MR imaging of hypoglycemic encephalopathy: lesion distribution and prognosis prediction by diffusion-weighted imaging

Abstract

The results of this study showed that white matter was more sensitive to hypoglycemia than previously thought and there was no specific association between the patterns of injury and clinical outcomes whether the cerebral cortex, deep gray matter, and/or white matter were affected. Diffuse and extensive injury observed on the DWI predicts a poor neurologic outcome in patients with hypoglycemic injuries.

Neuroimaging in Patients with Abnormal Blood Glucose Levels

“…6,7,15,50,51 Severe hypoglycemia may present with altered mental state or coma. 6,[52][53][54] Occasionally, patients may develop hemiparesis or quadriparesis and mimic a stroke. 12,51,53 In general, autonomic symptoms usually develop before neuroglycopenic symptoms.…”

“…6,[52][53][54] Many authors have also pointed out the role of aspartate-induced injury in hypoglycemia, in contrast to hypoxia, in which the neuronal damage is secondary to glutamate. 15,52,55,56 Absence of glucose results in accumulation of oxaloacetate, which in turn leads to generation of excess aspartate. Aspartate is a known neurotoxin and has been shown to cause preferential neuronal necrosis in the cerebral cortex, neostriatum, and hippocampus.…”

“…15,49 On MR imaging, the earliest changes are seen on DWI sequences. [52][53][54] The involved regions show restricted diffusion with corresponding ADC hypointensity. 6,7,12,15,53 The extent of these abnormalities depends on severity and duration of hypoglycemia.…”

“…7,11,12,53,54,56 In fact, involvement of the WM is now thought to be earlier and more common than gray matter involvement. 52,53 Some cases may show diffuse gray matter and WM involvement. 6,7,53,54 The thalamus, brain stem, and cerebellum are invariably spared, and this may help to differentiate hypoglycemia from hypoxic injury, which often involves the thalamus.…”

“…6,7,53,54 The thalamus, brain stem, and cerebellum are invariably spared, and this may help to differentiate hypoglycemia from hypoxic injury, which often involves the thalamus. 6,52,55,56 Because these patients often present in an altered mental state, underlying hypoglycemia may not be apparent. NCCT in these patients is often unremarkable.…”