Diabetes Insipidus Flashcards
1
Q
Pathophysiology
A
Deficiency of ADH (cranial DI)
Insensitivity to ADH (nephrogenic DI)
2
Q
Causes of cranial DI
A
Idiopathic Post head injury Pituitary surgery Craniopharyngiomas Histiocytosis X DIDMOAD is the association of cranial DI, DM optic atrophy and deafness (Wolfram's syndrome)
3
Q
Causes of nephrogenic DI - tx with thiazide diuretic
A
Genetic: the more common forms affect the vasopressin (ADH) receptor, less common forms affect the gene that encodes the aquaporin 2 channel
Electrolytes: hypercalcaemia, hypokalaemia
Drugs: lithium, demeclocycline
Tubulointerstitial disease: obstruction, sickle-cell, pyelonephritis
4
Q
Features
A
Polyuria
Polydipsia
5
Q
Investigations
A
High plasma osmolality, low urine osmolality (if urine > 700 them excludes DI)
Water deprivation test
