<prompt> Which of the following is the most common cause of late neurological deterioration in a case of cerebrovascular accident :RebleedingVasospasmEmbolismHydrocephalus  <response>: Answer is B Vasospasm: Vasospasnt: Narrowing of the aeries at the base of the brain following SAH occurs regularly. This vasospasm causes symptomatic ischemia and infarction in approximately 30 of patients and is the major cause of delayed morbidity or death. Sign of ischemia appear 4 to 14 days after the haemorrhage, most frequently at about 7 days - Harrisons 16th 2309 Four major causes of delayed neurological deficit Rerupture Hydrocephalus Vasospasm Hyponatremia 