Monafilament testing used in Diabetes Assessment:
Doppler Machine used in Diabetes Assessment:
Diabetes and Feet
Diabetes is a disease that occurs from having too much glucose in the blood due to the body’s inability to produce or use insulin properly. Diabetes may lead to acute or chronic complications, mainly due to its effect on the blood vessels in the body. In your feet, high blood glucose levels can damage nerves (peripheral neuropathy) and impede circulation (peripheral vascular disease). Regular follow ups with medical professionals (GP, podiatrist) are recommended to pick up any abnormalities and ensure good and healthy organ function.
Diabetes is the most common cause of peripheral neuropathy or damage to the peripheral nerve cells and fibers, including sensory nerves, motor nerves, and autonomic nerves. Half of the people with diabetes will develop some degree of neuropathy. Each person has different symptoms which include but are not limited to numbness, burning sensations, pins and needles, and tingling. In most cases, peripheral neuropathy affects the longest nerve fibres first, starting from the furthest part of the body and progresses upwards, causing the “glove and stocking” sensation.
The sensory nerves are responsible for informing the brain of any stimulants, such as stepping on something, the pavement being too hot, or your shoes being too tight. In people with peripheral neuropathy, the stimuli are either reduced or gone altogether, hence preventing individuals from realising that their foot is injured until they see it.
To check for any abnormalities, we use different tools to check different basic sensations.
- Monofilament 5.07 – loss of ability to detect the 10g pressure created by this monofilament is associated with loss of large-fibre nerve function. They are slow adaptors and detect constant pressure and can discriminate the amount of force used. The test is done on the top and bottom of the foot, which indicates areas of risk due to increased plantar pressure in diabetes.
- Vibration test – test is done using a 128-Hz tuning fork on the skin above bony prominence. Having vibratory perception deficit or loss of vibration perception is related to an increased risk of diabetic foot ulceration.
- Proprioception – this is the body’s ability to understand body position without having to look. The test is for A-alpha fibres. Loss of proprioception and inability of knowing where one’s feet and toes are, affects stability, balance, and gait.
- Reflex test – tests on the lower limbs are differentiated to deep tendon reflex (done on the knee and ankle) and superficial reflex (bottom of the foot). Reflex text involves some sensory signals and some motor responses ensuring the pathway is intact.
The best way to slow down the progression of diabetic neuropathy is by good blood glucose control. Daily visual check is important as people with reduced sensation may not realise they have injuries. Wearing socks with good fitting shoes is another simple tip to ensure feet are free from unnecessary rubbing, which may lead to blisters and eventually wounds.
Diabetes affects the large and small blood vessels in the body which supply blood to different organs, muscle and skin throughout the body. This leads to an increased risk of peripheral arterial disease. Decrease blood flow to the foot can cause pain in lower limbs, impedes healing, and increase the risk of wound infection. Furthermore, decrease blood flow often causes pain in your leg when walking (intermittent claudication) or during night, usually when lying down in bed (rest pain).
To check for the artery supply in your feet, we have a few things that we rely on in the clinic.
- External indicators – skin condition (shiny, dryness) and presence of hair growth are generic indicators of vascular supply to the feet. Shiny, dry feet with minimal hair growth often found in people with decreased blood supply to their legs and feet.
- Temperature gradient of the lower limbs – your feet should be the coldest part of your lower limb with gradual decrease in temperature.
- Checking for pulses – feet have a few easily palpable pulses that allows the clinician to check for your circulation. Superficial capillary refill time may also be tested in the clinic.
- Doppler machine – a machine that uses reflected ultrasound waves and provides an audible pulse waveform. In a normal state, the arterial pulse forms three clear sounds (triphasic response). Dampened waveform usually indicates disease.
Decrease in circulation is a result of multiple comorbidities and holistic approach should be taken to improve the circulation. Appropriate exercise according to your fitness level is encouraged to help with the blood circulation. Taking proper medications prescribed by GP and controlling blood sugar, cholesterol and blood pressure are some examples that will decrease any complication due to peripheral artery disease.
The changes in nerve and vascular supply to the foot caused by diabetes, in turn, may lead to deformities causing musculoskeletal conditions of the foot, most commonly involving the forefoot region. These deformities are known to increase the plantar pressure especially around the ball of the foot which can lead to ulceration. One important change that is often overlooked is a deformity known as Charcot arthropathy or “Charcot foot”.
Charcot foot involves the middle part of the foot, where, mostly due to trauma, the arch starts to flatten. It affects diabetic patients with neuropathy and is often presented with a red, hot, swollen foot. Charcot foot has to be treated immediately to minimise arch flattening; failure to do so may lead to “boat shaped” foot, an increase risk of ulceration and bone infection in the area, as well as difficulty in finding shoes and sometimes walking.
When you visit us, we usually check your muscle strength and reflexes to make sure that they are within normal range. Any deformities such as claw/hammer toes, bunion, or Charcot foot will be noted and advise given accordingly.
As the largest organ, your skin’s main function is to act as a barrier against micro-organism, pressure, and environmental elements, on top of regulating body temperature and allowing sensation. Any injury or trauma to the skin will weaken the barrier and may allow micro-organism to enter into the body.
People with diabetes often have dry skin which if left unattended, may lead to fissuring in the skin (such as cracked heels) which can be painful. Due to muscle changes and/or skin changes, there is often increased pressure at the bottom of the foot which results in calluses or corn. Often, in people with peripheral neuropathy, besides rubbing from the shoes, these areas of high pressure are where they would develop wounds and ulcers.
To check for your skin status, we usually look for:
- General skin health – dryness, presence of tinea pedis or fungal infection of the skin. These conditions decrease the skin integrity and breakdown may happen easier.
- Redness or hotspots from rubbing with footwear – prolonged rubbing if not alleviated, may cause breakdown and ulceration. Good fitting footwear is important and using simple gel padding or plaster help as well.
- Any skin build-up such as corns or calluses – corns or calluses continue to build up unless the pressure is re-distributed by using, for example, simple padding or orthotics. Any excessive calluses or corns, if left undebrided may lead to ulceration underneath the hard skin and often overlooked as the overlying skin is still intact.
- Any break in the skin which may lead to ulceration
The best way to maintain skin integrity is by applying emollient to the feet daily, avoiding in-between the toes. Avoid using things such as corn plasters or shaving the calluses by yourself as it increases your risk of wound. See a podiatrist that can help you remove them safely instead.
Here at Foot Focus Podiatry, we have a team of podiatrist dedicated to look after you and your feet. If you worry that you might have an ulcer of the foot, speak to one of our team members to get the best treatment for you. We also have a few podiatrists that work in high-risk hospital setting, if you prefer.