Type 2 Diabetes Mellitus

Question 1

What is the definition of type 2 diabetes mellitus (TD2M)? [2]

Answer 1

a class of diabetes mellitus due to a combination of insulin resistance / and less severe insulin deficiency

Question 2

What is the epidemiology of T2DM? [5]

Answer 2

1. ‘epidemic’ levels due to affluent lifestyle, ageing population and increasing obesity
2. usually >40 years of age
3. often overweight
4. higher prevalence in Asians, men and the elderly
5. ~80% concordance in identical twins so stronger genetic influence

Question 3

What is the aetiology of T2DM? [3]

Answer 3

1. decreased insulin secretion
2. increased insulin resistance
3. associated with obesity, lack of exercise, calorie and alcohol excess

Question 4

What are the risk factors of T2DM? [6]

Answer 4

1. family history - genetics
2. increasing age
3. obesity
4. sedentary lifestyle/poor exercise
5. poor diet
6. ethnicity - middle Eastern and Asian

Question 5

What is the pathophysiology of T2DM? [2]

Answer 5

1. T2DM and insulin resistance strongly associated with central obesity, hypertension, hyperlipidaemia and increased cardiovascular risk
2. hyperglycaemia and lipid excess toxic to beta cells (glucotoxicity) resulting in further beta cell looss and deterioration of glucose homeostasis

Question 6

What is the preliminary phase of T2DM? [4]

Answer 6

1. T2DM typically progresses from a preliminary phase of impaired glucose tolerance (IGT) or impaired fasting glucose (IFG)
2. unique window for lifestyle intervention to prevent full T2DM progression
3. IGT - fasting plasma glucose <7mmol/L and oral glucose tolerance test (OGTT) 2hr glucose >7.8mmol/L but <11.1mmol/L
4. IFG - fasting plasma glucose >6.1mmol/L but <7mmol/L

Question 7

What is the clinical presentation of T2DM? [5]

Answer 7

1. often asymptomatic or present with complications
2. hypertension - 50% of patients with T2DM
3. retinopathy
4. polyneuropathy
5. arterial disease resulting in MI or peripheral gangrene

Question 8

How is T2DM diagnosed? [7]

Answer 8

symptomatic = 1 abnormal value

1. symptoms of hyperglycaemia
2. fasting plasma glucose >7mmol/L OR
3. random plasma glucose >11.1mmol/L

asymptomatic = 2 abnormal values

4. fasting plasma glucose >7mmol/L AND/OR
5. random plasma glucose >11.1mmol/L AND/OR
6. oral glucose tolerance test (OGTT) 2hr value >11.1mmol/L

haemoglobin A1c
7. HbA1c >48mmol/mol (6.5%)

Question 9

What can cause secondary diabetes? [6]

Answer 9

1. pancreatitis/pancreatectomy
2. acromegaly
3. Addison’s disease
4. neoplasia of pancreas
5. Cushing’s disease
6. drugs - thiazides, beta-blockers

Question 10

What is the first line treatment of T2DM? [6]

Answer 10

1. lifestyle and dietary changes are essential
2. dietary factors - low sugar and fat, high starch and fibre
3. blood pressure control - ace inhibitors (ramipril)
4. hyperlipidaemia control - statins
5. exercise
6. weight loss if obese - orlistat reduces absorption of fat from diet and promotes weight loss

Question 11

What is the second line treatment of T2DM? [3]

Answer 11

1. usually in association with diet and lifestyle changes
2. oral metformin - increases insulin sensitivity, reduces rate of hepatic gluconeogenesis, helps with weight issues and reduces CVS risk in diabetes
3. if HbA1c > 58mmol/mol consider dual therapy with metformin + sulphonylurea (oral gliclazide)