In suspected meningococcal meningitis, which sequence of steps is recommended before performing a lumbar puncture to exclude mass effect?

• A. Head CT before LP
• B. LP first
• C. MRI before LP
• D. EEG before LP

Answer: (A)

When meningitis is suspected, performing a lumbar puncture to analyze CSF is essential for diagnosis, but removing CSF can worsen pressure if a mass lesion or significant edema is present. To prevent this danger, you first look for signs of mass effect with neuroimaging. In the acute setting, a head CT is the quickest way to detect mass lesions or midline shift that would contraindicate LP. If the CT is negative for mass effect and there are no other contraindications, you can proceed with the lumbar puncture and start appropriate therapy. MRI can also detect mass lesions but is less practical as an initial step in urgent cases due to longer timing and availability. EEG has no role in assessing mass effect prior to LP.