Diagnosis of Diabetes

Question 1

What are symptoms of hyperglycaemia?

Answer 1

• Polyuria
• Polydipsia
• Unexplained weight loss
• Visual blurring
• Genital thrush
• Lethargy

Question 2

What is the random venous blood glucose required for a diagnosis of diabetes?

Answer 2

> 11.1mmol/L

Question 3

What is the fasting venous blood glucose required for a diagnosis of diabetes?

Answer 3

> 7mmol/L

Question 4

What is the HbA1c required for a diagnosis of diabetes?

Answer 4

> 48mmol/mol

>6.5%

Question 5

What is the OGTT required for a diagnosis of diabetes?

Answer 5

2 hour value >11.1mmol/L

Question 6

What does impaired glucose tolerance (IGT) mean?

What is it a precursor to?

Answer 6

Fasting plasma glucose <7 but OGGT 2h glucose >7.8mmol/L and <11.1mmol/L
Shows impaired post prandial glucose regulation

Type 2 diabetes
Managed with lifestyle and annual review

Question 7

What does impaired fasting glucose (IFG) mean?

What is it a precursor to?

Answer 7

Fasting plasma glucose >6.1mmol/L but <7mmol/L
Shows abnormal fasting plasma glucose regulation

Do an OGTT to exclude T2DM
Managed with lifestyle and annual review

Question 8

What is acanthosis nigricans?

Answer 8

A skin condition causing dark pigmentation of skin folds - particularly the axilla, groin and neck which suggests insulin resistance

Question 9

What are risk factors for T2DM?

Answer 9

• Obesity and inactivity
• Family history
• Ethnicity - Asian, African, Afro-Carribean
• History of gestational diabetes
• Diet
• Drug treatment - statins, steroids, thiazides, beta blockers
• PCOS
• Metabolic syndrome

Question 10

What is persistent hyperglycaemia defined as?

Answer 10

• HbA1c over 6.5%
• Fasting plasma glucose over 7mmol/L
• Random plasma glucose 11.1mmol/L WITH symptoms

If symptomatic - Single HbA1c/fasting plasma glucose can be used but sensible to repeat testing
If asymptomatic - Do not diagnose on 1 test, Arrange repeat testing.

Question 11

What additional features would suggest a diagnosis of T1DM rather than T2DM?

Answer 11

• Ketosis
• Rapid weight loss
• Age of onset <50
• BMI below 25
• Personal or family history of autoimmune disease

Question 12

What should you do if T1DM is suspected?

Answer 12

• Refer person immediately to diabetes specialist team to confirm the diagnosis and provide immediate care

Question 13

When should you measure C peptide/autoantibody titres to confirm T1DM?

Answer 13

• T1DM is suspected but atypical presentation (>50)
• T1DM is diagnosed and treatment started but monogenic form of diabetes suspected
• Classification of T1DM is uncertain and confirming diagnosis would have implications for availability of treatment eg with insulin pump