Cryptococcal meningitis (CM) is a subacute meningoencephalitis caused primarily by Cryptococcus neoformans, responsible for ~223,000 cases and ~180,000 deaths annually, predominantly in patients with advanced HIV (CD4 <100 cells/mm³). [1] It is uniformly fatal without treatment and carries a case fatality rate of 10–20% in high-income countries and 35–65% in sub-Saharan Africa. [2] The presentation is often insidious, evolving over weeks, and can easily evade diagnosis in the ED. [3]
1. History
- Headache is the most common symptom (~97%), typically progressive over a median of 2 weeks [4-5]
- Fever, malaise, nausea, vomiting — often low-grade and nonspecific [2][4]
- Encephalopathic symptoms: lethargy, altered mentation, personality changes, memory loss (often from elevated ICP) [4]
- Classic meningeal symptoms (neck stiffness, photophobia) present in only 25–33% of HIV-associated cases [4]
- Visual changes: diplopia (CN VI palsy), blurred vision, hearing loss (CN VIII involvement) [6]
- Ask about HIV status, ART adherence, recent ART initiation (unmasking IRIS), immunosuppressive medications, organ transplant history [4][6]
- Duration and tempo of symptoms — subacute onset over days to weeks is characteristic
- Important negatives: absence of fever does not exclude CM (fever present in only ~50% of non-HIV patients) [6]
2. Alarm Features
- Altered mental status / declining GCS — independent risk factor for death (OR 6.9) [5]
- Seizures — independent risk factor for mortality (OR 3.1) [5]
- Signs of elevated ICP: papilledema, CN VI palsy, blurred vision, lower extremity clonus, vomiting [4]
- Rapid neurologic deterioration despite antifungal therapy (suggests uncontrolled ICP) [4]
- New focal neurologic deficits
- Symptoms developing shortly after ART initiation → consider IRIS [4]
- Respiratory distress (pulmonary cryptococcosis can mimic PCP or present as ARDS) [4]
3. Medications
Induction (2 weeks — preferred in resource-available settings):
- Liposomal amphotericin B 3–4 mg/kg IV daily + flucytosine 25 mg/kg PO QID × 2 weeks [4][7]
- Alternative: Amphotericin B deoxycholate 0.7–1.0 mg/kg IV daily + flucytosine × 1–2 weeks [4]
- Resource-limited: Single-dose liposomal amphotericin B 10 mg/kg + flucytosine + fluconazole 1200 mg daily × 2 weeks (AMBITION-cm regimen) [6-7]
Consolidation (8 weeks)
- Fluconazole 800 mg PO daily[4][7]
Maintenance (≥12 months)
- Fluconazole 200 mg PO daily[4][7]
Key medication cautions
- Flucytosine: dose-adjust for renal impairment; monitor levels (target peak 25–100 mg/L); bone marrow toxicity (pancytopenia) [4][8]
- Amphotericin B: nephrotoxicity, hypokalemia, hypomagnesemia, renal tubular acidosis, infusion reactions; presupplementation with IV fluids and electrolytes reduces toxicity [6][9]
- Corticosteroids, mannitol, and acetazolamide are NOT recommended for ICP management in CM [4][7]
- Echinocandins have no activity against Cryptococcus [8]
- Do NOT initiate ART in the ED — risk of IRIS [3][7]
4. Diet
- No specific dietary triggers or restrictions for CM
- Aggressive IV hydration with normal saline prior to and during amphotericin B infusion to reduce nephrotoxicity [6]
- Electrolyte supplementation: potassium and magnesium replacement during amphotericin B therapy [4]
- Ensure adequate nutrition in patients with advanced HIV/AIDS and cachexia
5. Review of Systems
- Neuro: headache, vision changes, hearing loss, confusion, seizures, weakness, gait instability
- Constitutional: fever, weight loss, night sweats, fatigue
- Pulmonary: cough, dyspnea (pulmonary cryptococcosis)
- Dermatologic: skin lesions — umbilicated papules mimicking molluscum contagiosum, nodules, ulcers [4][6]
- GI: nausea, vomiting (may reflect elevated ICP)
- Psychiatric: personality changes, memory loss [4]
6. Collateral History and Family History
- HIV status and ART history: adherence, recent initiation, CD4 count, viral load
- Prior opportunistic infections or AIDS-defining illnesses
- Immunosuppressive medications: glucocorticoids, anti-TNFα agents (infliximab), ibrutinib, fingolimod, alemtuzumab, calcineurin inhibitors [6]
- Organ transplant history
