People with diabetes are vulnerable to a variety of complications over time. Health-care providers all agree that strict control of blood sugar makes complications less likely. This was shown clearly by the Diabetes Control and Complications Trial. Control of blood sugar is the best way to minimize the risk of complications.

Even the very best control may not be able to eliminate all complications, and the risk of increases with the length of time you have diabetes. Diabetes complications affect the eyes, kidneys, nerves, and large and small blood vessels. Here is a list.

Eyes

Diabetes can affect the lens, which focuses light reflected from objects, the vitreous, a clear jelly-like substance through which light passes from the lens to the retina, and the retina, where images are formed and translated into electric impulses for interpretation by the brain.

Diabetic Retinopathy

Diabetic Retinopathy is a deterioration of the small blood vessels that nourish the retina. Although diabetic retinopathy is a serious cause of blindness, only a small percentage of persons with diabetic retinopathy lose their sight. There are two forms of diabetic retinopathy:

• Background retinopathy is an early stage of retinopathy that usually involves no apparent symptoms. Blood vessels within the retina develop tiny bulges (microaneurysms), which leak fluid, causing swelling and forming deposits (exudates ). In some cases, the macula (part of the retina where central vision occurs) becomes swollen, resulting in vision. Mild background retinopathy is normally not treated.
• Proliferative retinopathy develops from background retinopathy when fragile, new blood vessels on the retina rupture, bleeding into the vitreous and blocking light from the retina. Ruptured blood vessels in the vitreous form scar tissue which may tighten and pull on the retina, eventually detaching it from the back of the eye. Proliferative retinopathy is treated with laser surgery (photocoagulation).

When massive bleeding into the vitreous has occurred, a vitrectomy may be performed. In this surgical procedure, the bloody vitreous is removed and replaced with clear, sterile fluids, restoring vision. To minimize the risk of diabetic retinopathy:

• Keep your blood sugar level in good control. The Diabetes Control and Complications Trial has proven beyond doubt that good blood sugar control reduces the risk of diabetic retinopathy.
• Maintain normal blood pressure. If you take medication for high blood pressure, don't forget it.
• See an ophthalmologist for a complete eye exam at least once a year.

Cataracts are clouding of the normally clear lens. A cataract develops over years and causes blurred vision when a large part of the lens becomes cloudy. Causes of cataracts include aging, eye injuries, disease, heredity, and birth defects. Senile cataracts are acommon eye problem among the elderly. Poor diabetes control can hasten the formation of senile cataracts. Metabolic cataracts are sometimes found in younger people with diabetes. Both types are treated by surgical removal of the lens. Eyeglasses, contact lenses, or intraocular lens implants restore vision following surgery.

To minimize the risk of cataracts, see your ophthalmologist for a complete eye exam at least once a year.

The kidneys filter waste products from the blood, rid the body of excess water, and eliminate certain chemicals. Needed chemicals, proteins, and red and white blood cells remain in the blood stream. The kidneys produce about a quart of urine every day to maintain the body's fluid balance.

Diabetic nephropathy is a complication of long-term diabetes that results in damage to the bundles of capillaries that form the kidneys' filtering system. Diabetic nephropathy develops in stages over many years. Kidney filtering becomes less efficient, and certain proteins leak out. Protein in the urine may be the first sign of nephropathy. Other signs include high blood pressure, weight gain from fluid retention, fatigue, and just feeling ill. Kidney function tests help determine the degree of kidney damage. Treatments for kidney failure include hemodialysis (done at the hospital 3 times a week), peritoneal dialysis (done 3 to 4 times a day at home), and kidney transplants. To minimize the risk of diabetic nephropathy:

• Keep your blood sugar level in good control.
• Maintain normal blood pressure. If you take medication for high blood pressure, don't forget it.
• Follow the specific diet recommended by your health-care provider.

Diabetic bladder dysfunction occurs when damage to the nerves of the bladder results in incomplete emptying of the bladder. Urine that remains in the bladder is stagnant, and bacteria grow in it. The bacteria travel up to the kidney and cause infection. Surgery may be required, but sometimes medication helps. Urinary tract infections

Urinary tract infections may develop in persons with uncontrolled diabetes. Symptoms include excessive urination, a burning sensation with urination, and low back pain. If untreated, the infection travels up the ureters to the kidney, possibly causing permanent damage. Women are more likely to develop urinary tract infections. Prompt treatment with antibiotics prescribed by your doctor is essential. Remember to take the pills for the period prescribed, even if your symptoms go away.

