diabetes insipidus Flashcards
1
Q
what is the primary pathology of diabetes insipidus?
A
-failure to produce OR respond to ADH in the kidney
2
Q
What are the symptoms of diabetes insipidus?
A
- polyuria
- polydipsia
- nocturia
- Sx of severe dehydration - altered mental state, hypotension
3
Q
There are 2 types of diabetes insipidus, what are they? What are their main causes?
A
Craniogenic:
- idiopathic
- iatrogenic - post adenoma removal
- TBI/stroke/meningitis
Nephrogenic (rare):
- hereditary
- medications - lithium
- hypkalaemia, hypercalcaemia
4
Q
How do you treat nephrogenic diabetes insipidus?
A
- discontinue causative agent
- thiazide like diuretic
- NSAIDs
- amiloride (specific for lithium induced)
5
Q
How do you treat craniogenic diabetes insipidus?
A
-desmopressin
6
Q
What are the causes of SIADH?
A
- stroke/sub arach/sub dural
- desmopressin
- SCLC
- TB/pneumonia
- drugs - glipizide, carbemazepine, cyclophosphomide
7
Q
What are the expected findings in SIADH?
A
-hyponatraemia secondary to dilutional effects
8
Q
What symptoms along with hyponatraemia would make you thing that this patient has SIADH?
A
- normotensive
- NO oedema (w/ oedema would make you think CHF)
9
Q
What are the treatment principles of SIADH?
A
- fluid restriction
- increase salt intake
- SLOW correction of Na+ because CPM
- vasopressin replacement therapy = VAPTANS = tolvaptan
10
Q
How do you investigate diabetes insipidious?
A
- corrected to rule out hypercalcaemia (i.e. parathyroid or Ca)
- blood glucose - to rule out DM
- water deprivation test - 8hrs NBM (no fluids), then give desmopressin - compare urine and blood osmolality pre and post
