Macrovascular complications Flashcards
What is included in the term microvascular disease?
- Early widespread atherosclerosis
- Ischaemic heart disease
- Cerebrovascular disease
- Peripheral vascular disease
Summarise the development of atherosclerosis
- initial lesion
- fatty streak
- intermediate lesion - now visible with the naked eye
- atheroma
- fibroatheroma (main change is that the surface is fibrous and has calcium in it)
- complicated lesion (-> the main difference is that there is a surface defect; rare before the age of 50 -> causes thrombosis on top of the lesion or sends thromboembolism
1-3 clinically silent
4-6 clinically silent or overt
=> gradual process
What are the components of the metabolic syndrome?
- fasting glucose above 6.0 mmol/L
- Waist circumference: Men>102; Women>88
- HDL Men<1.0; Women<1.3
- Hypertension (BP > 135/80)
- Insulin resistance
- Inflammation CRP
- Adipocytokines
- Urine Microalbumin
=> all risk factors for IHD and are also important in early diabetes
Why is hyperglycaemia associated with significantly decreased life expectancy?
- Mainly due to the microvascular complications
- the longer you have diabetes, the more harm does it do (more lost years of life)
Correlation between IR and CHD events
The more insulin resistant someone is (higher insulin), the higher their risk of having a CHD event.
Risk of CVD events (+examples) in men and women
- higher relative risk in women (diabetes in women equalises the risk difference between men and women)
- events include: HF, Stroke, CHD, intermittent claudication
Non-modifiable risk factors for macrovascular disease
- age
- sex
- genetic background and family history
- birth weight
What are the modifiable risk factors for microvascular disease?
- smoking
- diabetes
- dyslipidaemia
- hypertension
=> it is important to look at ethnicity when looking at risk of heart disease
Why is the risk of malignancy lower in diabetes?
Sadly because they may have died of a heart attack before they would have developed cancer.
HbA1c and micro and microvascular disease risk.
- There is an increased risk with higher sugar.
- people don’t get retinopathy unless they have diabetes
- people without diabetes are also at risk of heart disease
- higher inclination of risk with sugar level in microvascular disease
How is the age adjusted mortality different in diabetes?
3x higher than in people that don’t have diabetes
What is the major cause of morbidity and mortality in diabetes?
IHD
Cerebrovascualar disease and diabetes
- Stroke is more likely if someone has diabetes
- more likely to have widespread small infarcts
- occurring younger
Peripheral vascular disease in diabetes
- contributes to diabetic foot disease with neuropathy
- narrowing of arteries with atheroma in major blood vessles e.g. to the legs - may block of itself or send showers of emboli clogging up further down
- once a bit of tissue is dead it is very hard to recover
- can cause gangrene and loss of toes
Renal artery stenosis in diabetes
- the vessel can undergo atheroma
- this can cause partial blockage, restricted blood flow which itself can cause hypertension
- can lead to progression of renal failure on that side.
Is sugar control enough to prevent macrovascular disease?
NO you have to treat multiple risk factors
- lipids / cholesterol
- blood pressure
- stop people smoking
- treat the sugar
treating cholesterol and blood pressure in diabetes is extremely successful
Canakinumab
- new agent for diabetes
- Reduces inflammation, without [lipid] reduction
- Monoclonal Ab targets interleukin-1Β
N=10,061, median 3.7yr
previous MI and CRP>2
HbA1c lower - 0.85 (0.74-0.98) lower risk recurrent cardiovascular events
- Higher risk infection
- Reduces inflammation in arteries
- is inflammation a part of diabetes or something that just tags on?
CRP of 3-5
subclinical inflammation, seen in people developing microvascular disease
Epidemiology of diabetic foot disease
- Prevalence of diabetes in England and Wales = 2-3 %
- Prevalence of current or past foot ulceration in diabetes: 5 - 7 % (about 50,000 in England and Wales)
- Risk of amputation up to 60× in diabetes. Poor subsequent prognosis.
