S10) Diabetes Mellitus

Question 1

What is diabetes mellitus?

Answer 1

• Diabetes mellitus is a group of metabolic disorders in which there are high blood sugar levels over a prolonged period
• Over time, damage of small and large blood vessels causes premature death from cardiovascular diseases

Question 2

What is a metabolic syndrome?

Answer 2

A metabolic syndrome is a cluster of the most dangerous risk factors associated with CVD – diabetes and raised fasting plasma glucose, abdominal obesity, high cholesterol and BP

Question 3

Identify the requirements of a metabolic syndrome

Answer 3

• Waist measurement > 94cm (men) / > 80 cm (women)
• Any two of the following:

I. Raised triglyceride

II. Reduced HDL cholesterol

III. Raised blood pressure

IV. Raised fasting blood glucose

Question 4

Identify some causes of a metabolic syndrome

Answer 4

• Insulin resistance
• Central obesity
• Genetics
• Physical inactivity
• Ageing

Question 5

What are the two causes for hyperglycaemia seen in diabetes mellitus?

Answer 5

• Inability to produce insulin due to beta cell failure and
• Adequate insulin production but insulin resistance prevents insulin working effectively

Question 6

Identify the following cell

Answer 6

Pancreatic islet cell

Question 7

Outline the pathophysiology of Type I diabetes

Answer 7

Type I diabetes is due to autoimmune beta cell destruction:

• Beta cells secrete insulin
• Autoantibodies are directed against beta cells and insulin producing cells destroyed

Question 8

Outline the pathophysiology of Type II diabetes

Answer 8

• Insulin deficiency – pancreas may not produce enough insulin
• Insulin resistance – cells do not use insulin properly i.e. insulin cannot fully “unlock” the cells to allow glucose to enter

Question 9

How does Diabetes Mellitus present?

Answer 9

• Symptoms of hyperglycaemia – polyuria, polydipsia, blurring of vision, urogenital infections (thrush)
• Symptoms of inadequate energy utilisation – tiredness, weakness, lethargy, weight loss

Question 10

Which tests are requested for in the diagnosis of a patient with suspected diabetes?

Answer 10

• Fasting glucose
• Oral glucose tolerance test
• HbA1c

Question 11

What is required to diagnose diabetes mellitus in a patient?

Answer 11

• Symptoms & 1 abnormal test
• If asymptomatic, 2 abnormal tests

Question 12

What is Type I Diabetes?

Answer 12

• Type I Diabetes is the absolute lack of insulin secondary to autoimmune destruction of β cells
• The aetiology not fully understood but the patient is usually young (< 30 years)

Question 13

What are the symptoms of Type I Diabetes?

Answer 13

• Rapid onset (usually weeks)
• Weight loss
• Polyuria
• Polydipsia
• Vomiting due to ketoacidosis (late presentation)

Question 14

Which blood results assist in diagnosing Type I Diabetes?

Answer 14

• Elevated venous plasma glucose (random > 11 mmol/L)
• Presence of ketones (breakdown products of fats)

Question 15

How can one confirm the presence of ketones in a patient with suspected Type I Diabetes?

Answer 15

Most easily measured in urine using “ketostik” – signifies absolute lack of insulin

Question 16

Describe the treatment of Type I Diabetes

Answer 16

Exogenous insulin – given by subcutaneous injection several times per day

Question 17

What is Type II Diabetes?

Answer 17

• Type II Diabetes is a long-term metabolic disorder that is characterised by high blood sugar, insulin resistance, and relative lack of insulin
• 90% of patients are overweight/obese, over 40 years old and often asymptomatic (diagnosis made at routine health checks)

Question 18

What causes insulin resistance to develop?

Answer 18

• Obesity (85% – central)
• Muscle and liver fat deposition
• Elevated circulating free fatty acids
• Physical inactivity
• Genetic influences

Question 19

How can one prevent Type II Diabetes?

Answer 19

Maintain a healthy body weight – BMI of 20 to 25 kg/m²

Question 20

Symptoms of Type II Diabetes are very variable as there is a slower rise in blood glucose.

Regardless, identify the usual presentations

Answer 20

• Polyuria
• Polydipsia
• Weight loss
• No urinary ketones
• May be asymptomatic

Question 21

What are the consequences of uncontrolled Diabetes Type II?

Answer 21

• Gradual worsening of symptoms
• Hyperglycaemic
• Inadequate energy utilisation
• Onset of complications of diabetes

Question 22

What are the consequences of uncontrolled Diabetes Type II on the NHS?

Answer 22

Significant morbidity, mortality and financial cost

Question 23

How does one treat Diabetes Type II?

Answer 23

• Lifestyle
• Non-insulin therapies (drugs)
• Insulin
• Look for other vascular risk factors (BP, smoking, exercise, diet)
• Surveillance for chronic complications

Question 24

Identify some acute complications of diabetes mellitus in terms of the following:

• Complications of hyperglycaemia
• Complications of hypoglycaemia

Answer 24

• Hyperglycaemia – diabetic ketoacidosis (type 1), hyperosmolar non-ketotic syndrome (type 2)
• Hypoglycaemia – coma due to hypoglycaemic therapy

Question 25

Identify some chronic complications of diabetes mellitus in terms of the following:

• Macrovascular complications
• Microvascular complications

Answer 25

• Macrovascular – cerebrovascular, cardiovascular, peripheral vascular disease i.e. stroke, heart attack, intermittent claudication, gangrene
• Microvascular – retinopathy, nephropathy, neuropathy i.e. blindness, erectile dysfunction, foot ulceration, painful peripheral neuropathy