A patient following head injury was admitted in intensive care ward with signs of raised intracranial pressure. He was put on ventilator and ataed on intravenous fluids and diuretics. Twenty four hours later his urine output was 3.5 litres, serum sodium 156 mEq/l and urine osmolality of 316 mOsm/kg. The most likely diagnosis based on these parameters is
High output due to diuretics Diabetes insipidus Too much infusion of normal saline Cerebral salt retaining syndrome