Peritonitis, an inflammation of the peritoneal cavity, can be caused by various factors. The presence of ascites in a cancer patient is concerning for either metastasis or advanced cancer. Diagnosing acute peritonitis in a patient with cancer-related ascites can be quite challenging and often requires additional diagnostic procedures, such as paracentesis, to confirm the diagnosis and identify the exact cause of the ascites. Even with paracentesis, determining the exact cause of ascites can be a diagnostic challenge. Peritoneal carcinomatosis, with a poor survival rate, can originate from the peritoneal lining itself or result from intra-abdominal cancer, and trying to determine its origin can be difficult. We present the case of a 68-year-old female patient with a known history of cancer experiencing worsening ascites and peritonitis.

Background This study aims to contribute to peritonitis management strategies by comparing the demographic, clinical, and laboratory characteristics of patients diagnosed with spontaneous bacterial peritonitis (SBP), peritoneal dialysis-related peritonitis (PDrP), and secondary peritonitis. Methods This study included 86 patients diagnosed with peritonitis between 2016 and 2022. Patients were categorized and compared as SBP, PDrP, and secondary peritonitis. Results SBP was diagnosed in 36% of patients, secondary peritonitis in 36% and PDrP in 28%. The mean age of patients with PDrP is 43.71 ± 14.74, which is significantly lower compared to those with SBP and secondary peritonitis (p<0.001). Patients with hypertension (HT), chronic kidney disease (CKD), and those undergoing dialysis most commonly have PDrP whereas those without HT, without CKD, and not undergoing dialysis are most often diagnosed with secondary peritonitis (p=0.002, p<0.001, p<0.001). In peritoneal fluid cultures, the growth of Gram-positive bacteria was most commonly identified in patients with PDrP, while the growth of Gram-negative bacteria was most frequently seen in patients with secondary peritonitis (p=0.018). CRP levels and sedimentation rates were found to be higher in patients with secondary peritonitis (p<0.001, p=0.003). Conclusion The distinct characteristics observed across different types of peritonitis underscore the importance of tailored approaches to diagnosis and treatment. Parameters such as CRP levels, sedimentation rates, and patient age could serve as valuable indicators in discerning between various types of peritonitis. When selecting empirical antibiotic therapy, it\'s crucial to consider coverage for Gram-positive pathogens in cases of PDrP and Gram-negative pathogens in secondary peritonitis.

Peritonitis is still known as an important complication of continuous ambulatory peritoneal dialysis (CAPD). Multi-drug resistant (MDR) Acinetobacter baumannii is an increasing problem worldwide. Moreover, the increasing reports of carbapenem-resistant A. baumannii strains is common. Although peritoneal dialysis-related peritonitis with MDR A. baumannii is rarely reported, infection with this organism always results in serious peritonitis and increases the possibility of dropout or mortality. Here, we present 7 cases of peritonitis caused by A. baumannii species. Among those 7 cases, 2 involved MDR A. baumannii, and 1 involved a carbapenem-resistant strain. All the MDR bacterial infections failed treatment. We also review the literature about Acinetobacter peritonitis and current treatment protocols.