Which cause of diffuse peritonitis is the deadliest in the tropics? A retrospective analysis of 305 cases from the South-West Region of Cameroon

Pathological conditions requiring surgery contribute significantly to the global disease burden [1]. It is well established that injuries contribute more than 70 % of death toll in the emergency departments of low and middle-income countries (LMICs) [2]. However, non-trauma related conditions are still responsible for a high number of in-hospital deaths and require specific attention, especially in the tropics [2‐4].

Acute generalized peritonitis is a common surgical emergency worldwide and has been reported as one of the major contributors to non-trauma deaths in the emergency department despite improvements in diagnosis, surgical treatment and intensive care support [4‐6]. The causes of generalized peritonitis vary widely from one setting to another and seem to be correlated to mortality [3, 7, 8]. It is known that community acquired peritonitis represent the vast majority of cases and is largely related to bowel perforation [3, 9]. This latter cause of peritonitis seems to carry the highest mortality rate (10 to 32 %) [7, 9‐12]. Analysis of the contribution of various forms of perforative peritonitis to morbidity and mortality indicate that while results of treatment of peritonitis secondary to peptic ulcer perforation seem to have improved over the past decades [13‐15], other frequent causes in the tropics such as typhoid fever related perforation of the small bowel still carry a heavy morbidity and mortality rates [4, 16‐18].

Some factors influencing outcome of peritonitis which have been studied and reported so far include age, co-morbidities, severity of sepsis, delay before initiation of treatment and immune suppression [3, 6, 8]. Early prognostic evaluation of patients with acute generalized peritonitis is desirable to select patients with a higher risk of adverse event who may be eligible for a more aggressive treatment. Various approaches to anticipate the outcome by grading the severity of peritonitis have been proposed. They generally rely on scoring systems such as APACHE II and the Mannheim Peritonitis Index (MPI).

Data on the burden and outcome of peritonitis in sub-Saharan Africa are very scarce and few studies have attempted a differential analysis of various causes of diffuse peritonitis. As a consequence, surgeons performing in these areas of the world generally lack management guidelines which are adapted to their local conditions characterized by absence of health insurance, poor technical background and limited access to intensive care unit.

The aim of this study is to identify the most common causes of diffuse peritonitis in the tropical latitudes and their relative contribution to morbidity and to death toll. The ultimate goal is to help surgeons identify cases which are likely to require a more aggressive therapy and rationalize the decision to refer patients towards a center with an intensive care unit. We hypothesized that peritonitis secondary to peptic ulcer perforation was the highest contributor to death toll in the tropics.

This study is one of the few conducted in the LMICs, that includes a large sample size and analyzes complications and fatality rates for various causes of diffuse peritonitis.. It is a contribution to the advocacy in favour of global surgery as outlined by the Lancet commission for Global surgery and its objectives for the year 2030 and by the World Health Assembly’s resolutions on the need to reduce the global burden of surgical conditions potentially correctable by surgery, especially in Low and middle income countries [26, 27].

Our study suggests that spontaneous perforation of small bowel, usually typhoid fever related is a substantial problem especially in paediatric populations. Also, peptic ulcer perforation is still a major concern in these areas of the world. Septic complications of illegal abortions also require a specific attention. Large proportion of patients with diffuse peritonitis still present to the hospital with unacceptable delays and this probably accounts for the high incidence of sepsis and high MPI scores at the time of diagnosis with the consequences that it entails in terms of outcome. In settings with limited technical background, the diagnosis of this common clinical entity can still rely largely on clinical arguments. Patients operated on for diffuse peritonitis are likely to develop wound dehiscence, sepsis, prolonged paralytic ileus or multi-organ failure. These complications often occur in combination especially in those with typhoid related small bowel perforation, and can be deadly in more than 15 % of cases. The highest contributors to death toll are all cases of peritonitis originating from bowel perforations, especially those related to complications of typhoid fever which is endemic in the region.

