:
    • - usually associated with disseminated disease
    • - tongue, palate, buccal mucosa, gingiva, floor of the mouth
    • - mimics malignancy clincially
  10. What is a differential diagnosis of histoplasmosis?
    It looks like oral cnacer and can be evaluated as non-cancerous because often the patient will also have pulmonary disease.
  11. what are the histologica signs of Histomplasmosis?
    • granulomatous inflammation
    • pseudoepitheliomatous hyperplasia (PEH)
    • Periodotc acid Schiff reagent, methenamine silver
    • yeasts 1-2u in diameter (this is what mimics cancer)
  12. How do you diagnose histoplasmosis?
    • tissue sections
    • serological testing for antibodies
    • detection of H.capsulatum antigen
  13. What is the treatment for histoplasmosis?
    • actue is usually self limiting
    • chronic: amphotericin B, ketoconazole, itraconazole
    • Disseminated has the same treatment as chronic
  14. What is the prognosis for histoplasmosis?
    • chronic w/out treatment may be progressive and death in 20%
    • disseminated disease mortality 20% w/ treatment
  15. Balstomyces dermatitidis
    A mold in moist soil that causes blastomycosis
  16. What are some other facts about Blastomycosis?
    • It is more common in males
    • It is rare in immunocompromised individuals
    • infections are acquired by inhaling spores (often after rain)
  17. What are the clinical features of blastomycosis?
    • acute pneumonia: fever, cough, night sweats, chest pain,
    • chronic is more common and mimics TB: low grade fever, night sweats, productive cough, infiltrate on chest radiograph (no calcification like histoplasmosis
    • Disseminated pulmonary - skin oral (oral lesions mimic malignancy)
  18. What are some differential diagnosis for blastomycosis?
    • TB - chest radiographs show clear diffuse infiltrate or nodes
    • Malignancy - oral lesions look cancrous
  19. What are histological classifications of blastomycosis?
    • acute and granulomatous inflammation
    • pseudoepitheliomatous hyperplasia (PEH)
  20. what are some characteristics of the etiological agent of blastomycosis?

    What stain is used to detect it?
    Blastomyces dermatitidis is 8-20u in diameter with a doubly refractile cell wall w/ broad attachment btw budding cells

    PAS and methenamine (Grocott-Gomori) silver special stains
  21. How do you diagnose blastomycosis?
    • examine tissue section
    • KOH (potassium hydroxide prep) digest cellular matter and leaves KOH crust.
    • culture from sputum or non-fixedbiopsy specimen
    • DNA probe on mycelia phase 5-7 da culture
  22. What is the treatment for Blastomycosis?
    • usually no treatment is required
    • if seriously ill (more than 2 weeks): itraconazole, ketoconazole, amphotericin B

    For the serious illness, there was a 80-90% mortality prior to amphotericin B.
  23. Coccidioides immitis?
    A dimorphic fungus found in soil that causes coccidioidomycosis
  24. How is coccidioidomycosis transmitted?
    • It is acquired via inhalation
    • It has a 1-4 week incubation period
    • It is more common in blacks and fillipinos
    • It causes a disseminated disease (body wide spread) disease in immunocompromised patients
  25. What is the histological presentation of coccidioidomycosis?
    • You find C. immitis with acute and granulomatous inflammation
    • Special stains of PAS and methenamine silver are used to ID it
  26. What is the diagnosis of coccidioidomycosis?
    • Tissue specimen
    • Cytology
    • Culture
    • Serological testing and skin testing
  27. What is the treatment of coccicioidycosis?
    In immunosuppresed/life treatening condition of disease: ketoconazole or flucanzole with amphotericin B

    The prognosis is pretty good but HIV patiens will need life-long daily antifungal medications.
  28. Cryptococcus neoformans
    A fungi who's inhaled spores cause cryptococcosis
  29. What are the manifestations of cryptococcosis?
    It is caused by cryptococcus neoformans and usually manifests as flu-like symptoms.

    In immunosuppresed patients it can can become disseminated and spread to the skin, menininges, bones, and prostate.

    Oral lesions are rare
  30. What is the treatment of cryptococcosis?
    200mg fluconazole 2x daily for 8 weeks; then 200mg maintenance for life
  31. What is the histology of cryptococcosis?
    • granulomatous inflammation
    • 4-6y round to oval mo w/ clear capsule
    • It is usually detected with PAS methanmine silver or mucicamine
  32. How do you diagnose cryptococcosis?
    • biopsy
    • culture
    • detection of crytococcal antigen in CSF - the meninges are often invovled so some CSF can also be used to find the histological features of the MO
  33. What is the treatment for cryptococcosis?
    • amphotericin B and flucytosine
    • fluconazole and itraconazole

    prognosis depends on control of underlying condition and response to antifungal meds
  34. Zygomycosis?
    An oppertunistic infection usually caused by saprophytic (an organism that lives on dead material) mo such as Absidia, Mucor, and Rhizopus.
  35. How is Zygomycosis spread?
    Spores are usually inhalled in a rhinocerebral form. It is poorly controlled in diabetes, leukema, and other systemic disorders.
  36. What are the clinical features of Zygomycosis?
    • Nasal obstruction
    • discharge
    • facial pain
    • headache
    • visual distrubance
    • facial swelling
    • intraolra swelling/ulceration
  37. What are the radiographic features of Zygomycosis?
    • Opacification of sinus due to destruction of bone
    • It mimics malignancy
  38. What is another agent of Zygomycosis?
    Mucromycosis, phycomycosis
  39. What is the histology of Zygomycosis?
    • Large right angle branching nonseptate hyphae
    • invovles small BV walls and occlude (fungal angilitis)
    • Tissue invasion
  40. What is the treatment of Zygomycosis?
    • Surgical debridement
    • Antifungal medication-amphotericin B
    • Contorl underlying disease

    It has a poor prognosis
  41. Why does Zygomycosis have a poor prognosis?
    The antifungal medication - amphotericin B can cause renal failure.
  42. Aspergillosis?
    • An allergic reaction in normal host or invasive in immunocompromised
    • It is caused by Aspergillus Saprophytic mo in soil or water (A. Falvus and A. Fumigatus are the most common)
  43. How is Aspergillosis spread?
    Infection results from inhalation of spores (possible to be spread through hospital ventilation systems)
  44. What are the clinical features of Aspergillosis?
    • allergic symtpoms such as allergic fungal sinusitis
    • Low grade infection of sinus such as a fungus ball (aspergilloma)
    • Localized pain, swelling, yellow or black ulcer
    • Disseminated lung --> CNS, eye, skin, bone, GI (leukemia, corticosteroids)