Diabetes - Type 1 Diagnosis

  • Diagnosis

    Type 1 diabetes is a disorder characterized by high levels of sugar (glucose) in the blood. Diabetes consists of two forms: type 1, previously called "juvenile-onset" diabetes, and type 2, previously called "adult-onset" diabetes. Type 1 diabetes usually starts suddenly before age 30, and usually in children before age 13, but may occur at any age. Type 2 diabetes, conversely, tends to affect adults above the age of 30, but also may affect children and young adults. Type 1 diabetes accounts for 10% of cases of diabetes. It requires daily insulin injections because the body loses its ability to manufacture any insulin, the hormone that regulates blood sugar. Type 2 diabetes, on the other hand, is caused by a combination of insulin resistance and an inability of the cells of the pancreas to produce enough insulin.

    Over time, high blood sugar levels can damage blood vessels and nerves, and lead to serious health problems. Some of the problems that can be caused by uncontrolled diabetes include:

    • blindness
    • kidney failure
    • heart attack
    • stroke

    In type 1 diabetes, the body does not produce enough insulin, the hormone that regulates blood sugar Figure 01. Insulin is secreted by the pancreas (a pear-shaped organ near the stomach) to maintain proper blood sugar levels, which should range anywhere from 60 mg/dL to 110 mg/dL. Blood sugar (glucose) is the fuel the body needs to perform every function. Carbohydrates from food are broken down into this simple sugar, which the body uses for immediate energy needs, or else stores (as glycogen) for future use.

    Click to enlarge: Cellular mechanisms of diabetes (animation and audio)

    Figure 01. Cellular mechanisms of diabetes (animation and audio)

    After a meal, blood sugar rises, and a healthy pancreas secretes insulin into the bloodstream. Insulin acts like a lock and key, and opens the door for cells to use glucose. As blood sugar falls, a healthy pancreas scales back insulin production accordingly to maintain the blood sugar in the normal range. In people with type 1 diabetes, this process is disrupted. For unknown reasons, the body’s immune system turns on and attacks the cells in the pancreas that make insulin (beta cells). This faulty immune response obliterates beta cells and shuts down insulin production. Consequently, blood sugar levels can become dangerously high.

    Type 1 diabetes usually comes on suddenly, and the first symptoms are often related to high blood sugar (hyperglycemia). Hyperglycemia is characterized by frequent urination, excessive thirst and appetite, and weight loss Table 01. The increased need to urinate results from the extra water produced by the kidneys to dilute excess blood sugar in the urine. This excess urination can in turn lead to dehydration and thirst. Blurred vision, fatigue, and recurrent infections (vaginal, bladder, and skin) are other symptoms associated with hyperglycemia.

    Table 1.  Symptoms of Hyperglycemia

    Frequent urination
    Increased appetite
    Weight loss
    Blurred vision
    Infections (vaginal, bladder, skin)

    In some cases, a potentially dangerous complication of diabetes called diabetic ketoacidosis is the first sign that something is wrong. When the body lacks the insulin it needs to use glucose, it turns to the fat stores for energy. Fatty acids get broken down in the liver and produce by-products called ketone bodies (ketones). A build-up of ketones increases the acidity of the blood, and can deplete key minerals. In very severe cases, coma or death can result.

    Symptoms of diabetic ketoacidosis include:

    • fruity-smelling breath
    • difficulty breathing
    • nausea and vomiting

    Type 1 diabetes usually appears during childhood or in young adults. Type 1 diabetes is rarely diagnosed in middle-aged adults. The incidence of the disease rises from birth to adolescence and peaks at around age 12. Heredity seems to play a role in the development of the disease, but many patients have no family history. Researchers think that type 1 diabetes may be triggered in certain people by environmental factors such as early exposure to certain viruses, but they are still trying to determine all of these risk factors.

    To diagnose diabetes, your doctor will take your medical history and do a physical examination. Certain clinical features can help your doctor determine if you have diabetes. For example, he or she will check your urine for glucose; a high amount of blood sugar in the urine is a clue that something is wrong. Your doctor will also check your blood pressure and weight, and test your reflexes for evidence of nerve damage. A thorough examination of your eyes and feet should also be done. Your doctor will also check your eyes for retinopathy—a complication of diabetes that results when blood vessels that supply the retina have been damaged. Foot sores that go unnoticed because of loss of sensation in the feet are another complication of the illness.

    Blood tests are needed to confirm diabetes. A definitive diagnosis of diabetes can be made by measuring how much glucose is in your blood. Your doctor may do a random blood test or ask you to fast for 8 hours beforehand. A blood glucose concentration of 200 mg/dL or more on a random sample and one of 126 mg/dL or above on a fasting sample confirms diabetes. If your fasting level falls between 110 and 125 mg/dL, your doctor may wish to perform a glucose tolerance test. This involves drinking water that contains 75 grams of glucose and having your blood collected two hours later. Levels in the 140 mg/dL to 200 mg/dL range indicate impaired glucose tolerance.

    Currently, there is no way to prevent type 1 diabetes; however, several research projects focusing on type 1 diabetes prevention are underway.

  • Prevention and Screening

    Currently, there is no way to prevent type 1 diabetes; however, several research projects focusing on type 1 diabetes prevention are underway.

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