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 In Podiatry Resources

How does diabetes affect your feet?

Diabetes, both type 1 and 2 can have a large impact on your feet. According to Diabetes Australia there are over a million people in Australia who have been diagnosed with diabetes of either type. There is also up to an estimated 500,000 people who currently have undiagnosed type 2 diabetes. Diabetes can affect your feet as it can impact blood flow and circulation, it also has an affect on the nerves and your sensations. Those who have had diabetes for a long time, have poorly controlled blood glucose levels and poor lifestyle choices can see a negative impact on both the circulation (peripheral arterial disease) and nerves which can result in peripheral neuropathy. 

Peripheral arterial disease occurs as a result of the narrowing and hardening of the blood vessels. This reduced blood supply to the feet, negatively impacts the body’s ability to heal potential wounds and ulcerations. Foot ulcers and diabetic wounds provide an opening for infections to invade the body. When these infections, such as osteomyelitis get into the bone, this can potentially lead to amputation. Cramping, coolness and pain are also some of the other impacts of a reduction in blood supply to the feet. The other major impact is damage to the nerves and most importantly can lead to a loss of protective sensations. Without protective sensation the foot is unable to feel pain which greatly increases the chances of a foot ulceration. With the loss of protective sensation, you could step on glass and not feel any pain and potentially there could be some time before treatment of the issue. Nerve damage can also result in sensations such as burning, tingling and numbness.

How to avoid diabetes complications

There are ways to reduce the chance of suffering from circulation and blood supply issues. Most importantly blood glucose levels need to be kept low and within a particular threshold. It would be advised to speak to a doctor or a diabetes educator to get an understanding of what your daily levels should be. It is also important to ensure that you are controlling your diabetes according to your plan. That can be through medication or diet and exercise. If blood glucose levels remain low and stable this can greatly reduce the chances of suffering from peripheral arterial disease or peripheral neuropathy. If you’re wondering about food and drink then a dietician/nutritionist would be good to speak to as they could outline what to avoid and eat in moderation.

Lifestyle choices are also very important in reducing the chances of complications from diabetes. Daily exercise is essential, it can be as simple as going for a half an hour walk every day. By completing exercise daily it gets the blood flowing around the body and can improve blood glucose control. Smoking is also detrimental to diabetics as it can reduce blood flow as well as impair wound healing. With impaired wound healing the chances of amputation increase.

You should visit your podiatrist at least once a year for a comprehensive foot examination. They can assess your blood flow and sensations to ensure there are no changes or the beginning of any complications. If you are unable to reach your toes properly, have trouble seeing or unsteady hands then it would be advised that you see a podiatrist every 6-10 weeks to have your nails done. Cutting your own nails must be done carefully due to the risks of infection from a tear in the skin via cutting nails incorrectly. Ingrown nails should also be left for your podiatrist as they can remove these safely for you as a poor attempt to self-treat can leave the nail bed traumatised and has the potential to become infected. The same applies to any skin care including callus, corns or fissures of the heels. If wanting to self treat these then its advised to use items such as a pumice stone that pose very little risk of causing skin tears.

Other self care methods include the daily use of moisturiser in order to prevent the skin from drying out. In particular the heels as these can crack open and these cracks can not only become painful, they can also open up and bleed which presents an opportunity for infection. Checking your shoes for any rocks or any other foregin objects that may have gotten into you shoes should be done every day. It’s advised to also check underneath the soul of the shoe. Buying correctly fitted shoes is also very important. Shoes that apply pressure on any bony prominences such as bunions or prominent metatarsal heads lead to an increased risk of ulceration. The stitching inside of the shoe should also be checked to ensure that it will not lead to an excessive amount of pressure and friction.

 

What will happen during your diabetes foot assessment?

During your diabetic foot assessment your blood flow and sensations will be assessed. Your foot structure and skin will also be examined and a brief history will also be taken. Once the assessment has been completed your results will be discussed and the relevant education and advice will be given.

