Diagnosis and Treatment
The diagnosis of diabetes insipidus is based on a series of tests, including a urine osmolality and water deprivation test.
With diabetes insipidus, the urine is less concentrated with low salt and waste levels. The concentration of the urine can be tested by measuring osmolality, which is how many particles are in about a quart of water.
A water deprivation test is a complicated procedure that requires specially trained medical professionals. It should be done in a controlled setting where the patient can be monitored closely throughout the entire test. The water deprivation test measures changes in body weight, urine output, and the make-up of the urine, and levels of salts in the blood when fluids are withheld and as dehydration occurs. Measuring blood levels of the hormone ADH is also usually performed. Samples are taken every hour over a several-hour period.
An x-ray test called an MRI scan may be done to look for abnormalities in the pituitary gland, although alone, this is not diagnostic of diabetes insipidus. However, at diagnosis, it is estimated that 71% of patients show an abnormally thickened pituitary stalk on MRI.
Diabetes insipidus can be corrected by giving a synthetic vasopressin called DDAVP, which works on the kidneys to help decrease the amount of urine made. A normal balance between water intake and urine output is usually quickly restored. Most patients receive DDAVP as a pill or spray into the nose. However, if this is not possible due to the age or condition of the patient, DDAVP can be given by injection. It may be given in the hospital, clinic, or home. The dosage and method of receiving this hormone will depend on each individual case and should be discussed with your physician.
Fortunately, this treatment can be taken on trips, kept in the nurse’s office at school, and for other occasions when out of the home. Life-long treatment of diabetes insipidus is usually necessary.