Poor/Slow Wound Healing

Many wounds pose no challenge to the body's innate ability to heal; some wounds, however, may not heal easily either because of the severity of the wounds themselves or because of the poor state of health of the individual.  Any wound that does not heal within a few weeks should be examined by a healthcare professional because it might be infected, might reflect an underlying disease such as diabetes, or might be a serious wound requiring medical treatment. All wounds follow roughly the same healing process, which consists of an orderly progression of events that reestablish the integrity of the damaged tissue.  The initial wound touches off a series of separate - yet interdependent - responses to the injury, including inflammation, epithelialization (growth of new skin), angiogenesis (blood vessel regeneration), and the accumulation of cells necessary to heal the tissue.

There are many different causes of wounds.  Partial-thickness wounds penetrate the outer layers of the skin (the epidermis and the superficial dermis) and heal by regeneration of epithelial tissue (skin).  Full-thickness wounds involve a loss of dermis (deeper layers of skin and fat) and of deep tissue, as well as disruption of the blood vessels; they heal by producing a scar.

Wounds are classified by 'stage'.

• Stage 1 wounds are characterized by redness or discoloration, warmth, and swelling or hardness.
• Stage 2 wounds partially penetrate the skin.
• Stage 3 describes full-thickness wounds that do not penetrate the tough white membrane (fascia) separating the skin and fat from the deeper tissues.
• Stage 4 wounds involve damage to muscle or bone and undermining of adjacent tissue.  They may also involve the sinus tracts (red streaks indicating infected lymph vessels).

Ulcers are open sores on the skin (or a mucous membrane) that cause destruction of surface tissue.  An ulcer can be shallow or deep and crater-shaped.  Ulcers are usually inflamed and painful.  Types of ulcers include traumatic ulcers, arterial ulcers (tissue death due to impaired arterial circulation), venous ulcers (caused by faulty backflow valves within veins), diabetic foot ulcers (caused by a narrowing of the small arteries), and pressure ulcers (also known as bedsores).

Burns fall into three categories:

• A first-degree burn results in a superficial reddened area on the top layer of the skin (epidermis) like that caused by a mild sunburn.
• A second-degree burn involves the epidermis and second layer of the skin.  It results in a blistered injury that heals spontaneously after the blister fluid has been removed.
• A third-degree burn penetrates all layers of the skin and will usually require surgical intervention in order to heal.

The Stages of Wound Healing
Wounds with even edges that come together spontaneously (minor cuts) or can be brought together with sutures usually heal well with routine wound care.  Wounds with rough edges and tissue deficit (a crater) may take longer to heal.  When there is a crater and the edges of a wound are not brought together (left open intentionally), bumpy granulation tissue grows from the exposed tissue.  The granulation tissue is eventually covered by skin that grows over the wound from the cut edges to the center.  When healing is complete, the granulation tissue develops into tough scar tissue.

All wounds heal in three stages:

1. Inflammatory Stage, occurring during the first few days.  The wounded area attempts to restore its normal state by constricting blood vessels to control bleeding.  Platelets and thromboplastin make a clot.  Inflammation (redness, heat, swelling) also occurs and is a visible indicator of the immune response.  White blood cells clean the wound of debris and bacteria.
2. Proliferative Stage, lasting about 3 weeks (or longer, depending on the severity of the wound).  Granulation occurs, which means that special cells called fibroblasts make collagen to fill in the wound.  New blood vessels form.  The wound gradually contracts and is covered by a layer of skin.
3. Maturation and Remodeling Stage, lasting up to 2 years.  New collagen forms, changing the shape of the wound and increasing strength of tissue in the area.  Scar tissue, however, is only about 80% as strong as the original tissue.

The Danger of Infection
Poorly healing wounds may partially be due to the types of offending organisms they harbor.  Tissue is constantly in contact with pathogens which, under the proper conditions, are able to proliferate to create pathological conditions.  Many different types of pathogens may be involved.

Infection of a wound with a large number of bacteria, a process known as colonization, will slow the healing process.  However, all wounds contain some bacteria.  This contamination usually does not affect the healing process.  The difference between contamination and colonization is the concentration of bacteria.  Signs of infection include red skin around the wound, discharge containing pus, swelling, warmth, foul odor, and fever.

Anaerobic bacteria such as bacteroides, clostridium and streptococcus may be active at deeper levels of the dermis, insulated from the healing influence of oxygen.  Anaerobic bacteria are responsible for many devastating infections resulting in gangrene.  Aerobic bacteria are more closely identified with superficial epidermal layers but may also be involved in infective processes and include staphylococcus epidermis, corynebacteria, propionobacteria.

Causes and Development; Contributing Risk Factors

Poor circulation plays a part in most wounds that do not heal readily.  Diabetes provides an example of this, where there can be impaired circulation and altered carbohydrate metabolism.  In cases where diabetes affects the peripheral circulation, tissues such as the epidermis and dermis become compromised, and thus are more prone to injuries and persistent infections.  Diabetic ulcers frequently develop following simple injuries and are notoriously difficult to treat.

In a study of women being treated for venous leg ulcers, it was revealed that the women had suboptimal dietary intake of energy-providing food sources and key wound-healing nutrients such as vitamin C and zinc even though they had well-organized food habits [Wissing et al.  1997].

