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Difficulty: MediumInfectious Diseases

A 45-year-old man is brought to the emergency department by his wife due to a 24-hour history of high fever, severe headache, and progressively worsening confusion. On physical examination, his temperature is 39.2°C (102.6°F), blood pressure is 130/80 mm Hg, and heart rate is 110/min. He has marked nuchal rigidity. Neurologic examination reveals a lethargic patient who only opens his eyes to painful stimuli. He demonstrates mild left-sided hemiparesis. Arrange the following steps in the most appropriate chronological sequence for the initial management of this patient.

  1. 1Obtain blood cultures
  2. 2Administer empiric intravenous antibiotics and dexamethasone
  3. 3Perform a non-contrast CT scan of the head
  4. 4Perform a lumbar puncture

Answer

The correct sequence is: Obtain blood cultures, followed by administration of empiric antibiotics and dexamethasone, then a non-contrast CT scan of the head, and finally a lumbar puncture.
In the management of suspected bacterial meningitis, the universal first step is to obtain blood cultures, immediately followed by the administration of empiric intravenous antibiotics (and dexamethasone). While a lumbar puncture is the definitive diagnostic test, patients with "red flag" clinical features—such as altered mental status, focal neurologic deficits, papilledema, new-onset seizures, or an immunocompromised state—must undergo a head CT prior to the lumbar puncture to rule out a mass lesion or significant cerebral edema. Performing a lumbar puncture in the presence of elevated intracranial pressure can precipitate fatal brain herniation. Crucially, antimicrobial therapy must not be delayed while awaiting the CT scan or lumbar puncture.

Step-by-Step Solution

1
Recognize the clinical presentation of suspected acute bacterial meningitis with high-risk features.
The patient has fever, headache, nuchal rigidity, altered mental status, and a focal neurologic deficit.
Identifying these classic symptoms establishes the need for urgent meningitis workup, while the focal deficit and altered mental status mandate neuroimaging prior to lumbar puncture.
2
Prioritize microbiological sampling before treatment.
Blood cultures are placed first in the sequence.
Drawing blood cultures prior to antibiotic administration is essential for identifying the organism and tailoring future therapy.
3
Initiate life-saving empiric therapy immediately.
Antibiotics and dexamethasone are sequenced second.
Delays in antibiotic administration significantly increase mortality in bacterial meningitis. Therapy must be given immediately after blood cultures and before any imaging.
4
Determine the safety of performing a lumbar puncture.
A head CT is placed third, followed by the lumbar puncture fourth.
Because the patient has "red flag" signs for increased intracranial pressure, a CT scan must be performed first to rule out mass effect and prevent herniation during the subsequent lumbar puncture.

Key Concept

Management sequence for suspected bacterial meningitis with indications for neuroimaging prior to lumbar puncture.
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Topics

Infectious Diseases

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