Type 1 Diabetes is an autoimmune disease characterized by an absolute insulin deficiency due to the loss of ß-cells. Although it most commonly presents in younger people, it can develop at any age.
While you will see many more cases of Type 2 Diabetes in your adult patients, pay attention to the presenting history to get the diagnosis right. Just because your patient is elderly or obese doesn’t mean that their diabetes can’t be Type 1 Diabetes. These patients will need insulin early in their course, and only a basal bolus insulin regimen – either as multiple daily injections or a pump – will achieve glycaemic control. Pre-mixed insulin has a very limited role in these people.
When you’re not sure about the diagnosis, treat your patient as having Type 1 Diabetes until your results have confirmed or excluded the diagnosis. Start insulin and wait for the results of your diagnostic tests.
Clues that this is a case of Type 1 Diabetes:
How to diagnose type 1 diabetes
Understanding Type 1 Diabetes
As an autoimmune disease, type 1 diabetes starts with a genetic predisposition and is triggered by an environmental factor. The stronger the genetic predisposition, the earlier the diagnosis is likely to be. For these children, the decline in insulin levels is rapid, so they tend to present very quickly and in DKA.
When diabetes is diagnosed in adults, the decline in ß-cells is slower, so the trigger occurred 5 – 10 years earlier and may not be easily identified. The decline in insulin levels continues after the diagnosis, but while the endogenous insulin persists, glycaemic control is easier to achieve.
This is the “honeymoon period” and can be prolonged by:
LADA (Latent Autoimmune Diabetes of Adulthood)
This is used to describe Type 1 Diabetes that is diagnosed in an adult. At the time of diagnosis, there is a reasonable amount of endogenous insulin, so it tends to present more gradually than a typical presentation of Type 1 Diabetes. In some cases, there are intermittent episodes of hyperglycaemia that resolve by itself, so it can be confused with Type 2 Diabetes.
The diagnosis is confirmed with a positive result for islet cell antibodies. The fasting c-peptide result may be normal because the endogenous insulin production hasn’t yet fallen to critical levels. Insulin treatment is required to control glucose levels.
Clues to the diagnosis are the same as for Type 1 Diabetes.