[Symptomatic hyponatremia in a 43-year-old woman after a skiing accident with head injuries]

This article reports the case of a 43-year-old woman who presented to the emergency room with headache and paresthesia after a fall on the head while skiing. She had clinical signs of volume depletion and blood test showed severe hyponatremia. Cerebral imaging was unremarkable. The diagnosis of cerebral salt-wasting syndrome (CSWS) was made, which is defined by the presence of extracellular volume depletion due to a tubular defect in renal sodium transport in patients with normal adrenal and thyroid function. The disease is mostly secondary to a neurological disease or head trauma. The patient rapidly improved after volume therapy and treatment with mineralocorticoids. The differentiation of CSWS from the syndrome of inappropriate antidiuretic hormone (SIADH) secretion can be challenging but the distinction is important because treatment options are very different.