Diabetes Mellitus

Question 1

What are the symptoms and signs of DM?

Answer 1

Increased thirst

Increased urination

Dry mouth

Fatigue

Weight loss - despite normal appetite (can be increased)

Blurred vision (chronic)

Tingling limbs (chronic)

Question 2

How is DM diagnosed?

Answer 2

Symptomatic

• Fasting glucose = 7mmol/l
• Random glucose 11.1mmol/l
• 75g OGTT 2 hour plasma glucose = 11.1mmol (MOST RELIABLE)

Asymptomatic = above must be demonstrated on 2 diff occasions

Underlying haemolytic disease = high turnover of RBC which will affect HbA1c - Therefore OGTT = more reliable

Question 3

How is DM classified?

Answer 3

Type 1

Type 2

Gestational (GDM)

Maturity onset diabetes of the young - autosomal dominant (15-25yrs)
- Don’t require insulin - give sulfonylureas

Question 4

Outline T1DM

Answer 4

Pathophysiology = autoimmune, Ab against bet cells of pancreas, islet-associated Ab (IAA)

Management = insulin (basal-bolus, long + short term)

Question 5

Outline T2DM

Answer 5

Pathophysiology = insulin resistance, insulin def

Risk = older, asian, obesity

Treatment = HbA1c target dependant on anti-DM drug type
- First line = metformin
- Lifestyle = diet control, weight loss, HTN control (ACEi - target 140/80), statin (with 10 yr CVS risk - QRISK2)
‣ GI ( glycaemic index) = low index food
‣ High fibre, low fat, low saturated and trans fat

Question 6

What is metformin and its SEs?

Answer 6

Mechanism = increase insulin sensitivity

SE = GI upset (2 weeks), lactic acidosis

500mg OD

Contraindications - hepatic/renal failure, eGFR <30, alcohol abuse

Question 7

What are sulfonylureas and there SEs?

Answer 7

Mechnaism = insulin secretagogue

SE = hypoglycemic episodes (dizziness, sweating - tell pt to carry food around with them), weight gain

Question 8

What are thiazolidinediones and there SEs?

Answer 8

Mechanism = increases peripheral insulin sensitivity

SE = fluid retention, weight gain, liver impairment, increased risk of fractures

Question 9

What are Glucagon-like peptide 1 mimetics and there SEs?

Answer 9

Inject subcut 60 mins before meal

Mechanism = agonists of the GLP-1 receptor, increasing insulin secretion and inhibiting glucagon release

SE = N+V, risk of pancreatitis, risk of renal impairment, weight loss

Should be used when = insulin would othrwise be started, BMI >30

Question 10

What are Dipeptidyl peptidase-4 inhibitor and there SEs?

Answer 10

Sitagliptin

Mechanism = increase incretin levels (GLP-1 and GIP), which inhibit glucagon release, which in turn increases insulin secretion

SE = GI disturbance, nausea, flatulance, dirrahoea, constipation

Question 11

What are the complications of DM?

Answer 11

Macrovascular
- Accelerated atherosclerosis = MI, stroke, TIA, PVD

Microvascular (advanced glycosylation end products)

• Painful neuropathy
• Autonomic neuropathy - gastroparesis, ED
• Nephropathy
• Retinopathy and diabetic CNIII palsy (spare pupil)

Question 12

Outline the pathophysiology of diabetic retinopathy?

Answer 12

• Damage to the endothelium (inappropriate glycosylation)
• Leakage from weakened vessels = protein exudates forming
• Microvascular occlusion (‘cotton-wool spots’)
• Local hypoxia
• New vessels form (stimulated by VEGF)
• New vessels aren’t as strong -> more likely to bleed