Flummoxed by the flaps – case report

BACKGROUND: Asterixis, or “flapping tremor,” is typically described in the setting of metabolic encephalopathies such as hepatic or uremic encephalopathy. However, electrolyte disturbances can also precipitate asterixis, though this is less commonly reported. Hypomagnesemia is an underrecognized cause, particularly in older adults with type 2 diabetes mellitus, where magnesium depletion is multifactorial. Reporting such cases is important to highlight the diagnostic challenge and the potential for fully reversible neurological manifestations. CASE PRESENTATION: We describe a 72-year-old woman with long-standing type 2 diabetes mellitus, hypertension, and stage 3 chronic kidney disease, who presented with tingling in all four limbs for 8 months and muscle cramps for 1 month. On examination, she exhibited bilateral asterixis, with otherwise normal neurological findings. Brain imaging showed chronic ischemic changes without basal ganglia involvement, and electrocardiography revealed prolonged QTc. Laboratory studies identified hypomagnesemia (serum magnesium 1.1 mg/dL), while serum calcium and potassium levels were normal. No gastrointestinal losses, drug use, or alcohol history were evident, suggesting diabetes-related magnesium depletion as the underlying cause. After magnesium supplementation, her asterixis resolved completely. CONCLUSIONS: This case emphasizes hypomagnesemia as a rare but reversible cause of asterixis. In older adults with diabetes, magnesium depletion is multifactorial and underdiagnosed. Early recognition and correction are crucial to prevent complications.