diabetes insipidus Flashcards
function of ADH
allow the reabsorption of water via aqua priors mainly in the collecting ducts
how does vasopressin work
- constricts vessels
2. increases volume
exemples of neprhrogeni
drugs - phenytoin alcohol naloxone lithium any kidney disease- PCKS, sickle cell Wolfram’s syndrome- DM, DI, deafness, bvisual problems
examples of central causes
infection, granulomatous like sarcoidosis , Sheehans
what are the receptors
V2 receptors in collecting duct
dx of DI
primary polydipsia, patients have an intact system but they are taking excessive amount fo water, could be psychogenic (schizophrenia) or dipsogenic
lab values for DI
hypernatremia which increases the serum osmality
urine osmolality goes down as a lot of water
urine /cretaine - normal or slightly elevated due to marked dehydration
symptoms of DI
nocturia + excessive thirst
what can we do to prove diabetes insipidus
a fluid deprivation test followed by a desmopressin test
dx of DI
diabetes mellitus
primary polydipsia - dipsogenic +psychogeic
hypercalcemia - also has polyuria
in DI what would a fluid deprivation test show
no conenration of the urine even after being deprived
whats the function the desmopressin test
to distinguish between central and peripheral cause of DI
tx pf DI
central : give desmopressin
neprhrogenic=THIAZIDE diuretics to deplete sodium , you can use desmopressin in greater amounts with variable results and
nsaid such as indomethicicn
causes of SIADH
small cell lung cancer - some medications - antidepressants , carbamzazepine infection post brain surgery some pulmonary diseases
labs of SIADH
hyponatremia
increase in urine osmolity
decrease in serum osmalitiy
hypertension possible
peripheral edema
seizures due to hyponatremia (before this they are confused sleepy_
