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Complications

By Mayo Clinic staff

Type 2 diabetes can be easy to ignore, especially in the early stages when you're feeling fine. But diabetes affects many major organs, including your heart, blood vessels, nerves, eyes and kidneys. Controlling your blood sugar levels can help prevent these complications.

Although long-term complications of diabetes develop gradually, they can eventually be disabling or even life-threatening. Some of the potential complications of diabetes include:

  • Heart and blood vessel disease. Diabetes dramatically increases the risk of various cardiovascular problems, including coronary artery disease with chest pain (angina), heart attack, stroke, narrowing of arteries (atherosclerosis) and high blood pressure. The risk of stroke is two to four times higher for people with diabetes, and the death rate from heart disease is two to four times higher for people with diabetes than for people without the disease, according to the American Heart Association.
  • Nerve damage (neuropathy). Excess sugar can injure the walls of the tiny blood vessels (capillaries) that nourish your nerves, especially in the legs. This can cause tingling, numbness, burning or pain that usually begins at the tips of the toes or fingers and gradually spreads upward. Poorly controlled blood sugar can eventually cause you to lose all sense of feeling in the affected limbs. Damage to the nerves that control digestion can cause problems with nausea, vomiting, diarrhea or constipation. For men, erectile dysfunction may be an issue.
  • Kidney damage (nephropathy). The kidneys contain millions of tiny blood vessel clusters that filter waste from your blood. Diabetes can damage this delicate filtering system. Severe damage can lead to kidney failure or irreversible end-stage kidney disease, requiring dialysis or a kidney transplant.
  • Eye damage. Diabetes can damage the blood vessels of the retina (diabetic retinopathy), potentially leading to blindness. Diabetes also increases the risk of other serious vision conditions, such as cataracts and glaucoma.
  • Foot damage. Nerve damage in the feet or poor blood flow to the feet increases the risk of various foot complications. Left untreated, cuts and blisters can become serious infections. Severe damage might require toe, foot or even leg amputation.
  • Skin and mouth conditions. Diabetes may leave you more susceptible to skin problems, including bacterial and fungal infections. Gum infections also may be a concern, especially if you have a history of poor dental hygiene.
  • Osteoporosis. Diabetes may lead to lower than normal bone mineral density, increasing your risk of osteoporosis.
  • Alzheimer's disease. Type 2 diabetes may increase the risk of Alzheimer's disease and vascular dementia. The poorer your blood sugar control, the greater the risk appears to be. So what connects the two conditions? One theory is that cardiovascular problems caused by diabetes could contribute to dementia by blocking blood flow to the brain or causing strokes. Other possibilities are that too much insulin in the blood leads to brain-damaging inflammation, or lack of insulin in the brain deprives brain cells of glucose.
  • Hearing problems. Diabetes can also lead to hearing impairment.
Preparing for your appointment Risk factors
References
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  2. Standards of medical care in diabetes — 2011. Diabetes Care. 2011:34:S11.
  3. McCulloch DK, et al. Risk factors for type 2 diabetes mellitus. http://www.uptodate.com/home/index.html. Accessed Feb. 18, 2011.
  4. Your guide to diabetes: Type 1 and type 2. National Institute of Diabetes and Digestive and Kidney Diseases. http://diabetes.niddk.nih.gov/dm/pubs/type1and2/index.htm. Accessed Feb. 22, 2011.
  5. McCulloch DK. Initial management of blood glucose in type 2 diabetes mellitus. http://www.uptodate.com/home/index.html. Accessed Feb. 18, 2011.
  6. McCulloch DK, et al. Prediction and prevention of type 2 diabetes mellitus. http://www.uptodate.com/home/index.html. Accessed Feb. 18, 2011.
  7. Screening for type 2 diabetes mellitus in adults. U.S. Preventive Services Task Force. http://www.uspreventiveservicestaskforce.org/uspstf08/type2/type2rs.htm. Accessed Feb. 27, 2011.
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  9. What people with diabetes need to know about osteoporosis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Bone/Osteoporosis/Conditions_Behaviors/diabetes.asp. Accessed Feb. 22, 2011.
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  14. Huxley R, et al. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus. Archives of Internal Medicine. 2009;169:2053.
  15. Hyperosmolar hyperglycemic nonketotic syndrome (HHNS). American Diabetes Association. http://www.diabetes.org/living-with-diabetes/complications/hyperosmolar-hyperglycemic.html. Accessed Feb. 27, 2011.
  16. Diabetic ketoacidosis. National Center for Biotechnology Information. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001363. Accessed Feb. 24, 2011.
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DS00585 Jan. 25, 2012

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