Diabetes mellitus

Definition

Diabetes mellitus is a condition in which the pancreas no longer produces enough insulin or when cells stop responding to the insulin that is produced, so that glucose in the blood cannot be absorbed into the cells of the body. Symptoms include frequent urination, tiredness, excessive thirst, and hunger.

Description

Diabetes mellitus is a chronic disease that causes serious health complications including renal (kidney) failure, heart disease , stroke, and blindness. Approximately 14 million Americans (about 5% of the population) have diabetes. Unfortunately, as many as one-half of them are unaware that they have it.

Background

Every cell in the human body needs energy in order to function. The body's primary energy source is glucose, a simple sugar resulting from the digestion of foods containing carbohydrates (sugars and starches). Glucose from the digested food circulates in the blood as a ready energy source for cells. Insulin is a hormone or chemical produced by cells in the pancreas, an organ located behind the stomach. Insulin binds to receptor sites on the outside of cells and acts like a key to open a doorway into the cell through which glucose can enter. Some of the glucose can be converted to concentrated energy sources like glycogen or fatty acids and saved for later use. When there is not enough insulin produced or when the doorway no longer recognizes the insulin key, glucose stays in the blood instead of entering the cells.

The body will attempt to dilute the high level of glucose in the blood, a condition called hyperglycemia, by drawing water out of the cells and into the bloodstream. The excess sugar is excreted in the urine. It is not unusual for people with undiagnosed diabetes to be constantly thirsty, to drink large quantities of water, and to urinate frequently as their bodies try to get rid of the extra glucose. This creates high levels of glucose in the urine.

At the same time that the body is trying to get rid of glucose from the blood, the cells are starving for glucose and sending signals to the body to eat more food, thus making patients extremely hungry. To provide energy for the starving cells, the body also tries to convert fats and proteins to glucose. The breakdown of fats and proteins for energy causes acid compounds called ketones to form in the blood. Ketones will also be excreted in the urine. As ketones build up in the blood, a condition called ketoacidosis can occur. If left untreated, ketoacidosis can lead to coma and death.

Types of diabetes mellitus

Type I diabetes, sometimes called juvenile diabetes, begins most commonly in childhood or adolescence. In this form of diabetes, the body produces little or no insulin. It is characterized by a sudden onset and occurs more frequently in populations descended from northern European countries (Finland, Scotland, Scandinavia) than in those from southern European countries, the Middle East, or Asia. In the United States, approximately 3 people in 1,000 develop Type I diabetes. This form is also called insulin-dependent diabetes because people who develop this type need to have injections of insulin 1-2 times per day.

Brittle diabetics are a subgroup of Type I where patients have frequent and rapid swings of blood sugar levels between hyperglycemia (a condition where there is too much glucose or sugar in the blood) and hypoglycemia (a condition where there is abnormally low levels of glucose or sugar in the blood). These patients may require several injections of different types of insulin or an insulin pump during the day to keep their blood sugar within a fairly normal range.

The more common form of diabetes, Type II, occurs in approximately 3-5% of Americans under 50 years of age, and increases to 10-15% in those over 50. More than 90% of the diabetics in the United States are Type II diabetics. Sometimes called age-onset or adult-onset diabetes, this form of diabetes occurs most often in people who are overweight and do not exercise. It is also more common in people of Native American, Hispanic, and African-American descent. People who have migrated to Western cultures from East India, Japan, and Australian Aboriginal cultures are also more likely to develop Type II diabetes than those who remain in their original countries.

Type II is considered a milder form of diabetes because of its slow onset (sometimes developing over the course of several years) and because it can usually be controlled with diet and oral medication. The consequences of uncontrolled and untreated Type II diabetes, however, are the just as serious as those for Type I. This form is also called noninsulin-dependent diabetes, a term that is somewhat misleading. Many people with Type II diabetes can control the condition with diet and oral medications, however, insulin injections are sometimes necessary.

