Neuro-ophthalmic Manifestations of Hyperglycemic Encephalopathy

Poorly controlled diabetes mellitus is associated with multiple ocular manifestations including diabetic retinopathy and diabetic papillopathy. A potentially life-threatening consequence of uncontrolled diabetes is hyperosmolar hyperglycemic state (HHS) which is typically found in patients with blood glucose >600 mg/dL and a serum osmolality >320 mOsm/kg without significant ketone production or acidemia. HHS often presents as encephalopathy, obtundation, or more focal neurologic deficits such as hemiparesis or hemianopsia. However, focal deficits can manifest in hyperglycemic patients with substantially lower serum osmolality. We discuss four patients with serum osmolality >300 but <320 presenting with ophthalmologic symptoms.