A 72 years old patient with BPH underwent transurethral resection of prostate under spinal anaesthesia. After one hour, he developed vomiting and altered sensorium. The most probable cause is:

- If surgery prolonged or when the size of prostate >75gm it leads to dilutional hyponatremia or water intoxication known as TUR syndrome. TUR syndrome (Dilutional Hyponatremia or water intoxication)* Results from a hypervolemic, hyponatremic state due to absorption of the hypotonic irrigating solution.* Clinical features: Nausea, vomiting, confusion, hypeension, bradycardia, & visual disturbances * The risk increases with resection time > 90 minutes or gland size > 75 gm* Rx- Diuresis (furosemide) and in severe cases, hypeonic saline (3%) administration.