Another form of diabetes, called gestational diabetes, can develop during pregnancy and generally resolves after the baby is delivered. This diabetic condition develops during the second or third trimester of pregnancy in about 2% of pregnancies. The condition is usually treated by diet, however, insulin injections may be required. Women who have diabetes during pregnancy are at higher risk for developing Type II diabetes within 5-10 years.

Diabetes can also develop as a result of pancreatic disease, alcoholism, malnutrition, or other severe illnesses that stress the body.

Causes & symptoms

The causes of diabetes mellitus are unclear, however, there seem to be both hereditary (genetic factors passed on in families) and environmental factors involved. Research has shown that some people who develop diabetes have common genetic markers. In Type I diabetes, an autoimmune response is believed to be triggered by a virus or another microorganism that destroys the cells that produce insulin. In Type II diabetes, age, obesity, and family history of diabetes play a role.

In Type II diabetes, the pancreas may produce enough insulin, however, cells have become resistant to the insulin produced and it may not work as effectively. Symptoms of Type II diabetes can begin so gradually that a person may not know that they have it. Early signs are tiredness, extreme thirst, and frequent urination. Other symptoms may include sudden weight loss, slow wound healing, urinary tract infections, gum disease , or blurred vision. It is not unusual for Type II diabetes to be detected while a patient is seeing a doctor about a health concern that was caused by the yet undiagnosed diabetes.

Individuals who are at high risk of developing Type II diabetes mellitus include people who:

• Are obese (more than 20% above their ideal body weight).
• Have a relative with diabetes mellitus.
• Belong to a high-risk ethnic population (African-American, Native American, Hispanic, or Native Hawaiian).
• Have been diagnosed with gestational diabetes or have delivered a baby weighing more than 9 lbs (4 kg).
• Have high blood pressure (140/90 mmHg or above).
• Have a high density lipoprotein cholesterol level less than or equal to 35 mg/dL and/or a triglyceride level greater than or equal to 250 mg/dL.
• Have had impaired glucose tolerance or impaired fasting glucose on previous testing.

Several common medications can impair the body's use of insulin, causing a condition known as secondary diabetes. These medications include treatments for high blood pressure (furosemide, clonidine, and thiazide diuretics), drugs with hormonal activity (oral contraceptives, thyroid hormone, progestins, and glucocorticorids), and the anti-inflammation drug indomethacin. Several drugs that are used to treat mood disorders (such as anxiety and depression) can also impair glucose absorption. These drugs include haloperidol, lithium carbonate, phenothiazines, tricyclic antidepressants, and adrenergic agonists. Other medications that can cause diabetes symptoms include isoniazid, nicotinic acid, cimetidine, and heparin.

Symptoms of diabetes can develop suddenly (over days or weeks) in previously healthy children or adolescents, or can develop gradually (over several years) in overweight adults over the age of 40. The classic symptoms include feeling tired and sick, frequent urination, excessive thirst, excessive hunger, and weight loss.

Ketoacidosis, a condition due to starvation or uncontrolled diabetes, is common in Type I diabetes. Ketones are acid compounds which form in the blood when the body breaks down fats and proteins. Symptoms include abdominal pain, vomiting, rapid breathing, extreme tiredness, and drowsiness. Patients with ketoacidosis will also have a sweet breath odor. Left untreated, this condition can lead to coma and death.

With Type II diabetes, the condition may not become evident until the patient presents for medical treatment for some other condition. A patient may have heart disease, chronic infections of the gums and urinary tract, blurred vision, numbness in the feet and legs, or slow-healing wounds. Women may experience genital itching.

Diagnosis

Diabetes is suspected based on symptoms. Urine tests and blood tests can be used to confirm a diagnosis of diabetes based on the amount of glucose in the urine and blood. Urine tests can also detect ketones and protein in the urine which may help diagnose diabetes and assess how well the kidneys are functioning. These tests can also be used to monitor the disease once the patient is under treatment.

