Micro and macrovascular complications of DM Flashcards
What are the microvascular complication of Dm
1) retinopathy
2) nephropathy
3) Neuropathy
What are teh macrovascular complications of DM
1) cerebrovascular disease
2) Ischaemia heart disease
3) peripheral vascular disease
how does increase HbA1c link to microvascular conditions
Extent of hyperglycaemia (as judged by HbA1c) is strongly associated with the risk of developing microvascular complications
Target HbA1c to reduce risk of microvascular complications
= 53 mmol/mol (<7%)
how does hypertensions cause complications of microvascular disesase
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
name the risk factors that could lead to microvascular complications
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
what is the mechanism of damage of hyperglycaemia and hyperlipidaemia leading to how they cause microvascular complications
1) hyperglycaemia and hyperlipidaemia cause:
a) Age - Rage:
Generation of glycated plasma proteins to form advanced glycation end products (AGEs)
b) Oxidative stress ; Increased formation of mitochondrial superoxide free radicals in the endothelium
c) hypoxia
2) leads to inflammatory signalling cascades
3) activation of pro inflammatory cytokines
4) inflammation –> damaged endothelium results in leaky capillaries + ischaemia
4) This causes nephropathy , retinopathy , neuropathy
What is diabetic retinopathy and what does it cause
Main cause of
visual loss in people with diabetes
blindness in people of working age
why is a screening programme needed for diabetic retinopathy
The early stages of retinopathy are all asymptomatic, therefore screening is needed
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
what does a normal retina look like
Can see optic disk ,
macula - central , high res, colour vision
see docs for images
what is background retinopathy
Hard exudates ( cheese colour , lipid) Microaneurysms ( dot) Blot haemorrhages
What are reproliferate retinopathies + features
Cotton wool spots called soft exudates represent retinal ischemia
present with haemorrhage of eye and cotton wool spots
How do proliferative retinopathies present
Visible new vessels on disc or elsewhere in retina
How do maculopathies present
heard exudates / oedema near the macula
same disease as background but happens to be near macula
this can threaten vision
what are the different types of retinopathy
1) background
2) reproliferate
3) proliferative
4) maculopathies
How can you treat retinopathies and maculopathies
for all
Improve HbA1c, stop smoking, lipid lowering,
good blood pressure control <130/80 mmHg
1) background –> Continued annual surveillance
2) reproliferative –. If left alone will progress to new vessel growth
So, early panretinal photocoagulation
3) Proliferative –>panretinal photocoagulation
4) Diabetic maculopathy
–> Oedema: Anti-VEGF injections directly into the eye (VEGF: vascular endothelial growth factor)
Grid photocoagulation
What is pan- retinal photocoagulation
wt
What other diseases is diabetic nephropathy associated with
Associated with progression to end-stage renal failure requiring haemodialysis
Associated with progression to end-stage renal failure requiring haemodialysis
Healthcare burden
whit is diagnosis of diabetic nephropathy
Progressive proteinuria (urine albumin:creatinine ratio - ACR)
Increased blood pressure
Deranged renal function (eGFR)
Advanced: peripheral oedema
Progressive proteinuria (urine albumin:creatinine ratio - ACR)
Increased blood pressure
Deranged renal function (eGFR)
Advanced: peripheral oedema
what is the mechanism of diabetic nephropathy
Diabetes –> hyperglycaemia + hypertension
increases glomerular hypertension –> proteinuria –> glomerular and interstitial fibrosis –> glomerular filtration rate decline –> renal failure
what is the renin angiotensin system
Angiotensinogen made in liver –> combined with renin from kidney –> angiotensin I
Angiotensin I + ACE ( from lungs) –> angiotensin II
Angiotensin II acts via angiotensin receptors ( to cause vaso constriction and aldosterone production in zonal glomerulosa )
ACE inhibitors (ACEi) are antihypertensives which block ACE
( prevents angiotensin I –> angiotensin II)
Angiotensin receptor blockers (ARBs) are antihypertensives which block angiotensin receptors
what are the mechanism of action of ACE inhibitors
ACE inhibitors (ACEi) are antihypertensives which block ACE ( prevents angiotensin I --> angiotensin II)
what are the mechanism of action of Angiotensin receptor blockers
Angiotensin receptor blockers (ARBs) are antihypertensives which block angiotensin receptors
what does blocking Renin angiotensin system do to diabetic nephropathy
Blocking RAS with an ACE inhibitor (‘-pril) or angiotensin 2 receptor blocker (ARB, ‘-sartan’) reduces blood pressure & progression of diabetic nephropathy
when should ACE / ARB be givin
All diabetes patients with microalbuminuria/proteinuria should have an ACEi/ARB even if normotensive
No benefit to having both ACEi/ARB simultaneously
what is microalbuminuria a risk factor of
CVD
what is the management 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
what is diabetic neuropathy
Diabetes mellitus is the most common cause of neuropathy and therefore lower limb amputation
Small vessels supplying nerves are called vasa nervorum
Neuropathy results when vasa nervorum get blocked
what is vasa nervorum
Small vessels supplying nerves are called vasa nervorum
what are the risk factors for diabetic neuropathy
Risk factors include
- Age - Duration of diabetes - Poor glycaemic control - Height (longer nerves in lower limbs of tall people) - Smoking - Presence of diabetic retinopathy
what region of teh body does diabetic neuropathy commonly occur in and why is this dangerous
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)
can cause foot ulceration
what is checked for in pateints with diabetic foot ulceration + how often must they be check for this
All people with diabetes: annual foot check
- Look for foot deformity, ulceration - Assess sensation (monofilament, ankle jerks) - Assess foot pulses (dorsalis pedis and posterior tibial)
What are the risk factors for foot ulceration
All people with diabetes: annual foot check
- Look for foot deformity, ulceration - Assess sensation (monofilament, ankle jerks) - Assess foot pulses (dorsalis pedis and posterior tibial)
what is the management of diabetic foot disease caused by peripheral neuropathy
All people with diabetes: annual foot check
- Look for foot deformity, ulceration - Assess sensation (monofilament, ankle jerks) - Assess foot pulses (dorsalis pedis and posterior tibial)
what is the management of diabetic foot disease caused by peripheral neuropathy with ulceration
Multidisciplinary diabetes foot clinic Offloading Revascularisation if concomitant PVD Antibiotics if infected Orthotic footwear Amputation if all else fails
what are the types of neuropathies
1) peripheral neuropathy
2) peripheral neuropathy with ulceration
3) mononeuropathy
4) autonomic neuropathy
what are symptoms of mononeuropathy
Usually, sudden motor loss
eg wrist drop, foot drop
Cranial nerve palsy
double vision due to 3rd (oculomotor) nerve palsy ( eye looking down and out)
What is autonomic neuropathy
Damage to sympathetic and parasympathetic nerves innervating GI tract, bladder, cardiovascular system
What are the GI and cardio effects of autonomic neuropathies
GI tract
- Delayed gastric emptying: nausea and vomiting (can make prandial short-acting insulin challenging)
- Constipation / nocturnal diarrhoea
Cardiovascular
- Postural hypotension: can be disabling - collapsing on standing.
- Cardiac autonomic supply: sudden cardiac death
What are treatments for macrovascular complications
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
what are the modifiable and non modifiable risk factors for macrovascular disease
Non-modifiable Age Sex Birth weight FH/Genes
Non-modifiable Age Sex Birth weight FH/Genes
how can you manage cardiovascular risk in DM
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
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