Pathophysiology of Type I Diabetes
By MJ Wainwright, RN
Wednesday, October 17, 2001
- Introduction to Diabetes
- Pathophysiology of Type I Diabetes
- Treatment of Type I Diabetes
- Bibliography
Introduction to Diabetes
Diabetes has been known to man since about 2000 BC. The Romans and Greeks gave diabetes its name. They named it Diabetes Mellitus. Diabetes means "siphon" (frequent urination). Mellitus means "honey" (sugar in the urine). Aretacus of Cappadocia, a Greek physician, described life for sufferers of the disease as " short, disgusting and painful." He was describing the symptoms of what we now know as the Type I Diabetic. In 1921, Drs. Banting and Best found that diabetics lacked an important hormone made in the pancreas. They named this hormone "insulin". They tried insulin injections on a 14 year-old patient. He weighed 78 Lbs., had extremely high blood sugar levels and was near death. After insulin therapy was initiated, he was able to eat a normal diet, gained weight and lived to maturity.
Today approximately 16 million Americans have diabetes. It is estimated that for every known diabetic there is one unknown diabetic. Every year there is a 5 - 6% increase in the incidence of diabetes.
Diabetes Mellitus is a disease of the metabolism, the process by which our body breaks down the foods we eat to produce the energy we need to function. In diabetes, the human body does not properly convert glucose, a simple sugar, into energy. There are two main types of diabetes. Ten percent of diabetics are Type I. They produce no insulin because the Islet cells (insulin making cells) have been destroyed. Ninety percent of diabetics are Type II. They make insulin, but their bodies don't use it very well. This paper will mostly be about Type I, because that's the kind that is most common to children and young adults.
It is important to know that both kinds of diabetes cause high blood sugar. However, if blood sugar is allowed to remain high over very many years, severe damage to the body occurs. The elevated sugar impairs circulation to the capillaries, eventually causing retinopathy, neuropathy and kidney damage. Many Type II diabetics can have high blood sugar for years before it is discovered. By the time they know about it, they may have chronic, life threateningl problems. Type I diabetics tend to be diagnosed in an emergency situation called Diabetic Ketoacidosis (DKA). Although DKA is a severe medical emergency, the diagnosis of diabetes can be done in an early stage. With proper management, the complications of this type of diabetes can now be significantly reduced.
Pathophysiology of Type I Diabetes
Type I diabetes occurs when all the insulin producing islet cells have been destroyed. It takes three things to cause Type I diabetes. (1) You tend to have a certain blood (HLA) type - Dr3, Dr4. Over 90% of Type I diabetics have these genes. (2) You have to produce islet cell antibodies that destroy the islet cells. These antibodies are made when your body's immune system makes a "mistake" and makes killer cells against itself. This reaction is called an autoimmune (self-immune) reaction and occurs after you get a virus or are exposed to something (still unknown) in the environment. (3) You must make enough antibodies to kill 90% of your islet cells. When 90% of them are destroyed you begin to show symptoms of Type I diabetes.
All cells need sugar for fuel. Sugar is supplied by the foods we eat. All food is made up of carbohydrates, proteins and fats. In our stomach and intestines portions of these foods are broken down into glucose (simple sugar). One hundred percent of carbohydrates are broken down into glucose with lesser amounts provided by proteins and fats. After food is broken down, glucose is absorbed through the walls of the intestine and passes into the bloodstream. Some of the glucose is used immediately by the body's cells for energy, but most is stored away in the liver and muscle cells for future use. Think of glucose in the body as you would think of gasoline in your car. It is needed to keep the little engines going in the cells of your body. For glucose to enter a cell, INSULIN must be present to act as a transport system. Insulin is the KEY which opens the door to let glucose pass through into the cell.
Insulin is a hormone produced by the beta cells within the Islets of Langerhans in the pancreas. When food enters the body, the beta cells are signaled to produce insulin. The more food broken down, the more insulin is needed to carry the glucose into the cells.
When a person has type I diabetes, the food is broken down into glucose and enters the bloodstream in the normal way. But because the Type I Diabetic no longer produces insulin, the glucose remains in the bloodstream. As the blood sugar (glucose in the bloodstream) rises higher it overflows through the kidneys into the urine. This high level of sugar in the bloodstream draws water into the circulatory system to aid in flushing the excess glucose from the system via the kidneys. The results are the common first symptoms of diabetes:
- Frequent passing of large amounts of urine
- Frequent drinking of liquids: to make up for losses caused by diuresis
- Hunger, because the cells still are not able to receive glucose from the bloodstream for fuel (However, in younger children hunger may not be experienced)
- Weight loss: When the body can't get sugar into the cell, it burns its own fats and proteins for fuel.
