Diabetes Insipidus Flashcards
1
Q
What is diabetes insipidus?
A
Deficiency of ADH (cranial) or insensitivity to ADH (nephrogenic)
2
Q
What are causes of cranial DI?
A
- Idiopathic
- Post head injury
- Pituitary surgery
- Craniopharyngiomas
- Histiocytosis X
- DIDMOAD / Wolfram’s syndrome
- Haemochromatosis
3
Q
What are causes of nephrogenic DI?
A
- Genetic → more common form affects ADH receptor
- Electrolytes → hypercalcaemia, hypokalaemia
- Drugs → lithium / demecloycline
- Tubulo-interstitial disease → obstruction / sickle cell / pyelonephritis
4
Q
What are the clinical features of DI (2)?
A
- Polyuria
- Polydipsia
5
Q
What do investigations show for DI?
A
- High plasma osmolality (very salty)
- Low urine osmolality (not v salty)
- Urine osmolality >700 excludes DI
- Water deprivation test
6
Q
What is the treatment for DI?
A
- Nephrogenic → thiazides, low salt/protein diet
- Cranial → desmopressin
