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Difficulty: MediumGeneral Internal Medicine

A 68-year-old man is brought to the emergency department by his wife due to a 24-hour history of severe headache, high fever, and progressive confusion. His temperature is 39.2°C (102.6°F), blood pressure is 145/85 mmHg, heart rate is 112/min, and respiratory rate is 18/min. Neurologic examination reveals a lethargic patient who only opens his eyes to painful stimuli. He demonstrates marked nuchal rigidity and profound weakness of the right upper and lower extremities.

Arrange the following management steps in the most appropriate chronological sequence for this patient.

  1. 1Obtain peripheral blood cultures
  2. 2Administer empiric intravenous antibiotics and dexamethasone
  3. 3Obtain a non-contrast computed tomography (CT) scan of the head
  4. 4Perform a lumbar puncture for cerebrospinal fluid analysis

Answer

The correct sequence is to first obtain blood cultures, immediately administer empiric intravenous antibiotics and dexamethasone, then obtain a non-contrast CT scan of the head, and finally perform a lumbar puncture.
The patient presents with signs of acute bacterial meningitis. The presence of altered mental status and a focal neurologic deficit (right-sided weakness) are classic indications that a non-contrast CT scan of the head must be performed prior to a lumbar puncture to rule out a space-occupying lesion and prevent cerebral herniation. Because the CT scan will delay the lumbar puncture, empiric therapy cannot be withheld. The correct sequence is to first draw blood cultures (to maximize diagnostic yield), immediately administer empiric antibiotics and dexamethasone (to prevent mortality associated with delayed treatment), perform the CT scan, and finally perform the lumbar puncture if the CT is clear of contraindications.

Step-by-Step Solution

1
Recognize the clinical presentation and identify indications for neuroimaging prior to lumbar puncture.
The patient has signs of bacterial meningitis complicated by altered mental status and a focal neurologic deficit (right-sided weakness), necessitating a CT scan before a lumbar puncture.
Performing a lumbar puncture in the presence of a mass lesion or significantly elevated intracranial pressure can cause fatal cerebral herniation.
2
Determine the priority of interventions.
Since obtaining a CT scan will delay the lumbar puncture, empiric treatment must not be delayed.
Delays in antibiotic administration in bacterial meningitis are strongly associated with increased mortality and worse neurologic outcomes.
3
Sequence the immediate initial steps.
Blood cultures are drawn first, followed immediately by the administration of empiric antibiotics and dexamethasone.
Drawing blood cultures prior to antibiotics maximizes pathogen recovery, while immediate subsequent antibiotic administration ensures rapid, life-saving treatment.
4
Sequence the diagnostic steps.
The patient undergoes a CT scan of the head, followed by a lumbar puncture if the CT shows no contraindications.
This confirms the safety of the lumbar puncture and allows for definitive cerebrospinal fluid analysis.

Key Concept

In patients with suspected bacterial meningitis who have indications for a CT scan before a lumbar puncture (e.g., focal neurologic deficit, altered mental status, papilledema, immunocompromised state), blood cultures should be drawn first, followed immediately by empiric antibiotics and corticosteroids, before proceeding to the CT scan.
Estimated Time:1m 30s
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General Internal Medicine

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