Diabetes Insipidus

Question 1

Define diabetes insipidus.

Answer 1

Diabetes insipidus (DI) is a metabolic disorder characterised by defective ability to concentrate urine in the kidneys, resulting in the production of large quantities of dilute urine.

Question 2

Explain the aetiology/risk factors of diabetes insipidus.

Answer 2

Iatrogenic
Idiopathic
Drug induced
Pituitary surgery

Question 3

Summarise the epidemiology of diabetes insipidus.

Answer 3

DI is uncommon, although the exact prevalence in the general population is difficult to estimate. For both central DI and nephrogenic DI, there are no clear differences in prevalence between genders or among ethnic groups.

Question 4

Recognise the presenting symptoms of diabetes insipidus. Recognise the signs of diabetes insipidus on physical examination.

Answer 4

Polyuria
Polydipsia
Nocturia
CNS symptoms of hyponatraemia

Question 5

Identify appropriate investigations for diabetes insipidus and interpret the results.

Answer 5

BM
Water deprivation test without ADH
Water deprivation test with ADH
Serum salts

Question 6

Generate a management plan for diabetes insipidus.

Answer 6

Desmopressin: V2 agonist
IV or oral fluids may be given in acute complications.

Question 7

Identify the possible complications of diabetes insipidus and its management.

Answer 7

Hypernatraemia
Thrombosis
Bladder and renal dysfunction
Iatrogenic hyponatraemia

Question 8

Summarise the prognosis for patients with diabetes insipidus.

Answer 8

Diabetes insipidus is a life-long condition but most patients are well controlled on DDAVP.