Trying to explain what diabetes insipidus is can be challenging enough, without having it confused with "the other diabetes"-sugar diabetes (diabetes mellitus). Both share the word "diabetes" in the name, and both involve thirst and frequent urination, although in DI, urination is more frequent and in much greater volumes than the more common sugar diabetes, and the urine is subsequently extremely dilute and a very pale yellow color or almost clear. But beyond that, there's not much else in common. Some people with DI refer to their condition as either "central DI" or "nephrogenic DI" (depending on what's applicable), because it avoids the confusion caused when people not familiar with DI hear the word diabetes.

The more you know about both diabetes insipidus and diabetes mellitus, the better able you are to explain your condition to others-from family members to primary care physicians or emergency technicians.

A good starting place is to know the meaning of the words themselves. Diabetes is derived from the Greek verb diabainein, which means to stand with legs apart, as in urination. Diabetes mellitus means, literally, honey-sweet urine (back when doctors would sometimes actually taste people's urine to make a diagnosis). Diabetes insipidus means bland or insipid urine.

There are four forms of DI: central DI (also referred to as pituitary or neurogenic DI), nephrogenic DI, gestational DI and dipsogenic DI. DI is caused by the lack of the  antidiuretic hormone (vasopressin) or the kidney's inability to respond to this hormone.

Sugar diabetes, or diabetes mellitus, comes in two different forms: adult-onset diabetes and insulin-dependent diabetes. Sugar diabetes is caused by lack of the hormone insulin. Not only are DI and sugar diabetes separate conditions, but the diagnostic tests and treatments are different, as well.

The table below sums up the major differences.