Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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March 29, 2018
Irreversible Cortical Blindness in Nonketotic Hyperglycemia
- Background:
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Hyperglycemia can cause encephalopathy, focal motor seizures, complex partial seizures, aphasia, and movement disorders like chorea, athetosis, and hemiballismus. Occipital seizures and reversible hemianopia have been described.
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To the best of our knowledge, bilateral cortical visual loss that is irreversible in spite of the correction of hyperglycemia has not been described in the literature.
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Like hypoglycemia, hyperglycemia can give rise to irreversible damage if not corrected early.
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- Clinical Presentation:
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Visual field defects, changes in visual acuity, and visual hallucinations including flashes of light, in the context of hyperglycemia.
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- Key Diagnostic Features:
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Predilection for involvement of the occipital lobes, with subcortical hypointensity on T2/ FLAIR imaging.
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The underlying etiology of the T2/FLAIR hypointensity is unknown, however postulated mechanisms include intracellular osmotic dehydration, mineral deposition, and free radical accumulation.
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Gyral contrast enhancement suggestive of cortical necrosis.
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Possible involvement of the pons.
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- Differential Diagnoses:
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Encephalitis/meningitis: clinical presentation (febrile, septic), not necessarily bilateral and symmetric pattern of involvement.
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Acute infarction: not typically bilateral and symmetric, usually with T2 hyperintensity affecting cortical/subcortical region that does not cross boundaries of vascular territory
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PRES: vasogenic edema with T2 hyperintensity within subcortical white matter, no restricted diffusion
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- Treatment:
- Correction of hyperglycemia and other electrolyte abnormalities
