Vascular complications of DM Flashcards
what are the microvascular complications of diabetes mellitus?
retinopathy
nephropathy
neuropathy
what are the macrovascular complications of diabetes mellitus?
cerebrovascular disease
ischaemic heart disease
peripheral vascular disease
what is the target HbA1c to reduce risk of microvascular complications?
53mmol/mol (<7%)
what are the other risk factors (besides HbA1c) for complications of diabetes?
duration of diabetes smoking- endothelial dysfunction genetic factors hyperlipidaemia hyperglycaemic memory- inadequate glucose control early on can lead to higher risk of complications later even with improved HbA1c hypertension
how do we aim to detect retinopathy?
through screening as early stages are asymptomatic
we want it to be early when it can be treated before visual disturbances/loss
describe the appearance of a normal retina
optic disk: bright spot visible
thin veins semi visible
macula: dense/pink spot visible
describe background retinopathy?
hard exudates (white cheesy spots)
microaneuyrsms (dots)
blot haemorrhages
enhanced blood vessels
describe pre proliferative retinopathy
more extensive haemorrhage
soft exudates (cotton wool spots)
represents retinal ischaemia
describe proliferative retinopathy
new vessels visible
on disk or elsewhere in retina
describe maculopathy retinopathy
hard exudates/oedema near macula
(same as background just near macula)
can threaten vision
how do you treat background retinopathy?
you can’t.
annual surveillance
lifestyle changes
how do you treat pre proliferative retinopathy
early panretinal photocoagulation
how do you treat proliferative retinopathy?
panretinal photocoagulation
how do you treat diabetic maculopathy?
grid photocoagulation
anti-VEGF injections directly into eye
what are the risks of panretinal photocoagulation?
loss of some peripheral vision
how do you diagnose diabetic nephropathy?
Progressive proteinuria (urine albumin:creatinine ratio): - Microalbuminuria: >2.5mg/mmol - Proteinuria = ACR >30mg/mmol - Nephrotic range >3000mg/24hr Increased BP Deranged eGFR Advanced: peripheral oedema
what is the mechanism of diabetic nephropathy?
hypertension & hyperglycaemia lead to glomerular hypertension
this leads to proteinuria, glomerular &interstitial fibrosis
glomerular filtration rate decline
renal failure
what is the renin-angiotensin system?
angiotensinogen in liver, kidney produces renin which converts this to angiotensin I
angiotensin converting enzyme converts this to angiotensin II which causes vasoconstriction and release of aldosterone from the zona glomerulosa of the adrenal cortex
what is given to prevent further decline of nephropathy?
Block RAS with ACE inhibitors (ACEi) or angiotensin-2 receptor blockers (ARB)- no evidence that both at the same time is beneficial (Can lead to hyperkalemia)
when are nephropathy treatments prescribed?
even when normotensive with microalbuminuria or proteinuria
how is nephropathy managed?
smoking cessation tighter glycaemic control reduce blood pressure via ACEi or A2RB aim for BP <130/80mmhg start SGLT-2 inhibitor if T2DM
when does diabetic neuropathy occur?
Small blood vessels supplying nerves are called vasa nervorum
Diabetic neuropathy occurs when vasa nervorum get blocked (blood vessels supplying nerves)
what are the risk factors of diabetic neuropathy?
age duration of diabetes poor glycaemic control height smoking prescence of diabetic retinopathy
where is most common for diabetic neuropathy to show?
What is an associated danger?
glove & stocking distribution
longest nerves supply feet- so most common in feet
danger is that patients will not sense injury foot
what is included in annual foot checks?
inspection for foot deformity, ulceration assess sensation (monofilament, ankle jerks) assess foot pulses (dorsalis pedis, posterior tibial)
when is the risk of ulceration highest?
patients with reduced foot sensation (peripheral neuropathy)
poor vascular supply to feet (peripheral vascular disease)
what is the management of peripheral neuropathy with ulceration?
multidisciplinary diabetes foot clinic offloading revascularisation if concomitant PVD antibiotics if infected orthotic footwear amputation
presentation of mononeuropathy
usually sudden motor loss (foot drop, wrist drop)
cranial nerve palsy - double vision due to 3rd nerve palsy
what is autonomic neuropathy?
damage to sympathetic & parasympathetic nerves innervating GI tract, bladder, CV system
what are the GI effects of autonomic neuropathy?
delayed gastric emptying (makes post prandial insulin hard)
constipation/nocturnal diarrhoea
how is the CV system affected by autonomic neuropathy?
postural hypertension (collapsing on standing) cardiac autonomic supply causing sudden cardiac death
what are the non-modifiable risk factors for macrovascular complications of DM?
age
sex
birth weight
FH/genetics
what are the modifiable risk factors for macrovascular complications of DM?
dyslipidaemia
hypertension
smoking
central obesity
how is CV risk in DM managed?
support smoking cessation blood pressure control lipid profiles weight interventions annual microalbuminuria screens
What is the mechanism of damage leading to microvascular complications?
Increased formation of mitochondrial superoxide free radicals in endothelium
Generation of glycated plasma proteins to form advanced glycation end products (AGEs)
Activation of inflammatory pathways (pro-inflammatory cytokines)
Damaged endothelium results in:
- leaky capillaries
- ischaemia
What are 3 things hyperglycemia and hyperlipidemia can lead to in the mechanism of damage?
Oxidative stress
AGE-RAGE
Hypoxia
How is diabetic retinopathy screened for in the uk?
Annual screening for all patients with diabetes
Why is diabetic nephropathy important?
Associated with progression to end-stage renal failure requiring haemodialysis
Healthcare burden
Associated with increased risk of CV events
what is the management of peripheral neuropathy no ulceration?
Regular inspection of feet by affected individual
Good footwear
Avoid barefoot walking
Podiatry and chiropody if needed
Whos most at risk of cardiovascular mortality?
Males with T1DM
Females with T1DM