If insulin is still not produced, the cells begin to starve. They will break down fat and muscle as an emergency way to supply the body with fuel. The body's ability to breakdown fats and muscle (protein) to provide fuel for the cells is a "backup" system for the body to use in times of hunger or illness. It is not meant to be the primary source of energy. When the body utilizes the backup system for fuel an acidic byproduct, ketones, are released into the bloodstream.
The Type I diabetic at the time of diagnosis is usually only using the "backup" system of the body for fuel, because no insulin is available. Therefore, we usually have a patient who presents with the symptoms of (1) high blood sugar, (2) dehydration due (3) electrolyte imbalance due to losses because of dehydration, - this becomes more severe as losses continue, (4) acidosis due to both ketosis and dehydration. This sequence of events, which started with an elevation of blood sugar would eventually lead to shock, coma and death in the Type I Diabetic. Insulin must be made available, (along with fluids and correction of electrolytes) to reverse this sequence.
Advanced Diabetic Ketoacidosis (DKA) is a medical emergency requiring Pediatric Intensive Care. Careful fluid and insulin administration are needed to stabilize the patient. Treatment of DKA, due to its complexity, needs to be managed with extreme accuracy to prevent significant complications. The families of Type I diabetics will be taught how to recognize the signs and symptoms of hyperglycemia wich eventually could lead to DKA.
Patients and families will also be taught the signs and symptoms of low blood sugar (hypoglycemia) which can occur if too much insulin or not enough food is eaten. Hypoglycemia is the most common side effect of insulin administration. However, with proper care and education the occurrence of hypoglycemia should be rare and the effects should be insignificant.
Treatment of Type I Diabetes
Because the Type I Diabetic produces no insulin there are 3 factors that must be managed to control his or her blood sugar:
- INSULIN
- DIET
- EXERCISE
Most importantly, insulin must be provided to the body around the clock. Remember, without insulin, the cells cannot take glucose from the bloodstream. Secondly, glucose in the form of meals and snacks must be provided to the body in a manner that matches the effects of the insulin. Thirdly, the diabetic must exercise to help control their blood sugars. The amount of exercise a type I diabetic does must also be calculated, along with insulin and food, to provide adequate glucose to the cells and to enhance the effectiveness of the insulin provided.
The goals of treatment for Type I diabetes:
- Blood sugar ranges within appropriate parameters for age:
- Less than 5 yrs. of age blood sugar range from 100 to 200.
- Ages 5 to 12 blood sugar ranges from 80 to 180.
- Ages 12 and above blood sugar ranges from 70 to 150.
- Hemoglobin A1C from 6 to 8% depending on age.
- Participation in all activities appropriate for age (i.e. Normal lifestyle).
- Less than 2 moderate hypoglycemic events per month.
- Less than 2 hyperglycemic events/month with symptoms requiring intervention.
- Lack of complications due to diabetes (Hospital Admissions, retinopathy, kidney disease, and neuropathy).
Our challenge as medical professionals is to teach the patients and families of Type I Diabetics how to manage the factors of diet, exercise and insulin administration to achieve our goals.
The best way to do this is by utilizing a "Diabetes Team" approach with a pediatric endocrinologist, a diabetic educator, a dietician, nursing, and social services or counseling services available. The patient and their family are always at the center of the team. The goals won't be met if we can't make it work for them. We need to teach them how to control diabetes and not let the diabetes control them.
As pediatric nurse,,and health professionels caring for the Type I diabetic an understanding of the pathophysiology and basic treatment principles is critical in providing safe and effective care. The specific regimen for insulin administration, diet and blood glucose testing will be ordered by the physician. Education should be provided by the diabetic nurse educator and dietician. However, nursing must be able to reinforce the teaching that has been provided to the families.
- Insulin administration and insulin action
- Diet
- Effects of exercise
- Safety (hypoglycemic reactions and hyperglycemia), care of equipment, medical bracelets, school protocols.
- Blood glucose testing
- Resources for information
Bibliography
Roth, Jesse. "Diabetes." World Book. Chicago, Scott Fetzer Company, copyright 1992.
Silverstein, Alvin, Virginia, & Robert. Diabetes. Springfield, New Jersey, Enslow Publishers, Inc. ©1994.
Chase, Peter. Understanding Insulin-Dependent Diabetes. Denver, Colorado. United Artists Pictures, Inc. ©1995.
Milchovick, Sue K. & Dunn - Long, Barbara. Diabetes Mellitus. Palo Alto, California. Bull Publishing. ©1995.
Wong, Faye L. "Diabetes Public Health Resource. " CDC's Diabetes Program. Atlanta, Georgia, Centers for Disease Control, ©2000. (11/20/00). www.cdc.gov/diabetes/faqs.htm
Burgess, Maria. "Pathophysiology." Pathophysiology of Diabetes. Milburges Company, ©1998. (11/26/00). www.kines.uiuc.edu/courses/kines352/lectures/diabetes/index.htm
MJ Wainwright, CCRN
Fountain Valley Community Hospital
Inservice - June 21, 2001
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