Type 1 Diabetes: Causes, Symptoms, Complications and Treatment

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By : dLife Editors

Reviewed by: Steven Chessler, M.D., Ph.D. 5/18.

Type 1 diabetes is an autoimmune disease that occurs when insulin-producing beta cells within the pancreas are gradually destroyed and eventually too few remain to produce sufficient insulin.

Insulin is a hormone that helps the body’s cells use glucose for energy. Blood glucose (or blood sugar) is manufactured from the food we eat (primarily carbohydrates) and by the liver. If glucose can’t be absorbed by the cells, it builds up in the bloodstream instead.

Untreated, the high blood sugar levels that result can be toxic to every system of the body, causing serious complications.

Type 1 diabetes accounts for 5 to 10 percent of all diagnosed diabetes in the United States. Although type 1 diabetes develops most often in children and young adults, the disease can be diagnosed at any age.

Of the 1.25 million Americans living with type 1 diabetes, about 200,000 are younger than twenty years old. Unlike type 2 diabetes, type 1 diabetes is more common in Caucasians than in those of Latino, African American, or other non-Caucasian backgrounds. The rate of type 1 diabetes has been increasing by roughly 2 to 5 percent each year, globally.

Type 1 Diabetes Causes

Researchers have identified several genes associated with the development of type 1 diabetes. While the causes are complex and not completely understood, the prevailing belief about the etiology, or cause, of type 1 diabetes is that while someone may have a genetic predisposition for developing the disease, it takes an environmental trigger or series of triggers (e.g., virus, toxin, drug) to set off the autoimmune process that destroys insulin-producing beta cells of the pancreas.

Risk factors for developing type 1 diabetes may include:

·       Family History

A child with an immediate relative with type 1 diabetes has a risk of developing type 1 diabetes ten to twenty times higher than the general population. The risk varies depending upon which relative it is.

·       Autoimmune Diseases

The presence of other autoimmune disorders, such as thyroid disease and celiac disease, raises the risk of type 1 diabetes.

·       Early Cessation of Breastfeeding and/or Exposure to Cow’s Milk

Some clinical research indicates that breastfeeding for at least three months decreases the risk of type 1 diabetes. Other studies suggest that exposure to cow’s milk or cow’s milk-based formula before one year of age may increase diabetes risk, although other studies have not borne out this link.

·       Being Caucasian

In America, Caucasians have a greater risk of type 1 diabetes than African Americans, Native Americans, Asian Americans, and Latinos. Worldwide, Finland and Sweden have the highest incidence of type 1 diabetes.

·       History of Childhood Viruses

Viruses that have been associated with type 1 diabetes as environmental triggers include Coxsackie B, enteroviruses, adenovirus, rubella, cytomegalovirus, and Epstein-Barr virus.

Type 1 Diabetes Symptoms

Symptoms of type 1 diabetes usually develop quickly over a short period. If not diagnosed and treated with insulin, a person with type 1 diabetes can lapse into diabetic ketoacidosis (DKA), which can lead to a coma if left untreated.

DKA is life-threatening, so it’s important to contact your healthcare provider immediately if you are experiencing symptoms.

Type 1 diabetes symptoms include:

  • Excessive thirst
  • Frequent urination
  • Extreme hunger
  • Unexplained weight loss
  • Fatigue, or a feeling of being “run down” and tired
  • Tingling or burning pain in the feet, legs, hands, or other parts of the body
  • Blurry vision
  • Confusion
  • Stomach pain
  • Nausea
  • Vomiting
  • Breath that smells sweet, or has a fruit or wine odor to it
  • Dry, itchy skin
  • Frequent or recurring infections, such as urinary tract infections, yeast infections, and skin infections
  • Slow healing of cuts and bruises
  • Irritability, depression

Complications of Type 1 Diabetes

1.     Heart or blood vessel disease (Diabetic Angiopathy)

The presence of constant high amounts of glucose in the blood vessels affects the innermost layer of vessels, especially the microvasculature, causing the cells called pericytes to die. This and a complex set of other abnormalities affecting the vessels affects the blood flow to the cells and tissue of the extremities, retinas, and kidneys as these are supplied by the micro-vessels.

2.     Nerve Damage (Diabetic Neuropathy)

The nerves that are supplied by the micro-vessels are affected in diabetes because of the peripheral angiopathy in diabetics and also as a direct result of high glucose levels being toxic to nerve tissue. Affected nerves are damaged and may die affecting the nerve function.

Tingling, numbness, burning or pain in the toes or fingers may result.  Over time, the sensation will move upwards and if blood glucose is poorly controlled, all senses in the affected areas may be lost.

3.     Infections

Generally, patients with type 1 diabetes are more prone to infections or are more likely to suffer serious complications of the disease.

