Symptoms of Diabetes

The most common early symptoms of diabetes are increased thirst and frequent urination. These initial symptoms are usually related to hyperglycemia, the medical term for high blood glucose levels.

Type 1 Diabetes Symptoms

The initial symptoms of type 1 diabetes often occur suddenly and are very serious. As insulin production decreases, glucose accumulates in the bloodstream instead of being transported into the body's cells, which need it for energy. To generate this missing energy, the body breaks down fat tissue and releases fatty acids. These fatty acids are then metabolized into toxic chemicals called ketones, which increase the blood's acidity to dangerous levels (a state called ketoacidosis).

The initial symptoms of diabetic ketoacidosis include excessive thirst and urination, dehydration, weight loss, nausea, vomiting, fatigue, dry or flushed skin, rapid breathing, abdominal pain, and mental confusion. One sure sign is breath that smells like fruit or nail polish remover. Diabetic ketoacidosis is a medical emergency that requires immediate hospitalization. If you or a loved one develops any of the symptoms of ketoacidosis, call your doctor or an ambulance immediately. Death can occur, but the vast majority of people recover with aggressive administration of insulin and fluids.

Type 2 Diabetes Symptoms

Type 2 diabetes develops gradually over many years and the initial symptoms may be almost unnoticeable. In fact, many people find out that they have type 2 diabetes when a routine laboratory test shows high blood glucose levels. As glucose levels continue to increase, most people develop the classic initial symptoms of:

  • increased frequency of urination
  • increased thirst and fluid intake
  • and, in later stages, weight loss despite increased hunger and food intake

Fortunately, these symptoms go away once blood glucose levels are brought under control.

Other common symptoms of type 2 diabetes include blurred vision (due to changing levels of glucose in the eye), weakness and fatigue, recurrent vaginal yeast infections, and infections of the skin and gums. These symptoms are temporary, do not indicate any permanent damage, and can be eliminated by controlling blood glucose levels.

In some people, complications of diabetes such as peripheral neuropathy (nerve damage in the hands or feet) or coronary heart disease are the first indication of diabetes. These complications can be controlled but cannot be cured once they develop.

Another possible initial symptom of diabetes is hyperosmolar nonketotic syndrome. It occurs when the stress of an injury or major illness, such as a stroke, heart attack, or severe infection, causes extremely high blood glucose levels (above 1,000 mg/dL). Although insulin levels are adequate to avert excessive ketone production (as occurs in ketoacidosis), the insulin levels are not high enough to prevent high blood glucose and hyperosmolarity, a condition in which the blood has high concentrations of sodium, glucose, and other molecules that draw water from cells into the bloodstream.

Symptoms of hyperosmolar nonketotic syndrome include a dry, parched mouth; increased hunger; nausea or vomiting; and warm, dry skin. Severe dehydration worsens the problem, causing lethargy, confusion, and even loss of consciousness. In extreme cases, the result is a coma. Immediate treatment with insulin and large amounts of fluids is vital to prevent death. If you or a loved one develops any of these symptoms, call your doctor or an ambulance immediately.

Publication Review By: Written by: Christopher D. Saudek, M.D.; Simeon Margolis, M.D., Ph.D.

Published: 19 Apr 2009

Last Modified: 11 Sep 2015