diabetes insipidus Flashcards
defined as?
passing large volumes of water per day
what two reasons are there for causing this
reduced secretion of ADH or impaired response of the kidney to ADH
what would cause a central (unable to secrete adequate ADH?)
idiopathic (most common) genetic sarcoidosis pituitary tumour trauma to stalk
causes of nephrogenic DI?
genetic
CKD
Drugs: lithium
Low potassium/high calcium
presentation ?
polydypsia
polyuria (extremely excessive, all consuming)
dehydration
gold standard diagnosis?
water deprivation test
what is the water deprivation test?
give water and determine whether body is able to concentrate urine
how can you differentiate between central and nephrogenic diabetes insipidus?
give ADH and check urine concentration and osmolality. urine will become more concentrate in central but not nephrogenic
treatment of central DI?
give ADH synthetic = desmopressin
if it is nephrogenic - obviously desmopressin will be useless. what would you give?
thiazide diuretics which will generate hyponatraemia and drive water reabsorption
