What can be done to help peripheral arterial disease (PAD)?

The screening process for PAD is simple and consists of checking, via palpation, for the two pulses in each foot. If either of these pulses are present during the screening process then the circulation to the foot is perceived to be adequate. These pulses are the Dorsalis Pedis (DP) and the Posterior Tibial (PT). The individual should be asked if they have any signs of intermittent claudication (cramping in the calf muscle after walking a certain distance) and also be given advice regarding lifestyle changes, most importantly stopping smoking.

If during the screening process neither of the pulses can be palpated or the individual presents with any of the aforementioned problems they may need to be referred for a more in depth assessment of their PAD, leading in some cases to the implementation of an Education / Management plan to try and improve the situation or referral to vascular services for surgical intervention where appropriate.

What are the signs of peripheral arterial disease (PAD)?

  • Absent foot pulses
  • Skin is thin, shiny and without hair
  • Colour – may be a dusky red due to stagnation of blood in maximally dilated arterioles, pale and mottled or cyanotic blue
  • Temperature – skin feels cool or cold to touch
  • Individual complains of intermittent claudication

What are the effects of peripheral arterial disease (PAD)?

PAD itself in isolation rarely causes ulceration, it is usually a combination of PAD, neuropathy and trauma that is the pathway to ulceration.

PAD specifically effects the feet in individuals with diabetes by reducing the amount of blood reaching the area. This results in a reduced ability for the tissues to repair themselves after injury.

Early signs that there is a problem with the circulation can be intermittent claudication (cramping in the calf muscle after walking a certain distance) or the inability to palpate the foot pulses.

Peripheral arterial disease (PAD)

PAD is a common complication of diabetes, secondary to poor blood glucose control and adverse arterial risk factors – high cholesterol, raised blood pressure and smoking.

Both large and small vessels can be affected;

  • Microvascular (small blood vessel disease)
  • Macrovascular (large blood vessel disease)

Diabetic peripheral neuropathic pain (DPNP)

DPNP can greatly affect an individuals quality of life and is very difficult to treat and should be referred to a specialist. The symptoms associated with DPNP are:

  • Shooting, burning, tingling sensations
  • Worse at night, but not with exercise
  • May be minor or cause considerable pain and disruption to sleep, work, social activities
  • May be acute or chronic

There is good evidence that several pharmalogical agents can improve symptom control and quality of life in individuals with DPNP. The evidence base for direct comparison of different agents is limited. For more information please read:

Autonomic neuropathy

The main effect of autonomic neuropathy on the feet can be loss of sweating, resulting in dry inelastic skin less capable of resisting shearing and pressure. The skin may then become split and cracked particularly around the heels resulting in a portal for infection.

The classic signs of Autonomic neuropathy are:

  • Dry, split skin
  • Distended veins over the top of the foot and ankle
  • Bounding pulses

Heels of feet showing signs of autonomic neuropathy

The recommended treatment for anhidrosis (unusually dry skin leaving it flakey and in some cases thickened and liable to crack) is a Urea based cream. Individuals with diabetes suffering from anhidrosis can obtain this via prescription. An example of a Urea based cream, which is recommended by The College of Podiatry, can be found on the Flexitol website. This website includes information regarding the appropriate use of Flexitol to enable you as a clinician to advise your patients and also downloadable support materials for clinical use.

Motor neuropathy

Motor neuropathy is less frequent. It can cause weakness of the small muscles that maintain normal foot shape resulting in a change to foot shape. The foot may develop a high arched shape with clawing of the toes (Pes cavus). A foot with Pes cavus is characterised by a high arch and retracted toes. The change of shape in the foot results in increased pressure on the metatarsal heads in the forefoot, this can lead to an excessive build up of callus, resulting in the tissues breaking down and an ulcer developing.

Foot with Pes cavus

Sensory neuropathy

Many individuals who have developed sensory neuropathy have no symptoms whatsoever and maybe unaware of the presence of this condition. This is why screening for any signs of neuropathic changes is so important. This will be carried out by any appropriately trained healthcare professional/worker every 2 years for anyone in the Low Risk category and annually for anyone in the Moderate Risk category.

What are the symptoms of sensory neuropathy?

  • Lack of sensation
  • Lack of awareness of pain
  • Lack of awareness of hot and cold
  • Pins and needles
  • Burning sensation
  • Shooting pains
  • Numbness

Paradoxically, although loss of sensation is a prominent symptom it may also be associated with painful symptoms. In some individuals the skin may be very sensitive to light touch and even the weight of the bed clothes at night may cause discomfort, this is called Painful Peripheral Neuropathy (PPN).

Peripheral neuropathy

There are 3 main types of peripheral neuropathy that affect the feet of individuals with diabetes;

  1. Sensory neuropathy
  2. Motor neuropathy
  3. Autonomic neuropathy

Foot ulcers

Why are individuals with diabetes more likely to develop foot ulcers which may lead to amputation?

Not all individuals with diabetes will develop foot problems but the most important factors related to the development of foot ulcers are;

  1. Peripheral neuropathy – reduced nerve functioning due to peripheral diabetic neuropathy. This means that nerve that usually carry pain sensation to the brain from the feet do not function as well
  2. Peripheral arterial disease – narrowing of the arteries that can reduce the blood flow to the feet
  3. Significant structural foot deformities – resulting in areas of increased pressure which may lead to ulceration
  4. Significant callus – resulting in increased pressure to underlying tissues which may result in a breakdown and ulceration
  5. Minor foot trauma – causing injury which may lead to ulceration
  6. Poorly fitting footwear – resulting in trauma to areas of the foot which may lead to ulceration
  7. Previous foot ulceration – is the highest risk factor for future ulceration
  8. Visual/mobility problems – resulting in the individual being unable to check their feet