Diabetic Foot Ulcers

  • Definition
  • Wound Care
  • Patient Advice and Prevention
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Diabetic foot ulcer (Malum Perforans Pedis)

To know more about diabetic foot ulcers, click herediabetic-foot-ulcer-01

This is a chronic, painless and clean ulceration that develops because of vascular, neurological and metabolic disorders in diabetes.

Diabetic foot ulcers are usually located under the head of the 2nd or 3rd metatarsal bone or on any other point of normal or abnormal pressure on the underside of the foot.

They can be readily complicated by infections, abscesses or osteitis and frequently result in amputation if untreated.

Diabetes

Diabetes is a state of hyperglycaemia (high blood glucose) resulting from both genetic and environmental factors.

Definition of glycaemia

Glycaemia: level of glucose in the blood.

  • Normal glycaemia in a healthy subject, on an empty stomach, is between 0.7 and 1.1g/l.
  • Hypoglycaemia: below 0.7 g/l.
  • Hyperglycaemia: above 1.1 g/l.
  • Diabetes: above 1.26 g/l.

Type I Diabetes (10% of diabetics)

This form of diabetes is characterised by the complete or almost complete disappearance of insulin secretion by the pancreas. This lack of insulin is responsible for serious hyperglycaemia and will have a fatal outcome if not treated by frequent insulin injections.

Type 2 Diabetes (90% of cases)

This form of diabetes is characterised by insulin resistance, frequently accompanied with obesity. Need for insulin treatment is rarely necessary when diet is controlled and glucose lowering drugs such as metformin are efficient. Unfortunately, insulin becomes necessary after several years of evolution.

 

In both types of diabetes, chronic hyperglycaemia is responsible for long-term complications that explain the high morbidity and mortality associated with the disease.

Pathophysiology

If the patient does not pay careful attention to their feet, ulcers can develop quickly.

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Neurological abnormality in the diabetic foot reduces the skin’s ability to sweat, leaving the skin dry, liable to fissure and open to infection. Lack of sensation and alterations in the structure of the foot contribute to the formation of ulcers at points of excessive pressure.

Incidence/prevalence

Approximately, 15% of diabetic patients have or have had a wound on their feet. The risk of amputation is 15 to 20 times higher in the diabetic population than it is in the general population.

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Between 5% and 10% of people with diabetes will, at some stage, have to undergo an amputation (toe/leg). In 30% to 50% of cases, there is a risk of contralateral amputation within 5 years. The mortality rate is 50% within 5 years after amputation.

The extent of this human and financial problem should prompt improvements in preventive care.

Characteristics

The ulcer takes the form of a wound with well-defined keratinous and sharp edges. The greatest risk is from infection. Typically painless, the patient may be unaware that infection has set in. The foot ulcer provides a gateway for infection that can have long term consequences.

Even in the absence of infection poor blood supply can lead to the establishment of “dry” or diabetic gangrene, where the lack of blood supply causes the affected tissue to slowly die, if there is peripheral arterial occlusive disease the risk of amputation is high.

diabetic-foot-ulcer-04

Healing diabetic foot wounds is a complex process due to poor vascularisation and other metabolic changes in diabetes. Vascular assessment should be made when a patient presents with an ulcer because it influences the eventual healing process.

The care protocol involves cleaning the wound with physiological serum before dressing and using preventive measures to stabilise the pressure on the foot with off-loading.

Dressing choice will depend on level of exudate and infection. A flexible dressing also offers a considerable advantage given the often difficult location of the ulcers:

  • Occlusive dressings should be avoided
  • If the wound is not infected then a dressing that ensures a moist wound healing environment can be used to accelerate healing in the presence of high levels of MMPs.
  • Dressings should be changed frequently and the wound must be closely monitored:
    • If a silver containing dressing is used, it should be changed every 1 to 3 days depending on the level of exudate and condition of the wound:
      •  It is recommended to use silver containing dressings for at least two weeks, and then to re-assess the wound.
      • A maximum of four weeks is usually recommended.

See the links below for more information about:

  • Debridement
  • Infection

The patient’s blood sugar must be well monitored and steps taken to achieve optimal glycaemia, to prevent periods of prolonged hyperglycaemia which will impede wound healing.


These advices or recommendations do not replace expert opinion based on a full diagnosis.

Care of the feet is essential in all patients with diabetes.

To find out more

It is important that healthcare professionals frequently check the sensitivity of the foot (cold, heat, foreign body, reflexes, etc.). Insensitivity is a major contributory factor to the development of a foot ulcer.

Podiatrists are experts that can pay special attention to the fit of shoe and the general conditions of the foot checking regularly for any signs of injury or infection.

Patients should avoid walking bare footed and careful hygiene is essential.


These advices or recommendations do not replace expert opinion based on a full diagnosis.
Last update : December 9, 2017