Diabetes Mellitus, Type 1 (Insulin-Dependent Diabetes)

Basic Information

Insulin-dependent diabetes (IDDM) or Type 1 diabetes is also known as juvenile or autoimmune diabetes. Clinical manifestations vary from a state without symptoms to coma induced by diabetic ketoacidosis but there is a complete deficiency of insulin in all patients and a destruction of islet cells in the pancreas in most patients. The insulin-dependent patient requires insulin to survive as well as to avoid ketoacidosis

Type 1 diabetes has an early onset, peaking between ages 12 to 15 years, with most cases occurring under 30 years of age. The prevalence is rarer than for the Type 2 or non-insulin-dependent patient with approximately 300,000 individuals or 0.5% of the population having this disease. Insulitis occurs in 50 to 70% of patients at onset of the disease and their islet cell mass is substantially reduced.

Though Type 1 diabetes is a worldwide problem the incidence is highest in the Scandinavian countries and among Caucasians in the United States. Genetic and environmental factors seem to play a part in the development of this illness. A genetically susceptible individual may become exposed to a specific viral infection (an environmental factor) and an autoimmune reaction can lead to a progressive but sustained loss of insulin secretory capacity. Eventually clinical diabetes occurs. Other inherited factors may include the ability of human lymphocyte antigens to induce autoimmunity to islet cells, and Class 2 proteins may increase the risk or influence susceptibility of diabetes by ten.

Eight percent of cases of legal blindness are caused by diabetes and it is the leading cause of end-stage renal disease in America. Men tend to be slightly more at risk than women.

With Type 1 diabetes the body is unable to metabolize nutrients in a normal way. Insulin is a hormone produced by beta cells in the pancreas though with patients with Type 1 diabetes the beta cells are obliterated by the patient's own immune system so insulin-dependent diabetes can be classified as an illness of the insulin-producing cells of the pancreas. Why this occurs is unknown but what is known is that the body is not able to use carbohydrates for energy and the end result is that sugar becomes built up in the bloodstream. This buildup of sugars is called glucose.

Unfortunately there is no cure for diabetes. Management and education are the key to its control. It is a very serious illness which puts Type 1 diabetes patients at risk of coronary heart disease as well as kidney failure, blindness, nerve damage and peripheral vascular disease. These problems usually occur after a number of years of Type 1 diabetes.

Symptoms

Symptoms of diabetes mellitus include:

• rapid weight loss
• extreme fatigue
• frequent urination (most often at night)
• excessive thirst
• blurred vision
• nausea
• neuropathy (pain or numbness in the feet or hands)
• enlarged liver which may cause abdominal pain
• loss of calories (glucose) (one of the few illnesses in which weight loss occurs despite a normal intake of calories).

There are many shared symptoms between Type 1 and Type 2 diabetes. The onset of symptoms in Type 1 patients is rapid and the symptoms, secondary to hyperglycemia, are more severe.

Diagnosis/Treatment

Type 1 diabetes is generally easily diagnosed. If the patient's serum glucose is above 200mg/dL a positive diagnosis can be inferred. Also when the patient has hyperglycemia and ketoacidosis and is under 20 years of age Type 1 diabetes is suspected and the need for insulin therapy is indicated. If you have symptoms of Type 1 diabetes your health care provider may look for low blood pressure, dehydration (with a rapid pulse rate) or deep prolonged respirations (if ketoacidosis is present).

A physical exam and family medical history should be taken along with a complete ophthalmology exam, neurologic examinations and a consideration of vascular risk factors. Helpful laboratory tests may include urinalysis, serum chemistry, glucose levels and, for adults, an ECG or electrocardiogram

Once a diagnosis is made initial insulin therapy must be explained meaning that the correct techniques for injecting insulin and learning about adjustments to the dosage must be mastered and practiced repeatedly so that the patient may independently administer this medication.

A management team of professionals who understand and treat diabetes including a physician, diabetes educator and dietician can be put together by your health care professional. How will these professionals help? The physician will prescribe the insulin as well as make a physical evaluation and take a medical history of the patient. The diabetes educator will explain insulin injection techniques as well as home blood glucose monitoring. The dietician will provide a specific meal plan with proper carbohydrates and calories and determine specific time of day for consumption.

Since diabetes is a chronic disorder with long-term care required, the better the patient understands the illness and has the ability to proactively care for him or herself the more self confident and self-reliant the patient becomes and the prognosis for long-term care is better than for the patient with poor control methods.

Variations exist as to the different type of insulin and the correct time for injection but nearly all patients require two injections of insulin each day. Human insulin is the preferred type of insulin. One of the most common side effects in the treatment of diabetes is low blood sugar or hypoglycemia in which the patient can undergo a hypoglycemic reaction and may have a seizure or lose consciousness.. Patients must be taught the difference between the symptoms of uncontrolled diabetes and hyperglycemia, and family members and/or reliable friends should understand how to administer glucose in case of emergencies. To help prevent these hypoglycemic reactions patients must take their insulin as described and not miss their regular meals at the time that has been recommended for them by their medical team. The patient must be sure that he or she does not run out of insulin or skip his or her doses. Hypoglycemia rarely causes death or permanent neurologic problems but it can be a serious episode and the patient must learn to combat the onset by rapidly taking in food that can be quickly absorbed. These might include candy, fruit juices or a pack of "instant glucose"

There are chronic medical problems related to this disease, many of which are quite serious. These can include:

• ketoacidosis (a metabolic disturbance that can result in coma)
• hypoglycemia
• blindness or retinopathy (90% of type A diabetics develop retinopathy after 20 years). Renal transplantation has proven effective in many cases for end-stage renal disease but be sure you have an annual eye exam if you have had Type 1 diabetes for more than 5 years.
• nephropathy
• neuropathy
• dermopathy (shin spots or scars)
• kidney failure

New techniques for treating diabetes are occurring, the most dramatic of which is pancreatic transplantation which restores gluco metabolism to normal and allows the patient after a successful transplant procedure to be free of the need for insulin.

If you feel you may have diabetes mellitus Type 1 or that your child may have this disease please see your health care provider promptly.

Additional Resource(s):

• American Diabetes Association 1-800-232-3472