Burn Wound: An update focusing the classification, Immune responses and management resources aid in healing

 

Shubhangi Dwivedi*, Prashant Tiwari

School of Pharmacy, Chouksey Engineering College, Bilaspur, India-495004

*Corresponding Author E-mail: shubh12987@hmail.com

 

ABSTRACT:

Burns are one of the most familiar and distressing forms of trauma which results from excess exposure to heat, caustic chemicals, solar, lumpectomy/ mastectomy, or radiation. Burn wound development remains an amazing challenge for burn diagnosis and therapy. Patients with serious thermal injury require immediate specialized care in order to reduce morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to complications due to bacterial colonisation and invasive bacterial infection. The review sheds spotlight on the current outline of classifications of burn wound infections, immunological responses of burns, treatment strategies. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Moreover bioresources from plant and animal has served as an existing therapy in healing of wounds and in restoration of skin’s integrity.  Improved outcomes for severely burned patients have been accredited to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control parameters in the aid of such harrowing condition .

 

KEYWORDS: Burn Wound, Immunologic responses, treatment, silver impregnated devices.

 

 

1. INTRODUCTION:

1.1 Human Skin—A Major Host Defense

An intact human skin surface is imperative to the preservation of body fluid homeostasis, thermoregulation, and the host's shielding against infection. The skin also has immunological, neurosensory, and metabolic functions such as vitamin D metabolism but thermal injury results in infringement on the surface of the skin. A basic knowledge of skin anatomy and physiology is required to understand emergency burn assessment and approaches in burn care management(1-3).

 

 

1.2 Immunological Response of Burns

Notable thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. Early annotations of the immunodeficiency that follows thermal injury were linked to works on “burn toxins” (4-6). Moreover these observations were supported by the findings of prolonged allograft survival, anergy, and increased susceptibility to infection in burn patients (7-12). Despite improvements in the preliminary care of burn patients, systemic inflammatory response syndrome, severe sepsis, and multiple-organ dysfunction syndrome still remain as major causes of morbidity and mortality (13-15). As a consequence, of which further efforts in the development of immune modulators shows signs for future imminent enduring research.

 

Host defense against infection can be divided into innate and adaptive immune responses. The innate immune response acts immediately after the integument system is breached and relies on a phylogenetically ancient system for microbial recognition in which germ line-encoded receptors (pattern recognition receptors) recognize structural components of microorganisms and viruses (pathogen-associated molecular patterns) (16). The adaptive immune response often takes longer, especially if it involves exposure to new antigens. However, the adaptive immune response is a more efficient system for dealing with recurrent infections, relying on immune cell memory, antigen recognition, and clonal proliferation. The immunosuppression associated with burn injuries has effects on both of these systems. Many in vitro and in vivo studies have been conducted to characterize the immune responses and the relationships between various cell types and inflammatory mediators. (17-21) with the summation of the fact that the post alterations occurs in immune response after injuries caused by burns.

 

1.3 Epidemiology of Burn Wound Infections

Burn wound infections is a severe complications that occur in the acute period following injury (22-27). The most important patient characteristics that influence morbidity and mortality from burn wound infection and sepsis is outlined below. In addition, the impact of early excision on reducing burn wound infections is discussed. Other factors that have played a significant role in decreasing the overall fatality rates from burn wound infection and sepsis include the use of topical and prophylactic antibiotics and advances in infection control measures in modern burn units.

 

2. Types of Burn Wound Infection

2.1 Burn wound impetigo. 

Impetigo involves the loss of epithelium from a previously reepithelialized surface, such as grafted burns, partial-thickness burns allowed to close by secondary intention, or healed donor sites. Burn wound impetigo is not related to inadequate excision of the burn, mechanical disruption of the graft, or hematoma formation.

 

2.2 Burn-related surgical wound infection. 

Both excised burn and donor sites that have not yet epithelialized are included in Surgical wound infections in burn patients. The wound has purulent exudates that is culture positive. Surgical wound infections in open areas of the burn show loss of synthetic or biological covering of the wound, changes in wound appearance (such as hyperemia), and erythema in the uninjured skin surrounding the wound.

 

2.3 Burn wound cellulitis. 

Burn wound cellulitis results from an extension of infection into the healthy, uninjured skin and soft tissues surrounding the burn wound or donor site. This condition is recognized by extension of erythema in the uninjured skin surrounding the burn beyond what is expected from the injury itself. Burn wound cellulitis is not associated with other signs of wound infection, but at least one of the following manifestations is present: localized pain or tenderness, swelling or heat at the affected site, progression of erythema and swelling, and signs of lymphangitis and/or lymphadenitis extending from the affected skin area along routes of lymphatic drainage to the area.

