Which statement most accurately describes LP timing in suspected meningitis?

• A. False, LP should be performed immediately
• B. True, head CT should be ordered before LP
• C. False, LP should never be performed if fever
• D. False, imaging is unnecessary before LP

Answer: (B)

In suspected meningitis, the main idea is balancing rapid diagnosis with safety from brain herniation. A lumbar puncture is essential to confirm the diagnosis, but if there are signs that raise concern for increased intracranial pressure or a mass lesion, you don’t want to risk herniation. That’s why ordering a head CT before performing a lumbar puncture is the best approach when red flags are present—altered level of consciousness, new focal neurologic deficits, papilledema, seizures, or a history of CNS disease. Imaging helps identify dangerous causes of increased ICP so you can plan the LP safely.

If there are no red flags, you can proceed with the LP promptly after drawing blood cultures, so you don’t delay diagnosis and antibiotic therapy. Fever itself isn’t a contraindication to LP, and imaging isn’t universally required before LP.