Microvascular complications
Diabetes Outreach
(August 2011)
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Microvascular complications
Learning outcomes> understands the 3 main
microvascular complications of diabetes
> can state the complication screening required for microvascular disease
> is aware of broad management principles.
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Microvascular disease
Microvascular disease refers to the disease of the small blood vessels associated with thickening of the basement membranes.
Consequences are:
eye disease - retinopathy
kidney disease - nephropathy
nerve damage - neuropathy
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What are the risk factors?
> hypertension > dyslipidemia> poor glycaemic control> age and duration of diabetes> family history> smoking.
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Prevention, Prevention, Prevention
General principles:> initial screening: depends on type of diabetes
and/or age of onset of diabetes> ongoing screening (cycle of care) at least annual
screening (kidneys and nerves, second yearly for eyes)
> early identification leads to early treatment.
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Diabetes and the eye
Short term issues > high glucose causes the lens to swell and
distort which can affect vision temporarily
> blurry vision is common when newly diagnosed and will settle down once blood glucose levels are reduced.
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Diabetic retinopathy
> occurs as a result of microvascular disease of the retina. It happens when elevated blood glucose levels damage the fine blood vessels of the retina
> if retinopathy is diagnosed early (eg before vision loss) vision can be preserved
> there are different levels of retinopathy depending on severity.
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BBBBB
Retina
Optic Nerve
Iris
Macula
Pupil
Lens
Cornea
The eye
Bleeding blood vessels
The eye
Bleeding blood vessels
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Other eye problems
> Cataracts: an opaque or cloudy lens can be made worse by high blood glucose.
> Glaucoma: fluid in the eye builds up causing increased pressure and damage to the retina.
> Infections: if glucose levels are high bacteria can grow.
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Screening and treatment for retinopathy
> Review should occur at the time of diagnosis and then at least every two years and more frequently if problems exist.
> Inform the person that retinopathy can occur without symptoms and so screening is essential for early identification and treatment.
> If retinopathy is found laser is used to delay and prevent further vision loss.
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Diabetes and the kidney (nephropathy)
Nephropathy is a microvascular (small blood vessels) complication related to high blood glucose and high blood pressure.> Glucose attaches to the small blood vessels
in the nephron causing damage.> High blood pressure puts extra strain on the
blood vessels.
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Screening for nephropathy
> screen microalbuminuria annually by> performing an albumin/creatine ratio
(mg/mmol) using early morning spot urine> if first test is positive for microalbuminuria, 2
further samples need to be taken > glomerular filtration rate (GFR) can also be
used as a measure of kidney function.
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Treatment of nephropathy
> maintain BP at less than 125/75> ACE inhibitors even if BP normal> screen urine regularly for infection as this may
make diabetic nephropathy worse> adequate BGL control.
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Diabetes and the nerves (neuropathy)
> Peripheral neuropathy – affects the peripheral limbs of the body.
> Autonomic neuropathy – affects nerves that supply the body structures that regulate BP, heart rate, bowel and bladder emptying and digestion.
Neuropathy is a term used to describe nerve damage. There are two main types of neuropathy:
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Peripheral neuropathy
> refers to nerve damage that affects the peripheries
> nerve fibres are damaged and pain sensations can be altered
> people with peripheral neuropathy are at high risk of foot problems and require intensive foot care education.
16Image from Twigg and Sorensen, Med Today, 2010,11:3
Painful neuropathy
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Peripheral neuropathy
The person needs to:
> have their feet checked regularly > know if they have at risk feet> have a foot protection plan appropriate to their foot
risk> see a podiatrist if they have at risk feet> see their doctor at any sign of infection.
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Autonomic neuropathy
> orthostatic hypotension
> impaired gastric emptying (gastroparesis)
> diarrhoea > erectile dysfunction> silent MI’s> hypo unawareness.
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Autonomic neuropathy may result in:
> orthostatic hypotension > impaired gastric emptying> diarrhoea > delayed/incomplete bladder emptying> erectile dysfunction and retrograde ejaculation in
males> reduced vaginal lubrication with arousal in women> loss of cardiac pain and ‘silent’ ischaemia or
infarction> sudden, unexpected cardio-respiratory arrest
especially under an anaesthetic or treatment with respiratory depressant medication
> difficulty recognising hypoglycaemia.
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Treatment & management
> cardiac – ECG, regular review> postural hypotension – check for this and advise
to be careful when getting out of bed> gastrointestinal – dietary advice > bladder – encourage regular emptying and early
treatment of infections> erectile dysfunction – counselling, medication,
prostheses> hypo unawareness – adjustment of glycaemic
targets, and hypo action plan that includes glucagon.
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Summary
> Microvascular complications can progress without symptoms.
> All people with diabetes need regular screening for microvascular complications.
> Achieving glycaemic, BP and lipid targets are essential for preventing problems.
> People should be encouraged and supported to stop smoking.
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References
> Diabetes Outreach (2009) Diabetes Manual, Section 12, Long term complications.
> Kidney Health Australia (2007) Chronic Kidney Disease (CKD) Management in General practice. Available from www.kidney.org.au
> RACGP (2010) Diabetes Management in General Practice. Available from www.racgp.org.au/guidelines