Diabetes is diagnosed when a person has too much glucose (sugar) in the blood, as a result of the body having insufficient insulin or resisting the effects of insulin. Type 1 diabetes is a life-long variation of the disease that typically takes hold in childhood or adolescence, and is the result of the body’s immune system destroying the pancreas where insulin is made. Symptoms of Type 1 diabetes can appear suddenly. The condition can cause serious health complications over time but can be managed with insulin replacement therapy and lifestyle changes.
Diabetes mellitus (commonly referred to as diabetes) is a group of diseases characterised by high blood sugar levels over a prolonged period of time. This page deals with type 1 diabetes. Other diabetes variations include:
Type 1 diabetes accounts for 5-8% of people with diabetes, while type 2 diabetes is much more common, accounting for 85–90% of diabetes cases.
Type 1 diabetes used to be known as juvenile diabetes and most often occurs in childhood, but it can also develop in adults. The condition may affect around one in every 5000 New Zealanders under the age of 15. Type 1 diabetes is more common in New Zealand Europeans than other ethnic groups.
Although the exact cause of type 1 diabetes is unknown, it is generally considered to be an autoimmune condition in which the body's immune system mistakenly attacks and destroys the insulin-producing (islet) cells of the pancreas (a gland that secretes insulin into the blood). Once a critical number of islet cells have been destroyed, the body produces little or no insulin.
Insulin is a hormone that promotes the uptake of glucose from the blood into cells so that it can be metabolised (broken down) and used by the body as an energy source. In doing so, insulin lowers the level of glucose in the blood. Without insulin, glucose is not taken up into the cells and blood sugar levels increase potentially causing serious health complications.
Certain factors are associated with an increased risk of developing type 1 diabetes.
Known risk factors for type 1 diabetes include:
Possible risk factors include:
The signs and symptoms of type 1 diabetes can appear suddenly. The classic symptoms are:
Other signs and symptoms include:
A doctor should be seen if any of the above signs and symptoms develop, especially the classic symptoms of diabetes.
In the presence of the classic symptoms of diabetes, the following blood tests will confirm a diagnosis of type 1 diabetes:
A blood test called the glycosylated haemoglobin (Hb1Ac) test might also be performed. It is a measure of a person’s average blood glucose level over the past 2–3 months. An Hb1Ac level of 6.5% or higher on two separate tests indicates diabetes. The Hb1Ac test is also used to monitor the effect of treatment. It is generally recommended that HbA1C levels should be maintained below 7%.
Blood tests to check for immune system proteins that act against the islet cells and insulin (autoantibodies) may also be done. These tests help to distinguish between type 1 and type 2 diabetes.
Serious complications of type 1 diabetes that develop gradually over many years include:
Maintaining blood glucose levels as close as possible to normal can help to delay or prevent these complications from developing.
Potentially serious complications of type 1 diabetes that can develop suddenly are:
The goal of treatment for type 1 diabetes is to keep blood glucose levels as close to normal as possible, ie: daytime blood glucose levels before meals 3.9–7.2 mmol/L and no higher than 10 mmol/L two hours after meals. To achieve these goals, a combination of treatment approaches is required, including:
Type 1 diabetes requires lifelong insulin therapy, which is why the condition used to be known as insulin-dependent diabetes. Insulin can be given by injection or via a continuous insulin pump.
With insulin injections, a syringe with a fine needle or an insulin pen is used to inject insulin under the skin. Most people require two or more injections of insulin daily with different types of insulin and with doses adjusted based on self-monitoring of blood glucose levels.
There are two main types of insulin: basal insulin (continuous background insulin) and bolus insulin (an extra dose of insulin given before meals). Basal insulin is either long-acting (e.g. glargine) or intermediate-acting (e.g. isophane). Bolus insulin is either rapid-acting (e.g. lispro, aspart, or glulisine) or short-acting (e.g. neutral).
An insulin pump is a small device worn on the outside of the body. A tube connects a reservoir of insulin to a catheter that is inserted under the skin of the abdomen. The pump is programmed to dispense specific amounts of insulin. This would typically be a constant low dose of fast-acting insulin to act as the basal background insulin and the user giving a bolus dose of the fast-acting insulin to cover meals.
Optimal diabetic control requires frequent self-monitoring of blood glucose levels as this allows for timely adjustments in insulin doses. People with type 1 diabetes should learn how to self-monitor their blood glucose levels using a pocket-sized blood glucose meter and adjust their insulin doses accordingly.
Depending on whether daily insulin injections or an insulin pump is used, blood glucose levels will likely need to be checked at least four times a day. Careful monitoring is the only way to ensure that blood glucose levels remain within the target range.
Blood glucose testing involves using a lancing device to prick the skin to draw a drop of blood, which is placed on a test strip. The test strip is then inserted into a blood glucose meter, which provides a blood glucose level reading.
Blood ketone meters, which measure blood ketone levels, and work in a similar way to blood glucose devices, are available to test for ketoacidosis.
Careful management of type 1 diabetes is important to reduce the risk of acute and long-term serious complications. The following tips will help:
For further information and support contact your doctor, practice nurse, or:
Diabetes New Zealand
Postal address: PO Box 12441, Thorndon, Wellington
Freephone: 0800 DIABETES (0800 342 238)
Diabetes Youth New Zealand
Postal address: P.O. Box 56172, Dominion, Road Auckland
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