Endocrine ADH disorder Flashcards
how does diabetes insipidus differ from DM?
insipidus is related to kidneys not the pancreas producing insulin
in diabetes insipidus excess dilute urine leads to what
extreme thirst
(also a factor for DM)
ADH is also known as vasopressin, work in same way#its analogue, X, is used in tx of DI
desmopressin
Dosage is tailored to produce a slight diuresis every 24 hours to avoid what
water intoxication
what part of brain produces vasopressin (ADH) and where is it stored
hypothalamus,
in pituitary gland
in a normal person, when is adh released and how does it retain water to produce more CONCENTRATED urine
ADH released when water in body becomes too LOW
ADH retains water in body by reducing water lost through kidneys
more dilute urine is produced in DI how and why? ADH
Reduced production of ADH
Kidneys do NOT retain much water, so too much water passed from body
Causing extreme thirst/polyuria
Therefore, more DILUTE urine
2 types of DI
PITUITARY (CRANIAL)- lack of ADH production
common
NEPHROGENIC (PARTIAL)- NO response to ADH
tx for pituitary (cranial) DI?
vasopressin/ desmopressin
to replace the alr depleted ADH stores
tx for nephrogenic (partial) DI?
thiazide diuretic (paradoxical effect)
will somehow help kidneys retain fluid even though its a diuretic. opposite effect
desmopressin is X potent and has a Y duration of action than vasopressin
more, longer
vasopressin analogue, so lasts longer than og hormone made by body
t/f desmopressin has a vasocinstrictor effect
false. none
2 SEs of desmopressin
- hyponatraemia: due to body retaining water from effects of desmopressin thus diluting Na+ stores in body -> hypo
- nausea
inappropriate adh secrtion -> hyponatraemia
explain why
Increased ADH-> body stores too much water-> dilutes the salt conc. in blood-> hyponatraemia
hyponatraemia tx? FDT
fluid restriction
demeclocycline
tolvaptan (vasopress antagonist)
why does fluid restriction help in tx of hyponatraemia?
less fluid in blood, makes Na+ more conc in blood, stop hyponat
demeclocycline 2nd option to treat hyponatraemia. what does it do in terms of adh effect
blocks renal tubular effect of adh,
stops fluid absorption in kidneys
Why do we AVOID rapid correction of hyponatraemia w/ Tolvaptan?
Causes osmotic demyelination-> serious neurological events
what to thus monitor with tolvaptan sue
serum sodium concentration and fluid balance
