Acidosis: The Prime Determinant of Depressed Sensorium in Diabetic Ketoacidosis

OBJECTIVE: The etiology of altered sensorium in diabetic ketoacidosis (DKA) remains unclear. Therefore, we sought to determine the origin of depressed consciousness in DKA. RESEARCH DESIGN AND METHODS: We analyzed retrospectively clinical and biochemical data of DKA patients admitted in a community teaching hospital. RESULTS: We recorded 216 cases, 21% of which occurred in subjects with type 2 diabetes. Mean serum osmolality and pH were 304 +/- 31.6 mOsm/kg and 7.14 +/- 0.15, respectively. Acidosis emerged as the prime determinant of altered sensorium, but hyperosmolarity played a synergistic role in patients with severe acidosis to precipitate depressed sensorium (odds ratio 2.87). Combination of severe acidosis and hyperosmolarity predicted altered consciousness with 61% sensitivity and 87% specificity. Mortality occurred in 0.9% of the cases. CONCLUSIONS: Acidosis was independently associated with altered sensorium, but hyperosmolarity and serum "ketone" levels were not. Combination of hyperosmolarity and acidosis predicted altered sensorium with good sensitivity and specificity.