23.4 Diabetes + OHA

Question 1

a) In a patient with diabetes mellitus,
what clinical features may indicate autonomic involvement? (4 marks)

Answer 1

> > Cardiovascular:
resting tachycardia,
arrhythmias,
orthostatic hypotension.

> > Gastrointestinal:
bloating after meals,
constipation and diarrhoea.

> > Sweating:
gustatory sweating or
reduced ability to sweat.

> > Genitourinary:
impotence,
loss of bladder control.

Question 2

b) What are the other microvascular (3 marks) and macrovascular (3 marks) complications of diabetes mellitus?

Answer 2

Microvascular:

> > Retinopathy.

> > Nephropathy.

> > Neuropathy;
sensory and motor polyneuropathy
in glove and stocking
distribution,
and autonomic neuropathy.

> > Microvascular cardiac disease

Macrovascular:
» Coronary artery disease.

> > Cerebrovascular disease.

> > Hypertension.

> > Peripheral vascular disease.

Question 3

c) List the classes of oral hypoglycaemic agents that are available. (5 marks)

Describe
their mechanisms of action.
(5 marks)

Answer 3

1. Biguanides
   e.g. metformin.
   Decrease hepatic gluconeogenesis,
   improved peripheral insulin sensitivity.
2. Thiazolidinediones
   e.g. pioglitazone.
   Improved peripheral insulin sensitivity,
   increasing peripheral glucose uptake.
3. Sulphonylureas
   e.g. gliclazide.
   Stimulate pancreatic insulin secretion.
4. Meglitinides
   e.g. repaglinide.
   Stimulate pancreatic insulin secretion.
5. Alpha glucosidase inhibitors
   e.g. acarbose.
   Slow digestion of carbohydrate in gut,
   decreasing glucose absorption.
6. SGLT-2 (sodium-glucose-co-transporter) inhibitors
   e.g. canagliflozin.
   Inhibits glucose reabsorption in the kidney
7. DPP 4 inhibitors (gliptins)
   e.g. sitagliptin.
   Inhibit breakdown of endogenous
   GLP-1 by DPP 4,
   allowing GLP-1 to stimulate insulin secretion
   and inhibit glucagon release after meals.