Examkin

Question

Difficulty: MediumInfectious Diseases

A 64-year-old man is brought to the emergency department by his spouse due to worsening confusion, a severe global headache, and a high fever over the last 24 hours. His temperature is 39.4°C (102.9°F), blood pressure is 128/82 mmHg, and heart rate is 114/min. Physical examination shows a lethargic patient who only opens his eyes to painful stimuli. Marked resistance to passive neck flexion is present. Funduscopic examination reveals bilateral blurring of the optic disc margins with absent venous pulsations. Arrange the following steps in the most appropriate chronological order for managing this patient's condition.

  1. 1Obtain peripheral blood cultures
  2. 2Administer empiric intravenous antibiotics and dexamethasone
  3. 3Perform a non-contrast 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, perform a non-contrast CT scan of the head, and finally perform a lumbar puncture.
The patient presents with the classic presentation of meningitis (fever, severe headache, nuchal rigidity) complicated by altered mental status and papilledema. Papilledema indicates increased intracranial pressure. In cases of suspected bacterial meningitis with indications for neuroimaging prior to a lumbar puncture (such as papilledema, focal neurologic deficits, severe immunocompromise, new-onset seizures, or significantly altered level of consciousness), the correct sequence of interventions is highly critical. First, blood cultures must be drawn rapidly to help identify the pathogen. Second, empiric intravenous antibiotics and dexamethasone must be administered immediately. Waiting for a CT scan and lumbar puncture before giving antibiotics leads to life-threatening delays in treatment. Third, a non-contrast CT scan of the head is performed to rule out mass effect that could cause herniation during a lumbar puncture. Finally, once deemed safe by the imaging results, a lumbar puncture is performed.

Step-by-Step Solution

1
Identify the suspected diagnosis and high-risk clinical features.
The patient has signs of bacterial meningitis (fever, headache, nuchal rigidity) accompanied by altered mental status and papilledema (indicating increased intracranial pressure).
Recognizing signs of increased intracranial pressure dictates that a CT scan must precede a lumbar puncture to prevent brain herniation.
2
Determine the optimal timing for microbiological sampling versus empiric treatment.
Blood cultures should be drawn first, followed immediately by empiric antibiotics and dexamethasone, before sending the patient to the CT scanner.
Delaying antibiotics for a CT scan and subsequent lumbar puncture significantly increases mortality in bacterial meningitis. Blood cultures can be drawn rapidly without delaying therapy.
3
Sequence the diagnostic imaging and invasive procedure.
The CT scan is performed third, followed by the lumbar puncture as the final step.
The CT scan must rule out a mass effect before the lumbar puncture can be safely performed. CSF analysis is still necessary even if antibiotics have been administered.

Key Concept

In patients with suspected bacterial meningitis who have indications for a CT scan before lumbar puncture (e.g., papilledema, focal neurological deficits, altered mental status), blood cultures should be drawn and empiric antibiotics administered immediately, prior to neuroimaging.
Estimated Time:1m 0s
Rate this question

Topics

Infectious Diseases

More questions from this topic