Urine tests

Clinistix and Diastix are paper strips or dipsticks that change color when dipped in urine. The test strip is compared to a chart that shows the amount of glucose in the urine based on the change in color. The level of glucose in the urine lags behind the level of glucose in the blood. Testing the urine with a test stick, paper strip, or tablet is not as accurate as blood testing, however it can give a fast and simple reading.

Ketones in the urine can be detected using similar types of dipstick tests (Acetest or Ketostix). Ketoacidosis can be a life-threatening situation in Type I diabetics, so having a quick and simple test to detect ketones can assist in establishing a diagnosis sooner.

Another dipstick test can determine the presence of protein or albumin in the urine. Protein in the urine can indicate problems with kidney function and can be used to track the development of renal failure. A more sensitive test for urine protein uses radioactively tagged chemicals to detect microalbuminuria, small amounts of protein in the urine, which may not show up on dipstick tests.

Blood tests

Fasting glucose test. Blood is drawn from a vein in the patient's arm after the patient has not eaten for at least eight hours, usually in the morning before breakfast. The red blood cells are separated from the sample and the amount of glucose is measured in the remaining plasma. A plasma level of 7.8 mmol/L (200 mg/L) or greater can indicate diabetes. The fasting glucose test is usually repeated on another day to confirm the results.

Postprandial glucose test. Blood is taken right after the patient has eaten a meal.

Oral glucose tolerance test. Blood samples are taken from a vein before and after a patient drinks a sweet syrup of glucose and other sugars. In a non-diabetic, the level of glucose in the blood goes up immediately after the drink and then decreases gradually as insulin is used by the body to metabolize, or absorb, the sugar. In a diabetic, the glucose in the blood goes up and stays high after drinking the sweetened liquid. A plasma glucose level of 11.1 mmol/L (200 mg/dL) or higher at two hours after drinking the syrup and at one other point during the two-hour test period confirms the diagnosis of diabetes.

A diagnosis of diabetes is confirmed if a plasma glucose level of at least 11.1 mmol/L, a fasting plasma glucose level of at least 7 mmol/L; or a two-hour plasma glucose level of at least 11.1 mmol/L during an oral glucose tolerance test.

Home blood glucose monitoring kits are available so diabetics can monitor their own levels. A small needle or lancet is used to prick the finger and a drop of blood is collected and analyzed by a monitoring device. Some patients may test their blood glucose levels several times during a day and use this information to adjust their diet or doses of insulin.

Treatment

There is currently no cure for diabetes. Diet, exercise, and careful monitoring of blood glucose levels are the keys to manage diabetes so that patients can live a relatively normal life. Diabetes can be life-threatening if not properly managed, so patients should not attempt to treat this condition without medical supervision. Treatment of diabetes focuses on two goals: keeping blood glucose within normal range and preventing the development of long-term complications. Alternative treatments cannot replace the need for insulin but they may enhance insulin's effectiveness and may lower blood glucose levels. In addition, alternative medicines may help to treat complications of the disease and improve quality of life.

Diet

Diet and moderate exercise are the first treatments implemented in diabetes. For many Type II diabetics, weight loss may be an important goal to help them to control their diabetes. A well-balanced, nutritious diet provides approximately 50-60% of calories from carbohydrates, approximately 10-20% of calories from protein, and less than 30% of calories from fat. The number of calories required depends on the patient's age, weight, and activity level. The calorie intake also needs to be distributed over the course of the entire day so surges of glucose entering the blood system are kept to a minimum.

Keeping track of the number of calories provided by different foods can be complicated, so patients are usually advised to consult a nutritionist or dietitian. An individualized, easy-to-manage diet plan can be set up for each patient. Both the American Diabetes Association and the American Dietetic Association recommend diets based on the use of food exchange lists. Each food exchange contains a known amount of calories in the form of protein, fat, or carbohydrate. A patient's diet plan will consist of a certain number of exchanges from each food category (meat or protein, fruits, breads and starches, vegetables, and fats) to be eaten at meal times and as snacks. Patients have flexibility in choosing the foods they eat as long as they don't exceed the number of exchanges prescribed. The food exchange system, along with a plan of moderate exercise, can help diabetics lose excess weight and improve their overall health.

