In suspected bacterial meningitis, which imaging or test should be obtained before lumbar puncture if signs of increased intracranial pressure are present?

• A. MRI
• B. CT scan before LP
• C. Ultrasound
• D. No imaging required before LP

Answer: (B)

In suspected meningitis, signs of increased intracranial pressure make lumbar puncture risky because removing CSF can precipitate brain herniation if there is a mass effect or significant edema. The safest next step is to obtain imaging to look for such abnormalities, and a CT scan of the head is the test of choice in this scenario. It is fast, widely available, and can reveal mass effect, midline shift, hydrocephalus, or other lesions that would alter the safe approach to LP. If the CT shows no contraindication, you can proceed with LP to analyze the CSF and guide treatment. MRI is more sensitive but less practical in the acute setting, and ultrasound does not evaluate intracranial structures in this context. Skipping imaging before LP would be unsafe when signs point to raised intracranial pressure.