Dimorphic Endemic Fungi Quiz

Dimorphic Endemic Fungi

• Coccidioidomycosis ("Valley Fever"):
  • Etiology: Mold in soil, yeast in the body.
  • Epidemiology: Southwest US (AZ, NV), Mexico, Central America, South America.
  • Transmission: Inhalation of airborne spores; rare from organ transplants.
  • Course: Often subclinical, 50% spontaneous resolution; lifelong immunity prevents recurrence.
  • Risk Factors: Endemic region exposure, dusty outdoor activities, HIV, DM, elderly, Black or Filipino patients, pregnancy.
  • Symptoms (General): Fever, fatigue, headache, night sweats, weight loss, arthralgias.
  • Symptoms (Chest): Productive cough, dyspnea, hemoptysis, pleuritic chest pain.
  • Symptoms (Rash): Erythema nodosum, erythema multiforme.
  • Typical Presentation: Arizona construction worker.
  • Testing: IgM and IgG titers, moderate leukocytosis and eosinophilia, varying imaging results.
  • Treatment: Uncomplicated cases resolve spontaneously; Itraconazole 200 mg PO BID x 6 months; progressive disease requires Amphotericin B IV until titers decrease.

Other Dimorphic Fungi

• Blastomycosis:
  • Etiology: Mold in soil/water.
  • Transmission: Exposure to contaminated soil/decomposing timber, skin trauma, inhalation of spores.
  • Epidemiology: Ohio River Basin, Mississippi River Basin, Great Lakes, St. Lawrence River.
  • Pathophysiology: Incubation period 30-45 days.
  • Symptoms: Can be initially asymptomatic in 50% of patients; fever, sweating, cough, nocturnal joint pain.
  • Dissemination: Potential spread to bones, nervous system, lungs, liver, spleen, kidneys.
  • Diagnosis: Microscopy (broad-based budding), skin biopsy, bone marrow aspirate; Chest X-Ray, possible osteolytic lesions.
  • Treatment: Itraconazole PO x 6-12 months; severe cases require Amphotericin B.

Filamentous Fungi

• Aspergillus:

  • Pathophysiology: Produces aflatoxin, grows into surrounding tissue, sometimes forms aspergilloma. Invasive aspergillosis can affect lungs, sinuses, CNS, eyes.
  • Diagnosis: Cultures not sufficient; Galactomannan antigen detection test needed.
  • Allergic Bronchopulmonary Aspergillosis (ABPA): Hypersensitivity to spores causing bronchiole inflammation and eosinophilia.
  • Treatment (ABPA): Itraconazole and prednisone; voriconazole may also be used.
  • Treatment (Invasive): Voriconazole, surgical debridement (sinuses, focal lesions).

• Mucormycosis ("Black Fungus"):

  • Etiology: Infections of multiple molds.
  • Risk Factors: DM, cancer, immunosuppression, steroids.
  • Pathophysiology: Commonly infects sinuses, eyes, brain; invades blood vessels, causing tissue death.
  • Diagnosis: Biopsy, culture, imaging studies.
  • Treatment: Amphotericin B IV and surgical debridement; poor prognosis – over 50% mortality.

Fungus/Protozoa

• Pneumocystis:
  • Etiology: Classified as both a protozoan and fungus.
  • Risk Factors: HIV (CD4 count < 200), solid organ/stem cell transplant recipients, high-dose corticosteroids.
  • Symptoms (Initial): Fever, malaise, non-productive cough.
  • Symptoms (Pronounced): Sputum production, chest pain, chills, exertional dyspnea.
  • Imaging: Chest X-ray shows diffuse bilateral interstitial infiltrates ("batwinging").
  • Diagnosis: Sputum sample, PCR, blood test (Beta-D-glucan).
  • Treatment: 21 days of Trimethoprim-sulfamethoxazole.

Test your knowledge on Coccidioidomycosis, also known as Valley Fever. This quiz covers the etiology, epidemiology, transmission, course, symptoms, and treatment of this endemic fungal infection. Assess your understanding of this crucial topic in microbiology and infectious diseases.