Microvascular complications

1. Microvascular complications Diabetes Outreach (August 2011)

2. 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.

3. 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

4. What are the risk factors? • hypertension • dyslipidemia • poor glycaemic control • age and duration of diabetes • family history • smoking.

5. 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.

6. 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.

7. 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.

8. Lens Macula Cornea Optic Nerve Pupil Retina Iris The eye Bleeding blood vessels BBBBB

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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:

15. 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.

16. Painful neuropathy Image from Twigg and Sorensen, Med Today, 2010,11:3

17. 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.

18. Autonomic neuropathy • orthostatic hypotension • impaired gastric emptying (gastroparesis) • diarrhoea • erectile dysfunction • silent MI’s • hypo unawareness.

19. 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.

20. 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.

21. 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.

22. 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