In addition to poor circulation, neuropathy, and difficulty moving, factors that contribute to chronic wounds include systemic illnesses, age, and repeated trauma.
[12] Comorbid ailments that may contribute to the formation of chronic wounds include vasculitis (an inflammation of blood vessels), immune suppression, pyoderma gangrenosum, and diseases that cause ischemia.
[2] Emotional stress can also negatively affect the healing of a wound, possibly by raising blood pressure and levels of cortisol, which lowers immunity.
[2] Repeated physical trauma plays a role in chronic wound formation by continually initiating the inflammatory cascade.
Heroin users who lose venous access may resort to 'skin popping', or injecting the drug subcutaneously, which is highly damaging to tissue and frequently leads to chronic ulcers.
[16] Periwound skin damage caused by excessive amounts of exudate and other bodily fluids can perpetuate the non-healing status of chronic wounds.
[18] The reason a wound becomes chronic is that the body's ability to deal with the damage is overwhelmed by factors such as repeated trauma, continued pressure, ischemia, or illness.
[14] Nonetheless, current researchers now understand some of the major factors that lead to chronic wounds, among which are ischemia, reperfusion injury, and bacterial colonization.
[20] However, soluble mediators of the immune system (growth factors), cell-based therapies and therapeutic chemicals can propagate coordinated healing.
[21] It has been suggested that the three fundamental factors underlying chronic wound pathogenesis are cellular and systemic changes of aging, repeated bouts of ischemia-reperfusion injury, and bacterial colonization with resulting inflammatory host response.
More recently, an interplay between bacterial colonization and increases in reactive oxygen species leading to formation and production of biofilms has been shown to generate chronic wounds.
[23] Like ischemia, bacterial colonization and infection damage tissue by causing a greater number of neutrophils to enter the wound site.
[24] In addition, patients that carry drug resistant bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA) have more chronic wounds.
They are thought to be due to venous hypertension caused by improper function of valves that exist in the veins to prevent blood from flowing backward.
[17] Various methods exist to ameliorate these problems, including antibiotic and antibacterial use, debridement, irrigation, vacuum-assisted closure, warming, oxygenation, moist wound healing (the term pioneered by George D. Winter), removing mechanical stress, and adding cells or other materials to secrete or enhance levels of healing factors.
[34] For infected wounds, the following antibiotics are often used (if organisms are susceptible) as oral therapy due to their high bioavailability and good penetration into soft tissues: ciprofloxacin, clindamycin, minocycline, linezolid, moxifloxacin, and trimethoprim-sulfamethoxazole.
[39] A greater amount of exudate and necrotic tissue in a wound increases likelihood of infection by serving as a medium for bacterial growth away from the host's defenses.
[38] Debridement and drainage of wound fluid are an especially important part of the treatment for diabetic ulcers, which may create the need for amputation if infection gets out of control.
[8] The treatment also decompresses tissues and alters the shape of cells, causes them to express different mRNAs and to proliferate and produce ECM molecules.
[2][8] Recent technological advancements produced novel approaches such as self-adaptive wound dressings[40] that rely on properties of smart polymers sensitive to changes in humidity levels.
The dressing delivers absorption or hydration as needed over each independent wound area and aids in the natural process of autolytic debridement.
It effectively removes liquefied slough and necrotic tissue, disintegrated bacterial biofilm as well as harmful exudate components, known to slow the healing process.
[41] The treatment also reduces bacterial load by effective evacuation and immobilization of microorganisms from the wound bed, and subsequent chemical binding of available water that is necessary for their replication.
[43] Chronic wound healing may be compromised by coexisting underlying conditions, such as venous valve backflow, peripheral vascular disease, uncontrolled edema and diabetes mellitus.
For every pharmacological intervention there are possible benefits and adverse events that the prescribing clinician will need to consider in conjunction with the wound care treatment team.
[31] Some healthcare professionals use 'radiant bandages' to keep the area warm, and care must be taken during surgery to prevent hypothermia, which increases rates of post-surgical infection.
In other cases, skin from cadavers is grafted onto wounds, providing a cover to keep out bacteria and preventing the buildup of too much granulation tissue, which can lead to excessive scarring.
Though the allograft (skin transplanted from a member of the same species) is replaced by granulation tissue and is not actually incorporated into the healing wound, it encourages cellular proliferation and provides a structure for epithelial cells to crawl across.
[3] Collagen dressings are another way to provide the matrix for cellular proliferation and migration, while also keeping the wound moist and absorbing exudate.
[6] Additionally Collagen has been shown to be chemotactic to human blood monocytes, which can enter the wound site and transform into beneficial wound-healing cells.