Recognizing The Symptoms - Diagnosing Diabetes: Diabetes

Content provided by the Faculty of the Harvard Medical School

Recognizing the symptoms

Regardless of which type of diabetes you have, the symptoms of high blood sugar, or hyperglycemia, are similar.

Symptoms of type 1 diabetes

When beta cells stop producing insulin, your body's cells take in less glucose, while your liver releases more, resulting in a dramatic rise in blood sugar levels to as much as 10 times above normal. The excess sugar "spills" into your urine, drawing water with it. This accounts for the frequent urination (polyuria) and insatiable thirst (polydipsia) that can accompany this form of diabetes. It can also lead to dehydration.

Insatiable thirst is one symptom of type 1 diabetes.

You may also notice that while your appetite has increased, you've lost weight; this occurs because your cells are literally starved from a lack of nutrients and from the loss of sugar (since each gram of sugar in the urine equals four calories). Dehydration also contributes to weight loss. You may also feel fatigued and irritable, and your vision may be blurry because high sugar levels can change the shape of the lens in your eye and impair its ability to focus.

The start of symptoms in type 1 diabetes is usually abrupt and severe, occurring within days to weeks. Extreme hyperglycemia happens rapidly and leads to dehydration. Insulin deficiency causes other metabolic problems, including the unregulated breakdown of fat stores. This releases fatty acids, which are further broken down to ketones, products of fat digestion that accumulate in the blood. If your ketone concentration gets too high, your blood becomes acidic and diabetic ketoacidosis may occur, sending you into a coma. Fortunately, the condition can usually be averted or treated.

Symptoms of type 2 diabetes

Because blood sugar levels rise slowly in type 2 diabetes, the symptoms of this more common form of the disease may develop over years or may not occur at all. The early signs and symptoms are the same as for type 1 diabetes: repeated trips to the bathroom, thirst, and fatigue. But they may develop gradually enough to be easily overlooked. Other symptoms can include recurrent urinary infections, tingling or numbness in the hands and feet as a result of nerve damage, and recurring vaginal yeast infections.

Last updated:	January 23, 2007