MEH 14 - Diabetes Mellitus

Question 1

What is diabetes mellitus?

Answer 1

Blood glucose too high (hyperglycaemia) and over years leads to damage of small and large blood vessels causing premature death from CV diseases

Question 2

What occurs in type 1 diabetes?

Answer 2

• Autoantibodies directed against B-cells of pancreas, therefore insulin not produced (absolute insulin deficiency)

Question 3

What occurs in type 2 diabetes?

Answer 3

Either:

1) Pancreas doesn’t produce enough insulin (relative insulin deficiency)
2) Cells unable to use insulin properly, insulin unable to activate expression of GLUT channels (insulin resistance)

Question 4

What how DM present?

Answer 4

1) Hyperglycaemic symptoms = polyuria, polydipsia, blurred vision.
2) Inadequate energy utilisation symptoms = tiredness, weakness, lethargy, weight loss

Question 5

What methods are used to diagnose diabetes?

Answer 5

• Fasting glucose test - over 7mm/L
• Oral glucose tolerance test - over 11.1mm/L
• HbA1c
• Symptoms + 1 abnormal test, or asymptomatic + 2 abnormal tests.

Question 6

When does type 1 diabetes usually present?

How is type 1 diabetes treated?

Answer 6

• Usually young < 30 years (90% diagnosed), usual symptoms + presence of ketones.
• Exogenous insulin, SC injections several times a day. Needs to be prescribed immediately.

Question 7

How does ketoacidosis occur in T1DM patients?

How does this present?

Answer 7

• Ketone production suppressed by insulin, except in starvation. In absence of insulin, glucose metabolism switched in favour of fatty acid metabolism, ketones produced. (Ketones produced due to enhanced lipolysis)
• Causes vomiting, good sign of ketoacidosis (enhanced lipolysis) in diabetics

Question 8

Who does type 2 DM usually present in?

Answer 8

• Usually over 40
• 90% are overweight or obese (obesity accounts for 85% of risk)
• Often asymptomatic
• Increasingly being seen in younger people + children

Question 9

How does T2DM present + how is it different to T1DM?

Answer 9

• Variable as slower rise in blood glucose
• May have polyuria, polydipsia + weight loss
• NO urinary ketones - specific to type 1
• May be asymptomatic

Question 10

How is T2DM treated?

Answer 10

• Lifestyle changes are cornerstone - weight loss + exercise
• Look for other vascular risk factors - e.g.: BP/smoking/exercise etc.
• Metformin - inhibits gluconeogenesis

Question 11

What are the acute complications of diabetes?

Answer 11

• Acute complications of hyperglycaemia
• Ketoacidosis in type 1
• Hyperosmolar non-ketotic syndrome in type 2
• Coma if person goes hypoglycaemic (due to treatment)

Question 12

What are the chronic complications of diabetes?

Answer 12

• Macrovascular or large vessel disease - leading to CV or peripheral vascular disease - leads to stroke, heart attack, gangrene etc.
• Microvascular disease - leading to retinopathy, nephropathy + neuropathy.
• E.g.: blindness, renal replacement therapy, ED, foot ulceration, diarrhoea, constipation, painful peripheral neuropathy etc.

Question 13

What is metabolic syndrome + how is it caused?

Answer 13

• A cluster of the most dangerous factors associated with CV disease - diabetes, raised fasting plasma glucose, abdominal obesity, high cholesterol + high BP.
• Caused by insulin resistance, central obesity, genetics, physical inactivity + ageing.