This study brings to light once more the crucial problem of filing and conservation of data in LMICs with nearly 10 % of patients excluded for incomplete data. However, higher rates of patients with incomplete files have been reported in similar settings [2]. Also, it is questionable how the findings of this study can be compared to those from other centers where all the facilities for diagnosis and management are available. In particular, the absence of equipment for the laparoscopic approach is likely to influence the outcome. It has been reported that this approach could be proposed to as much as 27 % of patients [5] with a supposedly better outcome. Our choice to limit this study to diffuse peritonitis is inspired by the fact that this form of peritonitis is by far the most frequent with a higher death toll [3‐5].

While multiple reports indicate that diffuse peritonitis, especially when related to bowel perforation seem to affect young patients with a predominance of male sex [4, 8, 17, 28, 29], major differences in causes between LMICs and developed countries have been reported. In general, patients from LMICs tend to suffer perforations of the proximal gut while does in the western countries are more often affected with perforations of the large intestine [30]. The five most common causes of secondary peritonitis described in our study have been reported in numerous studies in similar settings [7, 9, 12, 29, 31, 32]. Peptic ulcer perforation is still a frequent complication and affects the duodenum in the large majority of cases [7, 9, 33, 34]. Typhoid related perforation of the ileum appears to be a major problem in paediatric populations together with appendicular peritonitis [35‐37]. Involvement of the biliary tract is rare as opposed to findings of western countries [5]. Health care induced peritonitis represents a smaller fraction but tend to be more severe [4, 38].

Late presentation is a major concern in many areas of the world and delays as long as 13 days have been reported [11, 16, 17]. The absence of modern diagnostic tools in settings with limited technical background cannot be considered a major problem as diffused peritonitis can generally be diagnosed or at least suspected on purely clinical grounds in more than 97 % of cases [8, 39].

The choice of antibiotics seem to rely to a large extend on the fact that E. coli has been identified as the most frequent causative agent [8, 40]. Its sensitivity pattern validates our choice of antibiotics combination which elements are very widely used [40, 41], although some studies have reported other germs with a different sensitivity pattern [42]. The replacement of 3^rd generation cephalosporin by ampicillin in the protocol has been proved to be a valid cost-effective regimen, especially if combined with gentamicin [43]. The use of chloramphenicol must be advocated in cases of perforation of terminal ileum suspected to be of typhoid origin [29]. Tertiary peritonitis is frequently polymicrobial and a strategy to tackle fungal infection needs to be considered [3, 38].

Although numerous scoring systems have been proposed to assess the severity of peritonitis, MPI has been largely recognized as a valid and reliable predictor of outcome [6, 8, 21, 44]. This simple, purely clinical assessment tool is particularly adapted to settings with limited access to para-clinical work-up tools and can be extensively used with accuracy comparable to other validated tools such as the various version of the APACHE scoring system [5, 10].

There is strong evidence that the management of diffuse peritonitis should still rely on three fundamental principles: (1) Elimination of the source of infection; (2) reduction of bacterial contamination of the peritoneal cavity; and (3) prevention of persistent or recurrent intra-abdominal infection [4]. Concerning the suppression of the cause, the source of peritonitis can usually be controlled in almost 90 % of cases [4, 28, 45]. Generally it appears that surgeon seem to be generally reluctant using the laparoscopic approach [5]. It has been proven that the results of this approach are equivalent to those of open surgery [13]. In peptic ulcer perforations, the surgical definitive treatment of the peptic ulcer disease is rarely proposed and procedures such has suture and omentoplasty after Graham is generally considered sufficient on the condition that the medical treatment be proposed post-operatively [3, 46]. This approach has the advantage of shortening the operation time and improving the outcome, especially in patients with sepsis. In fact, the results of treatment of all bowel perforation seem to favour simple suturing rather that resections and anatomosis, especially in typhoid related perforations of the small bowel [3, 16, 46‐48]. The need to protect the suture or anastomosis with a loop ileostomy has been discussed [36]. The prevention of persistent intra-abdominal infection currently opposes two strategies: on-demand re-laparotomy and systematic planned relaparotomies. Current literature seem to favour the on-demand approach in terms of length of hospitalization and intensive care unit stay [3, 49‐51].

