11.2 Disorders of the Endocrine System: Diabetes Mellitus V2
The following section is the same as in the unit 10.2 Disorders of the Endocrine System. It is reproduced here as it can apply to both units.
Dysfunction of insulin production and secretion, as well as the target cells’ responsiveness to insulin, can lead to a condition called diabetes mellitus, a common disease that affects the ability of the body to produce and/or utilize insulin. There are two main forms of diabetes mellitus.
Type 1 Diabetes is an autoimmune disease affecting the beta cells of the pancreas. The beta cells are destroyed by the immune system but can also occur due to a trauma or injury to the pancreas (Thota & Akbar, 2023). The beta cells of people with type 1 diabetes do not produce insulin; thus, synthetic insulin must be administered by injection or infusion. Presenting symptoms include polyuria, polydipsia, and polyphagia. Clients may also have unexplained weight loss and blurred vision. If left untreated the client can go into ketoacidosis, a life-threatening condition.
Type 2 Diabetes accounts for approximately 95 percent of all cases. It is acquired, with contributing factors of family history, over the age of 40, overweight, and lifestyle factors such as poor diet and inactivity greatly increase a person’s risk (Diabetes Care Community, 2023). In type 2 diabetes, the body’s cells become resistant to the effects of insulin. In response, the pancreas increases its insulin secretion, but over time, decompensation occurs as the impaired beta cells are unable to produce sufficient insulin to overcome insulin resistance. In many cases, type 2 diabetes can be reversed by moderate weight loss, regular physical activity, and consumption of a healthy diet. However, if blood glucose levels cannot be controlled, oral diabetic medication is prescribed.
Type 2 diabetes is a progressive disease, especially if blood sugars are not kept within target range. The client often begins with one oral anti-diabetic medication, and may be prescribed additional meds depending on their blood sugars, other health issues and symptom management. As with type 1 diabetes, blood sugar control is essential to avoid hypoglycemia and hyperglycemia fluctuations. Over time, long term physiological changes can occur especially in the arteries, such as retinopathy, neuropathies, nephropathy leading to kidney failure and cardiovascular disease.
Gestational Diabetes Mellitus (GDM):
Gestational Diabetes is a form of glucose intolerance or hyperglycemia that is first recognized during pregnancy. Left untreated, it poses significant short and long-term risks to both the mother and the fetus. GDM is similar to type 2 diabetes, caused by increased insulin resistance and a deficiency in insulin. Maternal pancreatic β-cell dysfunction results in decreased insulin secretion, leading to the inability to control maternal insulin resistance and maternal hyperglycemia. Screening for GDM occurs in week 24-28 of pregnancy. Risks to the mother include preeclampsia. The risk to the infant is macrosomia, shoulder dystocia and increased risk of diabetes later in life. GDM is treated with diet, exercise, metformin and if needed, insulin. Post-partum, many mothers return to their pre-pregnancy state. To learn more about GDM, go to Gestational diabetes – Diabetes Canada
Diagnosis of Diabetes
Screening for type 2 diabetes should be done every 3 years for individuals over 40 years of age or anyone considered high risk of developing diabetes. If a client has numerous risk factors, screening may be done q 6-12 months or by the recommendation of their health care provider.
Screening includes fasting or random plasma glucose and glycated hemoglobin (A1C).
High risk factors include: family history of diabetes, history of pre-diabetes or gestational diabetes, overweight, or a member of a high-risk group: African, Arab, Asian, Hispanic, Indigenous or South Asian descent, low socioeconomic status (Diabetes Canada Clinical Practice Guidelines Expert Committee, 2026).
| Fasting blood glucose levels (FBG) | Normal: less than 5.6 mmol/L
At risk: 5.6-6.0 mmol/L Pre-diabetes: 6.1 to 6.9 mmol/L Diabetes: greater than 7.0 mmol/L
|
Fasting at least 8 hours.
(Slight differences in values between some sources. Normal FBG 4.0-7.0 reported with Diabetes Canada) |
| Random blood glucose test
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Diabetes: 11.1 mmol/L or higher. | No fasting or preparation involved. |
| Oral glucose tolerance test (OGTT)
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Following ingesting 75 grams of glucose in a drink, after 2 hours:
Diabetes: BG level 11.1 mmol/L or higher Pre-diabetes: 7.8 – 11.0 mmol/L |
measures your body’s ability to use glucose.
Plasma glucose level drawn, followed by a 75 gram glucose load, then second blood glucose level. |
| Glycosylated hemoglobin, also called A1C | Normal: under 5.5%
At risk: 5.5-5.9% Pre-diabetes: 6-6.4% Diabetes: greater than 6.5%
|
Used to assess long-term blood glucose levels over 3 months. Good indicator of blood glucose control.
(Normal under 6.5% with Diabetes Canada) |
Tests for Diabetes Screening and Monitoring
For more information on testing for diabetes, go to: Diabetes Care Community (2023). Blood sugar levels in Canada. Blood Sugar Levels In Canada
For more information on diabetes management in Canada, go to the Diabetes Canada website: About diabetes – Diabetes Canada this is an excellent resource for clients and health care professionals.
References
Diabetes Canada Clinical Practice Guidelines Expert Committee (2026). Diabetes Canada clinical practice guidelines. Diabetes Canada. Clinical Practice Guidelines Quick Reference Guide
Diabetes Care Community (2023). Blood sugar levels in Canada. Blood Sugar Levels In Canada
Thota, S. & Akbar, A. (2023). Insulin. National Library of Medicine. StatPearls [Internet]. Treasure Island (FL). StatPearls Publishing.
