endocrinology Flashcards
what is diabetes insipidus
lack of ADH or lack of response to ADH which results in large amounts of dilute urine
types of diabetes insipidus
central
nephrogenic
what is central DI
problem with hypothalamus or pituitary gland → prevents ADH production or release
causes of central DI
brain tumours
head injury
brain infections
what is nephrogenic DI
problem with kidneys → unresponsive to ADH
causes of nephrogenic DI
genetic
meds e.g. lithium
kidney disorders
clinical presentation of DI
polyuria
polydipsia
dehydration
postural hypotension
hypernatremia
diagnostic investigation for DI
water deprivation test- no water
normal patient - high urine osmolality
patient with DI- low urine osmolality
serum and urine osmolality in DI
Low urine osmolality
High serum osmolality
what AVP (desmopressin) stimulation test
distinguish between central and nephrogenic DI
only patients with central DI respond resulting in reduced urine output and increased urine osmolality
management for DI
central - ADH and fluids
nephrogenic - fluids, treatment of underlying cause, sodium restriction
