Diabetes insipidus

Reassure

  • Longstanding history of drinking large amounts of sweet drinks (often from a baby bottle)
  • Blood glucose normal
  • Growth normal
  • No associated symptoms or signs
  • Puberty stage appropriate for age
  • No other associated risk factors for a brain tumour
  • Normal neurological examination
  • Normal visual assessment

Review/refer

  • Excessive drinking and passing increased amounts of urine, of recent onset
  • Blood glucose normal
  • Abnormal growth (weight gain/weight loss) and/or pubertal abnormality
  • Any risk factors for a brain tumour

Scan

  • Excessive drinking and passing increased amounts of urine, of recent onset
  • Abnormal neurological examination or visual assessment
  • One or more additional symptoms/signs which may be caused by a brain tumour

Diagnostic pitfalls

  • Failing to consider diabetes insipidus in children with excessive fluid intake and excessive urine production

Examination/assessment

  • Determine duration of excessive drinking
  • Ask about bedwetting/getting up at night to pass urine
  • If never dry at night, are they passing more urine at night
  • What and when do they drink and what do they drink from (a child with DI will drink any fluid from any container)
  • Ask specifically about associated symptoms and risk factors:
    • Personal or family history of a brain tumour
    • Leukaemia
    • Sarcoma and early onset breast or bowel cancer prior therapeutic CNS irritation
    • Neurofibromatosis types 1 and 2
    • Tuberous Sclerosis
    • Li Fraumeni Syndrome
    • Family history of colorectal polyposis
    • Gorlins Syndrome
    • Other familial genetic syndromes
  • Neurological examination (include assessment of vision (including acuity), gait and coordination)
  • Plot growth in all children and pubertal status if applicable
  • Plot head circumference in children under two
  • Measure capillary blood glucose using a blood glucose meter

Worrying features

  • Symptoms of new onset of excessive fluid intake and the need to pass urine so frequently that it disturbs sleep