Supplements

Several studies have had conflicting results on the effectiveness of chromium picolinate supplementation for control of blood glucose levels. In one study, approximately 70% of the diabetics receiving 200 micrograms of chromium picolinate daily reduced their need for insulin and medications. While some studies have shown that supplementation caused significant weight loss, and decreases in blood glucose and serum triglycerides, others have shown no benefit. Chromium supplementation may cause hypoglycemia and other side effects.

Magnesium deficiency may interfere with insulin secretion and uptake and worsen the patient's control of blood sugar. Also, magnesium deficiency puts diabetics at risk for certain complications, especially retinopathy and cardiovascular disease.

Vanadium has been shown to bring blood glucose to normal levels in diabetic animals. Also, people who took vanadium were able to decrease their need for insulin.

Chinese medicine

Non-insulin dependent diabetics who practiced daily qigong for one year had decreases in fasting blood glucose and blood insulin levels. Acupuncture may relieve pain in patients with diabetic neuropathy. Acupuncture may also help to bring blood glucose to normal levels in diabetics who do not require insulin.

Best when used in consultation with a Chinese medicine physician, some Chinese patent medicines that alleviate symptoms of or complications from diabetes include:

• Xiao Ke Wan (Emaciation and Thirst Pill) for diabetics with increased levels of sugar in blood and urine.
• Yu Quan Wan (Jade Spring Pill) for diabetics with a deficiency of Yin.
• Liu Wei Di Huang Wan (Six Ingredient Pill with Rehmannia) for stabilized diabetics with a deficiency of Kidney Yin.
• Jin Gui Shen Wan (Kidney Qi Pill) for stabilized diabetics with a deficiency of Kidney Yang.

Herbals

Herbal medicine can have a positive effect on blood glucose and quality of life in diabetics. The results of clinical study of various herbals are:

• Wormwood (Artemisia herba-alba) decreased blood glucose.
• Gurmar (Gymnema sylvestre) decreased blood glucose levels and the need for insulin.
• Coccinia indica improved glucose tolerance.
• Fenugreek seed powder (Trigonella foenum graecum) decreased blood glucose and improved glucose tolerance.
• Bitter melon (Momordica charantia) decreased blood glucose and improved glucose tolerance.
• Cayenne pepper (Capsicum frutescens) can help relieve pain in the peripheral nerves (a type of diabetic neuropathy).

Other herbals that may treat or prevent diabetes and its complications include:

• Bilberry (Vaccinium myrtillus) may lower blood glucose levels and maintain healthy blood vessels.
• Garlic (Allium sativum) may lower blood sugar and cholesterol levels.
• Onions (Allium cepa) may help lower blood glucose levels.
• Ginkgo (Gingko biloba) improves blood circulation.

Yoga

Studies of diabetics have shown that practicing yoga leads to decreases in blood glucose, increased glucose tolerance, decreased need for diabetes medications, and improved insulin processes. Yoga also enhances the sense of well-being.

Biofeedback

Many studies have been performed to test the benefit of adding biofeedback to the diabetic's treatment plan. Relaxation techniques, such as visualization, were usually included. Biofeedback can have significant effects on diabetes including improved glucose tolerance and decreased blood glucose levels. In addition, biofeedback can be used to treat diabetic complications and improve quality of life.

Allopathic treatment

Traditional treatment of diabetes begins with a well balanced diet and moderate exercise. Medications are prescribed only if the patients blood glucose cannot be controlled by these methods.

Oral medications

Oral medications are available to lower blood glucose in Type II diabetics. Drugs first prescribed for Type II diabetes are in a class of compounds called sulfonylureas and include tolbutamide, tolazamide, acetohexamide, chlorpropamide, glyburide, glimeperide, and glipizide. The way that these drugs work is not well understood, however, they seem to stimulate cells of the pancreas to produce more insulin. New medications that are available to treat diabetes include metformin, acarbose, and troglitizone. These medications are not a substitute for a well planned diet and moderate exercise. Oral medications are not effective for Type I diabetes, in which the patient produces little or no insulin.

