Focal Neurological Deficit Secondary to Severe Hyponatraemia Mimicking Stroke

Hyponatraemia is a common electrolyte abnormality seen by internists. Clinical features of hyponatraemia are primarily related to CNS dysfunction, and depend on the severity and acuity of changes in serum sodium concentration. Neurological manifestations of hyponatraemia range from nausea and malaise, with a mild reduction in the serum sodium, to lethargy, decreased level of consciousness, headache, seizures and coma in extreme cases. Focal neurological deficits are very rare in the setting of hyponatraemia. Here, we describe a patient with acute severe symptomatic hyponatraemia presenting with focal neurological deficits that resolved after correction of acute hyponatraemia. LEARNING POINTS: A rare presentation of hyponatraemia is described. Neuroimaging should be performed in patients with focal neurological deficits and hyponatraemia in order to rule out other serious neurological diseases. Correction of severe hyponatraemia can result in resolution of focal neurological deficits.