Necrotizing Fasciitis: A Comparative Analysis of 56 Cases: DISCUSSION

5 Dec
2009

The reported annual incidence of NF is 2-3 cases. Our yearly incidence of 14 cases, therefore, represents one of the highest ever reported worldwide; this might be a result of the general confusion surrounding the term NF and our inclusion of other necrotizing soft-tissue infections. Recently, Khan et al. reported about 20 cases in 15 months while evaluating the effect of high-dose quinolones therapy in patients with NF. We have chosen 15 years as a criterion mark between children and adults only for the purpose of this study. This choice was predicated by the common practice in northwestern Nigeria to get females, or sometimes males, to marry and bear children before the age of 15 years. Our findings in this study contradict the earlier assertion by some authors that NF is predominantly a disease of the adult population. In this study, over half of the patients (57.1%) were children aged <15 years. However, the age/sex distribution (Figure 1) is an affirmation that the disease can affect both sexes and all age groups.

In both age groups, the presenting features were similar, consisting mainly of pain, fever, tissue necrosis, significant undermining and toxemia. Although the precipitating factors appear similar, the premorbid pathology in children was mainly malnutrition; in the adult age group, this consisted mainly of diabetes mellitus, HIV/AIDS, and lymphedema. Adults presented to the hospital later than children. This is probably because most adults would have sought treatment from traditional healers or patent medicine stores before presenting to hospital, as is the case in other medical and surgical conditions. The observed mean BSA involved was higher at the extremes of life— probably a function of the body’s immunity and the virulence of the invading microorganisms among other factors. As noticed in other reports, the upper half of the body was the most commonly involved in children; in the adult age group, however, it was the lower half of the body (Table 1). Gram-positive organisms were the predominant isolated pathogens in the pediatric age group, while gram negatives were the most commonly identified organisms in adults. However, the polymicrobial nature of the isolates is obvious in both age groups as has earlier been observed by several workers. In NF, the primary pathogens are usually the aerobic partners, which contribute the destructive enzymes that lead to tissue necrosis, thus creating a favorable environment for invasion by the anaerobic organisms. Unfortunately, we could not carry out viral, fungal and anaerobic bacterial cultures in this study, which may partly explain some negative cultures obtained in the study. Unusual organisms, like vibrio vulnificus, Photobacterium damsela and Cryptococ-cus neoformans, have earlier been isolated in the gastrointestinal tract in fishermen and in renal transplant patients, respectively.

In both children and adults, several debridements were undertaken. This was necessary to forestall the ongoing tissue destruction that is usually evident in this condition. Our mean number of debridements of two is similar to but less than that reported by Moss et al., where an average of four of such procedures was required. This has financial consequences; also, debridements could be attended by significant blood loss and the need for blood transfusions. This (and other factors) warranted blood transfusion in 28.1% and 54.15% of children and adults, respectively, in our study. The use of pure natural honey as the primary wound dressing agent in our study may, among other reasons, account for the significantly fewer number of debridements and the high proportion of patients whose wounds healed by secondary intention. Experimental and clinical studies have proven that honey accelerates wound healing through its physical, chemical and biological properties. These properties include the following: debridement of wounds by chemical or enzymatic action; absorption of edema fluids around wounds; inactivation of bacteria; deodorization of offensive wounds; and promotion of granulation tissue formation and epithelialization. The chemical debridement action has been found to be of greatest advantage in necrotizing soft-tissue infections, including Fournier’s gangrene and cancrum oris. Honey has been found to contain a thermolabile bactericidal substance, inhibin. The hygroscopic property of honey enables it to dehydrate bacteria (rendering them inactive) and to dehydrate edematous and soggy wounds (rendering them more clearly defined), thereby promoting wound-healing. Its antimicrobial activity may also be related to its acidic pH. Furthermore, the viscose barrier formed by honey also prevents wounds from being penetrated and colonized by microorganisms. In both age groups, the morbidity was high in terms of prolonged hospital stay and complications. However, mortality was higher in adults (16.7%>) than children (9.4%>). The relatively low overall mortality (12.5%) in this study, compared to others, may also be connected to the variations in the nomenclature of soft-tissue infections. The deaths resulted mainly from septicemia, tetanus and complications of anemia.

In conclusion, NF is more common in children than in adults in northwestern Nigeria. Although polymicrobial in both age groups, gram positives are more common in children. The upper half of the body is most affected in children and the lower in adults. In both age groups, morbidity and mortality still remain high despite early recognition and aggressive therapy. There is a need for consensus among researchers on the classification of necrotizing soft-tissue infections in order to make their results comparable.

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