Closed continuous lumbar subarachnoid drainage is an accepted strategy in the management of cerebrospinal fluid (CSF) leaks. Post lumbar drain haematoma as a complication has been reported in various planes including intraventricular, subdural, subarachnoid, intraparenchymal and spinal extradural locations, most often in patients receiving anticoagulants. Supratentorial extradural haematoma secondary to intracranial hypotension due to spinal CSF drainage are extremely rare and have been reported in a few cases. We present a rare case of near fatal fronto-temporo-parietal extradural haematoma following a lumbar CSF drain and review the literature. We report a 50 year old lady who developed CSF rhinorrhea following trans-sphenoidal decompression of non-functioning pituitary macroadenoma. A lumbar CSF drainage was placed to manage the CSF leak. She became unconscious within 24 hours of placement of lumbar drain and an urgent CT scan demonstrated a large supratentorial extradural hematoma which required an emergency evacuation. A review of the five previously reported similar cases was performed in the light of the present case and salient features highlighted. The present report emphasizes the fact that a simple procedure like lumbar CSF drainage can have rare life threatening complications and needs immediate recognition and management.