Difference between revisions of "Histoplasmosis"
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Image:Histoplasmosis tuberculate chlamydospores.jpg|<center><p>'''Histoplasmosis tuberculate chlamydospores'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center></gallery> | Image:Histoplasmosis tuberculate chlamydospores.jpg|<center><p>'''Histoplasmosis tuberculate chlamydospores'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center></gallery> | ||
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+ | *Caused by [[Yeast-like fungi|''Histoplasma capsulatum'']] | ||
+ | *Gross lesions in lungs: | ||
+ | **Firm encapsulated granulomas ([[Granulomatous Pneumonia|granulomatous pneumonia]]) | ||
+ | *Microscopic lesions: | ||
+ | **Macrophages with inracytoplasmic yeasts | ||
+ | *Also in other tissues | ||
+ | |||
+ | ==Test yourself with the Systemic Mycoses Flashcards== | ||
+ | |||
+ | [[Systemic_Mycoses_-_Flashcards#Histoplasmosis|Histoplasmosis Flashcards]] | ||
+ | |||
+ | |||
[[Category:Systemic_Mycoses]] | [[Category:Systemic_Mycoses]] | ||
− | [[Category:To_Do_- | + | [[Category:To_Do_-_Clinical]] |
+ | [[Category:Respiratory Fungal Infections]] |
Latest revision as of 06:51, 5 April 2011
- Histoplasma capsulatum
- Non-contageous, systemic mycosis
- Commonly pulmonary infections occur
- Other organs can be involved
- Involves the reticuloendothelial system
- Intestinal form can also occur
- Acute and chronic disease can occur
- Endemic to the USA
- Isolated cases have been reported in Europe
- Respiratory infection
- Infection via ingestion can also occur
- Affects dogs, cats, cattle, horses and humans
- Found in soil contaminated by bird droppings, decaying vegetation and in caves inhabited by bats
- Fine, branching, septate hyphae with smooth-walled pyriform to spherical microconidia and large, thick-walled tuberculate macroconidia on simple conidiophores
- Dimorphic fungi
- Hard to demonstrate in smears as the organisms is very small
- Stain with Giemsa or Wright and examine under oil immersion lens
- Present intracellularly in macrophages as oval yeast cells with few buds
- Clear halo is seen around the darker staining central material
- Grows on Sabouraud's Dextrose agar
- Creamy white colonies, turning tan coloured and then brown
- Also grows on Blood agar
- Small, white yeast-like colonies
- Test using immunodiffusion, complement fixation and counterimmunoelectrophoresis
- Skin test of little value as it only indicates exposure
- Treatment with Amphotericin B
- If Amphotericin B is contra-indicated, imidazoles can be given orally
- The prognosis is poor in acute and disseminated cases
- Caused by Histoplasma capsulatum
- Gross lesions in lungs:
- Firm encapsulated granulomas (granulomatous pneumonia)
- Microscopic lesions:
- Macrophages with inracytoplasmic yeasts
- Also in other tissues