Insulin

Patients with Type I diabetes need daily injections of insulin to help their bodies use glucose. Some patients with Type II diabetes may need to use insulin injections if their diabetes cannot be controlled. Injections are given subcutaneously--just under the skin, using a small needle and syringe. Purified human insulin is most commonly used, however, insulin from beef and pork sources are also available. Insulin may be given as an injection of a single dose of one type of insulin once a day. Different types of insulin can be mixed and given in one dose or split into two or more doses during a day. Patients who require multiple injections over the course of a day may be able to use an insulin pump that administers small doses of insulin on demand.

Hypoglycemia, or low blood sugar, can be caused by too much insulin, too little food (or eating too late to coincide with the action of the insulin), alcohol consumption, or increased exercise. A patient with symptoms of hypoglycemia may be hungry, sweaty, shaky, cranky, confused, and tired. Left untreated, the patient can lose consciousness or have a seizure. This condition is sometimes called an insulin reaction and should be treated by giving the patient something sweet to eat or drink like candy, sugar cubes, or juice.

Surgery

Transplantation of a healthy pancreas into a diabetic patient is a successful treatment, however, this transplant is usually done only if a kidney transplant is performed at the same time. It is not clear if the potential benefits of transplantation outweigh the risks of the surgery and subsequent drug therapy.

Expected results

Uncontrolled diabetes is a leading cause of blindness, end-stage renal disease, and limb amputations. It also doubles the risk of heart disease and increases the risk of stroke. Eye problems including cataracts, glaucoma, and retinopathy are also more common in diabetics. Kidney disease is a common complication of diabetes and may require kidney dialysis or a kidney transplant. Babies born to diabetic mothers have an increased risk of birth defects and distress at birth.

Diabetic peripheral neuropathy is a condition where nerve endings, particularly in the legs and feet, become less sensitive. Diabetic foot ulcers are a problem since the patient does not feel the pain of a blister, callous, or other minor injury. Poor blood circulation in the legs and feet contribute to delayed wound healing. The inability to sense pain along with the complications of delayed wound healing can result in minor injuries, blisters, or callouses becoming infected and difficult to treat. Severely infected tissue breaks down and rots, often necessitating amputation of toes, feet, or legs.

Prevention

Research continues on ways to prevent diabetes and to detect those at risk for developing diabetes. While the onset of Type I diabetes is unpredictable, the risk of developing Type II diabetes can be reduced by maintaining ideal weight and exercising regularly. The physical and emotional stress of surgery, illness, and alcoholism can increase the risks of diabetes, so maintaining a healthy lifestyle is critical to preventing the onset of Type II diabetes and preventing further complications of the disease.

Key Terms

Cataracts

A condition in which the lens of the eye becomes cloudy.

Diabetic peripheral neuropathy

The sensitivity of nerves to pain, temperature, and pressure is dulled particularly in the legs and feet.

Diabetic retinopathy

The tiny blood vessels to the retina, the tissues that sense light at the back of the eye, are damaged, leading to blurred vision, sudden blindness, or black spots, lines, or flashing light in the field of vision.

Glaucoma

A condition in which pressure within the eye causes damage to the optic nerve, which sends visual images to the brain.

Hyperglycemia

A condition of having too much glucose or sugar in the blood.

Hypoglycemia

A condition of having too little glucose or sugar in the blood.

Insulin

A hormone produced by the pancreas that is needed by cells of the body to use glucose (sugar), the body's main source of energy.

Ketoacidosis

A condition due to starvation or uncontrolled Type I diabetes. Ketones are acid compounds that form in the blood when the body breaks down fats and proteins. Symptoms include abdominal pain, vomiting, rapid breathing, extreme tiredness, and drowsiness.

