Low serum sodium (<135mmol/L)

Renal failure

Nephrotic syndrome

Diarrhoea/vomiting

Small bowel obstruction

SIADH

Water overload (e.g. polydipsia)

Severe hypothyroidism

Addison’s disease

Glucocorticoid deficiency

Cardiac failure

Cirrhosis

Clinical features

Confusion

Lethargy

Personality changes

Complications

Convulsions

Coma

Death

Management

Treat the underlying cause