Cerebral edema is a rare, but life- threatening, complication of diabetic ketoacidosis usually occurring during its treatment. There is no documentation of the occurrence of cerebral edema outside the setting of diabetic ketoacidosis (1).

We report a 16-year-old boy who walked into our clinic complaining of limited joint mobility (involving hands, elbows, and knees), poor linear growth, and diminished vision for 2 years. On direct questioning, osmotic symptoms were present for 2 years. There was no personal or family history suggestive of connective tissue disorder. The patient was alert and oriented and able to explain his medical history . He was 147.5 cm tall (height age 12 years and 4 months by Indian standards), weighed 29 kg (BMI 13.1 kg/m2), and was in Tanner stage 2 of puberty. Pulse rate was 88 bpm and blood pressure 110/80 mmHg. There were no signs of dehydration or acidosis. The patient’s skin was dry, thickened, and waxy. The prayer sign was present, along with flexion deformity of the elbow and knee joints. There were no signs of joint inflammation, and he had bilateral posterior subcapsular cataracts. Systemic examination was normal, and no organomegaly was seen. Random blood glucose was 329 mg %, and urine ketones were large. Hemogram, serum sodiumand potassium, albumin, transaminases, and creatinine were normal. HbA1c was 21.4% (normal 4–6%). An abdominal ultrasonography did not reveal any pancreatic calcification. GAD antibody was negative, and the A3243G mitochondrial mutation was absent.

The patient was admitted and received regular insulin subcutaneously at 12:00 p.m. and regular with intermediate- acting insulin at 8:00 p.m. before dinner. Blood glucose was 319 mg % before dinner, 221 mg % at 2 :00 a.m., and 195 mg % at 7:00 a.m. the next morning. Urine ketones were negative at all of these times. After the patient had taken morning insulin and breakfast at 8:00 a.m., he vomited twice and became significantly drowsy. His pulse was 68 bpm, respiratory rate 22 bpm, and blood pressure 130/100 mmHg. His pupils, tendon reflexes, and plantars remained normal. Venous blood pH was 7.38, and cerebral edema was suspected. The patient’s sensorium normalized within 30 min of intravenous mannitol. His pulse reverted to 86 bpm and blood pressure to 120/80 mmHg. A similar trend of alteration of sensorium and vital signs after 6 h prompted mannitol therapy every 8 h for 24 h, after which his course was unremarkable. On follow-up, 9 months after discharge, the patient’s HbA1c was 9.2%, and he has microalbuminuria (125 μg/min) and requires insulin for blood glucose control.

To the best of our knowledge, this is the first reported case of cerebral edema outside the setting of diabetic ketoacidosis or hyperosmolar coma. It also highlights a remarkable degree of advanced glycation end product formation (2), as evidenced by very high HbA1c, limited joint mobility (3), and cataracts at diagnosis. Though the connection, if any, between this high degree of advanced glycation end product formation and cerebral edema is unclear, a long duration of hyperglycemia in a child may serve to provide a high index of suspicion for cerebral edema while starting insulin therapy.

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