Micro & Macro-vasculature complications of diabetes

Question 1

What are the Microvascular complications associated with diabetes?

Answer 1

Retinopathy
Neuropathy
Nephropathy

Question 2

What are the Macro-vascular complications of diabetes?

Answer 2

Cerebrovascular disease
Ischaemic heart disease
Peripheral vascular disease

Question 3

What is the relationship between glycemic control and microvascular complications?

Answer 3

Extent of hyperglycaemia (as judged by HbA1c) is strongly associated with the risk of developing microvascular complications

Question 4

What is the target HbA1c target to reduce risk of microvascular complications?

Answer 4

53 mmol/mol

Question 5

What is the relationship between systolic BP & microvascular complications?

Answer 5

Clear relationship between rising systolic BP and risk of MI and microvascular complications in people with T1DM and T2DM

Therefore, prevention of complications requires reduction in HbA1c and BP control

Question 6

What other risk factors are related to the development of microvascular complications?

Answer 6

Duration of diabetes
Smoking – endothelial dysfunction
Genetic factors – some people develop complications despite reasonable glycaemic control
Hyperlipidaemia
Hyperglycaemic memory – inadequate glucose control early on can result in higher risk of complications LATER, even if HbA1c improved

Question 7

What is the mechanism of damage that leads to microvascular complications?

Answer 7

DO NOT NEED TO MEMORISE
Increased formation of mitochondrial superoxide free radicals in the endothelium
Generation of glycated plasma proteins to form advanced glycation end products (AGEs)
Activation of inflammatory pathways
Damaged endothelium results in
- ‘Leaky’ capillaries
- Ischaemia

Question 8

Why is diabetic retinopathy important?

Answer 8

Main cause of
visual loss in people with diabetes
blindness in people of working age
The early stages of retinopathy are all asymptomatic, therefore screening is needed

Question 9

What is the aim of retinopathy screening?

Answer 9

To detect retinopathy EARLY when it can be treated before it causes visual disturbance / loss
Annual retinal screening in the UK for all diabetes patients.

Question 10

What is visible in Background retinopathy?

Answer 10

Hard exudates (cheese colour, lipid)
Microaneurysms (“dots”)
Blot haemorrhages
Needs continual annual surveillance

Question 11

What is visible in pre-proliferative retinopathy?

Answer 11

Cotton wool spots also called soft exudates
Represent retinal ischaemia
Early panretinal photocoagulation

Question 12

What is visible in proliferative retinopathy?

Answer 12

Visible new vessels
On disc or elsewhere in retina
Panretinal photocoagulation

Question 13

What is visible in Maculopathy?

Answer 13

Hard exudates / oedema near the macula
Same disease as background, but happens to be near macula
This can threaten visionOedema: Anti-VEGF injections directly into the eye (VEGF: vascular endothelial growth factor)
Grid photocoagulation

Question 14

What is a negative of Panretinal photocoagulation?

Answer 14

Patient can lose some peripheral vision

Question 15

Why is diabetic nephropathy important

Answer 15

Associated with progression to end-stage renal failure requiring haemodialysis
Healthcare burden
Associated with increased risk of cardiovascular disease

Question 16

How do you diagnose diabetic nephropathy?

Answer 16

Progressive proteinuria (urine albumin:creatinine ratio - ACR)

Increased blood pressure

Deranged renal function (eGFR)

Advanced: peripheral oedema

Question 17

What is the cut off for Microalbuminuria?

Answer 17

2.5 mg/mmol

Question 18

What is the threshold for Proteinurea?

Answer 18

Proteinuria = ACR > 30mg/mmol

Question 19

What is the threshold for Nephrotic Proteinurea?

Answer 19

> 3000mg/24hr

Question 20

What is the mechanism of action for diabetic nephropathy?

Answer 20

Hyperglycemia & Hypertension
Glomerular Hypertension
Proteinurea
Glomerular and interstitial fibrosis
Glomerular filtration rate decline
Renal failure

Question 21

What system do we want to manipulate in diabetic nephropathy?

