diabetes
Meaning of diabetes: One word covering two unrelated illnesses, though on its own it is almost always taken to mean the sugar one.
Definition of diabetes
Diabetes is a group of conditions in which the body fails to regulate either blood sugar or water. Used without qualification the word means diabetes mellitus, in which blood glucose runs abnormally high because the body makes too little insulin, responds poorly to the insulin it makes, or both. Diabetes insipidus is a separate and far less common disorder of water balance.
What does insulin do, and what happens without it?
Insulin is a hormone made by the pancreas. It acts as the signal that lets cells throughout the body take glucose out of the blood and use it for energy or store it. When insulin is missing or ignored, glucose stays in the bloodstream instead of entering the tissues, so the blood carries too much of it while the cells go short. Sustained high blood sugar damages the walls of small and large blood vessels and the nerves supplied by them, which is the route by which the condition affects the eyes, the kidneys, the feet, the heart and the circulation over time.
How do the main types differ?
| Type | What goes wrong |
|---|---|
| Type 1 | The immune system destroys the insulin-producing cells of the pancreas, so almost no insulin is made |
| Type 2 | Cells respond poorly to insulin and the pancreas cannot keep up with the extra demand |
| Gestational | Raised blood glucose appearing during pregnancy, usually settling after the birth |
| Other | Diabetes caused by pancreatic disease, certain medicines, or a single inherited gene change |
The types are alike in their effect on blood glucose and unlike in their cause, which is why diabetes mellitus is described by type rather than as one illness. Age is an unreliable guide to which type is present, since type 1 can begin in adulthood and type 2 is seen in young people.
Why do two different diseases share the name?
Both produce large volumes of urine and constant thirst, which is what physicians could observe long before either mechanism was understood. The Latin words that follow the name record how they were told apart: mellitus means honeyed, for urine that tasted sweet, and insipidus means tasteless. Diabetes insipidus has nothing to do with sugar. In it the body cannot concentrate urine, either because the pituitary gland fails to release the hormone that instructs the kidneys to conserve water or because the kidneys stop responding to that hormone. The two conditions share a name and a symptom, and nothing else.
Also known as
Used in a sentence
The patient's laboratory results were consistent with diabetes and prompted further evaluation of blood glucose control.
Good to know
Diabetes mellitus and diabetes insipidus share a name but not a mechanism, one being a disorder of blood glucose and the other of water balance, and the unqualified word diabetes conventionally refers to the former.
Word origin
Where “diabetes” comes from
From Greek diabetes, meaning a passing through, from dia- (through) and bainein (to go), an ancient reference to the large volumes of urine the condition produces.