  • Patients are more prone to infections like foot infections, yeast infections, urinary tract infections and surgical site infections.
  • Yeast infections like Candida infections are more likely to colonize the mucous membranes of the mouth, vagina, and nose in people with type 1 diabetes.
  • Gum disease in the mouth is also more likely

4.     Slow Healing Wounds

People with diabetes are more adversely affected than people without diabetes when they get infected because their immune responses are weakened, nerves are damaged, and they have poor blood circulation making it difficult for the blood to reach the injured skin and wounds.

5.     Diabetic Foot

Nerve damage in the arms and legs for type 1 diabetics often affects the sensation, particularly the feet.

  • Lack of sensation means foot injuries go unnoticed
  • Risk of developing foot ulcers
  • Untreated injuries can act as a point of entry for infectious agents into the body

6.     Genital Itching

Burning, redness or soreness around the genital areas.  Itching occurs because of yeast infection around the genitals. The high glucose content in the urine also provides a conducive environment for the yeast to thrive.

  • If you have type 1 diabetes and are experiencing itching around the genitals, then it may be an indication that your blood glucose levels may be higher, hence you should consult your medical advisor.

7.     Diabetic Retinopathy

A medical condition that causes damage to the retina of the eye also called diabetic eye disease. It’s one of the major complications of diabetes, most often seen in people with more than 20 years of diabetes.  It is a leading cause of blindness.

8.     Diabetic Nephropathy

Chronic loss of kidney function.  The onset of symptoms varies and is often 5-10 years after the disease begins. The first symptom is frequent urination at night called nocturia. Other symptoms are tiredness, headache, nausea, vomiting, loss of appetite, dry itchy skin and leg swelling.

9.     Diabetic Ketoacidosis

A complication that occurs due to the production of ketones as a byproduct. The accumulation of ketones in the blood can cause the following symptoms:  Loss of appetite, nausea, and vomiting, a fruity odor of breath and urine, dehydration, deep breathing, rapid heart rate, confusion, and disorientation.

10.   Depression

Recent studies claim that depression in children and adolescents with type 1 diabetes have been associated with negative diabetes-related health outcomes like poor glycemic control and recurrent diabetic ketoacidosis.  Studies indicate that the level of depressive symptoms in type 1 diabetic youth is double that of the general population.

11.   Gastrointestinal Problems

Studies have reported that type 1 diabetics have a higher frequency of occurrence of upper gastrointestinal symptoms such as loss of appetite, nausea, and vomiting than the general population.

Type 1 Diabetes Treatment

  • Insulin Therapy

People with type 1 diabetes must have insulin injections to supplement the failing insulin production of their pancreas. Insulin is injected with a syringe or pen injector, or through an infusion device called an insulin pump.

There are many types of insulin and insulin administration, classified by how long they take to work and how long they last in the body. Talk to your doctor about the options that may be best for you.

There are also adjunct, or companion, treatments for type 1 diabetes that may be prescribed along with insulin. For example, the injectable hormone pramlintide (Symlin) is taken with mealtime insulin to help avoid after-meal blood sugar spikes.

  • Blood Glucose Monitoring

Checking and tracking your blood glucose levels will help you know if you are meeting the treatment goals set by you and your doctor. These trends will help you understand how your body reacts to food, exercise, medication, illness, and more.

Talk to your doctor about when and how to check your blood glucose levels. There are blood glucose monitors used for individual tests, and continuous glucose-monitoring devices used to map out trends—and even alert you if your blood glucose levels are dangerously high or low.

Eating Well and Exercising

Good nutrition, particularly careful monitoring of carbohydrate intake, and regular physical activity are also important “treatments” for controlling type 1 diabetes and preventing long-term complications.

The food you eat directly impacts your blood glucose levels and diabetes management. Working with a certified diabetes educator or registered dietitian-nutritionist and/or taking an active role in medical nutrition therapy (MNT) can help you get and stay on the right track if healthy eating is something you struggle with.

Exercise makes it easier for your body to use insulin and can help prevent long-term complications. Talk to your doctor before beginning a new exercise routine, and be sure to check your blood glucose levels before, during, and/or after to prevent dangerously low levels.

Currently, there is nothing one can do to prevent type 1 diabetes.  Researchers are currently working on preventing the disease.  They are also actively researching ways to prevent the destruction of the islet cells in people who are recently diagnosed.


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Steven Chessler, M.D., Ph.D., is an associate professor and physician-scientist in the Department of Medicine, Division of Endocrinology, at the UC Irvine School of Medicine. He treats patients with diabetes and a variety of other endocrine disorders and, in the laboratory, carries out diabetes- and pancreatic-islet-related research.