Morbidity and mortality rates are extremely variable and do not seem to be superior in settings with a limited technical background [4, 8, 9, 18, 28, 29, 39, 45, 52], even in tertiary peritonitis [38]. The mortality rate reported in our study is unacceptably high. This is probably a direct consequence of some of the local conditions of surgical practice such as the scarcity of surgeons, the lack of appropriate diagnosis and management tools and the socio-economic conditions characterized by the total absence of social security even for such critical and potentially deadly conditions. Also, they are no clear standards and guidelines for the management of surgical emergencies which are adapted our settings. However, this heavy mortality rate is not exceptional. It is comparable to what have been reported in other regions and countries with similar settings [43, 46]. Even in some western countries, overall complication rates as high as 41 % have been reported [39, 45].

In differential analysis of relative contributors to death toll, our study clearly points complications of typhoid fever as a major problem. Over the past two decades, the trend of mortality of this type of peritonitis has been on the decline [16, 53, 54]. Such reduction can only be achieved by early recognition and diagnosis, timely surgical intervention, appropriate antibiotics and surgical technique and peri-operative care which all play a key role in reducing mortality in typhoid intestinal perforation [53]. Also, policies on typhoid vaccine and public health education may help to reduce morbidity and mortality due to this endemic disease [55].

Some factors have been reported as related to the morbidity of diffuse peritonitis. One of these factors is the delay before intervention which is considered by many as an important key [2, 4, 6, 17, 56, 57]. Other factors include the source of peritonitis with a higher complication rate for bowel perforations [4, 52, 58] and MPI [21, 22, 56]. The ability to suppress the source of infection also seems to play an important role [58].

The types of complications recorded in our study are generally the rule, especially in low-income settings [29, 31, 37, 59, 60]. Adesunkanmi et al. recorded 58 % of wound dehiscence in a neighbouring country [29].

Despite all the recent advances in the medical management of peptic ulcer disease, its contribution to the death toll of diffuse peritonitis is still unacceptably high and can be predicted with special scoring systems [14, 15, 34, 61]. It has been reported that the number of deaths attributable to peptic ulcer perforation is seven times the one of acute appendicitis [13]. Although the outcome of management of typhoid related perforation of small bowel seems to have improved over the recent years, it is still frequently reported as a major contributor to mortality rates [1, 18, 47]. Recognized mortality factors include age, origin of sepsis, MPI greater than 26 and multi-organ failure [6, 8, 21, 44, 58, 62]. Demmel et al. reported more than 50 % of sepsis related deaths [21].

Diffuse peritonitis is still a major life-threatening condition in LMICs. The diagnosis can reasonably still rely to a very large extend on a meticulous clinical assessment rather than sophisticated tools such as CT scan. In all cases, the clinical assessment must lead to the estimation of severity based on simple but reliable grading systems such as the MPI. Peritonitis originating from the perforation of a hollow viscus deserves special attention. The morbidity and mortality rates of diffuse peritonitis in the Fako are unacceptable high and health authorities need to consider the need for financing the management of such life-threatening surgical conditions as it is the main way to mprove their outcome. Some specific situations require special attention based on public health intervention. These include typhoid ileal perforation for which prevention and early detection are desirable, especially in children. Once the peritonitis has occurred, the adjustment of antibiotic regimen to match the special sensitivity pattern of Salmonella typhi will likely improve overall outcome. The same approach is applicable to complications of peptic ulcer perforation for which the reinforcement of the identification and management of patients suffering from this medical condition before perforation occurs would be beneficial.

For the prevention of persistent abdominal sepsis, surgeons in low-income setting can safely apply the on demand re-laparotomy approach which is likely to be cost-effective.