Complications: An Introduction

Author: Shauna S. Roberts
Source: Diabetes Forecast, July, 2005

DIABETES is a complicated disease–complicated to understand, complicated to treat. Diabetes can also cause what are called “complications.” These are other health problems linked to diabetes.

Diabetes can affect most organs of the body. In diabetes, levels of a sugar called glucose are too high in the blood. Because blood travels throughout the body, the damaging effects of too-high blood glucose levels can occur all over. Keeping blood glucose levels close to normal is key to preventing and treating complications.

Some complications are short-lived, such as too-low blood glucose levels. Some complications, such as kidney disease, are long-term. And other complications fall somewhere in-between–a bout of gum disease, for example.

The following list of complications is long, but don’t let it scare you. Some people live a long time with diabetes with few problems. Some complications, such as itchy skin, are mainly annoying. Most important, there are steps you can take to reduce your chances of developing complications, such as keeping your blood glucose and cholesterol levels in a healthy range.

Future columns will explore the major complications–as well as treatment and prevention strategies–in more depth; this column will briefly introduce you to some of them.

Low blood glucose episode (hypoglycemia, often called an insulin reaction). When blood glucose levels drop too low, the brain cannot function well. Very low levels can lead to a coma. The National Institute of Diabetes and Digestive and Kidney Diseases defines mild hypoglycemia as a blood glucose level of 60 to 70 mg/dl and severe hypoglycemia as a blood glucose level of below 40 mg/dl. Hypoglycemia needs to be treated right away with sugar or another simple carbohydrate to boost blood glucose levels to normal.

Too-high blood glucose levels. Diabetic ketoacidosis (DKA) is a condition in which a lack of insulin prevents adequate amounts of glucose from being taken up by the cells. Cells then burn fat for energy and make harmful by products called ketones. DKA is more common in people with type 1 diabetes. In hyperosmolar nonketotic coma (HNC or HHNC), blood glucose levels rise above 900 mg/dl, throwing body chemistry way out of whack. HNC is less common and occurs mostly in older people with type 2 diabetes.

Diabetic eye disease (retinopathy). The retina is the light-sensing lining at the back of the eyeball. Sometimes diabetes damages small blood vessels in the retina. In nonproliferative retinopathy, this damage can cause swelling (edema), blood leaks (hemorrhages), or reduced nourishment (ischemia). Sometimes the eye tries to correct the damage by growing new blood vessels. Because these vessels are fragile and often grow in the wrong places, they can bleed or cause other damage. This condition is proliferative retinopathy. In diabetic macular edema, swelling occurs in the macula, the area of the retina responsible for detailed vision (such as reading). This can cause vision loss.

Other eye diseases. Eye diseases that are especially common in people with diabetes include glaucoma (damage to the optic nerve in the eye, often caused by too-high eye pressures) and cataract (clouding of the lens of the eye).

Diabetic kidney disease (nephropathy). In nephropathy, the kidneys gradually lose their ability to filter waste products and toxins from the blood. When kidneys fail completely, people must get a kidney transplant or have their blood filtered by a machine (dialysis).

Diabetic nerve disease (neuropathy). Diabetes can affect many kinds of nerves in many ways. There are several kinds of neuropathy, including:

* Sensorimotor neuropathy (damage to the nerves that control movement in and transmit sensation from the arms, hands, legs, and feet)

* Autonomic neuropathy (damage to the nerves that control activities not under conscious control, such as sweating and digesting food) * Focal neuropathy (damage to just one nerve or nerve cluster; carpal tunnel syndrome is an example)

Heart and blood vessel diseases. Heart and blood vessel disorders are diabetes’ most deadly complications. High cholesterol (hypercholesterolemia) and high blood pressure (hypertension) add to the risk of developing these problems. Heart and blood vessel problems include:

* Coronary artery disease (in which arteries to the heart be come clogged, causing heart attack or chest pain due to restricted blood flow)

* Congestive heart failure (in which the heart pumps less blood than the body needs)

* Stroke (death of brain cells due to clogged blood vessels or bleeding)

* Peripheral vascular disease (in which leg arteries become clogged and do not allow enough blood to pass through)

Other complications. Diabetes can cause other sorts of problems, too. For example, it can affect the skin and joints, make infections more likely, interfere with sexual ability and stomach emptying, and cause foot problems.

In addition to your regular visits, you should also check in with your diabetes doctor if something just doesn’t seem right. It could be a sign that you are getting a complication or a new disorder. See your doctor if you experience vision problems (such as flashes or blurry vision), extreme tiredness, pain when walking, numbness or tingling in hands or feet, chest pain during exertion, or cuts or sores that stay infected or don’t heal.

Shauna S. Roberts, PhD, is a science writer in New Orleans, La.