Table Of Contents
Cryptococcal Meningitis
Cryptococcal menigitis is an invasive fungal infection of the central nervous system caused by Cryptococcus neoformans or Cryptococcus gatti. It is common in immunocompromised patients and presents as a “meningoencephalitis” rather than a pure meningitis since brain parenchyma is almost always involved. It occurs in patients with CD4 < 100/mL. It is clinically similar to CNS tuberculosis, although presentation as a mass lesion (cryptococcomas) is rare. It can presents as a fulminant infection (coma → death), especially since patients present late.
Cryptococci and their characteristics
| Fungus | Characteristics |
|---|---|
| Cryptococcus neoformans | Isolated from soil in areas frequented by pigeons and chicken. Associated with rotting vegetation |
| Cryptococcus gatti | From river red gum trees. Affects immune-competent individuals |
- Signs and symptoms
- Insidious onset
- Fever
- Malaise
- Intermittent painful headaches
- Meningismus (Neck stiffness, Positive Kerning’s and Brudzinski’s sign)
- Investigations
- Head CT: before performing a lumbar puncture if patient has signs of raised intracranial pressure. To rule out other causes of mass lesions.
- Lumbar puncture for CSF analysis, India ink test and culture: best initial test. Repeat CSF culture at 14 days after induction to monitor remission
- Very high opening pressure (> 200 mm on initial tap in 70% of patients)
- Slightly elevated WBCs (<50/uL) predominantly lymphocytes
- Slightly elevated proteins
- Low glucose
- Encapsulated yeast forms on india ink
- Serum CRAG (serology): may remain positive for years after treating cryptococcal meningitis 25 – 30% of patients with AIDS presenting with cryptococcal meningitis have normal CSF cell counts, glucose and proteins
- Treatment of cryptococcal meningitis
- Pre-treatment with acetaminophen, diphenhydramine or corticosteroids 30 minutes before infusion of amphotericin B to prevent infusion-related reactions e.g. fever and chills
- U/E/Cs to monitor renal function and electrolytes
- Induction therapy (duration based on culture and clinical response)
- Liposomal amphotericin B +/- flucytosine for 2 weeks
- Liposomal amphotericin B for 2 – 6 weeks
- Liposomal amphotericin B or fluconazole for 2 – 6 weeks
- Consolidation therapy
- Fluconazole for 8 weeks
- Maintenance therapy
- Discharge on maintenance PO fluconazole or itraconazole indefinitely or until CD4 > 100
- Beign HAART 2 – 10 weeks after starting antifungals to reduce the risk of immune reconstitution inflammatory response (IRIS)
- Serial lumbar puncture or lumbar drains to untile openng pressure reduces to < 20 cmH20 or 50% of the initial value.