History

An accurate history is a very important tool during a diabetic foot assessment as it can outline any potential risk factors as well some areas we may need to address in regards to management of blood sugar levels. Both your diabetic history and foot history will be discussed. What type of diabetes, how you control it, what your daily blood glucose levels are normally will all be discussed. The HbA1c result which is the 3 month average your doctor takes for you is also a relevant point. Any previous foot complications such as surgerys or previous ulcerations and amputations are important notes to take. Previous ulceration and amputation are a risk factor for future deterioration of the skin or limbs. Questions regarding drinking and smoking will also be asked, in particular around smoking due to the implications it has on blood flow and wound healing. Exercise levels are also important information that needs to be gathered.

General inspection

The general inspection includes looking at the skin, bones and footwear. As mentioned earlier it is extremely important to have footwear that suits your foot structure. This includes allowing for bony structures or deformities that could potentially be at risk for ulceration including bunions or prominent metatarsal heads. For example having a wide and deep toe box to allow for bunions to sit without suffering from excess pressure and friction. Looking at the sole of the shoe can also reveal wear patterns and will help to decide if there is a need for some offloading or correction through the use of orthotics or padding. 

Dermatological assessment

A dermatological assessment involves inspecting the skin around the foot and ankle and also the nails. When looking at the skin we are checking for any lesions or openings as these have the potential to become infected if not treated and dressed. Even small cuts should be treated with caution as they still provide a portal of entry for infection. It’s advised to dress any opening with betadine and a bandaid until you can see either a podiatrist or doctor. Checking between the toes for areas of maceration or splits in the skin as once again this can provide a portal of entry for bugs. Areas of callus are also something to note. These areas of hard skin arise from pressure or friction and similarly to skin tears have the potential to break down further. If left untreated then callus has the chance to deteriorate and open up resulting in a potential ulcer and another possibility for infection. Your podiatrist can remove this callus within the consult and home care like a pumice stone is a safe way to self manage. The nails should also be examined and a decision should be made on who is going to cut them going forward. If unable to cut your own nails safely then you should let your podiatrist handle this on a cycle around every 8-10 weeks. It is very easy to damage the surrounding skin whilst trimming your nails which is another potential risk for infection.

Musculoskeletal assessment

In the musculoskeletal assessment we look predominantly for any deformities of the foot that could potentially lead to any ulceration. There are particular deformities that are more common such as bunions and hammer toes. Both these conditions change how the foot sits within a shoe and how it functions. They create areas of excess pressure which increases the risk of a wound forming through the breakdown in skin. Your podiatrist can assess your footwear to ensure that these deformities are not at risk due to the footwear being worn. They can also provide ways to offload these areas with the use of felt padding, toe sleeves, splints and ottoform devices. The charcot foot is a deformity of the midfoot that is less common than the previously listed one. It is very important to get footwear and offloading correct with a charcot foot due to the levels of changes that occur within all structures. 

Neurological assessment

The neurological assessment involves checking for a loss of protective sensation within the feet due to the effect diabetes can have on the nerves. If a loss of protective sensation is discovered then the risk of ulceration and amputation increases and you’ll be diagnosed with peripheral neuropathy. 

10-g monofilaments

A monofilament device is used to apply pressure on specific areas of the foot to determine if there is any loss of protective sensation. It is carried out across 10 sites, the person being tested will close their eyes and answer yes when they can feel the pressure being applied via the 10-g monofilament. It is important to be honest about your results as if there is a loss of protective sensation then you are at a greater risk of suffering from an ulceration. The 10-g monofilament test can also allow us to determine where the loss of sensation is occurring, whether it be just the toes or the whole foot. 

128-Hz tuning forks

Tuning forks are used to test for vibration sensations. It is placed on particular landmarks and the person being tested should be able to feel the vibrations from the tuning fork. We would consider a loss of sensation if there is vibration felt and instead just the pressure being applied via the tuning fork.

Pinprick sensation

Pinprick sensation testing involves the use of a pin to impact on the skin’s surface. The person being tested should be able feel the pinprick and also be able to differentiate between sharp and dull pain. 

Ankle reflexes

Testing the ankle reflex is done because an absence of an ankle response is a risk factor for the development of ulceration. The person being tested is put into a position where their achilles is facing up via going prone or kneeling on a chair. The achilles is then hit with a tendon hammer which should result in a reflex moving the foot forwards or backwards.

