This common metabolic disorder can be fatal
Hyponatraemia is a common disorder among hospital inpatients that will often be identified, investigated, and managed by the junior doctor. Patients can become seriously unwell, and it can lead to death, yet guidelines on how to manage these patients are scarce.
Hyponatraemia (abnormally low serum sodium) is among the commonest metabolic disturbances that the junior doctor will encounter.1 Water imbalance results in excess water relative to sodium, although the patient may have a low, normal, or increased extracellular volume.
About 4% to 6% of patients admitted to hospital have serum sodium less than 135 mmol/l.23 In 100 hospital inpatients about three will have hyponatraemia less than 130 mmol/l, and of every 100 inpatients who are normonatraemic (normal sodium), about one will develop hyponatraemia every day.4 Other investigators have reported that 30% to 46% of patients in hospital had at least one episode of hyponatraemia less than 136 mmol/l56 and that