- 10 % of NHS bed occupancy due to diabetes related problems (50% foot disease)
Pathway to foot ulceration
- Sensory neuropathy (wire bending test, asses light touch with monofilament)
- Motor neuropathy (e.g. they place their foot differently when walking which causes ulceration mainly at the great toe metatarsal head where a lot of pressure is laid)
- Limited joint mobility (glycosylated tendons, e.g. they cannot put their palms against each other, sugar sticks to collagen and stops them working properly. it is dangerous in feet because it is difficult to walk properly).
- Autonomic neuropathy (control of sweat glands giving sweat and moisture to the feet is lost -> strength and integrity of skin is lost (use creams, take care of feet))
- Peripheral vascular disease (e.g. blood supply not getting to the feet, can add to problems)
- Trauma - repeated minor/discrete episode (adds to problems, retinopathy increases risk of trauma)
- Reduced resistance to infection
- Other diabetic complications eg. retinopathy (increased risk of falling, bumping into something -> trauma)
What are the 3 main types of foot disease?
- neuropathic foot
- ischaemic foot
- neuro-iscahemic foot
Neuropathic foot
numb, warm, dry (no autonomic control), palpable foot pulses, ulcers at points of high pressure loading (e.g. great toe metatarsal head)
Ischaemic foot
cold, pulseless, ulcers at the foot margins.
Neuro-ischaemic foot
numb, cold, dry, pulseless, ulcers at points of high pressure loading and at foot margins.
How do you assess the foot of a diabetic patient?
- Appearance - ? Deformity ? Callus
- Feel - ? Hot/cold ? Dry
- Foot pulses: dorsalis pedis / posterior tibial pulse
- Neuropathy: vibration sensation, temperature, ankle jerk reflex, fine touch sensation (fine touch is the best way to predict foot problems later).
Management of the diabetic foot from the diabetes perspective?
- Hyperglycaemia -> you want better sugar, but this won’t help the foot itself.
- Hypertension
- Dyslipidaemia
- Stop smoking -> enormous benefit
- Education (caring for their feet or having professionals do it)
Preventative management in diabetic foot disease
- Control diabetes
- inspect feet daily
- have feet measured when buying shoes
- buy shoes with laces and square toe box (trainers are a lot better than fashionable shoes)
- inspect inside of shoes for foreign objectsattend chiropodist
- cut nails straight across
- care with heat
- never walk barefoot (especially on hot sand or outside)
Who is in the MDT in diabetes management?
- diabetologist
- diabetes nurse
- vascular surgeon
- orthopaedic surgeon
- (amputation) limb fitting centre
- orthotist
- chiropodist
Management of foot ulceration
Relief of pressure
- bed rest (risk of DVT, heel ulceration)
- redistribution of pressure/total contact cast
- stop pressure on the ulcer!! they cannot feel the pain -> bed rest or casts that divert the pressure from the ulcerated area
Antibiotics, possibly long term
- some patients have osteomyelitis (once so far they need ABs for 3 months which is essential but can cause resistance
Debridement
- remove dead tissue (eg gangrene) because it might cause infection
Revascularization
- angioplasty
- arterial bypass surgery
Amputation
- Dead tissue cannot be restored either amputate or wait for autoamputation and try top avoid infection.
Abnormal foot shape in diabetic foot
- Foot has an abnormal shape (rocker bottom foot, weight in the middle of the foot, the pressure settings are wrong)
- almost Jigsaw puzzle of bones inside -> neuropathic foot, they cannot feel the pain, ulceration in the middle of the foot possible, which is not generally
What is now the most common cause of Charcot foot?
Diabetes
used to be described for tertiary syphylis
What is Charcot foot?
Charcot foot is a condition causing weakening of the bones in the foot that can occur in people who have significant nerve damage (neuropathy). The bones are weakened enough to fracture, and with continued walking, the foot eventually changes shape.
