Damage to large and small blood vessels throughout the body that can occur in people who have diabetes mellitus
- The underlying condition sometimes runs in families
- Smoking, a high-fat diet, lack of exercise, and excess weight are risk factors
- Age and gender are not significant factors
Vascular disease is a common long-term complication of diabetes mellitus, a condition that tends to run in families. There are two types of vascular disease that are more likely to affect people who have diabetes: atherosclerosis and small vessel disease.
In atherosclerosis, fatty deposits gradually build up in the walls of larger blood vessels, making these vessels narrower. This condition, which develops to some degree in most people as they become older, is likely to occur earlier and more extensively in people with diabetes.
Diabetic small vessel disease is not fully understood, but it is thought to involve thickening of the walls of the smaller blood vessels as a result of certain chemical changes. This thickening reduces the amount of oxygen passing from blood in the vessels into the surrounding body tissues.
These vascular conditions frequently occur together and each of them may lead to serious complications. The risk of developing either type of diabetic vascular disease is higher the longer a person has had diabetes mellitus. Lifestyle factors such as smoking and a diet that is high in fat increase the risk of developing diabetic vascular disease, as does poor control of blood sugar levels, and it is therefore important that your diabetes is managed effectively (see Living with diabetes).
Are there complications?
Atherosclerosis may eventually lead to blockage of the arteries, causing potentially life-threatening complications, in particular stroke, heart attack (see Myocardial infarction), and lower limb ischaemia.
Damage to small blood vessels may occur in many parts of the body. Small blood vessels in the eyes are commonly damaged (see Diabetic retinopathy), leading to blurred vision and sometimes even blindness. If the small vessels in the eyes are damaged, similar changes will have occurred in vessels throughout the body. If the blood vessels in the kidneys are affected, kidney function will be impaired (see Diabetic kidney disease). Kidney damage often leads to high blood pressure (see Hypertension).
Small vessel disease may also lead to nerve damage, most commonly in the feet (see Diabetic neuropathy). Such damage can reduce sensation in the affected area so that an injury goes unnoticed at first. In addition, the reduced supply of blood slows healing, and persistent skin ulcers (see Leg ulcers) and even gangrene may develop. Some people already have these complications when they are first diagnosed as having diabetes mellitus. In other cases, complications may not develop for many years after diagnosis.
What might be done?
It is essential that diabetes mellitus is diagnosed promptly and managed well. In order to prevent or reduce the effects of diabetic vascular disease on blood vessels, you should try to maintain effective control of your blood sugar levels (see Monitoring your blood glucose), follow a healthy, low-fat diet, and avoid smoking. If you have diabetes, your doctor will regularly measure your blood pressure (see Blood pressure measurement) and the level of cholesterol in your blood to assess your susceptibility to atherosclerosis. Samples of your urine may be tested for protein, the presence of which may be the first sign of kidney disease, and blood tests may be performed to find out if your kidneys are functioning normally. In addition, regular eye checks, using ophthalmoscopy and sometimes retinal photography, are carried out to ensure that retinal damage is detected as early as possible since early detection increases the chances of successful treatment.
If you have a high blood cholesterol level, your doctor may prescribe drugs to prevent atherosclerosis from worsening (see Lipid-lowering drugs). If protein is found in your urine, you may be prescribed ACE inhibitor drugs, which help to counteract the progression of small vessel damage in the kidneys. Treatment for high blood pressure will be given if necessary (see Antihypertensive drugs).
What is the prognosis?
Diabetic vascular disease is the most common cause of death in people who have diabetes mellitus, and the risk of developing it increases with time.
A person with diabetes is about 10 times more likely to develop lower limb ischaemia than someone without diabetes, four times more likely to have a heart attack, and twice as likely to have a stroke. Damage to small blood vessels in the eyes occurs in about 8 in 10 people with long-term diabetes. However, eye damage is often reversible if it is treated in the early stages. Kidney damage occurs in about 4 in 10 people who have had diabetes mellitus for longer than 15 years. About 3 in 10 people with diabetes develop nerve damage, but only 1 in 10 has severe symptoms.
If your diabetes mellitus is carefully managed and your blood pressure, cholesterol, and blood sugar levels are well controlled, the progress of diabetic vascular disease will be slowed and the risk of complications will be reduced.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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