Multifaceted hyponatraemia : a case of changing aetiologies

Abstract

Hyponatraemia is the most common electrolyte disturbance encountered both in the community and hospitalised patients, with a prevalence of 8% in the community and a particular risk among the geriatric population. The aetiology of hyponatraemia is multifactorial, with drugs and a poor diet being among the most common causes. Syndrome of inappropriate antidiuretic hormone secretion and endocrinopathies are less frequent aetiologies. This case report presents a patient with symptomatic severe hyponatraemia with an initial serum sodium level of 97mmol/litre, with recurrence following 10 days of hospitalisation. The change in aetiology, corroborated by investigations and response to treatment, are discussed in detail as thiazide-associated hyponatraemia and syndrome of inappropriate anti-diuretic hormone are described.