Kidney dialysis

A process by which blood is filtered through a dialysis machine to remove waste products that would normally be removed by the kidneys. The filtered blood is then circulated back into the patient. This process is also called renal dialysis.

Pancreas

The organ that produces insulin.

Symptoms of Diabetes Mellitus

Symptoms of Diabetes Mellitus

Excessive thirst

Increased appetite

Increased urination

Weight loss

Fatigue

Nausea

Blurred vision

Frequent vaginal infections in women

Impotence in men

Frequent yeast infections

Further Reading

For Your Information

Books

• Foster, Daniel W. "Diabetes Mellitus." In Harrison's Principles of Internal Medicine. 14th ed. Edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.
• Garber, Alan J. "Diabetes Mellitus." In Internal Medicine. Edited by Jay H. Stein, et al. St. Louis: Mosby, 1998.
• Karam, John H. "Diabetes Mellitus & Hypoglycemia." In Current Medical Diagnosis & Treatment 1998. 37th ed. Edited by L.M. Tierney, Jr., S.J. McPhee, and M.A. Papadakis. Stamford, CT: Appleton & Lange, 1998.
• McGrady, Angele and James Horner. "Complementary/Alternative Therapies in General Medicine: Diabetes Mellitus." In Complementary/Alternative Medicine: An Evidence Based Approach. Edited by John W. Spencer and Joseph J. Jacobs. St. Louis: Mosby, 1999.
• Sherwin, Robert S. "Diabetes Mellitus." In Cecil Textbook of Medicine. 20th ed. Edited by J. Claude Bennett and Fred Plum. Philadelphia, PA: W.B. Saunders Company, 1996.
• Smit, Charles Kent, John P. Sheehan, and Margaret M. Ulchaker. "Diabetes Mellitus." In Family Medicine, Principles and Practice. 5th ed. Edited by Robert B. Taylor. New York: Springer-Verlag, 1998.
• Ying, Zhou Zhong and Jin Hui De. "Endocrinology." In Clinical Manual of Chinese Herbal Medicine and Acupuncture. New York: Churchill Livingston, 1997.

Periodicals

• Fox, Gary N., and Zijad Sabovic. "Chromium Picolinate Supplementation for Diabetes Mellitus." The Journal of Family Practice 46 (1998): 83-86.
• "Trends in the Prevalence and Incidence of Self- Reported Diabetes Mellitus-United States, 1980-1994." Morbidity & Mortality Weekly Report 46 (1997): 1014-1018.
• "Updated Guidelines for the Diagnosis of Diabetes in the US." Drugs & Therapy Perspectives 10 (1997): 12-13.

Organizations

• American Diabetes Association. 1660 Duke Street, Alexandria, VA 22314. (703) 549-1500. Diabetes Information and Action Line: (800) DIABETES. http://www.diabetes.org.
• American Dietetic Association. 430 North Michigan Avenue, Chicago, IL 60611. (312) 822-0330. http://www.eatright.org.
• Juvenile Diabetes Foundation International. 120 Wall Street, New York, NY 10005-4001. (212) 785-9595. (800) JDF-CURE.
• National Diabetes Information Clearinghouse. 1 Information Way, Bethesda, MD 20892-3560. (301) 654-3327.
• National Institutes of Health. National Institute of Diabetes, Digestive and Kidney Diseases. 9000 Rockville Pike, Bethesda, MD 20892. (301) 496-3583. http://www.niddk.nih.gov.

Other

• Centers for Disease Control and Prevention Diabetes. http://www.cdc.gov/nccdphp/ddt/ddthome.htm.
• "Insulin-Dependent Diabetes." National Institute of Diabetes and Digestive and Kidney Diseases. National Institutes of Health, NIH Publication No. 94-2098.
• "Noninsulin-Dependent Diabetes." National Institute of Diabetes and Digestive and Kidney Diseases. National Institutes of Health, NIH Publication No. 92-241.

Gale Encyclopedia of Alternative Medicine. Gale Group, 2001.