Diabetes insipidus

• Who is diabetes insipidus most commonly seen in?

  Infants
• What is diabetes indipidus?

  Metabolic disorder characterised by inability to concentrate urine
• What are some signs and symptoms of diabetes insipidus?

  Polyuria

  Polydipsia

  Dehydration

  Postural hypotension
• What are the 2 causes of diabetes insipidus?


  Insensitivity to ADH

  Dec secretion of ADH from pituitary
• What are some causes of dec ADH secretion in diabetes insipidus?

  Brain tumour/ surgery/ infection/ injury

  Gene mutation
• What are some causes of insensitivity to ADH in diabetes insipidus?

  Gene mutation

  Kidney disease

  Hypercalcaemia

  Hypokalaemia

  Medication
• What is an important differential to exclude in diabetes insipidus?

  Primary polydipsia (drinking too much water))
• What are some risk factors for diabetes insipidus?

  Family history

  Autoimmunity

  Lithium

  Head injury

  Haemochromatosis
• What are some bedside investigations for diabetes insipidus?

  Urine dip

  Water deprivation test

  24 hour urine collection - >3L
• What bloods are done for diabetes insipidus?

  U&Es

  Glucose (exclusionary)

  High plasma osmolality

  Low urine osmolality (<700 mOsm/kg)
• What is the conservative management of diabetes insipidus?

  Fluids (nephrogenic/hyponatraemia)

  Low salt/protein diet (nephrogenic)
• What is the medical management of diabetes insipidus?

  Desmopressin

  Thiazides (nephrogenic)
• What water deprivation tests suggest cranial diabetes insipidus?

  Low urine osmolality after fluid deprivation

  High urine osmolality after desmopressin
• What water deprivation test results suggest nephrogenic diabetes insipidus?

  Low urine osmolality after fluid deprivation

  Low urine osmolality after desmopressin