Vascular complications of DM

Question 1

what are the microvascular complications of diabetes mellitus?

Answer 1

retinopathy
nephropathy
neuropathy

Question 2

what are the macrovascular complications of diabetes mellitus?

Answer 2

cerebrovascular disease
ischaemic heart disease
peripheral vascular disease

Question 3

Is extent of hyperglycaemia (as judged by HbA1c) associated with the risk of developing microvascular complications?
What is the target HbA1c to reduce risk of microvascular complications?
Name another factor that increases this risk

Answer 3

Yes, strongly
53mmol/mol (<7%)
Clear relationship between rising systolic BP and risk of MI and microvascular complications in people with T1DM and T2DM

Question 4

what are the other risk factors (besides HbA1c) for complications of diabetes?

Answer 4

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

Question 5

Mechanism of damage of hyperglycemia leading to microvascular complications

Answer 5

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 6

COmplications of diabetic retinopathy

Answer 6

Main cause of
visual loss in people with diabetes
blindness in people of working age

Question 7

how do we aim to detect retinopathy?
What is the aim of this?
How is this acheived in the UK

Answer 7

through screening as early stages are asymptomatic
Aim of screening - 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 8

describe the appearance of a normal retina

Answer 8

optic disk bright spot visible
thin veins semi visible
macula densa visible

Question 9

describe background retinopathy?

Answer 9

hard exudates (cheese colour, lipid)
microaneuyrsms (dots)
blot haemorrhages
enhanced blood vessels

Question 10

describe pre proliferative retinopathy

Answer 10

Cotton wool spots also called soft exudates
Represent retinal ischaemia
More extensive haemorrhage

Question 11

describe proliferative retinopathy

Answer 11

new vessels visible (on disc or elsewhere in retina)

Question 12

describe maculopathy retinopathy

Answer 12

Hard exudates / oedema near the macula
Same disease as background, but happens to be near macula
This can threaten vision

Question 13

General treatments to reduce risk of retinopathy

Answer 13

Improve HbA1c, stop smoking, lipid lowering,
good blood pressure control <130/80 mmHg

Question 14

how do you treat background retinopathy?

Answer 14

you can’t.
annual surveillance
lifestyle changes

Question 15

how do you treat pre proliferative retinopathy

Answer 15

If left alone will progress to new vessel growth
So, early pan-retinal photocoagulation

Question 16

how do you treat proliferative retinopathy?

Answer 16

panretinal photocoagulation

Question 17

how do you treat diabetic maculopathy?

Answer 17

Oedema: anti-VEGF injections directly into eye
grid photocoagulation

Question 18

what are the risks of panretinal photocoagulation?

Answer 18

loss of some peripheral vision due to burns

Question 19

Why is treating diabetic nephropathy improtant?

Answer 19

Associated with progression to end-stage renal failure requiring haemodialysis (healthcare burden)
Associated with increased risk of cardiovascular events

Question 20

how do you diagnose diabetic nephropathy?

Answer 20

urinalysis (microalbuminuria >2.5mg/mmol proteinuria (ACR>30mg/mmol), nephrotic range (>3000mg/24hr))
increased blood pressure
eGFR (deranged)

Question 21

what is the mechanism of diabetic nephropathy?

Answer 21

hypertension & hyperglycaemia–>glomerular hypertension–>progressive proteinuria (urine ACR)–> glomerular &interstitial fibrosis
glomerular filtration rate decline (eGFR)
renal failure
Advanced: peripheral oedema

Question 22

What receptors does angiotensin II bind to?
Name2 classes of antihypertensives. What does each block?

Answer 22

Angiotensin II acts via angiotensin receptors
ACE inhibitors (ACEi) are antihypertensives which block ACE
Angiotensin receptor blockers (ARBs) are antihypertensives which block angiotensin receptors ((on adrenal cortex and vasculature))

Question 23

Benefits of blocking RAAS with an ACEi/ ARB?
when are antihypertensive treatments prescribed?
Is it beneficial to have both an ACEi/ARB simultaneously

Answer 23

Blocking RAAS with an ACE inhibitor (‘-pril) or angiotensin 2 receptor blocker (ARB, ‘-sartan’) reduces blood pressure & progression of diabetic nephropathy
All diabetes patients with microalbuminuria/proteinuria should have an ACEi/ARB even if normotensive
No benefit to having both ACEi/ARB simultaneously

Question 24

how is nephropathy managed?

Answer 24

Aim for tighter glycaemic 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

What is the most common cause of neuropathy/ lower limb amputation?

Answer 25

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

Question 26

when does diabetic neuropathy occur?

Answer 26

when vasa nervorum get blocked (blood vessels supplying nerves)

Question 27

what are the risk factors of diabetic neuropathy?

Answer 27

age duration of diabetes poor glycaemic control height (longer nerves in lower limbs of tall people) smoking prescence of diabetic retinopathy

Question 28

where is most common for diabetic neuropathy to show?

Answer 28

Longest nerves supply feet – so more common in feet Commonly glove & stocking distribution – peripheral neuropathy

Question 29

Is diabetic nephropathy painful? What is the danger of diabetic nephropathy?

Answer 29

Can be painful Danger is that patients will not sense an injury to the foot (eg. stepping on a nail)

Question 30

what is included in annual foot checks?

Answer 30

inspection for foot deformity, ulceration assess sensation (monofilament, ankle jerks) assess foot pulses (dorsalis pedis, posterior tibial)

Question 31

when is the risk of ulceration highest?

Answer 31

- reduced sensation to feet (peripheral neuropathy) - poor vascular supply to feet (peripheral vascular disease)

Question 32

Management of peripheral neuropathy without ulceration

Answer 32

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

Question 33

what is the management of peripheral neuropathy with ulceration?

Answer 33

multidisciplinary diabetes foot clinic offloading revascularisation if concomitant PVD antibiotics if infected orthotic footwear amputation if needed

Question 34

presentation of mononeuropathy

Answer 34

usually sudden motor loss (foot drop, wrist drop) cranial nerve palsy - double vision due to 3rd nerve palsy

Question 35

what is autonomic neuropathy?

Answer 35

damage to sympathetic & parasympathetic nerves innervating GI tract, bladder, CV system

Question 36

GI effects of autonomic neuropathy

Answer 36

delayed gastric emptying which can lead to nausea and vomiting (makes prandial short acting insulin hard) constipation/nocturnal diarrhoea

Question 37

how is the CV system affected by autonomic neuropathy?

Answer 37

postural hypertension (collapsing on standing, can be disabling) cardiac autonomic supply causing sudden cardiac death

Question 38

What effect does treatment targeted to hyperglycemia alone have on risk of macrovascular complications? What does this mean?

Answer 38

Treatment targeted to hyperglycaemia alone has minor effect on increased risk of cardiovascular disease Prevention of macrovascular disease requires aggressive management of multiple risk factors

Question 39

what are the non-modifiable risk factors for macrovascular complications of DM?

Answer 39

age sex birth weight FH/genetics

Question 40

what are the modifiable risk factors for macrovascular complications of DM?

Answer 40

dyslipidaemia hypertension diabetes mellitus smoking central obesity

Question 41

how is CV risk in DM managed?

Answer 41

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.