Featured updated topic: Diabetes insipidus
Diabetes insipidus is characterised by polydipsia, polyuria, increased thirst, and formation of hypotonic urine. Two types exist: central DI, due to defective synthesis or release of arginine vasopressin (AVP) from the hypothalamo-pituitary axis; and nephrogenic DI, due to renal insensitivity to AVP. Both types of DI may be associated with hypernatremia, and this may present as a medical emergency. Treatment goals are correction of any pre-existing water deficits and reduction in ongoing excessive urinary water losses. In central DI, desmopressin is the treatment of choice. Nephrogenic DI is treated with an adequate fluid intake; salt restriction and diuretics may help reduce polyuria.