Diabetes Overview

Diabetes mellitus (DM) is a set of related diseases in which the body cannot regulate the amount of sugar (specifically, glucose) in the blood.
Glucose in the blood gives you energy to perform daily activities, walk briskly, run for a bus, ride your bike, take an aerobic exercise class, and perform your day-to-day chores.

• From the foods you eat, glucose in the blood is produced by the liver (an organ on the right side of the abdomen near your stomach).
  
  
• In a healthy person, the blood glucose level is regulated by several hormones, including insulin. Insulin is produced by the pancreas, a small organ between the stomach and liver. The pancreas secretes other important enzymes that help to digest food.
  
  
• Insulin allows glucose to move from the blood into liver, muscle, and fat cells, where it is used for fuel.
  
  
• People with diabetes either do not produce enough insulin (type 1 diabetes) or cannot use insulin properly (type 2 diabetes), or both (which occurs with several forms of diabetes).
  
  
• In diabetes, glucose in the blood cannot move into cells, so it stays in the blood. This not only harms the cells that need the glucose for fuel, but also harms certain organs and tissues exposed to the high glucose levels.

Type 1 diabetes: The body stops producing insulin or produces too little insulin to regulate blood glucose level.

• Type 1 diabetes comprises about 10% of total cases of diabetes in the United States.
  
  
• Type 1 diabetes is typically recognized in childhood or adolescence. It used to be known as juvenile-onset diabetes or insulin-dependent diabetes mellitus.
  
  
• Type 1 diabetes can occur in an older individual due to destruction of pancreas by alcohol, disease, or removal by surgery. It also results from progressive failure of the pancreatic beta cells, which produce insulin.
  
  
• People with type 1 diabetes require daily insulin treatment to sustain life.

Type 2 diabetes: The pancreas secretes insulin, but the body is partially or completely unable to use the insulin. This is sometimes referred to as insulin resistance. The body tries to overcome this resistance by secreting more and more insulin. People with insulin resistance develop type 2 diabetes when they do not continue to secrete enough insulin to cope with the higher demands.

• At least 90% of patients with diabetes have type 2 diabetes.
  
  
• Type 2 diabetes is typically recognized in adulthood, usually after age 45 years. It used to be called adult-onset diabetes mellitus, or non-insulin-dependent diabetes mellitus. These names are no longer used because type 2 diabetes does occur in younger people, and some people with type 2 diabetes need to use insulin.
  
  
• Type 2 diabetes is usually controlled with diet, weight loss, exercise, and oral medications. More than half of all people with type 2 diabetes require insulin to control their blood sugar levels at some point in the course of their illness.

Gestational diabetes is a form of diabetes that occurs during the second half of pregnancy.

• Although gestational diabetes typically goes away after delivery of the baby. Women who have gestational diabetes are more likely than other women to develop type 2 diabetes later in life.
  
  
• Women with gestational diabetes are more likely to have large babies.

Metabolic syndrome (also referred to as syndrome X) is a set of abnormalities in which insulin-resistant diabetes (type 2 diabetes) is almost always present along with hypertension, high fat levels in the blood (increased serum lipids, predominant elevation of LDL cholesterol, decreased HDL cholesterol, and elevated triglycerides), central obesity, and abnormalities in blood clotting and inflammatory responses. A high rate of cardiovascular disease is associated with the metabolic syndrome.
Pre-diabetes is a common condition related to diabetes. In people with pre-diabetes, the blood sugar level is higher than normal but not high enough to be considered diabetic.

• Pre-diabetes increases your risk of developing type 2 diabetes and of heart disease or stroke.
  
  
• Pre-diabetes can typically be reversed without insulin or medication by losing a modest amount of weight and increasing your physical activity. This weight loss can prevent, or at least delay, the onset of type 2 diabetes.
  
  
• An international expert committee of the American Diabetes Association redefined the criteria for pre-diabetes, lowering the blood sugar level cut-off point for pre-diabetes. Approximately 20% more adults are now believed to have this condition and may develop diabetes within 10 years if they do not exercise or maintain a healthy weight.

About 17 million Americans (6.2% of adults in North America) are believed to have diabetes. About one third of diabetic adults do not know they have diabetes.

• About 1 million new cases occur each year, and diabetes is the direct or indirect cause of at least 200,000 deaths each year.
  
  
• The incidence of diabetes is increasing rapidly. This increase is due to many factors, but the most significant are the increasing incidence of obesity and the prevalence of sedentary lifestyles.

Complications of diabetes
Both forms of diabetes ultimately lead to high blood sugar levels, a condition called hyperglycemia. Over a long period of time, hyperglycemia damages the retina of the eye, the kidneys, the nerves, and the blood vessels.

• Damage to the retina from diabetes (diabetic retinopathy) is a leading cause of blindness.
  
  
• Damage to the kidneys from diabetes (diabetic nephropathy) is a leading cause of kidney failure.
  
  
• Damage to the nerves from diabetes (diabetic neuropathy) is a leading cause of foot wounds and ulcers, which frequently lead to foot and leg amputations.
  
  
• Damage to the nerves in the autonomic nervous system can lead to paralysis of the stomach (gastroparesis), chronic diarrhea, and an inability to control heart rate and blood pressure during postural changes.
  
  
• Diabetes accelerates atherosclerosis, (the formation of fatty plaques inside the arteries), which can lead to blockages or a clot (thrombus). Such changes can then lead to heart attack, stroke, and decreased circulation in the arms and legs (peripheral vascular disease).
  
  
• Diabetes predisposes people to high blood pressure and high cholesterol and triglyceride levels. These conditions independently and together with hyperglycemia increase the risk of heart disease, kidney disease, and other blood vessel complications.

In the short run, diabetes can contribute to a number of acute (short-lived) medical problems.

• Many infections are associated with diabetes, and infections are frequently more dangerous in someone with diabetes because the body's normal ability to fight infections is impaired. To compound the problem, infections may worsen glucose control, which further delays recovery from infection.
  
  
• Hypoglycemia, or low blood sugar, occurs from time to time in most people with diabetes. It results from taking too much diabetes medication or insulin (sometimes called an insulin reaction), missing a meal, doing more exercise than usual, drinking too much alcohol, or taking certain medications for other conditions. It is very important to recognize hypoglycemia and be prepared to treat it at all times. Headache, feeling dizzy, poor concentration, tremors of hands, and sweating are common symptoms of hypoglycemia. You can faint or have a seizure if blood sugar level gets too low.
  
  
• Diabetic ketoacidosis is a serious condition in which uncontrolled hyperglycemia (usually due to complete lack of insulin or a relative deficiency of insulin) over time creates a buildup in the blood of acidic waste products called ketones. High levels of ketones can be very harmful. This typically happens to people with type 1 diabetes who do not have good blood glucose control. Diabetic ketoacidosis can be precipitated by infection, stress, trauma, missing medications like insulin, or medical emergencies like stroke and heart attack.
  
  
• Hyperosmolar hyperglycemic nonketotic syndrome is a serious condition in which the blood sugar level gets very high. The body tries to get rid of the excess blood sugar by eliminating it in the urine. This increases the amount of urine significantly and often leads to dehydration so severe that it can cause seizures, coma, and even death. This syndrome typically occurs in people with type 2 diabetes who are not controlling their blood sugar levels, who have become dehydrated, or who have stress, injury, stroke, or are taking certain medications, like steroids.