Internal Medicine
Endocrinology
Glucose Abnormalities

Glucose Abnormalities

Introduction

Welcome to the QBankMD MCCQE1 preparation guide on Glucose Abnormalities. This comprehensive resource is tailored specifically for Canadian medical students preparing for the Medical Council of Canada Qualifying Examination Part I (MCCQE1). Understanding glucose abnormalities is crucial for success in the MCCQE1 and for your future practice in the Canadian healthcare system.

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This guide aligns with the CanMEDS framework, emphasizing the roles of Medical Expert, Communicator, and Health Advocate in managing glucose abnormalities in the Canadian context.

Types of Glucose Abnormalities

In this section, we'll explore the main types of glucose abnormalities you need to know for the MCCQE1 exam.

Elevated blood glucose levels (>11.1 mmol/L)

Hyperglycemia

Hyperglycemia is defined as elevated blood glucose levels. For the MCCQE1, remember these key points:

  • Definition: Fasting plasma glucose >7.0 mmol/L or random plasma glucose >11.1 mmol/L
  • Causes: Diabetes mellitus, stress, medications (e.g., glucocorticoids), pancreatitis
  • Symptoms: Polyuria, polydipsia, polyphagia, blurred vision, fatigue

Hypoglycemia

Hypoglycemia is a common and potentially serious condition. Key points for MCCQE1:

  • Definition: Blood glucose <4.0 mmol/L
  • Causes: Excess insulin, oral hypoglycemics, alcohol, severe liver disease, insulinoma
  • Symptoms: Shakiness, sweating, tachycardia, confusion, seizures (severe cases)

Diabetes Mellitus

Diabetes mellitus is a chronic condition characterized by persistent hyperglycemia. For MCCQE1, focus on:

  1. Type 1 Diabetes:

    • Autoimmune destruction of pancreatic β-cells
    • Absolute insulin deficiency
    • Usually diagnosed in childhood or adolescence

  2. Type 2 Diabetes:

    • Insulin resistance and relative insulin deficiency
    • Most common form in Canada
    • Often associated with obesity and metabolic syndrome

  3. Gestational Diabetes:

    • Glucose intolerance with onset or first recognition during pregnancy
    • Increases risk of adverse pregnancy outcomes

Diagnostic Criteria for Diabetes in Canada

For the MCCQE1, memorize these Canadian Diabetes Association (CDA) diagnostic criteria:

TestDiabetesPrediabetes
Fasting Plasma Glucose (FPG)≥7.0 mmol/L6.1-6.9 mmol/L (IFG)
2h Plasma Glucose in 75g OGTT≥11.1 mmol/L7.8-11.0 mmol/L (IGT)
A1C≥6.5%6.0-6.4%
Random Plasma Glucose≥11.1 mmol/L + symptoms-

IFG: Impaired Fasting Glucose, IGT: Impaired Glucose Tolerance

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Note: Canadian guidelines use mmol/L for glucose measurements, unlike the mg/dL used in some other countries. Familiarity with mmol/L is essential for the MCCQE1 exam and Canadian practice.

Canadian Guidelines for Diabetes Management

The Diabetes Canada Clinical Practice Guidelines are essential knowledge for the MCCQE1 exam. Key points include:

  1. Screening: All individuals ≥40 years should be screened every 3 years
  2. Target A1C: ≤7.0% for most patients (may be individualized)
  3. Blood Pressure Target: <130/80 mmHg
  4. LDL-C Target: <2.0 mmol/L or >50% reduction
  5. Emphasis on patient-centered care and shared decision-making
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For comprehensive review, access the full Diabetes Canada Clinical Practice Guidelines at guidelines.diabetes.ca (opens in a new tab).

Sample MCCQE1-Style Question

# Sample Question

A 52-year-old woman presents to her family physician for a routine check-up. She has no significant past medical history and takes no medications. Her BMI is 31 kg/m², and her blood pressure is 138/88 mmHg. Fasting plasma glucose is 6.8 mmol/L. Which one of the following is the most appropriate next step in management?

  • A. Diagnose Type 2 Diabetes and start metformin
  • B. Order a 75g oral glucose tolerance test
  • C. Start a sulfonylurea
  • D. Recheck fasting plasma glucose in one year
  • E. Start an SGLT2 inhibitor

Explanation

The correct answer is:

  • B. Order a 75g oral glucose tolerance test

This patient has a fasting plasma glucose of 6.8 mmol/L, which falls into the Impaired Fasting Glucose (IFG) range (6.1-6.9 mmol/L) according to Canadian guidelines. To confirm the diagnosis of prediabetes or diabetes, a 75g oral glucose tolerance test (OGTT) is the most appropriate next step.

A. is incorrect because the fasting glucose alone is not sufficient to diagnose diabetes in this case. C. and E. are incorrect because pharmacological treatment is not indicated without a confirmed diagnosis. D. is incorrect because with an abnormal fasting glucose, further testing should be done sooner.

This question tests your knowledge of Canadian diagnostic criteria for glucose abnormalities and the appropriate diagnostic workup, which is crucial for the MCCQE1 exam.

References

  1. Diabetes Canada Clinical Practice Guidelines Expert Committee. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes. 2018;42(Suppl 1):S1-S325.

  2. Public Health Agency of Canada. (2021). Diabetes in Canada. Retrieved from https://www.canada.ca/en/public-health/services/publications/diseases-conditions/diabetes-canada-highlights-chronic-disease-surveillance-system.html (opens in a new tab)

  3. Punthakee, Z., Goldenberg, R., & Katz, P. (2018). Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome. Canadian Journal of Diabetes, 42, S10-S15.

  4. Health Canada. (2019). Canada's Food Guide. Retrieved from https://food-guide.canada.ca/en/ (opens in a new tab)

  5. Canadian Diabetes Association. (2021). Are You at Risk? Retrieved from https://www.diabetes.ca/about-diabetes/risk-factors/are-you-at-risk (opens in a new tab)

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