SubArachnoid Hemorrhage HEadache Treated by Lumbar Puncture

"Patient will be managed according to the current international recommendations in the Toulouse acute stroke center.~In the absence of clear recommendation in the literature headache will be treated according to our local predefined analgesic protocol: paracetamol 1g/6 h, and if the numerical scale ≥ 4 : continuous intravenous morphine starting at 1mg/h and increased per 0.5 mg/h every hour if numerical scale remains ≥ 4.~Lumbar puncture will be performed between day 3 and day 5 after subarachnoid hemorrhage onset by an independent scientist from our clinical investigator center. 30-mL CSF will be removed by LP.~Sham LP consisting in superficial skin puncture by a subcutaneous needle (27 gauge needle) during the usual procedure will be performed at the same time point."