Micro- And Macrovascular Complication Of Diabetes Flashcards
What are the microvascular complication of Diabetes?
Retinopathy
Nephropathy
Neuropathy
What are the macrovascular complications of Diabetes?
Cerebrovascular disease
Ischaemic heart disease
Peripheral vascular disease
What is the relationship between risk of microvascular complications and HbA1c levels?
Extent of hyperglycaemia, measured by HbA1c, is strongly associated with the risk of developing microvascular complications
What is the target HbA1c to reduce the risk of microvascular complications?
53 mmol/mol (<7%)
Is glycaemic control the only factor that should be monitored in prevention of microvascular complications?
No systolic BP must also be monitored as there is a relationship between rising systolic BP and risk of MI and microvascular complications in people with T1 and T2DM
What other factors are related to the development of microvascular complications in people with T1 and T2DM?
Duration of diabetes
Smoking - endothelial dysfunction
Genetic factors - development of complications despite reasonable glycaemic control
Hyperlipidaemia
Hyperglycaemic memory - inadequate glycaemic control early on may increase risk of complications later on despite improved HbA1c
What is the mechanism of damage in microvascular disease?
- Hyperglycaemia and hyperlipidaemia lead to increased formation of mitochondrial superoxide free radicals in the endothelium
- Generates glycated plasma proteins that form advanced glycation end products (AGEs)
- Activates inflammatory pathways that damage endothelium (exacerbated by smoking)
- Causes leaky capillaries (proteins flows out) and ischaemia (impaired blood flow)
What is the main cause of visual loss in people with diabetes?
Diabetic retinopathy
What is the main cause of blindness in people of working age?
Diabetic retinopathy
Why is screening necessary for diabetic retinopathy and what are the aims of screening?
Diabetic retinopathy is asymptomatic in early stages
Aim is to detect retinopathy early when it can be treated - before it causes visual disturbance/loss
What type of retinal screening is offered for patients with diabetes in the UK?
Annual retinal screening for all diabetes patients
What condition does this image show and what are the abnormalities?
Background retinopathy (early stage)
Hard exudates (cheese colour - lipids/protein)
Microaneurysms (dots)
Blot haemorrhages
Label the abnormalities on this image. What condition does it show?
Pre-proliferative retinopathy
‘Cotton wool spots’ - soft exudates
What do cotton wool spots represent?
Retinal ischaemia
What stage of retinopathy is shown in this image?
Pre-proliferative retinopathy
What condition does this image show and what are the abnormalities?
Proliferative retinopathy
Visible new vessels on disc or elsewhere in retina - response to ischaemia, susceptible to damage
How is maculopathy different from retinopathy?
Same disease as background retinopathy but happens to be around the macula
Threatens vision - macula is important for fine, detailed colour vision
Hard exudates/oedema near the macula
What is the first step of management for all stages of diabetic retinopathy/maculopathy?
Lifestyle:
Improve HbA1c
Stop smoking
Lipid lowering
Good BP control <130/80 mmHg
After lifestyle, what is the treatment for background retinopathy?
Continued annual surveillance
After lifestyle, what is the treatment for pre-proliferative retinopathy?
If left alone, will progress to new vessel growth
Early panretinal photocoagulation treatment - burning of new vessels to prevent haemorrhages
After lifestyle, what is the treatment for proliferative retinopathy?
Panretinal photocoagulation
After lifestyle, what is the treatment for diabetic maculopathy?
Anti-VEGF (vascular endothelial growth factor) injections directly into the eye
Grid photocoagulation
What is a consequence of pan-retinal photocoagulation?
Reduced peripheral vision (as you’ve burned a hole in the retina)
What does this image show?
Retina after pan-retinal photocoagulation (laser treatment)
Why is diabetic nephropathy important?
Associated with progression to end-stage renal failure requiring haemodialysis
Healthcare burden
Associated with increased risk of cardiovascular events
How is diabetic nephropathy diagnosed?
Progressive proteinuria (measured by urine albumin:creatinine ratio - ACR)
Increased BP
Deranged renal function (eGFR)
Advanced - peripheral oedema
How are microalbuminuria, proteinuria and the nephrotic range classified?
Microalbuminuria - ACR >2.5 mg/mmol
Proteinuria - ACR >30 mg/mmol
Nephrotic range - ACR >3000 mg/24hr (frothy urine, low blood albumin)
Is one urine sample test enough for a diagnosis of microalbuminuria?
