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Difficulty: HardInfectious Diseases

A 38-year-old man is brought to the emergency department by his partner due to a 2-week history of progressively worsening headaches, nausea, and confusion. He was diagnosed with HIV infection 5 years ago but has been nonadherent to his antiretroviral therapy for the past 2 years. His temperature is 38.2°C (100.8°F), blood pressure is 118/76 mm Hg, and pulse is 92/min. Physical examination shows lethargy and bilateral papilledema, but no focal motor weakness or sensory deficits. Laboratory studies show a CD4 T-lymphocyte count of 34 cells/mm³.

A CT scan of the head shows no mass effect, hemorrhage, or hydrocephalus. A lumbar puncture is performed with an opening pressure of 340 mm H2O340 \text{ mm H}_2\text{O}. Cerebrospinal fluid (CSF) analysis reveals:
Leukocyte count: 45/mm³ (85% lymphocytes)
Glucose: 30 mg/dL
Protein: 95 mg/dL
CSF cryptococcal antigen is positive.

He is admitted to the hospital and immediately started on intravenous liposomal amphotericin B and oral flucytosine. Four days later, his partner reports that the patient is significantly more difficult to arouse and has been complaining of severe blurred vision. His temperature is 37.6°C (99.7°F). Neurologic examination shows a sluggish pupillary light reflex bilaterally and worsening papilledema. Which of the following is the most appropriate next step in management?

  1. A
    Add intravenous dexamethasone
  2. B
    Initiate antiretroviral therapy
  3. C
    Switch to high-dose intravenous fluconazole
  4. Perform a therapeutic lumbar punctureAnswer
  5. E
    Consult neurosurgery for ventriculoperitoneal shunt placement

Answer

Perform a therapeutic lumbar puncture
This patient with advanced HIV has cryptococcal meningitis, which is being appropriately treated with induction therapy (liposomal amphotericin B and flucytosine). However, he has developed worsening lethargy, visual changes, and papilledema, which strongly suggest acutely elevated intracranial pressure (ICP). Elevated ICP in cryptococcal meningitis is thought to be caused by the mechanical obstruction of cerebrospinal fluid (CSF) outflow at the arachnoid villi by the shedding of the cryptococcal polysaccharide capsule. The definitive, first-line management for symptomatic elevated ICP in these patients is mechanical drainage of CSF via therapeutic lumbar puncture (often performed serially on a daily basis) to a target closing pressure of <200 mm H2O< 200 \text{ mm H}_2\text{O} or 50%50\% of the opening pressure. Medications that reduce ICP in other settings (e.g., mannitol, acetazolamide) are ineffective here, and corticosteroids are strictly contraindicated.

Step-by-Step Solution

1
Identify the primary diagnosis and current complication.
The patient has HIV with cryptococcal meningitis (positive CSF antigen, low CD4) and is now presenting with signs of worsening elevated intracranial pressure (lethargy, blurred vision, sluggish pupils, worsening papilledema) on day 4 of induction therapy.
Recognizing the complication is essential for selecting the appropriate management, as elevated ICP is a major cause of morbidity and mortality in cryptococcal meningitis.
2
Determine the optimal intervention for elevated ICP in cryptococcal meningitis.
The first-line intervention for symptomatic elevated ICP in this setting is mechanical removal of CSF via therapeutic lumbar punctures to a target closing pressure of < 200 mm H2O or 50% of the opening pressure.
Cryptococcal capsular polysaccharide physically obstructs CSF outflow at the arachnoid villi. Medical management (e.g., mannitol, acetazolamide, or steroids) is ineffective and potentially harmful.
3
Rule out alternative interventions.
Steroids are contraindicated, ART must be delayed to prevent IRIS, switching to fluconazole is premature, and VP shunting is reserved for refractory cases after serial LPs fail.
This confirms that a therapeutic lumbar puncture is the single best next step in management.

Key Concept

Elevated intracranial pressure is a common, life-threatening complication of cryptococcal meningitis that should be managed initially with serial therapeutic lumbar punctures rather than medical therapy (e.g., steroids) or immediate surgical shunting.
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Topics

Infectious Diseases

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