HISTOPLASMOSIS

• HISTOPLASMOSIS


  Caused by the inhalation of conidia from the fungus Histoplasma capsulatum
• Histoplasmosis


  • Intracellular mycotic infection of reticuloendothelial system
  • Lymph nodes, spleen, bone marrow
  • Disease mainly affects the lungs with most patients often showing minimal or no symptoms
  • Upon inhalation, the infection stays in the lungs before spreading to the reticuloendothelial system
• Reservoir of fungi: soil contaminated with bird or bat droppings
• Transmission

  Inhalation of bird/bat droppings
• Symptoms in 10 days (Average)
• T cell-mediated response in 2-4 weeks
• Disseminated to other organs (hence, systemic)
• Clinical Manifestations


  • Acute pulmonary histoplasmosis (lung disease)
  • Chronic pulmonary histoplasmosis
  • Progressive disseminated histoplasmosis
  • Ocular histoplasmosis syndrome (eye disease)
• Clinical Material


  • Skin scrapings
  • Sputum
  • Bronchial washings
  • CSF
  • Pleural fluid
  • Blood
  • Bone marrow
  • Urine
  • Tissue biopsies from various visceral organs
• Depends on what stage the infection is currently in
• Methods of Diagnosis


  1. Direct Microscopy

  2. Culture

  3. Antigen detection

  4. PCR
• Culture


  • Sabouraud's dextrose agar and Brain heart infusion agar supplemented with 5% sheep blood
  • Incubate at 37°C temperature - Conversion into narrow-based, round, budding yeast cells = CONFIRMATORY of histoplasmosis
  • Incubate at room temperature
• Antigen detection


  Radioimmunoassay or ELISA
• PCR allows a definitive diagnosis
• Monitoring


  Among those with mild symptoms
• Antifungal medicine


  Ketoconazole and itraconazole