TURP was done in an old pt. of BHP, after which he developed altered sensorium cause is -

Water intoxication is an impoant complication of TURP (Trans urethral resection of prostate) " The absorption of water into the circulation at the time of transurethral resection can give rise to congestive cardiac failure, hyponatremia and frequently confusion and other cerebral events often mimicking a stroke. The incidence of this condition has been reduced since the introduction of isotonic glycine for performing the resections and the use of isotonic saline for postoperative irrigation. The treatment consists of fluid restrictions". Ref : Bailey & Love 25/e p1352