Vibration perception threshold testing

Another method for testing vibration sensitivity is by vibration perception threshold test. This is done by using a handheld device called a biothesiometer. This reading helps to determine how at risk you are of ulceration. However we do not currently have the biothesiometer at our clinics and just use the tuning fork to test for vibration perception. If this test is required when can refer to someone else who has the required equipment.

Vascular assessment

The vascular assessment involves assessing the blood flow to the feet and monitoring the presence of vascular disease. The main issue we are looking to diagnose is peripheral arterial disease. Asking about cramping at night, in particular in the calves is very important to find out as this can be an indication there is some blockages in the legs. We begin by checking the dorsalis pedis and posterior tibial pulses to see if these are regular and present. Skin colour and temperature are also observed, the skin should appear normal both pale or blue. We would expect the temperature to be warm. If pedal pulses are unable to be palpated then the use of a doppler ultrasound can be implemented to check the pulses further. The ultrasound machine uses sound waves to show how much blood is circulating through the arteries. We look for a steady rhythm and a biphasic or triphasic pulse in both the posterior tibial and dorsalis pedis arteries. 

To test specifically for the level of peripheral arterial disease we can use two different tests. Firstly we can use an ankle brachial index which involves measuring the systolic blood pressure in both the dorsalis pedis and the posterior tibial arteries and take the highest result between the two. This result is then divided by the systolic blood pressure in the arm. The result is then put into a category of peripheral arterial disease. 

  • 0.91- 1.3 = normal
  • 0.7 – 0.9 = mild obstruction
  • 0.4 – 0.69 = moderate obstruction
  • <0.4 = severe obstruction
  • >1.3 = poorly compressible vessel

These results should be compared with other tests as the results can be skewered depending on what you did before having the test. The ankle brachial index can also give off inaccurate results if there has been calcification of the arteries. Another test that can be done is a toe pressure index. Similarly to the ankle brachial index, we measure the systolic pressure within the great toe. A normal toe pressure reading sits between 70 and 110mmHg, anything below this suggests there is some peripheral arterial disease and a result below 30mmHg is of great concern.

Risk classification and referral/follow-up

After your diabetic foot assessment your podiatrist should have all the information required to establish your plan going forward. There is a foot risk classification that can be used to put you directly into a category of which there are 4 levels of risk ranging from 0-3. These categories are predominantly based on the circulation and presence of peripheral arterial disease, loss of protective sensation and also previous amputations or ulcerations. A simple version of the classification is as follows

 

Category 0 = Nil circulation issues and no loss of protective sensation

Category 1 = A loss of protective sensation plus/minus a deformity of the foot

Category 2 = Both a loss of sensation and the presence of peripheral arterial disease

Category 3 = Previous history of amputation or ulceration

 

This risk classification is just an additional tool that can be used but ultimately your podiatrist will make their own judgement based on all your testing results. A referral to a high risk foot clinic is also an option if an ulcer or wound is not healing or if cost is an issue. If there is an indication that there is a reduced blood supply to the foot then a referral to a vascular specialist may be suggested. Without the adequate blood supply then healing becomes impaired so vascular surgery may be required which would be discussed with the vascular specialist. A neurologist is another referral that may be made if there is an issue with sensation. In some cases a diabetes educator may also be referred if there is a lack of understanding around diabetes as a whole from a client’s perspective. This can be very beneficial as a deeper understanding of diabetes and how it works can lead to improved diabetic control and a greater long term outlook. If controlling blood glucose levels through diet is an issue then a referral to a nutritionist or dietician can be made. 

At the very minimum a follow up should be done annually to go through the whole diabetic foot assessment once again. Depending on what other issues are occurring such as routine care which include nail care or treatment of corns and callus then you may be required to come in sooner. We recommended that routine care should be left to the professional hands of your podiatrist and should be performed around every 6-10 weeks.  

Want to see a podiatrist?

Make an appointment by booking HERE or by calling our Moorabbin clinic at 03 9553 0044, Edithvale at 03 9772 9579 and Malvern East at 03 9021 2067.

Foot Centre Group

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