- Travel history (endemic areas, sub-Saharan Africa) — reactivation of latent infection can occur years after exposure [6]
- Occupational exposures (pigeon breeders) [6]
- Family history is generally not contributory, though idiopathic CD4 lymphopenia may have a genetic basis
7. Risk Factors
- HIV/AIDS with CD4 <100 cells/mm³ — predominant risk factor [6]
- Solid organ transplant recipients on immunosuppression [7]
- Glucocorticoid therapy, sarcoidosis [6]
- Idiopathic CD4 lymphopenia [6]
- Immunosuppressive drugs: anti-TNFα, ibrutinib, fingolimod, alemtuzumab [6]
- Malignancy (hematologic malignancies in particular)
- ART nonadherence or virologic failure [1]
- C. gattii can cause disease in apparently immunocompetent hosts [7]
8. Differential Diagnosis
- Tuberculous meningitis — chronic meningitis with similar CSF profile; AFB smear/culture, TB PCR
- Bacterial meningitis — typically more acute; CSF with neutrophilic pleocytosis, low glucose
- Viral meningoencephalitis (HSV, CMV, VZV) — PCR testing on CSF
- CNS lymphoma — mass lesion on imaging; cytology
- Toxoplasmosis — ring-enhancing lesions on MRI; serology
- Progressive multifocal leukoencephalopathy (PML) — JC virus PCR; white matter lesions
- Neurosyphilis — RPR/VDRL, FTA-ABS on CSF
- Coccidioidomycosis / histoplasmosis meningitis — endemic fungal infections; antigen/antibody testing [10]
- Carcinomatous meningitis — CSF cytology
- IRIS (in patients recently started on ART) — culture-negative CSF with worsening symptoms [4]
9. Past Medical History
- HIV/AIDS — CD4 nadir, current CD4, viral load, ART regimen and adherence
- Prior cryptococcal disease or other opportunistic infections
- Organ transplant and immunosuppressive regimen
- Chronic kidney disease (affects amphotericin B and flucytosine dosing)
- Hepatic disease (affects azole metabolism)
- History of sarcoidosis, malignancy, autoimmune conditions
- Prior neurosurgical procedures (VP shunt)
10. Physical Exam
Vital signs
- Fever (present in ~50–72% of cases); may be absent in non-HIV patients [4-6]
- Tachycardia; hypotension (if septic)
Focused exam
- Neuro: mental status (GCS), cranial nerves (especially CN VI and VIII), fundoscopy for papilledema, motor/sensory exam, cerebellar signs
- Meningeal signs: nuchal rigidity, Kernig's, Brudzinski's — present in only ~25–50% [4][11]
- Skin: inspect for umbilicated papules (molluscum-like), nodules, ulcers — suggestive of disseminated disease [4][6]
- Pulmonary: auscultation for consolidation or crackles
- General: cachexia, lymphadenopathy, oral thrush (markers of advanced immunosuppression)
11. Lab Studies
Essential
- Serum CrAg (lateral flow assay) — sensitivity/specificity >99%; results in 15 minutes [4][6]
- CSF analysis: cell count, glucose, protein, opening pressure, CrAg, India ink (if available), fungal culture [4][7]
- Blood cultures (fungal) — positive in 47–70% of HIV-associated cases [4]
- HIV testing (if status unknown) with CD4 count and viral load [7]
- BMP (renal function, electrolytes — baseline before amphotericin B) [4]
- CBC with differential (baseline before flucytosine)
- LFTs (baseline before azole therapy)
Expected CSF findings
- Mildly elevated protein, low-to-normal glucose, variable lymphocytic pleocytosis [4]
- CSF may be entirely normal in severely immunosuppressed patients — CrAg is critical [12]
- Opening pressure ≥25 cm H₂O in 60–80% of HIV-associated cases [4]
- CSF CrAg sensitivity ~99% [13]
Key pearl: Serum CrAg LFA titer ≥1:160 suggests disseminated disease; ≥1:640 should be assumed to have CNS involvement [4][14]
12. Imaging
- CT head without contrast — obtain before LP if concern for mass lesion or obstructive hydrocephalus; often normal in CM [7]
- MRI brain with gadolinium (preferred) — may show leptomeningeal enhancement, cryptococcomas (especially C. gattii), hydrocephalus, gelatinous pseudocysts in basal ganglia [7]
- Chest CT — evaluate for pulmonary cryptococcosis (nodules, consolidation, hilar lymphadenopathy) [7]
- Imaging is often unremarkable in HIV-associated CM; a normal CT does not exclude the diagnosis
