How to spot early signs of foot complications in people with diabetes

By: Hillary Child

Diabetes Australia warns that for people with diabetes, small wounds can lead to infections, ulceration and amputation, and this can be a sobering thought. However, podiatry researchers have found that most diabetes-related foot complications are avoidable with a few simple steps. In this blog, we are going to look into how diabetes can lead to foot complications and then discuss some simple preventative measures you can take to minimise your risk.  

The International Working Group of the Diabetic Foot (IWGDF) (some would argue, the world’s experts in this area) refers to four main factors affecting foot complications in diabetes – blood glucose levels (BGLs), nerve health (having good sensation), blood supply, and the shape of your foot. 

Put simply, continual high blood sugar levels (BGLs over 10mmol/Mol) stop macrophage cells from working. Macrophage cells are like rubbish trucks that take away infection and make room for healing, so if they aren’t functioning it takes longer for wounds and scratches to heal. Maintaining good blood sugar levels is important for wound healing. Your health team may have suggested checking your BGLs at home, but your doctor will usually check your HbA1C levels every 3 months or so. Your HbA1C is a measure of the average BGLs over the last 90days.  

Our nerves are also affected by high blood sugar levels, with tiny changes in sensation and nerve conduction adding up over time, until we have difficulty feeling our feet. Your feet don’t have to be completely numb for you to lose the ability to notice small scratches, blisters and wounds. And if a wound doesn’t hurt – it’s hard to know to stop walking on it.  

Keeping pressure off a wound is a big part of helping it heal, so if we don’t stop the pressure, the wound is likely to get bigger, rather than smaller. Early-stage changes in nerves could be a feeling like cardboard on the bottom of the feet, numbness or tingling. Some patients even report feet becoming more sensitive, right before they lose the sensation altogether. A podiatrist usually checks your nerve sensitivity at your regular foot health assessment, they may use complex computerised technology, like a biothesiometer, or they may use a tuning fork and what looks like a piece of fishing line which is called a monofilament. The experts at IWGDF say that using a tuning fork and monofilament is accurate in determining your risk of a foot complication. 

Arteries and veins are also impacted by high blood glucose levels, and can become more narrow, and lose their elasticity. Smaller artery changes can affect the eyes, kidneys, hands and feet. Reduced blood supply can affect wound healing. Early changes in blood flow could look like a toe that has changed colour or swelling around the ankles. Indications of reduced blood flow can include feet that feel cold, less hair growth, cramping in bed or gripping pain in the calf muscles when walking that only sitting and resting can relieve. A podiatrist can check the blood flow in your feet to ensure foot health and wound healing. Podiatrists tend to check pulses and perfusion using their hands during a standard consultation. During a foot health assessment, though, they will use a doppler ultrasound to pick up more minor changes. The experts at IWGDF say that checking pulses and perfusion should occur regularly, and a doppler be done at least annually for those at low risk (no known concerns). The more “at risk” you are, the more regularly you should have a full foot health assessment with a podiatrist.  

Lastly, your foot shape can put you at higher risk of complications. Sometimes called foot deformities, things like hammer toes, bunions, or bony areas on the foot, can rub on shoes or on the ground. These “pressure points” are perfect spots for blisters. Most of us will take our shoes off when we get a blister or stop walking and rest. But if we don’t know it is there (through lack of sensation), we can keep up the pressure, and rub a hole in the skin. Without adequate sensation to tell us to send the healing chemicals to the sore, or without enough blood flow to deliver those chemicals, we can’t heal up the wound – creating an ulcer.  

Making sure that you have supportive shoes that fit the shape of your feet with space around the toes is very important. Nails can be affected by shoe pressure, or can just be tricky to reach, see and cut. Your podiatrist can care for your nails, or teach you the best way to cut them.  

By looking at your feet every afternoon, you should notice new areas of redness or callus. These are signs your foot is under pressure. Callus is a way of our body protecting us, but if we don’t change our walking pattern, or if the callus gets too thick, it can cause the skin underneath to fail and a wound to occur. A podiatrist can remove the callus early and offer shoe alternatives or orthotics to support your feet and reduce uneven pressure.  

So what should you do?  

Daily foot checks are an important part of looking after your feet. In good light, check between the toes and above and below the feet – you may need to use a mirror. You’re checking for changes in the foot colour, temperature, shape, smell, and new wounds or scratches. Contact your podiatrist or GP if you notice something new.  

You should also book an annual check with your podiatrist, starting as soon as you are diagnosed with diabetes mellitus. At that initial appointment, your podiatrist can set a baseline – how healthy your feet are right now, before you have any concerns. Then every year, they will check how close to that baseline they are staying. No changes? Fantastic! See you next year! Slight change? Let’s talk to your GP and see what can be done to slow down the progress and get a handle on these before there are enough changes to cause a problem. Those IWGDF experts suggest that you have foot health assessments more regularly if you have any unusual findings – your podiatrist will let you know what they recommend for your specific circumstances.  

The good news?  

With daily inspections and visits to your podiatrist (at least once a year) you will ensure that you have given your feet the best chance to stay healthy and whole. 

References:  

https://iwgdfguidelines.org/ 

https://www.diabetesaustralia.com.au/living-with-diabetes/preventing-complications/foot-care/ 

https://www.diabetesfeetaustralia.org/