Diabetes insipidus (excessive thirst)


  • Many babies and children, particularly toddlers, will drink a lot and consequently pass a lot of urine - this is known as 'habitual drinking'.
  • If a baby starts leaking from nappies, a child starts wetting the bed (and this is unusual for them) or is having accidents during the day, or a teenager finds that they are thirstier than usual and urinating more than previously, then this could indicate that they have diabetes mellitus or diabetes insipidus.
  • Diabetes mellitus (sugar diabetes, often referred to just as 'diabetes') can be checked by a doctor using a finger prick blood test – this is not associated with a brain tumour. If the blood test is normal, then this thirst can be due to diabetes insipidus, where the body is not able to concentrate urine properly. This is rare and is usually due to a disturbance of the regulation of the hormones released by a part of the brain, called the pituitary gland. A brain tumour can be one possible cause of such disturbance.
  • Brain tumours causing excessive drinking often also cause abnormal growth or delayed or arrested puberty – these additional symptoms should be looked for carefully.

In babies and young children who are unable to communicate, it may be difficult to realise that they are excessively thirsty. Signs and symptoms that could suggest diabetes insipidus include:

  • unexplained weight loss
  • large volumes of urine, and potential leaks from nappies

Children and teenagers who have diabetes insipidus will have:

  • excessive thirst - an ongoing desire to drink, often feeling dry no matter how much they drink (e.g. waking at night regularly to drink)
  • increased urination - needing to go to the toilet more frequently and often passing pale watery urine

Any baby, child or teenager with increased thirst and urination should be seen urgently by a doctor to determine whether this is due to a type of diabetes, and if so, the cause of the diabetes.

If you're a teenager and you're concerned about this symptom, it's best to get it checked out by your GP.

If you're a parent or carer of a teenager and you're concerned, explain that you think they should go to the GP and offer to make them an appointment. Bear in mind that, depending on their age and circumstances, they may choose to go to the GP on their own, although many appreciate having a parent or carer with them whatever their age.

Feeling Worried?

Are the symptoms exhibited persistent e.g. lasting more than two weeks?


Arrange an appointment with your GP as soon as possible


Request an immediate consultant referral as soon as possible

If the symptoms or signs are sudden onset or severe, either take them to the emergency department or call 999.