Diabetes insipidus

Diabetes insipidus is a rare but treatable condition that typically presents with extreme thirst (polydipsia) together with the passing of large amounts of dilute urine (polyuria). Distinguishing these symptoms from those of primary polydipsia, diabetes mellitus, and causes of urinary frequency without polyuria can be challenging. Diabetes insipidus is caused by a problem with vasopressin production in the pituitary gland (central diabetes insipidus), or action of vasopressin in the kidneys (nephrogenic diabetes insipidus). Desmopressin, an analogue of vasopressin, is an effective treatment for cranial diabetes insipidus. Between 2009 and 2016 there were four reported deaths in England resulting from omission of desmopressin, and a further 56 reported incidents where dosing errors resulted in harm.1 This Practice Pointer offers an approach to diagnosing suspected diabetes insipidus, and guidance on managing people with diabetes insipidus who have intercurrent illness or require hospital admission.