Nerves

Nearly 70% of persons with diabetes experience some degree of nerve damage or neuropathy. Neuropathy occurs in people with Type I and Type II diabetes, due to metabolic changes associated with diabetes. Constant high blood sugar destroys both nerve fiber (axon) and the fatty insulation that surrounds it (myelin ). Damaged nerves do not transmit proper signals, resulting in a loss of sensation, hypersensation, or pain.

Peripheral neuropathy is the most common form. Varying from mild to severe, it causes changes in sensation that begin in the toes move up to the feet and legs. One may experience numbness, tingling, burning, dull ache, or stabbing pain and cramping, which is worse at night. The skin can become so sensitive that pressure from clothes is painful. Severe neuropathy may cause weakness and unbalanced walking. The greatest danger is foot ulcers, which result when lack of sensation causes people to continuing walking on injured feet. Many treatments are available for peripheral neuropathy, including medications and topical creams. Not all are effective for everyone. Better diabetic control helps some patients. A painful neuropathy may change to a numb feeling after a while. And neuropathies sometimes disappear on their own. Autonomic neuropathy involves the nerve supply to small blood vessels and sweat glands of the skin, the stomach, the bowls, the bladder, the heart, and the nervous system. It is most often associated with long-term diabetes, poor control, and elevated blood sugar. Symptoms vary, depending on the affected area, and may include:

• Abnormal sweating after eating
• Inappropriate response to temperature changes, such as constricting blood vessels in warm temperatures
• Nausea and early fullness when eating, delayed emptying stomach, or vomiting
• Watery diarrhea, often at night and without warning
• Incomplete emptying of bladder, leading to urinary tract infections
• Sexual disfunction, including impotence and delayed vaginal lubrication
• Drop in blood pressure upon sitting or standing
• Rapid heart beat
• Loss of warning signs of hypoglycemia

Various medications may be prescribed to control nausea, vomiting, diarrhea, sudden drops in blood pressure, and recurrent urinary tract infections. Penile implants and vacuum systems are useful in treating impotence.

Blood Vessels

Macrovascular disease refers to changes in the medium to large-size blood vessels. The blood vessel walls thicken and become hard and non-elastic (arteriosclerosis). Blood vessels also become clogged with mounds of plaque (atherosclerosis). Eventually, the flow of blood may be blocked. Three types of this disease are:

Peripheral vascular disease refers to diseased blood vessels that supply the legs and feet. If blood flow is only partially interrupted, cramps, weakness, "charley horse," or pain in the legs when walking (claudication) may result. A completely blocked artery will cause severe pain and the leg will become cold and pale. Treatments include replacing the diseased artery surgically or opening the blood vessel by compressing plaque against the artery wall (angioplasty).

Coronary artery disease refers to diseased heart arteries. Cramping and angina may occur when blood flow is decreased. Complete blockage of an artery results in myocardial infarction (heart attack). Symptoms of angina and heart attack include chest pressure, cramping, heavy feeling in the chest, shortness of breath, and extreme fatigue. Treatments include coronary bypass surgery and angioplasty.

Cerebral vascular disease refers to diseased arteries in the brain. Partial blockage may result in temporary reductions of blood supply to a part of the brain (transient ischemic attacks). A complete loss of blood supply to an area of the brain due to clogging or breaking of a blood vessel results in a cerebral vascular accident (stroke). Symptoms include lightheadedness, dizziness, loss of ability to speak, slurred speech, confusion, and inappropriate behavior. If you experience symptoms of any form of macrovascular disease, go to a hospital emergency room at once.

To minimize the risk of macrovascular disease:

• Keep your blood sugar level in good control.
• Maintain normal blood pressure. If you take medication for high blood pressure, don't forget it.
• If overweight, try to reduce your weight.
• Reduce fats and cholesterol in your diet.
• Exercise in moderation, after consulting with your doctor or diabetes educator.

Information from the UNIVERSITY OF MASSACHUSETTS MEDICAL CENTER Worcester, MA