Upon digestion, foods that contain carbohydrates yield sugar, which normally enters the cells with the aid of insulin. When insulin is not available or not recognized by cell receptors, sugar remains circulating in the blood. Glucose levels rise and, at about 180 mg/dL the body responds by spilling sugar into the urine via the kidneys. If untreated, concentrations can continue to rise above 1000 mg/dL, which usually results in coma.
Frequent Urination
The body uses extra fluid to flush glucose out through the kidneys when the blood concentration rises to a certain level. Significant fluid loss results in extreme thirst. People report constant drinking without satisfying their thirst, and urinating many times during the day and night. These occurrences often prompt a visit to the doctor for the initial diagnosis of diabetes. In a person who has known diabetes, frequent urination is a common indicator of uncontrolled blood sugar levels.
Weight Loss
When glucose cannot enter the cells to be used for energy, the body loses a significant source of calories. The glucose molecules circulating in the blood or spilling into the urine are not accessible to the energy cycles inside the cells that provide calories to maintain body weight. Weight loss commonly is reported at the onset of diabetes.
Ketosis
When the body is unable to use glucose as a source of energy, an alternative source of energy is formed from other biochemical components in the body. The energy source, known as ketone bodies, can provide calories to keep the body functioning but produces side effects. Headache, fatigue and dizziness are the most common symptoms of ketosis. If ketosis persists for several days in someone with uncontrolled diabetes, the ketones can build to the point of becoming highly toxic and throwing off the body's delicate acid-base balance, resulting in a condition known as diabetic keto-acidosis (DKA).
Diabetic Ketoacidosis
Medline Plus reports symptoms of diabetic ketoacidosis including nausea and vomiting; rapid, deep breathing; a fruity odor on the breath; flushed face and dry mouth. The American Diabetic Association warns that ketoacidosis is life-threatening and requires immediate medical attention. This condition can lead to coma if left untreated.
Other Temporary Effects of High Blood Sugar
Some people report blurry eyesight when their blood sugar rises to a certain level. Others notice a tingling sensation in their extremities. There are people who notice nothing different when blood glucose levels are elevated. If symptoms are present from high blood sugar levels, they resolve shortly after the condition has been treated and blood glucose levels have been returned to normal range.
