1b Micro and Macro-Vascular Complications of Diabetes Flashcards
What are the three main microvascular complications of diabetes?
retinopathy
nephropathy
neuropathy
What are the three main macrovascular complications of diabetes?
Cerebrovascular Disease
Ischaemic Heart Disease
Peripheral vascular Disease
What is the target HbA1c level to reduce risk of microvascular complications?
< 53 mmol/mol
What does prevention of microvascular complications involve?
Reduction in HbA1c and Blood Pressue
What are some other factors which influence the development of microvascular complications of diabetes?
Smoking
Duration of Diabetes
Genetics
Hyperlipideamia
Hyperglycaemic memory
What is meant by hyperglycaemia memory?
When inadequate glucose control early on can result in higher risk of complications LATER - even if HbA1c is improved
What forms as a result of endothelial damage?
Mitochondrial superoxide free radicals in the endothelium
What are AGEs?
Glyctaed plasma proteins - forms Advanced Glycation End Products
What does the formaiton of AGE’s result in?
Kick starts the inflammatory pathways
What are the consequences of a damaged endothelium?
Leaky Capillaries
Ischaemia
What causes the blurred vision which is sometimes seen in patients with diabetes?
Swelling of the lens due to more glucose in the blood = not the same as retinopathy
Why is screening for retinopathy needeD?
Early stages of retinopathy is asymptomatic , therefore screening is needed to detect it early on before it causes a visual disturbance
What are the three main characteristics of background retinopathy?
Hard exudates
Microaneurysms
Blod Haemorrhages
What are hard exudates?
Leakages of lipid from the capillary
What are the signs of pre-proliferative retinopathy?
Cotton wool Spots / soft exudates
haemorrhage
What do the changes associated with pre-proliferative retinopathy indicate?
Retinal ischaemia
What is the sign of proliferative retinopathy?
Visible new blood vessels - on the disc or elsewhere in the retina
What is maculopathy?
Same disease as background retinopathy - hard exudates, but NEAR THE MACULA
Why is maculopathy particularly threatening?
Macula is important for nearby colour vision, so loss can threaten vision significantly
What is the first step in treating any stage of retinopathy?
- improve HbA1c, Stop Smoking, Lower Lipids
- Good blood pressure control
What is the treatment of background retinopathy?
Continued annual surveillace
What is the treatment of pre-proliferative retinopathy?
panretinal photocoagulation
What is the treatment of proliferative retinopathy?
Panretinal photocoagulation
What is the treatment of maculopathy?
Anti-VEGF directly into the eye
Vascular Endothelial Growth Factor
Grid Photocoagulation
What is the side effect of pan-retinal photocoagulation?
reduces peripheral vision
What is diabetic nephropathy associated with?
increase risk of Cardiovascular events
What is the early sign of diabetic kidney damage?
Microalbuminuria - >2.5 mg/mol
What is needed for a diagnosis of nephropathy?
- Progressive proteinuria
- Increased blood pressure
- Deranged renal function
- Peripheral oedema - advanced
how is proteinuria measured?
Albumin:Creatinine Ratio (ACR)
What is the mechanism of diabetic nephropathy?
- Hyperglycaemia and Hypertension causes pressure to build up in the glomerulus
- This causes proteinuria as protein is forced out into the urine
- This leads to glomerular and interstitial fibrosis which damages the glomerulus
- GFR declines, leading to renal failure
Describe how the RAS system works?
- Liver releases Angiotensinogen
- Renin from the kidney converts Antiotensinogen to Angiotensin I
- Angiotensin I -> Angiotensin II through ACE
What are the two main effects of Angiotensin II?
- vasoconstriction
- Acts on the zona glomerulosa of the adrenal cortex to promote water reabsorption through the release of aldosterone
What are the two antihypertensive medications which are given to treat nephropathy
ACEi
ARB
All diabetes patients with microalbuminuria/proteinuria should be given what?
ACEi / ARB, even if they have a normal blood pressure
Microalbuminuria is a risk factor for what?
Cardiovascular complications
What is the management of diabetic nephropathy?
- tighter glycaemic control
- ACEi/ARB
- Reduce BP
- Stop smoking
What is neuropathy?
Damage to nervex
What is the name of the small blood vessels which supply nerves called?
Vasa nervorum
When does neuropathy occur?
When vasa nervorum get blcoked
Describe the effect of height in diabetic nephropathy?
Taller = longer nerves = more vulnerable to neuropathy
Why is diabetic neuropathy most common in feet?
Longest nerves supply the feet - so more common
What is the most common distribution of diabetic neuropathy?
Glove and Stocking distribution - worse at night
What two things are assessed for in the foot clinic for patients at risk of diabetic neuropathy?
Assess Sensation
Assess Foot Pulses
What is looked for in the annual foot check?
Foot ulceration
Which patients have a higher risk of foot ulceration?
When you have reduced sensation to the feet - peripheral neuropathy
When you have poor vascular supply to the feet - peripheral vascular disease
What is the management of peripheral neuropathy?
- regular foot checks
- Good footwear / avoid being barefoot
What is the management of peripheral neuropathy with ulceration?
- DIabetes foot clinic
- Offloading
- revascularisation if needed
- Antibiotics if affected
- Orthotic footwear
- Amputation
What is mononeuropathy?
Sudden motor loss eg foot drop / wrist drop
What palsy is an example of mononeuropathy?
3rd nerve palsy - eye looks down and out
What is autonomic neuropathy?
Damage to the sympathetic and parasympathetic nerves innnervating the GI Tract, bladder and CV system
What are the GI effects of autonomic neuropathy?
Delayed gastric emptying: nausea and vomiting
Constipation / nocturnal diarrhoea
What are the cardiovascular complications of autonomic neuropathy?
Postural hypertension when the blood pressure gets too low
Cardiac autonomic supply - sudden cardiac death
What does the prevention of macro-vascular disease involve?
aggressive management of multiple risk factors
What are the non-modifiable risk factors for macrovascular disease?
Age
Sex
birth Weight
FH/genes
What are the modifiable risk factors for macrovascular complications?
Dyslipidaemia
Hypertension
Smoking
DM
Central Obesity
How is the CV risk managed in DM?
Smoking Cessation
Blood Pressure - might need multiple agents
Lipid profile
Weight - discuss lifestyle intervention
Annual microalbuminuria screen
