Reversible Bilateral Lower Extremity Weakness Secondary to Severe Hypomagnesemia Following Acute Diarrheal Illness.

Hypomagnesemia is a common electrolyte abnormality that can cause a wide range of neuromuscular symptoms, including muscle weakness, tremor, and tetany. However, it is a rare cause of isolated lower extremity weakness. We present a case of a 71-year-old female with multiple comorbidities who developed severe bilateral lower extremity weakness and upper extremity tremor in the setting of profound hypomagnesemia (serum magnesium level of 1.0 mg/dL) after an acute diarrheal illness. The patient's weakness and tremor rapidly improved with intravenous magnesium supplementation. This case highlights the importance of considering hypomagnesemia in the differential diagnosis of acute bilateral lower extremity weakness and the potential for rapid reversal with magnesium repletion.