Diabetes insipidus is caused by a decrease in the level or function of antidiuretic hormone (ADH), also known of as vasopressin. ADH helps regulate the amount of fluid in the body and it is manufactured in the hypothalamus and stored in the pituitary gland.
In healthy individuals, when the body fluids are depleted, ADH is released from the pituitary gland and prevents the excretion of fluids from the body in form of urine. In people with diabetes insipidus, however, there is either a reduced level of ADH or an interruption of its function and the kidneys carry on excreting dilute urine.
There are two main symptoms of diabetes insipidus:
- Excessive thirst or polydipsia. The throat may feel parched, a sensation that may persist despite drinking water repeatedly.
- Frequent passing of large amounts of urine or polyuria. The urine is usually pale, and passed in large volumes of up to 20 litres every 15 to 20 minutes.
Other associated symptoms of diabetes insipidus include:
- Difficulty in sleeping due to waking up to urinate multiple times
- Disruption of daily activities such as work and studying due to excessive urination
- Excessive fatigue and listlessness due to dehydration and lack of sleep. Irritability and difficulty in concentrating may also manifest.
- Malaise or feeling unwell.
- Fungal infections around the genital area caused by wetting of underwear and clothes. Children with diabetes insipidus may develop nappy rash or rash around the genitalia.
- Children may have impaired growth and weight loss.
- Body temperature may be raised, especially in children with the condition.
- Other problems in children include bed wetting and loss of appetite.