Type 1 diabetes

Question 1

Epidemiology

Answer 1

Prevalence 0.5%

Peak onset adolescence
- 6/12 to 80

M=F

white caucasian

Seasonal variability

More prevalent northern latitudes

Question 2

Genetic predisposition

Answer 2

0.5% background risk

1-2% if mother affected

3-6% if father affected

6% if sibling has affected

36% if monozygotic twin affected

Question 3

Genetic predisposition

Answer 3

Association with HLA antigens:

HLA DR3-DQ2 and DR4-DQ8 predispose

90% of Scandinavians with type 1 diabetes positive for 1 or both

Question 4

Pathophysiology

Answer 4

Beta cell events trigger autoimmune response

Antibodies to insulin or GAD generally appear first

Other beta cell antibodies follow
- IA2, Zn2+ transporter 8

Selective immune beta cell destruction

Question 5

Autoimmune trigger

Answer 5

Viral infection (Coxsackie)

ER stress

Cytokines

Question 6

Associations with type 1 diabetes

Answer 6

Coeliac disease

Hypothyroidism

Grave’s disease

Addison’s disease

Hypogonadism

Pernicious anaemia

Vitiligo

Autoimmune polyglandular syndromes

Question 7

Symptoms

Answer 7

Lethargy

Polyuria

Polydipsia

Blurred vision

Candida infections

Weight loss

Ketosis/ ketoacidosis

Death

Question 8

Diagnosis of type 1 diabetes

Answer 8

Age of onset

Rapidity of onset

Phenotype

PMH

FH

Weight loss

Ketosis

GAD? IA2? Zn2+ transporter 8 antibody positive

C peptide

Question 9

C peptide

Answer 9

Produced in 1:1 molar ratio with insulin

Need adequate stimulus for secretion

Question 10

Insulin

Answer 10

Necessary for survival

Peptide hormone needs to be given parenterally

• subcutaneous
• inhaled
• mucous membranes

Various types

• primary structure (animal, human, analogue)
• duration of action (addition of protamine, altered solubility, fatty acid chain)
• strength

Question 11

Typical insulin regimen

Answer 11

Basal bolus regimen

• rapid acting insulin pre meal (bolus)
• long acting background insulin (basal)

Balanced regimen

Rapid acting insulin reflects CHO intake

Question 12

Factors affecting blood glucose

Answer 12

Diet

Injection site

Temperature

Exercise

Illness

Stress

Alcohol

Menstrual cycle

Question 13

Hypoglycaemia autonomic symptoms

Answer 13

Palpitations

Sweating

Tremor

Question 14

Hypoglycaemia neuroglycopaenic symptoms

Answer 14

Confusion

Question 15

Transplantation

Answer 15

Pancreas
- almost always SPK or PAK

Islet cell

• edmonton protocol
• UK islet cell programme

Question 16

Monitoring

Answer 16

Glucose monitoring

• minimum 4 x daily
• driving
• unwell
• hypoglycaemia

CGMS

Ketone monitoring

• blood (beta-hydroxybutyrate)
• urine (acetoacetate)

Question 17

Monitoring (clinician)

Answer 17

HbA1c (glycated haemoglobin)

• reflects glucose over last 3 months
• weighted towards 6 weeks
• affected by red cell lifespan