Treatment and Prevention

Wound Treatment. Hyperbaric Oxygen Therapy is used to treat very serious wounds.  The patient breathes 100% oxygen in a pressurized chamber for 90-120 minutes.  The oxygen dissolves into the blood and is distributed throughout the body, providing extra oxygen to the cells attempting to heal the wound.  Hyperbaric oxygen treatments have been found to increase the rate of collagen deposition, angiogenesis, and bacterial clearance.  Another benefit is that, if the wound environment has more oxygen, certain types of bacteria that cause serious infections cannot grow.  This method has been used for many years in treating difficult or complicated, nonhealing wounds.  It is well recognized as a very effective treatment.

Whirlpool Therapy is used by physical therapists once or twice daily for about 20 minutes during the inflammatory stage of healing to enhance circulation and bring more oxygen into the wound area.  The whirlpool also softens and loosens dead tissue and cleanses the wound.  Some patients find that whirlpool therapy relieves wound pain.  Whirlpool therapy should not be used on wounds that are in the proliferative stage of healing because it will damage the fragile skin cells.  It should not be used on venous ulcers which result from too much blood in the area.

Ultrasound treatment uses mechanical vibration delivered at a frequency above the range of human hearing.  Physical therapists report that covering the wound area with a hydrogel film and applying ultrasound during the inflammatory and proliferative stages stimulates the cells involved in wound healing and also warms the tissue, enhancing healing by improving circulation.

Electrical Stimulation mimics the body's own bioelectric system that influences wound healing by attracting repair cells, changing the permeability of cell membranes, and therefore affecting secretions and orienting cell structures.  A current is generated between the skin and inner tissues when a break in the skin occurs.  This current is enhanced by a moist wound environment and can be mimicked by electrical stimulation which is believed to accelerate the healing process.  Electrical stimulation uses electrodes that are positioned around the wound area.  It can be used on most wounds during all three stages to support, speed, and even improve wound healing.  Use of this therapy results in a smoother, thinner scar.  In 1994, the Agency for Health Care Policy and Research endorsed electrical stimulation therapy for treating Stage III and IV pressure ulcers, based on data from five clinical trials involving 147 patients.

Magnetic therapy has a rationale similar to that for electrical stimulation, because the body's magnetic field is related to its bioelectric system.  The use of magnets has been reported to increase blood flow and enhance cell growth by transferring energy.  Magnets also affect nerve signals in ways that may relieve pain.  A published case study describes the complete healing of a long-standing abdominal wound by using magnet therapy for one month.  [Szor et al.  1998]

Growth Factors are being studied intensively.  These are biological substances that exert their influence by causing cellular growth and proliferation.  In an ideal wound-healing situation, new tissue growth would replace damaged tissue resulting from a wound with no functional or cosmetic impairment.  In other words, the newly-grown tissue would work as well as the previous tissue that was damaged, and it also would be identical in appearance.  Understandably, research involving growth factors in wound care management is among the most intriguing research being conducted.  There is hope that we are on the eve of learning how to manipulate growth factors, as well as cytokines, to control wound healing, improving function and aesthetics.

Drugs
Less researched, Dilantin (Phenytoin) is a drug commonly used to treat epilepsy and seizure disorders.  One of the known complications of Dilantin is gingival overgrowth (overgrowth of tissue at the gum margins in the mouth), suggesting that Dilantin might have an ability to alter and improve healing in chronic wounds by the same mechanism of encouraging tissue growth.  Although no studies have been reported in the United States, Dilantin has been reviewed in Great Britain and suggested for this use [Talas et al.  1999].  In another study, topical Dilantin was compared with glucose analogs (honey) in patients with chronic leg ulcers over a 4-week period and showed superiority [Oluwatosin et al.  2000].

Nutritional Supplements
Research has shown that certain nutrients such as aloe vera, arginine, glutamine, zinc, copper, and vitamin C play key roles in wound healing [Vaxman et al.  1990; Worwag et al.  1999].  The typical Western diet is deficient in these nutrients.

Complications

With any type of wound - even seemingly minor injuries - there is always danger of rapid multiplication of bacteria.  The elderly and persons with reduced immunity are at great risk for wound-related infections.  Once bacteria escape from the primary location of a wound, they enter the blood.  This condition is commonly called blood poisoning, septicemia, sepsis, or septic shock.  Sepsis is always a serious, life-threatening condition, with 56% mortality.  In the United States, sepsis occurs annually in some three cases per 1,000 population.  In sepsis and septic shock, circulation is reduced; blood pressure is markedly reduced, causing vital organs to receive reduced blood supply; heart, kidney, and liver functions are reduced or show signs of shutdown (multiorgan failure); and abnormal bleeding can develop.  Symptoms of septicemia and septic shock are sudden onset of illness, high fever, chills, rapid breathing, headache, and altered mental state.  If the infection is identified promptly and the patient is treated aggressively (in an intensive care facility), full recovery from sepsis is possible.

Tetanus prophylaxis is essential in wounds.  Tetanus used to be a common cause of death, but is seldom seen now because of antibiotic treatment and vaccinations.  However, in an unvaccinated person over 60 who develops tetanus, mortality is in excess of 60% once the disease process begins, regardless of what treatments are begun at that time.  Persons with uncomplicated wounds who have not been vaccinated for tetanus in the prior 5 years should receive a tetanus booster.  In complicated wounds – those that are particularly dirty or contain a large amount of devitalized tissue – tetanus vaccination should be updated after 5 years.  Symptoms of tetanus include irritability, headache, fever, and painful muscle spasms resulting in a condition called lockjaw.