Diabetes Complications

People with diabetes are prone to complications over time. Healthcare providers all agree that strict control of blood sugar puts you at less risk for complications. This was shown clearly by the Diabetes Control and Complications Trial. Control of blood sugar is the best way to lessen your risk of complications.

Even the very best control may not be able to prevent all complications as your risk increases with age and with the amount of time you have had diabetes. Diabetes complications affect the eyes, kidneys, nerves, and large and small blood vessels and are listed below:

Complication Organ Affected
Coronary artery disease Heart
Dermopathy Skin
Macroangiopathy Large blood vessels
Microangiopathy Small blood vessels
Nephropathy Kidney
Neuropathy Nerves
Peripheral vascular disease Blood vessels of legs and feet
Retinopathy Eyes



Diabetes can affect almost every part of the eyes.  Three primary problems that can occur in the eyes as a result of uncontrolled diabetes are diabetic retinopathy, vitrectomy, and cataracts, which will all be explained below.

Diabetic Retinopathy

Diabetic retinopathy is a breakdown of the small blood vessels that nourish the retina.  The retina of the eye reflects what we see and send the image to our brains to process.  Therefore when the small blood vessels in the eye are damaged they can become swollen, they can rupture, and may also form scar tissue which can all lead to blockage of light from the retina and loss of vision.  Untreated, has been known to cause blindness in some people.


When massive bleeding into the vitreous, or fluid layer of the eye has occurred, a vitrectomy may be performed. This involves the bloody vitreous being removed and replaced with clear, sterile fluids that restore vision.


Cataracts are clouding of the lens, or filter of the eye. A cataract can form over years and causes blurred vision. A cataract can be caused by aging, eye damage, disease, family history, and birth defects. One type of cataract, a senile cataract, is common among elder adults and can be caused by poor diabetes control. Another type of cataract, a metabolic cataract, can be found in younger people with diabetes. Both types are treated by removing the lens. Eyeglasses, contact lenses, or lens implants can restore vision after surgery. Lower your risk of cataracts by getting an eye exam each year.


The kidneys filter waste products from the blood and remove the body’s excess water. The kidneys produce about a quart of urine every day to maintain the body’s fluid balance. When the vessels that form the filter system of the kidney is damaged from long-term uncontrolled diabetes, you could get diabetic nephropathy. This disease damages the filter system of the kidney, which causes certain proteins to leak out into the urine. Protein in the urine may be the first sign of this disease. Other signs include high blood pressure, weight gain from fluid, fatigue, and just feeling ill. Kidney function tests help figure out the degree of kidney damage. Treatments for kidney failure include hemodialysis 3 times a week at the hospital, peritoneal dialysis 3 to 4 times a day at home, and kidney transplants. To lower your risk of diabetic nephropathy:

  • Keep your blood sugar level in good control.
  • Maintain normal blood pressure.
  • Follow the diet prescribed by your healthcare team.

Other Diabetes-related kidney problems

Bladder Damage

Damage to the kidney from uncontrolled diabetes can also cause damage to the nerves of the bladder. This can result in the bladder not voiding all the way and the urine that remains in the bladder grows stagnant. Bacteria can grow in the stagnant urine, can travel up to the kidney, and can cause infection. Medicine can help, but surgery may be needed in some cases.

Urinary tract infections

Urinary tract infections (UTIs) may occur in those with uncontrolled diabetes. Symptoms include a burning feeling while voiding urine, voiding urine very often during the day, and low back pain. If untreated, the infection travels up the ureters to the kidney and could cause damage to the kidneys. Women are more likely to get UTIs. Your doctor can prescribe antibiotics to help treat UTIs.  The medicine must be taken for the time prescribed even if your symptoms go away.


Nearly 70% of people with diabetes get some degree of neuropathy, or nerve damage. Nerve damage can occur in people with Type I and Type II diabetes, due to high blood sugar hurting both nerve fiber and the fatty tissue around the nerve. Damaged nerves do not transmit proper signals, which result in numbness, extra sensation, or pain.

Peripheral neuropathy is the most common form of nerve damage that causes changes in sensation that begins in the toes and then moves up to the feet and legs. It can cause numbness, tingling, burning, dull ache, or stabbing pain and cramping, which is worse at night. Severe nerve damage may cause weakness and lack of balance in walking. The greatest danger is foot ulcers, which result when numbness causes people to keep walking on injured feet.

Treatments for this type of nerve damage are pills and creams. Not all treatments work for all people, so it is best to make better blood sugar control your number one defense against nerve damage.

Autonomic neuropathy is another type of nerve damage that involves nerve supply to small blood vessels and sweat glands of the skin, stomach, bowels, bladder, heart, and the nervous system. This type of nerve damage may cause symptoms such as:

  • Sweating after eating
  • Feeling cold in warm weather due to damaged vessels
  • Nausea and early fullness when eating
  • Delay of food being emptied from stomach
  • Watery stools, often at night and without warning
  • Bladder not emptying all of the way
  • Frequent UTIs
  • Sexual problems such as impotence
  • Drop in blood pressure upon sitting or standing
  • Rapid heart beat
  • Loss of warning signs of low blood sugar

Treatment may be prescribed to control nausea, vomiting, diarrhea, sudden drops in blood pressure, and UTIs. Penile implants and vacuum systems are useful in treating impotence.

Blood Vessels

Blood vessels can be damaged in many ways due to lack of control of diabetes. The most common diseases include peripheral vascular disease (PVD), coronary artery disease (CAD), and cerebral vascular disease (CVD).

Peripheral vascular disease

PVD refers to diseased blood vessels that supply the legs and feet. If blood flow is only partly blocked than you may get cramps, weakness, charley horse, or pain in the legs when walking. If your vessel is blocked all of the way, then you will have severe pain and the leg will become cold and pale. Treatments include replacing the diseased artery or opening the blood vessel by using a device to compress plaque against the vessel wall.

Coronary artery disease

CAD refers to diseased heart vessels. Cramping and chest pain may occur when blood flow is decreased. Complete blockage of a vessel results in a heart attack. Symptoms of chest pain or heart attack include chest pressure, cramping, heavy feeling in the chest, shortness of breath, and extreme fatigue. Treatment will likely involve surgery of some kind to open the vessel and remove any blockage

Cerebral vascular disease

CVD refers to diseased vessels in the brain. Partial blockage may result in some loss of blood supply to a part of the brain. A complete loss of blood supply to an area of the brain may result in a stroke. Symptoms include feeling light-headed, dizzy, loss of speech, slurred speech, being confused and sometimes changes in the way you act. If you have any of these symptoms go to a hospital right away!

To minimize the risk of Vessel disease

  • Keep your blood sugar level in good control.
  • Maintain normal blood pressure.
  • If you’re overweight, try to reduce your weight.
  • Reduce fats and cholesterol in your diet.
  • Stay active as often as is prescribed by your healthcare team.


Reviewed and updated by Di Bush, PhD

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