Diabetes Mellitus (Type 1/2)

Question 1

What is it

Answer 1

• DMT1 = insulin deficiency

- DMT2 = insulin resistance

Question 2

How common is it

Answer 2

> 120 million people worldwide

Question 3

Who does it affect

Answer 3

Type 1
- Usually juvenile (can be any age)
Type 2
- Older (>40yrs) obese, Asian, african, middle-eastern

Question 4

What causes DMT1

Answer 4

• Insulin deficiency –> destruction pancreatic B-cell
• Ass w. HLA DR3/4 and Islet cell Ab
• Combo autoimmune + genetic predisposition
• Triggers = virus, environmental stress, dietary factors

Question 5

What causes DMT2

Answer 5

• decrease insulin secretion + insulin resistance due to B-cell dysfunction
• Ass. obesity, lack exercise, HTN, hypertriglyceridaemia, Hx gestational DM, low fibre/high-glycaemia index diet, FHx, low birth weight
• typically progressed from impaired glucose tolerance

Question 6

What is the presentation of DM

Answer 6

• Polyuria - hyperglycaemia causes osmotic diuresis
• Polydipsia (+++ thirst) - resulting loss fluids + electrolytes
• Weight loss - fluid depletion + breakdown muscle/fat
• Lethargy
• Boils, pruritis vulvae, freq infection

TYPE 1 presentation (ACUTE - ass. w. other AI cond)

• Weight loss
• dehydration
• Ketonuria
• Hyperventilation

Question 7

What are the investigations

Answer 7

1. symptoms + 1 abnormal result
2. no symptoms + 2 abnormal resiluts
3. glucose tolerance test

Fasting plasma glucose >7mmol/L
Random plasma glucose >11.1 mmol/L
GTT >11.1mmol/L (fast overnight, give glucose water in morning, measure 2hrs later)

HbA1c - used as Dx test –> 48mmol/mol = cut off point for Dx

Question 8

What are some signs of DMT1

Answer 8

Type 1 = presence autoAb, islet cell Ab

Question 9

How do you treat DM

Answer 9

• Education, diet/lifestyle (medication only after these changes made)
• Control CV risk = ACEi, statin, low-dose aspirin

TYPE 1 = ALWAYS need INSULIN (short/long-acting, inhaled forms)

TYPE 2

• Metformin
• Sulfonylureas (gliclazide, chlopropamide, tolbutamide)
• Thiazolidinediones (‘glitazones’)
• finally insulin
• maybe gastric band/ bypass surgery

Question 10

How do you measure control of diabetes

Answer 10

1. urine dipstick
   - if pt doesn’t perfrom home blood glucose testing
   - if dipstick persistently -ve + no symptoms = well controlled
   - Also checks for proteinuria –> diabetic nephropathy
   - PROB = urine glucose lags behind blood
2. Home capillary blood glucose testing
   - 4 samples on 2 days/week
3. HbA1c
   - Covalent bond between glucose + terminal valine B-chain Hb
   - Depends on prevailing [glucose] –> average blood glucose conc over Hb molecule lifetime
   - Idea of past 6 weeks
   - Not good if RBC lifespan reduced or abnormal Hb

Question 11

What are some of the complications that can arise from DM

Answer 11

Macrovascular
- Stoke (x2), MI (x3-5), Amputation for foot gangrene (x50)

MICROVASCULAR
RETINA
- Diabetic retinopathy - T1 = rapid progression to proliferative, T2 = slower
- cataracts - blood sugar changes = osmotic change in lens = refractive error
- External ocular palsies - 3rd + 6th
RENAL GLOMERULUS
- Glomerular damage - renal hypertrophy –> intraglomerular pressure increase = damage –> sclerosis + thickening BM + disruption protein cross-links –> proteinuria
- Ischaemia - hypertrophy arterioles
- Ascending infections (UTIs) –> autonomic neuropathy = bladder stasis
NERVE SHEATHS - schwann cells affected
SYMMETRICAL SENSORY POLYNEUROPATHY
- loss vibration + temp, loss balance, ‘cotton wool’
ACUTE PAINFUL NEUROPATHY
- burning/crawling pain in feet, shins, thighs –> worse at night
MONONEUROPATHY + MONONEURITIS MULTIPLEX
DIABETIC AMYOTROPHY
- older men, wasting quads/shoulders, babinski reflex may dev
AUTONOMIC NEUROPATHY
- Rarer - CV, GI, Bladder, erectile dysfunction
DIABETIC FOOT ULCERS
DIABETIC KETOACIDOSIS