Diabetes mellitus

Question 1

Diabetes mellitus

Answer 1

A condition characterised by high blood glucose, high blood pressure, and high cholesterol. It is a common chronic condition associated with significant morbidity. It is manageable with training and support, although this can be expensive.

Question 2

Common symptoms of diabetes

Answer 2

• weight loss
• polyuria
• thirst
• fatigue
• blurred vision
• coma

Question 3

HbA1c test

Answer 3

Measures the level of glycated haemoglobin in red blood cells, reflecting the previous 10 weeks of ambient circulating glucose. The cut off for diagnosis of diabetes is 48 mmol/mol.

Question 4

Blood glucose tests

Answer 4

Measures the concentration of glucose in the blood. The cut off for diagnosis of diabetes is 11.1 mmol/L at random, and 7.0 mmol/L in a fasting state.

Question 5

Oral glucose tolerance test

Answer 5

Blood glucose is measured in the patient in a fasting state. A 75mL glucose drink is administered over 5 minutes, and blood glucose is measured again after 2 hours.

Question 6

Insulin

Answer 6

A hormone produced by the beta cells in the Islets of Langerhans of the pancreas. Produced via cleavage of a large precursor molecule called proinsulin.

Question 7

Function of insulin

Answer 7

Moves glucose out of the bloodstream for anabolism and storage in the liver, muscle and adipose tissue.

• maintains the supply of glucose to tissues
• regulates metabolism in muscle
• promotes protein synthesis
• inhibits breakdown of fat

Question 8

Type I diabetes

Answer 8

An absolute insulin deficiency, caused by the autoimmune destruction of beta cells in the pancreas. Onset is typically early and dramatic, in patients who are normal weight or slim. Ketones may be present and insulin is required to sustain life.

Question 9

Type II diabetes

Answer 9

A relative insulin deficiency, caused by desensitisation/resistance and insufficient production due to beta cell dysfunction. Onset is typically later (although now getting younger) and may go unnoticed at first, in patients who are overweight or obese. Ketones are not produced and insulin is not required to sustain life

Question 10

Gestational diabetes

Answer 10

Insulin resistance increases during pregnancy, which may lead to diabetes in women who are predisposed to the condition. The condition subsides almost immediately after birth.

Question 11

Treatment of type I diabetes

Answer 11

Type I diabetes is insulin-dependent, and may be managed with a combination of insulin therapy and lifestyle factors. In insulin therapy, a background level of longer-acting insulin is maintained, while doses of short/ rapid acting insulin are administered after each meal. Lifestyle factors such as exercise can increase insulin sensitivity, decreasing the amount required.

Question 12

Treatment of type II diabetes

Answer 12

Type II diabetes is insulin independent, so is primarily treated using methods to reduce blood glucose and insulin resistance. These include lifestyle changes eg. exercise, and medications eg. insulin sensitisers, promoters of glucose secretion etc.

Question 13

Blood glucose targets

Answer 13

• before a meal; 4-7 mmol/L
• upon waking; 5-7 mmol/L
• after a meal; 5-9 mmol/L

Hypoglycaemia= 4 mmol/L or less

Question 14

Complications of diabetes

Answer 14

Mainly arise through damage to blood vessels, caused by platelet dependent thrombosis. High blood glucose causes platelets to stick to the endothelium, resulting in the narrowing of blood vessels.

Question 15

Microvascular complications

Answer 15

• retinopathy; damage to the blood vessels of the eyes, leading to blurred vision and blindness
• neuropathy; damage to nerves, causing pain and numbness
• nephropathy; damage to the kidneys

Question 16

Macrovascular complications

Answer 16

• brain; increased risk of stroke and cerebrovascular disease
• heart; high blood pressure and increased risk of coronary heart disease
• extremities; peripheral vascular disease, reduced blood flow, slow healing and higher risk of infections

Question 17

Diabetic neuropathy

Answer 17

Sensory, motor and autonomic nerves can all be damaged as a complication of diabetes. The longest nerves, such as those supplying the feet, often get damaged first. Autonomic neuropathy affects the smooth muscles and glands, causing an array of symptoms including digestive issues, bladder problems, dizziness and faintness.

Question 18

Diabetic ketoacidosis

Answer 18

When insulin is insufficient, the body starts to break down fatty acids for energy, producing ketones which build up in the blood. A common sign of DKA is the fruity smell of acetone, which is excreted in the breath.