Type 2 diabetes-- the most common type of diabetes--causes blood sugar levels to rise. Known as hyperglycemia, high sugar levels in the blood can affect nearly every bodily system over time. People with type 2 diabetes who keep their blood sugar levels in or near normal range suffer fewer effects from type 2 diabetes than those who have uncontrolled hyperglycemia. Hyperglycemia causes long-term, cumulative, devastating effects.
Eye Damage
Hyperglycemia damages the small blood vessels in the eyes, often interfering with vision and in some cases, leading to blindness over time. Eye damage from hyperglycemia, known as diabetic retinopathy, affects most people with type 2 diabetes, the American Diabetes Association states. Diabetic retinopathy occurs in two forms: non-proliferative and proliferative. Non-proliferative, the more common and less damaging type, affects the small blood vessels called capillaries. Proliferative retinopathy causes abnormal new blood vessel growth. People with type 2 diabetes are also 40 percent more likely to develop glaucoma, elevated pressure within the eye that damages the optic nerve and 60 percent more likely to develop cataracts, or clouding of the lens in the eye, according to the ADA.
Heart Damage
Because hyperglycemia damages blood vessels, it can lead to heart damage. People with type 2 diabetes have two to six times the risk of developing atherosclerosis, build-up of fatty plaque in the blood vessels, the Merck Manuals Online Medical Library warns. Elevated blood sugar levels increase the risk of heart attack and stroke, the site adds.
Kidney Damage
Kidney damage can occur in people with type 2 diabetes and hyperglycemia; about 44 percent of all kidney damage occurs because of diabetes, the National Institute of Diabetes and Digestive and Kidney Disorders states. Having both hyperglycemia and high blood pressure--both common in type 2 diabetics--increases the chance of developing kidney disease, the same site states. Testing for protein in the urine helps diagnose kidney damage early, so medications to reduce kidney damage can be given. Without treatment, hyperglycemia can lead to dialysis or kidney transplantation.
Infection
High blood sugar levels in the blood and tissue make it easier for bacteria to grow. Hyperglycemia can also cause reduced sensation in the extremities, especially the feet. Known as neuropathy, reduced sensation allows injuries to the feet often go unnoticed and untreated, giving bacteria time to multiply. People with type 2 diabetes often have a reduced immune response, which also allows infections to worsen. Hyperglycemia prevents white blood cells from effectively fighting infection, the Merck Manuals state.
