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Difficulty: MediumNeurosurgery

A 62-year-old woman is evaluated in the neurosurgical intensive care unit on postoperative day 5 following a right temporal craniotomy for glioblastoma resection. Over the past 12 hours, she has become progressively lethargic. She now only opens her eyes to painful stimuli and mutters incomprehensibly. Her temperature is 38.9°C (102.0°F), blood pressure is 145/88 mmHg, heart rate is 105/min, and respiratory rate is 16/min. Physical examination reveals pronounced nuchal rigidity. The surgical incision is well-approximated, clean, and has no fluctuance or drainage. An indwelling urinary catheter, placed prior to surgery, remains in situ. Which of the following is the most appropriate next step in management?

  1. Perform a non-contrast CT scan of the headAnswer
  2. B
    Perform an immediate lumbar puncture
  3. C
    Remove the indwelling urinary catheter and send a urine sample for culture
  4. D
    Initiate broad-spectrum intravenous antibiotics and observe clinically
  5. E
    Administer intravenous haloperidol and obtain a psychiatric consultation

Answer

The most appropriate next step is to perform a non-contrast CT scan of the head.
The correct answer is to perform a non-contrast CT scan of the head. This patient is presenting with fever, altered mental status, and nuchal rigidity on postoperative day 5 following a craniotomy, which is highly suspicious for postoperative bacterial meningitis or an intracranial space-occupying infection (such as a subdural empyema or brain abscess). In any patient with suspected meningitis who has 'red flag' features—such as severe altered mental status, focal neurologic deficits, papilledema, immunocompromise, or a history of recent central nervous system surgery—a CT scan of the head must be performed prior to a lumbar puncture. This is crucial to rule out increased intracranial pressure, hydrocephalus, or a mass lesion, as performing a lumbar puncture in these settings can precipitate a pressure gradient shift and subsequent fatal cerebral herniation. If neuroimaging is significantly delayed, blood cultures should be drawn and empiric antibiotics administered immediately, but imaging remains the definitive next procedural step.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and timeline.
The patient presents with high fever, nuchal rigidity, and severely altered mental status on postoperative day 5 following a craniotomy.
To establish the most likely differential diagnosis, which in this case is a postoperative central nervous system infection (e.g., bacterial meningitis, subdural empyema, or brain abscess).
2
Evaluate the criteria for obtaining neuroimaging prior to a lumbar puncture.
The patient has critical 'red flag' criteria: a history of recent central nervous system surgery and a severely abnormal level of consciousness.
To determine the safest diagnostic workflow. A lumbar puncture in the setting of increased intracranial pressure or an undiagnosed mass lesion can cause fatal brain herniation.
3
Determine the most appropriate next procedural step.
A non-contrast CT scan of the head must be ordered before attempting cerebrospinal fluid analysis.
Neuroimaging is required to evaluate for midline shift, mass effect, or hydrocephalus to ensure structural stability of the brain before proceeding with invasive testing.

Key Concept

In patients with suspected bacterial meningitis who have high-risk features (e.g., recent neurosurgery, severe altered mental status, focal neurologic deficits, or papilledema), a CT scan of the head must be performed prior to a lumbar puncture to prevent cerebral herniation.
Estimated Time:1m 30s
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Neurosurgery

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