- Imaging is essential to exclude obstructive hydrocephalus before therapeutic LP, particularly in HIV-negative patients [6]
13. Special Tests
- CrAg lateral flow assay (LFA) — point-of-care, 15-minute turnaround, FDA-approved (IMMY CrAg LFA); can be performed on serum, plasma, whole blood, or CSF [4][6]
- BioFire FilmArray Meningitis/Encephalitis Panel — multiplex PCR includes C. neoformans and C. gattii; sensitivity drops to ~50% with low fungal burden (<100 CFU/mL); useful for distinguishing relapse (PCR+) from IRIS (PCR−) [4]
- India ink stain — 60–80% sensitivity; largely replaced by CrAg testing [4]
- Flucytosine therapeutic drug monitoring — target peak (2 hr post-dose) 25–100 mg/L [4]
- CSF opening pressure measurement — mandatory at every LP in CM [7]
14. ECG
- No disease-specific ECG findings for CM itself
- Amphotericin B can cause hypokalemia and hypomagnesemia → monitor for QT prolongation, U waves, arrhythmias (including ventricular fibrillation) [9]
- Amphotericin B has been associated with cardiac arrest, cardiac failure, and arrhythmias [9]
- Flucytosine — rare cardiac arrest and ventricular dysfunction reported [15]
- Obtain baseline ECG; monitor electrolytes closely during treatment
- If on concurrent digitalis, amphotericin B–induced hypokalemia potentiates digitalis toxicity [9]
15. Assessment
CM is a life-threatening opportunistic infection that presents subacutely and is easily missed. Key clinical pearls:
- Presentation is often subtle — headache and fever over weeks in an immunocompromised patient should prompt CrAg testing [3-4]
- Elevated ICP is the primary driver of acute mortality — associated with 92% of deaths in the first 2 weeks of therapy [4]
- CSF may appear deceptively normal in severely immunosuppressed patients; CrAg is the critical diagnostic test [12]
- Mortality risk factors: older age, altered consciousness, seizures, undetectable CSF CrAg, and a dose-dependent trend with increasing number of symptoms [5]
- Survivors have high rates of long-term morbidity: 69–73% have cognitive or physical impairment at 12 months [1]
16. Treatment Plan
ED Stabilization
- ABCs; advanced airway management if GCS severely depressed [3]
- IV access, fluid resuscitation, antipyretics
- Lumbar puncture with opening pressure measurement — this is both diagnostic and therapeutic [3-4]
- If opening pressure ≥25 cm H₂O with symptoms: drain CSF to reduce pressure by ≥50% or to <20 cm H₂O; if no manometer, remove 20–25 mL [4]
Empiric Treatment (initiate in ED if high suspicion)
- Empiric coverage for bacterial, viral, and fungal meningitis while awaiting results [3]
- Liposomal amphotericin B 3–4 mg/kg IV + flucytosine 25 mg/kg PO QID [4]
- Pre-hydrate with NS 500–1000 mL; supplement K⁺ and Mg²⁺ [6]
Three-Phase Treatment Approach
ICP Management
- Daily therapeutic LPs if symptomatic elevated ICP until pressure normalizes <20 cm H₂O [4][7]
- Scheduled repeat LP at 48–72 hours regardless of initial opening pressure [7]
- Lumbar drain or VP shunt if refractory [7]
- Do NOT use corticosteroids, mannitol, or acetazolamide for ICP [4]
ART Timing (HIV-positive patients)
- Delay ART initiation 4–6 weeks from start of antifungal therapy [7][16]
- Earlier initiation (2 weeks) may be considered if clinically improved, ICP controlled, and CSF cultures negative [16]
- Immediate/very early ART is NOT recommended (increased mortality risk) [7]
17. Disposition
Admission criteria (all patients with confirmed or suspected CM):
- All patients require inpatient admission, typically to a monitored setting [3][7]
- ICU admission for: altered mental status, refractory elevated ICP, hemodynamic instability, respiratory failure
- Most patients require 1–2 weeks or more of inpatient care [7]
Specialist consultation
- Infectious disease — early consultation is imperative [3]
- Neurosurgery — if refractory elevated ICP requiring lumbar drain or VP shunt [7]
- Ophthalmology — if visual symptoms or papilledema
Discharge criteria
- Clinical improvement with resolving symptoms
- Negative CSF culture at end of induction
- Transition to oral consolidation therapy (fluconazole)
- Stable or normalized ICP
