Diabetes mellitus, or diabetes, is a metabolic disorder characterized by high blood sugar (glucose) levels. The condition results from a defect in the body's ability to produce or utilize insulin. Insulin is a hormone secreted by the pancreas that is necessary to convert glucose into a form that can be used by cells for growth and energy. Diabetes causes abnormally high glucose levels (hyperglycemia), circulatory problems, and nerve damage.
Diabetes cannot be cured, but it often can be managed with proper medical care, diet, and regular exercise.
Types of Diabetes
There are three main types of diabetes: type 1 (accounts for 5–10% of cases), type 2 (accounts for about 90% of cases), and gestational diabetes (affects approximately 4% of pregnant women in the United States).
Type 1 diabetes, formerly called juvenile diabetes, is an autoimmune disease in which the immune system destroys insulin-producing cells in the pancreas. Type 1 diabetes occurs most often in children and young adults, but it can develop at any age. Because their bodies do not produce it, patients with this type must take insulin daily to regulate blood sugar levels.
Type 2 diabetes accounts for over 90% of cases. In most cases, patients with this type produce enough insulin but are unable to utilize it (called insulin resistance). Type 2 diabetes occurs most often in patients over the age of 40 who are overweight. Genetic (inherited) factors may increase the risk for this type.
Gestational diabetes occurs during pregnancy and usually resolves (goes away) after childbirth. Women who develop gestational diabetes have an increased risk for developing type 2 diabetes later in life.
Incidence & Prevalence of Diabetes
According to the Centers for Disease Control and Prevention (CDC), nearly 26 million people in the United States have diabetes and of those, about 7 million people are unaware that they have the condition. In addition, it is estimated that about 79 million adults in the United States have elevated blood sugar levels classified as prediabetes. Diabetes is the seventh leading cause of death in the United States. The World Health Organization (WHO) states that 220 million people worldwide have the condition.
Diabetes Signs & Symptoms
Symptoms of diabetes include the following:
- Blurred vision
- Constant hunger
- Frequent urination
- Increased thirst
In most cases, symptoms of type 1 diabetes develop suddenly. Type 2 diabetes, which may be asymptomatic (i.e., may not cause symptoms), often develops gradually over time and also may cause nausea, infection, and slow healing of wounds and Chronic complications of diabetes include the following:
- Charcot foot
- Coronary heart disease (CHD; e.g., atherosclerosis)
- Diabetic nephropathy
- Diabetic neuropathy
- Diabetic retinopathy
Studies have shown that diabetes also may increase the risk for dementia and Alzheimer's disease.
The fasting blood glucose test is used to diagnose diabetes. Type 2 and gestational diabetes may be diagnosed using the oral glucose tolerance test. The fasting blood glucose test is a blood test that is performed after the patient has fasted for at least 8 hours. Normal blood glucose levels are less than 110 mg/dL (milligrams per deciliter) and a level of 126 mg/dL or higher on two different blood tests indicates diabetes mellitus. Gestational diabetes is indicated in pregnant women when blood glucose levels are higher than 95 mg/dL.
In the oral glucose tolerance test, the patient fasts for at least 8 hours but fewer than 16 hours and blood is drawn and tested. The patient is then given a glucose drink and the blood test is repeated.
Diabetic Foot Care
Leg and foot problems are the most common reason for diabetes-related hospitalization, and diabetes is the leading cause for amputation in the lower leg and foot. Regular examinations and vascular testing (e.g., duplex imaging) are important to help diagnose inadequate blood flow in the legs and feet.
Diabetic neuropathy, a condition in which nerve function deteriorates in the body's extremities, leads to a gradual loss of feeling in the hands, arms, legs, and feet. Patients may experience numbness, loss of feeling, pain (e.g., tingling, shooting pain, burning sensation), and weakness in the extremities.
Without the ability to feel pain, patients often do not seek timely treatment for cuts, bruises, burns, or blisters that heal poorly due to diabetes-related circulatory problems. Because of this, minor foot conditions (e.g., calluses, blisters, small cuts) can worsen and become infected.
Patients with diabetes should wash their feet daily in warm water and should inspect them regularly, using a mirror to check the bottom of the feet. Hot water should be avoided because it can cause burns and dry skin. Moisturizing lotion may be used, but should not be applied between toes because it can promote the growth of bacteria and fungal infections.
Patients should avoid going barefoot and wearing open-toed shoes to reduce the risk for cuts and infections and injury. Socks made from natural fibers (e.g., cotton) are preferable to synthetic fabrics because they are breathable and provide better cushioning. Tight-fitting elastic-topped socks inhibit circulation and should not be worn.
Shoes should fit properly and should be made of soft, breathable materials, such as canvas or leather. New shoes should be broken in gradually and worn for short periods of time until they become soft enough to avoid causing blisters. Custom-molded orthotics can help to relieve pressure and reduce irritation.