Type 2 diabetes is a chronic disorder that develops when the body is resistant to the effects of--or fails to produce enough of--insulin, a hormone that regulates sugar. This insulin resistance inhibits blood glucose (a type of sugar) from entering cells to be stored for energy production. As a result, sugars build up in the bloodstream (hyperglycemia), causing a number of potentially serious effects on the body.
Common Symptoms
Individuals with type 2 diabetes can live with the condition for a long period of time without knowing they are afflicated because, in its early stages, the condition may cause only minor, nonspecific symptoms. According to the Mayo Clinic, some common symptoms include fatigue and irritability, increased thirst, frequent urination, increased hunger, weight loss, frequent or slow-healing infections and blurred vision. Some people will also develop patches of darkened skin (called acanthosis nigricans), particularly in the folds of the body (armpits or neck) that are caused by insulin resistance.
Eyesight
Those with type 2 diabetes may initially notice mild symptoms of blurred vision; however, diabetes' long-term effect on the eyes can be devastating. Over time, a worsening of eyesight can lead to a number of serious conditions such as macular edema (a leaking of fluid from blood vessels that causes retinal swelling and blurred vision), cataracts (clouding of the eye's lens), glaucoma (optic nerve damage that leads to acute or progressive vision loss or blindness) and diabetic retinopathy, according to the National Institutes of Health. Diabetic retinopathy is a general classification for eye disorders that affect the retina. The American Diabetes Association indicates that most people with type 2 diabetes are likely to get nonproliferative retinopathy, a specific type of retinopathy in which the blood vessels supplying the eyes become blocked. While there are no overt symptoms of nonproliferative retinopathy, it can lead to macular edema, which, if left untreated, can cause blindness.
Nerve Damage
Type 2 (or type 1) diabetes can cause significant nerve damage (neuropathy) throughout the body. In some people, this causes no symptoms, or mild to moderate sensations such as numbness or tingling in the hands and feet. In severe cases, nerve damage can interfere with the functioning of the eyes, heart, sex organs and digestive tract. According to the National Diabetes Information Clearinghouse (NDIC), proximal neuropathy--a condition that causes pain and weakness in the legs that prevents moving from a sitting to a standing position without assistance--is common among those with type 2 diabetes.
Other Serious Symptoms
Advanced type 2 diabetes can have serious or life-threatening effects on the blood vessels, nerves, heart and other vital organs. According to the National Institutes of Health, serious complications include high blood pressure, high cholesterol, stroke, peripheral vascular disease (impaired blood flow to the legs and feet), ulcerated sores on the feet that often become infected and lead to amputation, kidney disease and kidney failure, erection problems, and a variety of infections on the skin, urinary tract and female genital tract. The Mayo Clinic advises that type 2 diabetes may also cause hearing problems, osteoporosis, and infections of the mouth and skin. Gum infections, in particular, may become a problem for those with a history of poor hygiene. Type 2 diabetes can also increase the risk of developing Alzheimer's disease and vascular dementia, possibly because it blocks blood flow to the brain, or because insulin deficiencies deprive the brain of glucose.
