Diabetes complications occur primarily due to deleterious changes in the blood vessels caused by long-standing hyperglycemia (high blood sugar). Complications due to abnormalities in the smallest blood vessels--the capillaries--are microvascular complications and include retinopathy, neuropathy and nephropathy. Good blood sugar control that keeps glucose levels as close to normal as possible helps prevent diabetic microvascular complications.
Retinopathy
Diabetes-induced abnormalities in the blood vessels that supply the nerve tissues of the eyes cause the condition known as diabetic retinopathy. The National Eye Institute estimates more than 40 percent of diabetic adults in the U.S. have diabetic retinopathy. Destructive changes in the early stage of the disease--nonproliferative retinopathy--include weakening, ballooning and obstruction of the blood vessels of the eye. Without treatment, nonproliferative retinopathy advances to proliferative retinopathy. New blood vessels form in the eye, but they are faulty. Bleeding leads to retinal scarring and vision impairment. Early diagnosis and treatment of diabetic retinopathy can reduce the risk of significant vision impairment.
Neuropathies
Most people with long-standing diabetes develop one or more forms of nerve damage called diabetic neuropathy. According to the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK), diabetic neuropathies affect 60 percent to 70 percent of people with diabetes. Diabetes-induced changes in the microvasculature reduce blood supply to the nerves causing progressive damage. Damage to nerves in the extremities is peripheral neuropathy, which causes symptoms such as burning, tingling, pinprick sensations or numbness in the feet and hands. Loss of balance and inability to feel hot and cold may also occur. These symptoms are dangerous because they increase the risk of accidental injury. Autonomic nerves control involuntary organ functions such digestion and urination. Diabetes-associated autonomic neuropathy symptoms include constipation, delayed stomach emptying, dizziness on standing, impotence and urination problems. Another form of diabetic neuropathy, proximal neuropathy, can cause weakness and pain in the hips, thighs, legs and buttocks.
Nephropathy
The kidneys are vulnerable to damage caused by diabetes-related microvascular changes. Diabetes progressively damages the filtering units of the kidneys--the glomeruli--causing a form of chronic kidney disease called diabetic nephropathy. This disorder can lead to kidney failure. NIDDK reports diabetic nephropathy is the most common cause of kidney failure in the U.S. Diabetic nephropathy develops over a period of years; kidney failure rarely occurs until 15 to 25 years into the illness. As the glomeruli sustain increasing levels of damage, kidney function decreases. The risk of developing diabetic nephropathy increases with persistently elevated blood sugar levels. Daily efforts to keep your blood sugar under control are rewarded by decreasing your long-term risk of developing microvascular diabetes complications.
References
- Clinical Diabetes: Microvascular and Macrovascular Complications of Diabetes
- National Diabetes Education Program: Guiding Principles for Diabetes Care: For Health Care Professionals
- National Eye Institute: Diabetic Retinopathy
- National Institute of Neurological Disorders and Stroke: Diabetic Neuropathy
