29th July 2023

Cryptococcal meningitis

This is the primary manifestation of cryptococcosis in patients with HIV/AIDS, and is an AIDS-defining illness associated with high mortality. It can occur in other immunocompromised people, too. The yeast reaches the meninges through haematogenous spread from the lungs, where it causes an insidious onset of subacute meningitis or meningoencephalitis.

The onset is generally over 1-2 weeks, with the predominant symptoms of headache, fever, and malaise. Neck stiffness, photophobia, and other focal neurological deficits are rare but may occur. Cryptococcal meningitis is fatal if untreated.

Diagnosis is made through CSF analysis following lumbar puncture. The characteristic profile is of lymphopaenia, high protein, and low glucose, but it may also be normal. CSF fluid can then be stained with Indian ink to demonstrate the organisms.

Treatment with antifungals consists of an induction, consolidation, and maintenance phase. Induction is with IV amphotericin B, of which the liposomal forms are now generally preferred, alongside oral flucytosine. Induction is successful when no Cryptococcus organisms are detected on repeat LP and the patient is clinically improving. Following this, fluconazole is given at a high dose for 8 weeks as consolidation. If the patient remains clinically stable, a lower dose is maintained for at least one year.

If a patient has comorbid HIV/AIDS, then appropriate antiretroviral treatment is also essential to prevent relapse.