Answer 21

Renin-Angiotensin System

Question 22

What 2 drugs are used to treat diabetic nephropathy?

Answer 22

ACE inhibitor ( end in -pril)
Angiotensin 2 receptor blocker ( end in -sartan)
they reduce BP & progression of diabetic nephropathy, should be prescribed to all normotensive patients with microalbuminuria /proteinurea.
No benefit to having both

Question 23

What is Microalbuminurea a risk factor for?

Answer 23

Cardiovascular disease

Question 24

What are the management principles for diabetic nephropathy?

Answer 24

Aim for tighter glycemic control
ACEi/ARB even if normotensive as soon as patient has microalbuminuria
Reduce BP (aim <130/80 mmHg) usually through ACEi or A2RB
Stop smoking
Start an SGLT-2 inhibitor if T2DM?

Question 25

Why is diabetic neuropathy important?

Answer 25

Diabetes mellitus is the most common cause of neuropathy and therefore lower limb amputation

Question 26

What are the small vessels supplying nerves called?

Answer 26

vasa nervorum

Neuropathy results when vasa nervorum get blocked

Question 27

What are the risk factors for diabetic neuropathy?

Answer 27

• Age
  
  • Duration of diabetes
  • Poor glycaemic control
  • Height (longer nerves in lower limbs of tall people)
  • Smoking
  • Presence of diabetic retinopathy

Question 28

Where is diabetic neuropathy most common?

Answer 28

Longest nerves supply feet – so more common in feet
Commonly glove & stocking distribution – peripheral neuropathy
Can be painful
Danger is that patients will not sense an injury to the foot (eg. stepping on a nail)

Question 29

What would you do in an annual foot check?

Answer 29

• Look for foot deformity, ulceration
  
  • Assess sensation (monofilament, ankle jerks)
  • Assess foot pulses (dorsalis pedis and posterior tibial)

Question 30

Which patients have an increased risk of foot ulceration?

Answer 30

• reduced sensation to feet (peripheral neuropathy)

- poor vascular supply to feet (peripheral vascular disease)

Question 31

What is the management for Peripheral neuropathy?

Answer 31

1. Regular inspection of feet by affected individual
2. Good footwear
3. Avoid barefoot walking
   Podiatry and chiropody if needed

Question 32

What is the management for Peripheral neuropathy with ulceration?

Answer 32

Multidisciplinary diabetes foot clinic
Offloading
Revascularisation if concomitant PVD
Antibiotics if infected
Orthotic footwear
Amputation if all else fails

Question 33

What is Mononeuropathy?

Answer 33

Usually, sudden motor loss
eg wrist drop, foot drop
Cranial nerve palsy
double vision due to 3rd (oculomotor) nerve palsy

Question 34

What is Autonomic neuropathy?

Answer 34

Damage to sympathetic and parasympathetic nerves innervating GI tract, bladder, cardiovascular system

Question 35

What would happen with autonomic neuropathy of the GI Tract?

Answer 35

Delayed gastric emptying: nausea and vomiting (can make prandial short-acting insulin challenging)
- Constipation / nocturnal diarrhoea

Question 36

What would happen with autonomic neuropathy of the Cardiovascular system?

Answer 36

Postural hypotension: can be disabling - collapsing on standing.
- Cardiac autonomic supply: sudden cardiac death

Question 37

What are the non modifiable risk factors for macrovascular disease?

Answer 37

Age
Sex
Birth weight
FH/Genes

Question 38

What are the modifiable risk factors for macrovascular disease?

Answer 38

Dyslipidaemia
Hypertension 
Smoking
Diabetes mellitus
Central obesity

Question 39

What are the management criteria for managing cardiovascular risk in diabetes mellitus?

Answer 39

Smoking status – support to quit
Blood pressure < 140/80 mmHg, < 130/80 mmHg if microvascular complication (NB often needs multiple agents)
Lipid profile – total chol <4, LDL <2
Weight – discuss lifestyle intervention +/- pharmacological treatments
Annual urine microalbuminuria screen – risk factor for cardiovascular disease