 

2.4 Invasive infection in unexcised burn wounds. 

Patients with areas of unexcised deep partial-thickness or full-thickness burn wound have an increased risk of developing an invasive infection (28-30). This complication may be indicated by a speedy allied transformation  in burn wound appearance or character such as separation of the eschar or dark brown, black, or violaceous discoloration of the eschar. Manifestations of invasive infection of unexcised burn wounds include inflammation of the surrounding uninjured skin, such as edema, erythema, warmth or tenderness, evidence of microbial invasion into adjacent viable tissue on histological examination, and positive blood cultures with isolation of a pathogen in the absence of another identifiable source of infection and systemic signs of sepsis, i.e., tachypnea, hypotension, oliguria, unexplained hyperglycemia (e.g., increased serum glucose level that develops at a previously tolerated level of dietary carbohydrate), and/or mental confusion. Effective treatment requires surgical excision of the burn in addition to the medical measures outlined previously.

 

3. Approach for Burn Wound Infection Surveillance

The best approach for scheduled infection surveillance of burn wounds is to utilize the most appropriate sampling technique for the type of burn wound area being cultured, since no single method provides a clinically relevant and reliable result for unexcised wounds (e.g., eschar) versus those that have been excised. Superficial swabs provide an adequate sampling of the microbial flora present on the wound surface and are the most apposite and least invasive methodology currently available for sampling of excised burn areas. Surface swabs are also the only type of sample that may be taken from areas where the skin is too thin to do a biopsy, such as over the ears, eyes, and digits. However, quantitative cultures of burn wound tissue biopsy samples along with concomitant histological analysis are the preferred infection surveillance approach for burn areas that have not been or cannot be excised. Tissue biopsy samples should also be sent for quantitative culture from infected burn wound areas in patients with sepsis.

 

Simultaneous culture of quantitative tissue biopsy, blood, and urine samples provides the best approach for recovery and identification of the causative organisms and their antimicrobial susceptibilities in the septic burn patient. This method also provides an accurate assessment of the depth and extent of burn infection in areas of indeterminate injury. Tissue biopsy analyses are also necessary in order to diagnose unusual types of burn wound infection due to fungi and viruses.

 

 

The basic surgical trouble is to achieve permanent replacement of skin in extensive full-thickness and deep partial-thickness burn injuries along with chronic wounds. In the present scenario, split-thickness skin grafts are considered as the best material for surgical repair of an excised burn wound. But in case of burns that affect greater than 50% of total body surface area, split-thickness skin grafts cannot be harvested as the patient has insufficient areas .

 

Non surgical wounds include chronic ulcers (pressure or decubitus ulcers, venous ulcers, diabetic ulcers, ischaemic ulcers), burns and traumatic wounds. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation (i.e. presence of MRSA in the absence of clinical features of infection such as redness or pus discharge) or infection in chronic ulcers varies between 7% and 30%. MRSA colonisation or infection of non surgical wounds can result in MRSA bacteraemia (infection of the blood) which is associated with a 30-day mortality of about 28% to 38% and a one-year mortality of about 55%. People with non surgical wounds colonised or infected with MRSA may be reservoirs of MRSA, so it is important to treat them, however, we do not know the optimal antibiotic regimen to use in these cases. Moreover, basic aim is to compare the benefits (such as decreased mortality and improved quality of life) and harms (such as adverse events related to antibiotic use) of all antibiotic treatments in people with non surgical wounds with established colonisation or infection caused by MRSA.

 

Collagen based dressings which is extracted from bovine skin and Achilles tendons, are reconstituted for acute burn wound management in coastal areas like Chennai known for high humidity  as closed dressings becomes infected soon and treatment with topical antimicrobials, like Silver Sulfadiazine cream, quickly gets desiccated. Collagen membrane dressings, manufactured by the biomaterial laboratory of the Central Leather Research Institute (CLRI), Government of India in Chennai, with the procedural process is patented.

 

Moreover existing burn management is no longer exclusively meant at patient continued existence but also focuses on optimal functional and esthetic outcome. From a practical point of view, in order to avert hypertrophic scarring and functional impairment, burn care revolves around two major therapeutic options: one being conservative therapy applying dressings for burns with the potential to heal within 21 days, and the other being early excision and grafting, aiming to obtain early wound closure for burns that otherwise would take longer than 3 weeks to heal. In recent years, several new silver impregnated dressings have been developed and put on the market to overcome the shortcomings of 1% silver sulfadiazine(SSD). Most of these dressings are (semi) occlusive, require less dressing changes and demonstrate a prolonged antibacterial effect due to a sustained release of silver ions . (31,32)

In view of the lack of comparative studies on contemporary silver dressings in burn care, the study by Verbelen. J et al ,analysed  on wound healing, bacteriology, economics, nurse and patient experience and aimed to compare two frequently used silver dressings, the nanocrystalline silver dressing Acticoat and the Hydrofiber silver dressing Aquacel Ag, in the management of partial thickness burns with an objectively diagnosed healing potential between 7 and 21 days with the conclusion that Aquacel Ag dressing appreciably amplified ease for patients.

