Makindo Medical Notes

CSF may be unrevealing. Opening pressure is often high. Higher numbers of fungal organisms in the CSF are associated with higher opening pressures. Cryptococcal antigen testing is essential for diagnosis.

About

• Cryptococcosis: A serious fungal infection that primarily affects immunocompromised individuals, caused by an encapsulated yeast.
• The yeast measures 2 to 15 µm in diameter, with a thick sugar-based capsule that hinders immune system attacks.
• Requires aggressive antifungal therapy due to high morbidity and mortality risks.
• Can lead to both pneumonia and meningitis.

Aetiology

• Contracted through inhalation of spores from bird droppings and contaminated soil.
• The infection typically begins in the lungs (pulmonary infection) and can spread hematogenously to the brain and other organs.
• Commonly seen in patients with AIDS or other conditions causing impaired cell-mediated immunity.

Defective Cell-Mediated Immunity

• Conditions that predispose individuals to cryptococcal infection include:
  • AIDS and other causes of profound immunosuppression.
  • Organ transplantation with immunosuppressive therapy.
  • Reticuloendothelial malignancies.
  • Chronic corticosteroid therapy and sarcoidosis.

Clinical Presentation

• Symptoms may be subtle, including nausea, headache, fever, and general malaise.
• Neurological: Basal meningitis, which can cause cranial nerve palsies, stroke-like symptoms, or even form space-occupying lesions.
• Respiratory: Chest infection presenting with fever, malaise, dry cough, and in severe cases, acute respiratory distress syndrome (ARDS).
• Skin lesions: Often resemble molluscum contagiosum.
• Other manifestations: Can involve myocarditis, hepatitis, chorioretinitis, and renal abscess formation.

Investigations

• Basic tests: FBC, U&E, CRP, and HIV testing are essential. Chest X-ray may show abnormalities in cases with pulmonary involvement.
• CT Head: Recommended first for immunocompromised patients due to the high risk of mass lesions.
• CSF analysis: Often reveals elevated pressure, protein, and lymphocytes. High intracranial pressure (ICP) is common due to the fungal capsule blocking CSF transport at the arachnoid granulations.
• India Ink Stain: Detects encapsulated budding cells in about 90% of cases.
• Cryptococcal Antigen Test: Critical for diagnosis confirmation.
• Cultures: Cryptococcus may be cultured from blood, urine, sputum, and in some cases, bone marrow.

Imaging

• Cryptococcal abscesses: Imaging may reveal characteristic abscesses or lesions in the CNS.

Management

• Initial Therapy: IV liposomal Amphotericin B for 2 weeks. Monitor for nephrotoxicity and electrolyte imbalances.
• Consolidation Therapy: Transition to oral Fluconazole 400 mg daily for at least 8 weeks, especially in AIDS patients.
• Maintenance Therapy: In AIDS patients, ongoing low-dose Fluconazole (200 mg daily) is often recommended to prevent recurrence.
• HAART: In HIV-positive patients, consider starting HAART therapy 2 weeks after antifungal initiation to minimize the risk of immune reconstitution inflammatory syndrome (IRIS).
• Management of ICP: Serial lumbar punctures or ventricular drainage may be necessary in cases with elevated ICP.