Advanced Clinical Care - Management of Cryptococcal infection in the patient with HIV

Dr. Jillian Dawes welcomes attendees and outlines the webinar's focus: managing cryptococcal disease in HIV-positive patients. She covers a case scenario, the natural history and burden of the disease both globally and in South Africa, diagnostic methods, national screening and treatment algorithms (adult and pediatric), managing elevated intracranial pressure, special considerations for pregnant and breastfeeding individuals, and the treatment of non-meningeal cryptococcal disease.

Cryptococcal disease is primarily caused by Cryptococcus neoformans and Cryptococcus gattii, found in soil and bird droppings. Infection usually occurs via spore inhalation. In immunocompetent individuals, the immune system can eliminate the yeast, leading to mild lung involvement. However, in immunocompromised individuals, such as those with HIV, the disease is more severe and can be fatal, spreading hematogenously to the CNS, bones, lymph nodes, and skin.

Globally, there are an estimated 220,000 cases of cryptococcal meningitis in people with HIV/AIDS, resulting in 181,000 deaths annually, primarily in sub-Saharan Africa. In South Africa, 6,370 new cases were diagnosed in 2019, with 93% being meningitis. The highest burden is seen in males aged 35-49, with a mean CD4 count of 28 and a 34% in-hospital fatality ratio.

A 30-year-old HIV-positive woman, ZJ, is diagnosed with HIV (WHO stage 2, ARV naive). She has no significant symptoms except a mild headache. Her CD4 count is 95, and serum CrAg is positive. The recommended management is to continue TLD and perform a lumbar puncture to assess for cryptococcal meningitis.

The national consolidated guidelines recommend serum CrAg testing for all HIV-positive individuals with CD4 < 100. If positive, a lumbar puncture is mandated for adults regardless of symptoms. The management algorithm differentiates based on CSF CrAg results: negative CSF leads to two weeks of high-dose fluconazole, then 800mg daily for two months, with ARV initiation at two weeks. Positive CSF (meningitis) requires aggressive treatment with IV amphotericin B and oral fluconazole for two weeks, followed by 800mg fluconazole daily for two months, with ARV initiation delayed to 4-6 weeks.

Antigen testing of CSF is the standard for diagnosing cryptococcal meningitis. India ink staining, while classic, has low sensitivity (78%). Lateral flow assays are highly sensitive (94-100%). Fungal culture can identify Cryptococcus neoformans (most common in SA) and Cryptococcus gattii. Antifungal susceptibility testing is not routine for initial diagnosis but is reserved for recurrent or relapsing cases.

ZJ's CSF results show an opening pressure of 32 cmH2O (elevated), clear appearance, lymphocyte predominance, elevated protein, and normal glucose. India ink and CrAg are positive for cryptococcus. No TB or bacterial meningitis is detected. ZJ's stable clinical picture requires inpatient management due to the need for IV antifungals.

Treatment involves induction, consolidation, and maintenance phases. For CSF-negative CrAg, induction with high-dose oral fluconazole for two weeks, then consolidation with 800mg fluconazole for two months, and ARV initiation at two weeks. For CSF-positive CrAg (meningitis), induction is IV amphotericin B and oral fluconazole for two weeks, followed by consolidation, with ARV initiation delayed to 4-6 weeks. Alternative regimens, including amphotericin B with flucytosine, show improved outcomes and reduced toxicity.

Elevated ICP in cryptococcal meningitis affects 75% of patients and is potentially life-threatening due to CSF outflow obstruction. Symptoms include severe headaches, vomiting, confusion, and visual disturbances. Serial lumbar punctures are therapeutic, removing 30-60ml of CSF to reduce pressure below 20 cmH2O. Frequent LPs may be needed, but they don't extend the induction phase. A spinal manometer is the most accurate for measuring opening pressure, as IV giving sets underestimate it.

Pregnant HIV-positive women with cryptococcal meningitis follow the same treatment algorithm as non-pregnant individuals. High-dose fluconazole, despite being an FDA category D drug with potential teratogenic effects in the first trimester, is recommended because the benefits of treating cryptococcal meningitis outweigh the risks to the fetus. Close monitoring with high-resolution ultrasounds at 18-22 weeks gestation is advised.

Pediatric CrAg screening is recommended for CD4 < 200. Lumbar puncture is preferred for all CrAg-positive children. Dosing is weight-based (milligram per kilogram per day) for adolescents and children under 18. Induction involves amphotericin B and fluconazole for 14 days, followed by consolidation with fluconazole for eight weeks. ARV initiation is similar to adults. Maintenance involves fluconazole for at least one year with immune reconstitution (two CD4 counts > 200 six months apart).

For localized non-meningeal cryptococcal disease (e.g., pulmonary, bone, skin), the WHO guidelines recommend an induction, consolidation, and maintenance phase exclusively with fluconazole at lower doses (800mg for two weeks, then 400mg for eight weeks, then 200mg for maintenance). Cryptococcomas, rare encapsulated lesions, require an extended six-week induction phase with amphotericin B and fluconazole/flucytosine, similar to meningitis, followed by standard consolidation and maintenance.

Amphotericin B deoxycholate is a common IV antifungal in the induction phase. It's reconstituted with sterile water (not saline) and administered in 1L of 5% dextrose water over at least four hours. Common toxicities include renal tubular toxicity (hyperkalemia, hypomagnesemia), anemia (up to grade 4), phlebitis, and infusion-related reactions (fevers, rigors). Pre-hydration with normal saline and potassium chloride, routine oral potassium and magnesium supplementation, and careful monitoring are essential to mitigate these effects.

For renal failure (e.g., GFR < 50 or two-fold creatinine increase), the next amphotericin B dose should be skipped. More frequent pre-hydration (1L normal saline every 8 hours) and daily GFR monitoring are necessary. Restart amphotericin at a lower dose (0.7mg/kg/day) upon improvement. For hyperkalemia, aggressive IV potassium replacement is needed. Hypomagnesemia must be corrected. Anemia often requires blood transfusions. Febrile reactions require stopping the infusion, pre-medication with paracetamol or hydrocortisone, and a slower infusion rate.

ZJ's acute onset of blurred vision and severe headache after two weeks of fluconazole consolidation suggests a recurrence. Potential causes include new CNS opportunistic infection, paradoxical cryptococcal meningitis IRIS, or fluconazole resistance. Paradoxical IRIS is a common immune response despite adequate treatment, not treatment failure. Relapses require repeat lumbar puncture, fungal culture (for susceptibility testing), and reinstitution of full induction therapy. Corticosteroids are used only for confirmed IRIS or life-threatening neurological deterioration.

Key takeaways include mandatory CrAg screening for HIV-positive individuals with CD4 < 200, lumbar puncture for all CrAg-positive patients, higher fluconazole doses (1200mg induction, 800mg consolidation), serial lumbar punctures with opening pressure measurement, use of spinal manometer for accuracy, consistent management in pregnancy, and adherence to ARV timing intervals (two weeks for no meningitis, 4-6 weeks for meningitis).