Acute Subdural Haemorrhage as a Complication of Diagnostic Lumbar Puncture

: Lumbar puncture (LP) is done daily for both spinal anesthesia and emergency cases for cerebrospinal fluid (CSF) analysis. Subdural hemorrhage (SDH) is a rare but severe complication following diagnostic LP, which could be potentially fatal, and early diagnosis may be life-saving. We present a 28-year-old female patient who presented to our emergency department with a headache, fever, and vomiting, with normal initial laboratory and imaging. Diagnostic lumbar puncture was done to exclude central nervous system infection. After CSF results and cultures were negative, and nasal influenza B detected, medication was started and she was discharged home. Three days post-procedure, she was complaining of a severe, persistent headache and a head computed tomography (CT) was done, which revealed acute SDH. Extensive workup searching for the cause of SDH was negative, and with a stationary course of SDH, she has discharged home again with a diagnosis of SDH post LP complication. In conclusion, a headache post LP is common and usually benign and self-limited. Severe persistent headache that is not positional and doesn't respond to analgesics with caffeine should be considered a red flag after LP and should be investigated carefully for other possibilities such as SDH.