The most common symptoms associated with diabetes insipidus (DI) are extreme thirst and excessive urination. Some patients may drink as much as a full glass of fluids every 10 to 20 minutes. As DI may start in the toddler age group, the excessive thirst and asking for fluids may be misinterpreted as “bad behavior” or habit and parents may be mistakenly told to withhold fluids to break the habit. It is important that these children are allowed open access to fluids until treatment is started. If unable to find fluids easily, some children have been known to drink directly from faucets, baths, pet dishes, swimming pools, and other unusual sources around the home.
The extreme urination may continue throughout the day and the night, sometimes as often as every 15-20 minutes, and often includes bed-wetting. The urine is usually pale, without color.
Symptoms of diabetes insipidus are very similar to those of diabetes mellitus, except that the urine does not contain high sugar levels. Diabetes insipidus can interfere with appetite and eating. In children, it can interfere with growth and weight gain. Signs of dehydration often appear, since the body is unable to keep enough of the water it takes in.
Symptoms of dehydration include:
- Dry skin
- Dry mucous membranes (sticky mouth) /reduced tears
- Sunken appearance to eyes
- Sunken fontanelles (soft spot in the skull) in infants
- Weight loss
- Low body temperature
- Muscle pains
- Rapid heart rate
- Low blood pressure/shock
Adults with untreated DI may be able to drink enough water to make up for the extreme loss of urine. However, there is a serious risk of dehydration and imbalances in the blood, such as salt and potassium.
Most patients with diabetes insipidus have an abnormal appearance of the pituitary region on MRI scans of the head, although MRI alone does not diagnose DI. Children with DI are more prone to develop other hormone deficiencies later, mostly involving slower growth.
Patients who develop diabetes insipidus that is undiagnosed and untreated, report a dramatic decline in quality of life. Because of the extreme urination and thirst, activities of daily living can be greatly affected: work and school schedules are interrupted, and social events may be compromised. Sleeping through the night is often not possible, and travel is difficult. Because this disorder is so rare and often undiagnosed, it may be mistaken for diabetes mellitus. Other patients have been told that they have a “compulsive drinking disorder” and must withhold fluids; however, this can then become dangerous and even life-threatening. Once diagnosed and treated with synthetic vasopressin called DDAVP, symptoms quickly improve, and a normal quality of life is restored.