Streptococcus Pneumoniae Primary Peritonitis Mimicking Acute Appendicitis in an Immunocompetent Patient

A Case Report and Review of the Literature

Francesco Cortese; Pietro Fransvea; Alessandra Saputelli; Milva Ballardini; Daniela Baldini; Aldo Gioffre; Roberto Marcello; Gabriele Sganga

Disclosures

J Med Case Reports. 2019;13(126) 

In This Article

Discussion

S. pneumoniae is the most common cause of community-acquired pneumonia and the second most common cause of purulent meningitis, while intra-abdominal pneumococcal infection is rarely found.[13–18]

We conducted a review of the literature by searching the PubMed database for all published series and case reports of PP due to S. pneumoniae in the worldwide literature up to 9 September 2017. We analyzed all cases reported in the literature.[18–60] Pediatric cases,[19–21] secondary peritonitis,[21,22] and cases arising in patients with ongoing predisposing conditions[23–25] were excluded. All other papers were reviewed in order to evaluate real cases of PP (Table 1).[26,31,32,34–40,44–51,53,54,56–60] While pneumococcal peritonitis in children has been recognized for almost 100 years, our review shows, according with the findings of Dugi et al.,[13] that primary pneumococcal peritonitis without pre-existing peritoneal disease is uncommon in healthy adults.[61–64] Without predisposing conditions, the virulence of some pneumococcus serotypes may contribute to the onset of this rare infection.[44,54] The physiopathology of primary pneumococcal peritonitis remains controversial. Pneumococci may gain entry to the peritoneal cavity via the genital tract, the gastrointestinal tract, or by hematogenous spread from the respiratory tract.[57] Hemsley and Eykyn[40] reported an increased prevalence in female adults, with the genital tract being the most common source of pneumococcus. In fact, occasionally, vaginal commensals can presumably cause ascending infection also without predisposing factors such as the presence of an IUD or history of recent delivery. However, all the cases reported in their paper have evidence of a presumptive sepsis focus and therefore are not definable as PP.

Of interest, a peculiarity of this condition is the absence of mixed organisms. In fact, no case reported an association of multiple infective agents.

There is no definite clinical pattern or features which might help in the diagnosis. Usually the clinical picture closely resembles that of appendicitis or secondary peritonitis with or without sepsis which, in most cases, is the presumptive diagnosis.[58–60]

Management of this condition is strictly linked to the diagnosis. While PP can be suspected in patients with comorbidities in the presence of a negative radiologic investigation, it is hardly recognizable in young and immunocompetent patients with no risk factors, like in our case. This confirms the fact that, based on an erroneous diagnosis, most of these patients are operated on despite negative results from imaging.

The best diagnostic algorithm is, in our opinion, Westwood and Roberts'.[63] Antibiotic therapy remains the first step in treatment of PP in patients with active comorbidities. The real clinical challenge arises with young, healthy, and immunocompetent patients. How can we suspect PP in those cases? In our opinion, with a negative CT scan, antibiotic therapy seems to be the first approach for 36–48 hours, despite several studies underlining that there seems to be little consensus regarding the antibiotic treatment for pneumococcal peritonitis and only little information has been published about the antibiotic regimens chosen for the treatment.[65] For patients infected by penicillin-susceptible organisms, penicillin remains the preferred treatment, while in areas where the prevalence of resistant pneumococci is high, cefotaxime or ceftriaxone is the empirical therapy of choice, as antibiotic-resistant strains of S. pneumoniae have been identified worldwide, and the prevalence of these resistant strains is as high as 57% in some countries.[61,64] In non-responders and in patients with sepsis, exploratory laparotomy is a well-accepted treatment.[65,66] The laparoscopic approach is pivotal, related to its low invasiveness and high diagnostic specificity and sensitivity, with peritoneal lavage or drainage being the diagnostic tool of choice.[67] It remains unclear, however, whether surgical exploration and lavage of the abdominal cavity with or without appendectomy is beneficial or detrimental for patients with primary pneumococcal peritonitis. One could assume that removal of infectious ascites and reduction of intra-abdominal bacterial load would support the healing process, while, in patients with cirrhosis with spontaneous bacterial peritonitis, surgery does not improve the course of the disease.[68] Laparotomy with abdominal debridement and visceral resection is a rare choice selected for advanced cases with complex peritoneal involvement.[69,70] Based on all these findings it can be assumed that the management of pneumococcal peritonitis involves timely surgical intervention and treatment with antibiotics.

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