Lumbar Puncture Findings in Patients With Secondary Headaches
Patients with normal CT scans who have symptoms consistent with either SAH or Idiopathic Intracranial Hypertension require an LP to confirm, or refute, the diagnosis.
In patients with a ventriculo-peritoneal shunt, a headache and fever, a shunt tap rather than an LP should be performed.
| Condition | CSF Findings |
| Idiopathic Intracranial Hypertension | High opening pressure. Remove 5-10 ml only at any one time |
| SAH | Best performed >12 hours after the onset of headache. Indicated only when the CT is normal. Xanthochromia is diagnostic |