Diabetes Insipidus (DI):
Due to deficiency of ADH/vasopressin – may be temporary or chronic. Characterised by persistent excessive quantities of urine and excessive thirst (from impaired resorption of water).
Primary unknown cause
Secondary due to pathologic lesions (eg cranial injuries, tumours, vascular lesions, infections)
Two types – cranial (deficient ADH production) and nephrogenic (renal tubules are unresponsive to ADH)
Polydipsia, polyuria and nocturia. Insidious or abrupt onset.
May progress to dehydration and hypovolaemia.
Diagnosis is ‘water deprivation test’
Diabetes insipidus, diabetes mellitus, optic atrophy and deafness.
Hormone replacement therapy (vasopressin injections or nasal sprays).
Diuretics can reduce polyuria