- Reliable outpatient follow-up established
18. Follow Up / Return Precautions
Follow-up timing
- Infectious disease follow-up within 1–2 weeks of discharge
- Repeat LP with CSF culture at end of induction (2 weeks) to confirm sterility [4]
- Monitor renal function, electrolytes, CBC, and LFTs during consolidation and maintenance
- Flucytosine TDM if still on therapy [4]
- CD4 count and viral load monitoring after ART initiation
Discontinuation of maintenance therapy
- May discontinue fluconazole after ≥1 year if CD4 >100 cells/mm³ and HIV viral load suppressed on ART [4][7]
- Failure to complete 1 year of maintenance is the most common reason for relapse [4]
Return precautions — instruct patients to return immediately for:
- Worsening or new headache, vision changes, confusion, seizures
- Fever, neck stiffness, vomiting
- Symptoms of IRIS (worsening after starting ART): new headache, fever, lymphadenopathy [4]
- Signs of medication toxicity: decreased urine output, easy bruising/bleeding, jaundice
Expected recovery
- Clinical improvement typically begins within the first 2 weeks of therapy
- Long-term cognitive and physical impairment is common (69–73% at 12 months) [1]
- Over one-third of survivors report work difficulties at 6 months [1]
- IRIS occurs in 10–30% of patients after ART initiation, most commonly within the first 30 days [4]
Images
References
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2. Early Versus Delayed Antiretroviral Treatment in HIV-positive People With Cryptococcal Meningitis. — Eshun-Wilson I, Okwen MP, Richardson M, Bicanic T. The Cochrane Database of Systematic Reviews. 2018.
3. Cryptococcal Meningitis: A Review for Emergency Clinicians. — Fisher KM, Montrief T, Ramzy M, Koyfman A, Long B. Internal and Emergency Medicine. 2021.
4. Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents With HIV. — Constance Benson, John Brooks, Shireesha Dhanireddy, et al Infectious Diseases Society of America; Office of AIDS Research Advisory Council (2025). 2025.
5. Clinical Characteristics and Risk Factors for Mortality in Cryptococcal Meningitis: Evidence From a Cohort Study. — Wang F, Wang Y, He J, et al. Frontiers in Neurology. 2022.
6. Cryptococcal Disease in Diverse Hosts. — Meya DB, Williamson PR. The New England Journal of Medicine. 2024.
7. Global Guideline for the Diagnosis and Management of Cryptococcosis: An Initiative of the ECMM and ISHAM in Cooperation With the ASM. — Chang CC, Harrison TS, Bicanic TA, et al. The Lancet. Infectious Diseases. 2024.
8. Guidelines for the Prevention and Treatment of Opportunistic Infections in Children With and Exposed to HIV. — Bill G. Kapogiannis, Franklin Yates, Wei Li, et al Office of AIDS Research Advisory Council (2025). 2025.
9. FDA Drug Label. — Updated date: 2022-01-03. Food and Drug Administration.
10. Chronic Meningitis. — Aksamit AJ. The New England Journal of Medicine. 2021.
11. Advances in the Diagnosis and Treatment of Fungal Infections of the CNS. — Schwartz S, Kontoyiannis DP, Harrison T, Ruhnke M. The Lancet. Neurology. 2018.
12. C. Neoformans Meningitis Without Pleocytosis, Hyperproteinorrachia, and Hypoglycorrhachia on Cerebrospinal Fluid Studies. — Sheffield B, Troendle M. The American Journal of Emergency Medicine. 2025.
13. Cryptococcal Antigen in Serum and Cerebrospinal Fluid for Detecting Cryptococcal Meningitis in Adults Living With Human Immunodeficiency Virus: Systematic Review and Meta-Analysis of Diagnostic Test Accuracy Studies. — Temfack E, Rim JJB, Spijker R, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2021.
14. Cryptococcal Antigen Titers and Semi-Quantitative Assay Scores Among People With HIV-associated Cryptococcal Antigenemia. — Mwamba TM, Blasich NP, Coetzee LM, Mashau R, Govender NP. Journal of Clinical Microbiology. 2026.
15. FDA Drug Label. — Updated date: 2022-02-02. Food and Drug Administration.
16. Antiretroviral Drugs for Treatment and Prevention of HIV in Adults: 2024 Recommendations of the International Antiviral Society–USA Panel. — Gandhi RT, Landovitz RJ, Sax PE, et al. The Journal of the American Medical Association. 2025.