Endocrinology

Question 1

What is diabetes mellitus

Answer 1

chronic condition characterised by abnormally raised levels of blood glucose

Question 2

Describe the pathophysiology of Type 1 diabetes mellitus (T1DM)

Answer 2

• Autoimmune disorder where the insulin-producing beta cells of the islets of Langerhans in the pancreas are destroyed by the immune system
• This results in an absolute deficiency of insulin resulting in raised glucose levels

Question 3

Symptoms of T1DM

Answer 3

Weight loss
Polydipsia
Polyuria

Question 4

Describe the investigation of T1DM

Answer 4

• urine should be dipped for glucose and ketones
• fasting glucose and random glucose
• HbA1c is not as useful for patients with a possible or suspected diagnosis of T1DM
• C-peptide levels are typically low i
• diabetes-specific autoantibodies

Question 5

Give 3 diabetes-specific autoantibodies that may be seen in T1DM

Answer 5

• Antibodies to glutamic acid decarboxylase (anti-GAD)
• Islet cell antibodies
• Insulin autoantibodies

Question 6

State the diagnostic thresholds for diabetes mellitus

Answer 6

• HbA1c >= 48 mmol/mol
  If the patient is symptomatic:
• fasting glucose greater than or equal to 7.0 mmol/l
• random glucose greater than or equal to 11.1 mmol/l (or after 75g oral glucose tolerance test)

If the patient is asymptomatic the above criteria apply but must be demonstrated on two separate occasions.

Question 7

What is the typical age of onset of T1DM

Answer 7

Typically < 20 years
however, 40% > 30 years

Question 8

What atypical factors would prompt further tests for suspected T1DM

Answer 8

• age 50 years or above,
• BMI of 25 kg/m² or above
• slow evolution of hyperglycaemia
• long prodrome