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