Magnetic resonance imaging characteristics of persistent vegetative state due to prolonged hypoglycemia

Hypoglycemia is the sudden decrease in serum glucose level <50mg/dL. Neurological manifestations complicating profound and prolonged hypoglycemia range from reversible focal deficits and transient encephalopathy to irreversible coma. Here, we report magnetic resonance imaging characteristics of a patient with prolonged hypoglylicemia. A 47-year-old woman with a history of insulin dependent diabetes mellitus has been brought to the emergency room by her relatives. She used mistakenly overdose insulin injection and probably stayed 11 hours with low level blood glucose. The initial blood sugar level was 39.6 mg/dL at the emergency department visit, which was recovered urgently by 50% dextrose. MR imaging revealed high intensities at the bilateral posterior parietal cortices, corona radiata and hippocampus, but not in the basal ganglia. Seventy-two hour after admission, confluent lesions in the posterior parietal, temporal, frontal cortices and splenium of corpus callosum were more prominent on DWI and FLAIR, and did not match typical arterial territories. None of the lesions were enhanced on contrast-enhanced T1-weighted images. The prognosis or neurologic sequelae of hypoglycemic encephalopathy may depend on the severity and duration of hypoglycemia and persistent, diffuse involvement of the cerebral cortex, basal ganglia, or hippocampus on the following MR imaging. MR imaging findings in hypoglycemic vegetative state can be helpful in the differential diagnosis distinguishing from other neurologic conditions.