Diabetes Insipidus

Question 1

What are the 2 types of diabetes insipidus?

Answer 1

Cranial diabetes insipidus

Nephrogenic diabetes insipidus

Question 2

Give 3 causes of nephrogenic diabetes insipidus

Answer 2

Drug: lithium
Congenital
Infiltrative: amyloidosis
Metabolic: hypercalcaemia, hypokalaemia
Post-obstructive uropathy

Question 3

Give 3 causes of cranial diabetes insipidus

Answer 3

Tumour: pituitary tumour
Iatrogenic: damage to posterior pituitary gland
Vascular: sheehan’s syndrome, pituitary apoplexy
Trauma: Head injury

Question 4

What biochemical findings do you see in diabetes insipidus?

Answer 4

Raised plasma osmolality
Reduced urine osmolality
Hypernatraemia

Question 5

What test can you do to show diabetes inspidus?

Answer 5

Water deprivation test