When Diabetes is Not Diabetes

Mention the word diabetes and the vast majority of people will assume that you are talking about either type 1 diabetes, which affects about 10% of diabetes sufferers, or type 2 diabetes, which is the most commonly seen form of the disease and is currently growing alarmingly. But did you know that there is a third type of diabetes which has no connection whatsoever with either type 1 or type 2 diabetes, apart from sharing the name diabetes.

Diabetes, whether type 1 or type 2, is a condition in which the body is unable to process sugar satisfactorily and, for this reason, it is sometimes known as sugar diabetes. By contrast, diabetes insipidus, is a condition in which the body is unable to process water correctly and, accordingly, it is sometimes known water diabetes.

Diabetes insipidus is characterized by an unusually high intake of fluid, high output of urine and, in some cases, an excessive thirst. The symptoms of diabetes insipidus include the frequent need to urinate, awakening at night to urinate or involuntary urination while sleeping. Also, the volume of urine output increases because the body is unable to concentrate it and it is usually very pale in color or colorless in appearance.
There are four types of diabetes insipidus:

Neurogenic Diabetes Insipidus
Neurogenic diabetes insipidus (also commonly referred to as pituitary diabetes insipidus) is caused by a lack of the hormone vasopressin, which is produced by the pituitary gland and is needed in order for the kidneys to function properly and to concentrate urine.

Gestagenic Diabetes Insipidus
Gestagenic diabetes insipidus (also known as gestational diabetes insipidus) occurs during pregnancy and is often the result of destruction of vasopressin within the placenta.

Nephrogenic Diabetes Insipidus
Nephrogenic diabetes insipidus occurs when, in spite of the normal production of vasopressin, the kidneys still fail to properly concentrate urine. This form of diabetes insipidus can be inherited and can also be the result of kidney disease and taking certain types of drug.

Dipsogenic Diabetes Insipidus
Dipsogenic diabetes insipidus is a type of primary polydipsia in which an excessive fluid intake suppresses the effects of the hormone vasopressin. This is usually caused by an abnormality in the part of the brain that regulates thirst. Dipsogenic diabetes insipidus is easily confused with neurogenic diabetes insipidus and the only way to identify which form of the disease you are looking at is to measure the body's production of vasopressin.

There is also a second type of primary polydipsia known as psychogenic polydipsia which, as its name would suggest, has a variety of psychosomatic causes.

Despite the fact that there is some similarity in the symptoms of diabetes and diabetes insipidus it seems strange, and more than a little confusing, that the medical profession should have decided to give these two quite different conditions the same name.