No, require at least two
False positives - high temp, UTI
What is microalbuminuria an early sign of and how is renal function affected?
Diabetic kidney damage
Indicator for increased cardiovascular risk
Often have normal renal function
What is the proposed mechanism of diabetic nephropathy?
Should a patient with two confirmed tests of microalbuminuria be started on treatment and if so, what treatment?
Yes, all diabetes patients with microalbuminuria/proteinuria should have an ACEi/ARB even if they are normotensive
When else should diabetes patients be started on an ACEi/ARB?
If they are hypertensive - BP over 130/80
What are the benefits of taking ACEi/ARB if there is confirmed microalbuminuria/proteinuria?
Reduces blood pressure and progression of diabetic nephropathy
What are the suffixes for ACEi and ARBs?
ACEi -> ‘-pril’
ARB -> ‘-sartan’
Microalbuminuria is a risk factor for what disease?
Cardiovascular disease
How is diabetic nephropathy managed?
Aim for tighter glycaemic control
ACEi/ARB for microalbuminuria even if normotensive
Reduce BP (aim for <130/80) usually through ACEi/ARB
Stop smoking
Can start SGLT2 inhibitor for T2DM
What is the most common cause of neuropathy and therefore lower limb amputation?
Diabetes Mellitus
What are the small vessels supplying nerves called?
Vasa nervorum
When does neuropathy occur?
When the vasa nervorum get blocked
What are the risk factors for diabetic neuropathy?
Age
Duration of diabetes
Poor glycaemic control
Height (longer nerves in lower limbs - tall people)
Smoking
Presence of diabetic retinopathy
Why is diabetic neuropathy more common in your feet and what other distributions are common?
Longest nerves supply feet
Also commonly glove and stocking distribution - peripheral neuropathy
Can be painful
What is the danger of diabetic neuropathy?
Patients may not sense an injury to the foot (e,g, stepping on a nail)
More susceptible to foot ulceration - diabetic foot
What does the annual diabetic foot check involve?
Looking for foot deformity/ulceration
Assessing sensation (monofilament, ankle jerks)
Assessing foot pulses (dorsalis pedis and posterior tibial)
What are risk factors for foot ulceration?
Reduced sensation to feet (peripheral neuropathy)
Poor vascular supply to feet (peripheral vascular disease)
How is peripheral neuropathy managed?
Regular inspection of feet by affected individual
Good footwear
Avoid barefoot walking
Podiatry and chiropody if needed
How is peripheral neuropathy with ulceration managed?
Multidisciplinary diabetes foot clinic
Offloading
Revascularisation with concomitant PVD
Antibiotics if needed
Orthotic footwear
Amputation - last resort
Give examples of mononeuropathy due to diabetes
Single nerve damage
Usually sudden motor loss, e.g, foot drop or wrist drop
Cranial nerve palsy - double vision due to 3rd nerve palsy (down and out)
Describe diabetic autonomic neuropathy
Damage to sympathetic and parasympathetic nerves innervating GI tract, bladder and cardiovascular system
What effects can autonomic neuropathy have on the GI tract?
Delayed gastric emptying causing nausea and vomiting (can make prandial short-acting insulin challenging - no digested food for insulin to act on, hypoglycaemia risk)
Constipation/nocturnal diarrhoea
What effects can autonomic neuropathy have on the cardiovascular system?
Postural hypotension - collapsing on standing
Cardiac autonomic supply - sudden cardiac death
Is HbA1c linked with cardiovascular risk?
Not really - implicated in microvascular complications
Management of BP and cholesterol are key in mitigating cardiovascular risk
Is focusing on cardiovascular risk in T2DM more important than in T1DM?
No, equally as important!
What are the non-modifiable risk factors of macrovascular disease?
Age
Sex
Brith weight
Family history/genetics
What are the modifiable risk factors of macrovascular disease?
Dyslipidaemia
Hypertension
Smoking
Diabetes Mellitus
Central obesity
How is cardiovascular disease managed in Diabetes Mellitus?
Smoking status - support to quit
BP - <140/80 mmHg, <130/80 mmHg if microvascular complications (may need multiple agents)
Lipid profile - total chol <4, LDL <2
Weight - lifestyle +/- pharmacological
Annual urine microalbuminuria screen - risk factor for CVD
