hyperglycemia
Meaning of hyperglycemia: Blood sugar rising is not felt at first, which is why the level is measured rather than judged from how a person feels.
Definition of hyperglycemia
Hyperglycemia is a higher than normal level of glucose in the blood. Glucose is the body's main fuel, and its concentration is normally held within a narrow range by insulin, the hormone that lets glucose move out of the blood and into cells. A rise means either that too little insulin is available or that cells are responding poorly to the insulin present.
How hyperglycemia is built
- hyper- Prefix · Greek above normal, excessive
- gluc/o, glyc/o Combining form · Greek sugar, glucose
- -emia Suffix · Greek condition of the blood
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
What pushes glucose up?
| Cause | What is happening |
|---|---|
| Type 1 diabetes | The pancreas makes little or no insulin after immune damage to the cells that produce it |
| Type 2 diabetes | Cells respond poorly to insulin, and production eventually fails to keep pace |
| Serious illness, injury or surgery | Stress hormones drive glucose up, sometimes in people with no diabetes |
| Medicines | Corticosteroids most often, along with some antipsychotics, diuretics and immune suppressants |
| Pancreatic and hormonal disease | Damage to insulin producing tissue, or an excess of hormones that oppose insulin |
Stress hyperglycemia during a serious illness is common and often settles as the illness resolves, although it also identifies people whose glucose handling was already borderline. A single high reading therefore says much less than a pattern of readings does, and a measure of average glucose over the preceding months is used alongside single values to separate the two situations.
What does it feel like?
Modest rises produce nothing at all, which is why the condition is usually found on a blood test rather than reported by the person who has it. Once the level climbs high enough that the kidneys cannot reabsorb all the glucose passing through them, sugar spills into the urine and drags water out with it. Thirst, frequent urination, tiredness and blurred vision follow, and weight loss can appear as cells are starved of fuel despite plenty circulating. Very high levels lead to two distinct emergencies: a buildup of acidic ketones where there is almost no insulin at all, seen more often in type 1 diabetes, and severe dehydration with an extreme glucose level and few ketones, seen more often in type 2.
Why does sustained hyperglycemia damage tissue?
Excess glucose attaches itself to proteins inside and around cells and changes how they behave, and the resulting deposits build up in the walls of small blood vessels. The tissues that suffer most are those least able to keep glucose out of their cells: the retina, the filtering units of the kidney, and the long nerves running to the feet and legs. Larger arteries stiffen and fur up faster too, which is why high blood sugar counts among the causes of heart attack and stroke as well as of eye, kidney and nerve disease. The damage accumulates silently over years, and it is the average level over time rather than any single peak that drives it.
Also known as
Used in a sentence
Laboratory results showed hyperglycemia consistent with poorly controlled diabetes.
Good to know
Hyperglycemia and hypoglycemia are opposites that can produce overlapping symptoms such as fatigue, sweating or confusion, so the two are told apart by measuring the glucose level rather than by how a person appears.
Word origin
Where “hyperglycemia” comes from
Formed from hyper-, Greek for over or above, glykys, meaning sweet, and -emia, meaning a condition of the blood.