 

Appropriate wound dressing selection is guided by an understanding of wound dressing properties and an ability to match the level of drainage and depth of a wound. Wounds should be assessed for necrosis and infection, which need to be addressed prior to selecting an ideal dressing. Moisture-retentive dressings including films, hydrogels, hydrocolloids, foams, alginates, and hydrofibers are useful in a variety of clinical settings. Antimicrobial-impregnated dressings can be useful in wounds that are superficially infected and are at high risk for infection. For refractory wounds that need more growth stimulation, tissue-engineered dressings have become a viable option in the past few decades, especially those that have been approved for burns, venous ulcers, and diabetic ulcers. As wounds heal, the ideal dressing type may change, depending on the amount of exudate and depth of the wound (33).

 

Delay in wound healing, graft losses, and development of sepsis may be due to Acinetobacter baumannii infections in burn patients. Determining the risk factors for multidrug resistant A. baumannii (MDR-AB) infections is essential for infection control which is assessed by evaluation of the risk factors for wound infections caused by A. baumannii in burn patients. Univariate analysis found that high acute physiological and chronic health evaluation II score, first excision time of wound, invasive device usage, admission day to hospital, and prior usage of broad-spectrum antibiotics were risk factors for nosocomial infections with the consequence that multiple factors contribute to multidrug resistance in A. baumannii. A combination of an early diagnosis of wound infections, appropriate antimicrobial treatments, surgical debridement, and early wound closure may be effective in the management (34).

 

4. Bioresources in the pharmacotherapy and healing of burns

For many years poor and chronic non healing wounds have constituted a serious problem to medicine. Moreover treating such wounds is an expensive and a long-lasting process consequently in this regard Professor Scheller's achievement is spotlighted in using ethanolic extract propolis(is a resinous substance derived from bees’ wax extract). It is claimed to have antimicrobial (antibiotic and antifungal), anti-inflammatory, or immunomodulating, emollient, and cicatrisation-enhancing properties.(35,36) in the treatment of patients suffering from burns, venous crural ulceration, local sacral bone pressure ulcers, suppurative osteitis and arthritis, suppurative postoperative local wound complications, and infected traumatic wounds. Reports also suggest use of Honey, a viscous, supersaturated sugar solution derived from nectar gathered and modified by the honey bee Apis mellifera, with evidence of its capacity to accelerate wound healing, particularly in acute wounds such as partial- thickness burns . For many decades Calendula officinalis, Berberis , Hypercium perforaturm and Aloe vera  has shown promising effect in ensuring reestablishment of the integrity of skin and extracellular matrix.

 

Successful reconstruction of extensive anterior chest wall defect following major electrical burn represents a very challenging surgery. Herein it is elaborated of using pedicled full-thickness abdominal flap combined with skin grafting to treat this injury with severe infection and exposure of pericardium and ribs in a Chinese patient. Following the performance of chest debridement to remove necrotic and infected tissues and the injection of broad-spectrum antibiotics to reduce infection, a pedicled full-thickness abdominal flap was used to cover the exposed pericardium and ribs, and skin grafting from the right leg of the patient was done to cover the exposed vital tissues. The patient was followed up for a total of 3·5 years, and satisfactory cosmetic and functional outcomes were obtained without complications. This report provides an effective method for the surgeons who encounter similar cases where reconstruction of extensive anterior chest wall is required.

 

Complications of infection can increase burn-related morbidity and mortality. Early detection of burn wound infection could lead to more precise and effective treatment, reducing systemic complications and the need for long-term, broad-spectrum intravenous antibiotics. Quantitative cultures from biopsies are the accepted standard to determine infection. However, this methodology can take days to yield results and is invasive (37).

 

 

Hyperbaric oxygen therapy (HBOT) is the use of 100% oxygen at pressures greater than atmospheric pressure. Today several approved applications and indications exist for HBOT. HBOT has been successfully used as adjunctive therapy for wound healing. Non-healing wounds such as diabetic and vascular insufficiency ulcers have been one major area of study for hyperbaric physicians where use of HBOT as an adjunct has been approved for use by way of various studies and trials. HBOT is also indicated for infected wounds like clostridial myonecrosis, necrotizing soft tissue infections, Fournier's gangrene, as also for traumatic wounds, crush injury, compartment syndrome, compromised skin grafts and flaps and thermal burns (38). 

 

 

CONCLUSION:

To deal with traumatic situation of burns ,skeleton of burn wound is depicted which includes classification, immune responses of burn wounds , pathophysiology, epidemiology and some of the updated treatment tools via surgical or non surgical techniques like incorporating silver im pregnated devives  and healing via sources derived from plant and animal origin mentioned in the article. So the current review focuses on the updated knowledge about the healing agent and novel approaches so that in forthcoming time it should be referred as a primary treatment plan and be widely available at burn care units to achieve the utmost goal of patient compliance.

 

ACKNOWLEDGEMENT:

The authors wish to thank the department of School of Pharmacy, Chouksey Engineering College, Bilaspur, India for providing all the facilities to make this work a success. 

 

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Received on 18.04.2014          Modified on 12.05.2014

Accepted on 08.06.2014      ©A&V Publications All right reserved

Research J.  Science and Tech. 6(3): July- Sept., 2014; Page 128-132