Understanding and managing hyponatraemia

Hyponatraemia is the most common electrolyte abnormality found in hospitalised children. The consequences can be serious, even fatal. Even mild hyponatraemia can cause significant motor and cognitive impairment. Much hyponatraemia is iatrogenic, caused by hypotonic intravenous maintenance fluids in patients with non-osmotic stimuli for increased ADH secretion; the remainder is caused by maladaptive responses to disturbed physiology. An understanding of the endocrine control of salt and water metabolism is essential to the understanding, prevention and management of hyponatraemia. Symptomatic hyponatraemic encephalopathy is a medical emergency and should be treated with intravenous administration of hypertonic saline solution.