Poor wound healing may occur in a number of situation but it is of particular concern to diabetics especially when it occurs on the legs. Due to the nature of the disease, diabetics may find that a minor injury with a small wound can rapidly progress into large ulcers and serious infections. Most diabetics are concerned about the onset of gangrene and the possibility of an amputation. A non-healing wound is often the starting point and it is important for diabetics to understand how and why it occurs.
What is a non-healing wound?
As the name suggests, a non-healing wound is tissue injury that does not heal properly and within a period of time that would be considered normal. It indicates a problem with healing mechanism in the body but does not only occur with diabetes. Many conditions can contribute to non-healing wounds and other factors like cigarette smoking, radiation exposure or corticosteroid use also play a role.
A non-healing wound would refer to any wound that does not heal within 6 to 8 weeks despite proper wound care. It would be considered a chronic non-healing wound if it does not heal within 3 months. Some chronic wounds may not heal for years. It may also be referred to as poor or impaired wound healing although non-healing wounds do not respond to measures utilized in traditional wound care management.
Healing starts within a few minutes to several hours after an injury is sustained. It can continue for several weeks to months thereafter although the continued healing may not always be visible on the surface. With non-healing wounds, the wound remains ‘open’ for weeks or months and often there are relapses even after some healing occurs.
How does wound healing occur?
It is important to understand the physiology behind wound healing, Despite individual differences in healing capability and the size and depth of the wound, all wound healing undergoes the same systematic process. It can be explained according to four phases that overlap although these are not separate events.
Phase 1 – Hemostasis
Hemostasis simply means to stop bleeding. It occurs almost immediately after the injury occurs and usually lasts for about 10 to 15 minutes. The blood vessels constrict to limit blood flow to the area and the clotting processes commences to seal the break. The initiation of clot formation also leads to the release of certain chemicals that attract inflammatory cells to the are of the injury. This allows for continuation of the next phase of wound healing.
Phase 2 – Inflammatory Phase
During this phase blood flow to the area is restored and it allows for a number of different cells to reach the area. These cells include neutrophils, macrophages and lymphocytes. It helps to destroy any microbes like bacteria in the area, breaks down damaged tissue and mops up cellular debris. Chemicals released by these cells then stimulate the formation of new tissue and repair of the injured area.
Phase 3 – Proliferative Phase
Granulation tissue starts to form at the site about 3 to 5 days after the injury. New blood vessels form in the area to expedite the tissue repair. The granulation tissue contracts thereby pulling the ends of the wound closer together. Epithelial tissue forms over the wound thereby sealing the wound from the environment. New skin grows over the wound and this phase of healing takes place over 2 to 3 weeks.
Phase 4 – Maturation Phase
Collagen, the main component of connective tissue, that was deposited in the earlier phases is removed and replaced with new collagen. One type of collagen is replaced by another and water is resorbed from the area thereby pulling collagen closer together. Remodeling starts around 3 weeks after the injury and may continue for about 60 days. However, it can continue indefinitely.
Poor Wound Healing in Diabetes
The impairment of wound healing is worse in long standing, poorly managed diabetes. This occurs for a number of reasons.
Firstly it is well known that the elevated blood glucose levels in diabetes has a major impact on blood vessels. There is gradual thickening and narrowing of these blood vessels, among a host of other changes that reduces blood flow through it. This affects even the smallest of blood vessels in the body.
Adequate blood is necessary to carry cells and components necessary for a heightened immune response and healing of the wound. It is also necessary for the greater oxygen and nutritional requirements at the site of the healing. Overall the reduced blood supply means that the process of wound healing is impaired.
However, the impairment of wound healing in diabetes is further complicated by the host of other effects that the disease has on the body. The immune system is weaker than normal and the formation of new blood vessels for wound healing is also impaired. The nerve damage (neuropathy) and decreased sensation also increases the risk of further injury to the area.
Furthermore, the wounds do not have the same strength as in non-diabetics. Normally the tensile strength of a wound is about 80% of uninjured areas. With diabetes the tensile strength is lower meaning that the wound may reopen more easily. The risk of infections at the site in light of the impaired immunity is a major stumbling block for proper wound healing.
Injuries and Wounds in Diabetes
Diabetics can sustain the same injuries as non-diabetics. It can vary from a minor cuts to deep ulcers. Even stubbing a toe or cutting a toe nail where there is no visible injury can progress into open wounds with time if it is left unattended. Apart from infections hampering wound healing, it can also spread into the deeper tissues leading to conditions like cellulitis. This condition can be difficult to treat in diabetics but it may also extend further.
Once the bacteria enter the bloodstream, it can spread throughout the body. This condition is known as septicemia and can be life-threatening. In other words, a small cut in the foot can become fatal in a diabetic. Wound care in diabetics has to therefore be carefully by a health care professional, even if it is a relatively minor wound. About 15% of diabetics will experience a non-healing wound in their lifetime. Any sign of a non-healing wound needs specialist care.