Diabetes Mellitus Type 1

Question 1

what is the definition of diabetes mellitus type 1?

Answer 1

metabolic autoimmune disorder from destruction of beta cells in the pancreas resulting in absolute insulin deficiency

Question 2

what is the epidemiology of type 1 diabetes?

Answer 2

5-10% of all diabetes patients, more common in white europeans than asians, commonly diagnosed in youth

Question 3

what is the aetiology of type 1 diabetes?

Answer 3

genetic - HLA-dR and HLA-DQ provide protection from or increase susceptibility to diabetes
environmental - viruses may trigger the destruction of beta cells

Question 4

what is the brief pathophysiology of type 1 diabetes?

Answer 4

• up to 90% of T1DM patients have autoantibodies to at least one of 3 antigens - glutamic acid decarboxylase, insulin, and islet auto-antigen-2
• hyperglycaemia develops when 80-90% of beta cells are destroyed.
• glucagon is stimulated causing gluconeogenesis, glycogenolysis and ketogenesis
• long term hyperglycaemia leads to oxidative stress and inflammation. this can lead to endothelial dysfunction allowing LDLP into vessel walls forming atherosclerosis

Question 5

what are the key presentations of type 1 diabetes?

Answer 5

polyuria, polydipsia, blurred vision, fatigue, tiredness

Question 6

what are the signs of type 1 diabetes?

Answer 6

young age <50, weight loss, low BMI, family history of autoimmune diseases, ketoacidosis

Question 7

what are the symptoms of type 1 diabetes?

Answer 7

thirst, dry mouth, lack of energy, blurred vision, hunger, weight loss

Question 8

what are the first line investigations for type 1 diabetes?

Answer 8

• random glucose tolerance test is presenting to GP >11.1mmol/L blood sugar level
• fasting plasma glucose
• 2-hour plasma glucose
• plasma or urine ketones

Question 9

what are the gold standard investigations for type 1 diabetes?

Answer 9

-glycated haemoglobin A1C test: average blood sugar for past 2-3 months, measured % glucose attached to haemoglobin (>6.5% = diabetes)

Question 10

what are other investigations for type 1 diabetes?

Answer 10

• symptoms + random plasma glucose >11mmol/L is sufficient for diagnosis
• Low C peptide levels
• elevated plasma or ketone levels

Question 11

what are the differential diagnosis for type 1 diabetes?

Answer 11

type 2 diabetes, other diabetes subtypes

Question 12

how is type 1 diabetes managed?

Answer 12

• basal-bolus insulin (insulin glargine s/c)
• pre-meal insulin correction dose
• amylin analogue (pramlintide)
• 2nd line = fixed insulin dose

Question 13

what are the side effects of type 1 diabetes management?

Answer 13

insulin can cause - hypoglycaemia, weight gain, lipodystrophy

Question 14

how is type 1 diabetes monitored?

Answer 14

• BP checked at each visit, treated to a goal of 140/90mmHg

- lipid profile checked if not on stains at time of first diagnosis, initial medical evaluation then 5-yearly

Question 15

what are the complications of type 1 diabetes?

Answer 15

microvascular - retinopathy, nephropathy, neuropathy

macrovascular - coronary artery disease, cerebrovascular disease, peripheral artery disease

Question 16

what is the prognosis of type 1 diabetes?

Answer 16

untreated - fatal due to diabetic ketoacidosis

poorly controlled - blindness, renal failure, foot amputations and MIs

Question 17

what are the risk factors for type 1 diabetes?

Answer 17

• geographic region (more common in Europe than Asia
• genetic predisposition
• infectious agents
• dietary factors