Acute hyperglycemia is a sudden and dramatic spike in blood sugar, and is a serious condition that can can result in immediate and lasting damage. It occurs most often in people whose blood sugar must be carefully managed with insulin injections, and may require hospitalization if the glucose level cannot be normalized. The exact level at which high blood sugar is considered to be acute hyperglycemia varies, though it typically falls into a range of 144 to 270 mg/dl (8 to 15 mmol/l). Symptoms may include excessive hunger, thirst, and urination, as well as blurred vision and fatigue. Since these symptoms may not appear until blood glucose has risen to dangerous levels, diabetics often monitor their blood sugar very closely.
Diabetes mellitus is the most common cause of both chronic and acute hyperglycemia. Chronic hyperglycemia is a condition in which blood sugar is consistently at a level considered to be higher than normal. Even this can cause organ and tissue damage if left untreated. People whose chronic hyperglycemia is managed with insulin injections may develop acute hyperglycemia if they fail to receive their insulin injections, or for other reasons.
Serious conditions, like osmotic diuresis, may occur with excessively high blood glucose levels. This related condition can result due to glucose entering the kidneys and causing osmotic diuresis. This, in turn, causes in polyuria, or excess urination, and polydipsia, or excess thirst. The thirst is caused by the body becoming dehydrated due to lack of water, while the fact that the kidneys are voiding excess urine may result in the inability to properly rehydrate by simply drinking water.
Related conditions, such as diabetic ketoacidosis, may be associated with acute hyperglycemia. Ketoacidosis is actually caused by a lack of insulin in the blood, so someone with type I diabetes who neglected to take their insulin supplements could exhibit both acute hyperglycemia and diabetic ketoacidosis. This serious condition can potentially result in coma or death, and typically also causes confusion, shortness of breath, and vomiting. Other symptoms can include a peculiar sweet or fruity odor on the breath, which is the result of fatty acids being released from adipose tissues and subsequently being turned into ketones.
Careful monitoring of blood glucose levels and the administration of insulin or other prescribed treatments can help avoid acute hyperglycemia. In cases where it cannot be avoided, the monitoring can allow foreknowledge of the condition before levels rise to the point where symptoms actually occur. This can allow help to be sought and stave off some of the serious complications of the condition.