Type 1 Diabetes

Question 1

Epidemiology

Answer 1

• Young (5-15)
• Lean
• Northern European (Finland)

Question 2

Risk Factors

Answer 2

HLA DR3-DQ2 (>90%)
HLA DR4-DQ8
Other autoimmune diseases
- Hashimoto’s thyroiditis
- Coeliac disease
- Addison’s disease
- Pernicious anaemia
Environmental
- Infectious agents (enterovirus e,g coxsackie B4)
- Dietary factors
- Vitamin D deficiency
- Cleaner environment may increase susceptibility

Question 3

Pathophysiology

Answer 3

Autoimmune destruction by autoantibodies of the pancreatic insulin secreting BETA CELLS in islets of langerhans = ABSOLUTE INSULIN DEFICINECY = hyperglycaemia, glycosuria + ketonuria
Impaired glucose clearance in skeletal muscle = increase blood glucose = thirst + polyuria
blood glucose = 10mmol/L = body no longer absorb glucose = thirst + polyuria
low cellular glucose = lypolysis + gluconeogenesis
Eventual complete destruction = absence of C-PEPTIDE
Hyperkalaemia = even though total body K+ = low = usually insulin shoves K+ INTO cells via Na+/K+ ATPases

Question 4

Aetiology

Answer 4

Genetic abnormality - HLA DR3 DQ2 + HLA DR4 DQ8
Autoimmune - autoantibodies forming against insulin and beta cells
Enterovirus - coxsackie B4
Secondary causes -
- Acromegaly + Cushings
- Haemochromatosis
- Thiazide diuretics/ Corticosteroids

Question 5

Signs

Answer 5

BMI < 25kg/m2
Glycosuria
Ketonuria
Failure to thrive in children
Glove and stocking sensory loss
Fruity breath (signs of DKA)

Question 6

Symptoms

Answer 6

(4 T’s - thirsty, tired, toilet, thinner)
Polyuria + Nocturia
Polydipsia
Weight loss + Polyphagia
Thirst
Blurred vision
Paraesthesia
N & V
Clinical dehydration
*if these present w/ diabetic complications = DIAGNOSTIC

Question 7

Diagnosis

Answer 7

FIRST LINE =
- Random Plasma Glucose > 11.1 mmol/L = Glucose taken randomly
- Fasting Plasma Glucose > 7.0 mmol/L = Glucose taken after 8hs fasting
(1 test diagnostic in symptomatic patients - 2 required in asymp)
For borderline cases =
- 2 hour plasma glucose (75 oral glucose) > 11.1 mmol/L
GOLD STANDARD =
- HbA1c > 6.5% or 48mmol/l = measures amount of glycated haemoglobin = suggests hyperglycaemia over the preceding 3 months

Question 8

Treatment

Answer 8

Aim to keep HbA1c = 48-52 mmol/mol
Aim to keep blood glucose 6-8 mmol/l

Basal Bolus Insulin
- basal = long acting, to maintain stable insulin levels throughout the day
- bolus = faster acting, 30 mins preprandial to give ‘insulin spike’
Insulins
- rapid = novorapid, aspart
- short = regular insulin
- intermed = NPH
- long = glargine, determir
Pregnant have aspirin after 12 months

Question 9

Complications

Answer 9

DKA
Lipo-hypertrophy or lipo-dystrophy at site of S/C injection
Diabetic foot
Diabetic retinopathy
Diabetic neuropathy
Diabetic nephropathy
Hypoglycaemia

Question 10

When can the HbA1c be abnormally high or low

Answer 10

Huge blood loss = low
Abnormally long RBC = high