Diabetes insipidus

Question 1

= what

Answer 1

passage of large volumes of v v dilute urine (3-20L!!) (poly+nocturia) + excessive thirst.

Question 2

divided into

Answer 2

central DI (decreased ADH secretion)
neprhogenic DI (resistance to ADH in kidney)

Question 3

causes of central diabetes inspidus

Answer 3

mets
brain tumour
infection
surgery
head trauma

Question 4

causes of neprogenic diabetes insip

Answer 4

renal disease
hypokal
hypercalc

Question 5

Ix

Answer 5

Na = hypernatraemia
urine osmolality = low
serum osmolality = high
water deprivation test

Question 6

what is the water deprivation test?

Answer 6

fluids withheld over 8 hours. if no change in water loss, give desmopressin (synthetic ADH) to distinguish between cranial and nephrogenic. if central there will be a response, if nephrogenic, urine is still dilute

Question 7

rx

Answer 7

desmopressin. treat underlying cause