Validity of Mannheim Peritonitis Index Score in Patients with Secondary Peritonitis

Introduction: Peritonitis accounts for 1% of emergent hospital admissions and overall mortality is 6% to 35% in patients who develop severe sepsis. Many scoring systems have been introduced to grade peritonitis. The Mannheim Peritonitis Index (MPI) is a special scoring system of parameters such as age; gender; duration, severity and extent of peritonitis; the presence of malignancy; and organ failure. This assesses the validity of MPI for the prediction of outcome in patients with perforation peritonitis. Methodology: A one-group cohort study was conducted from August 2019 to August 2020, and included 175 patients with suspected hollow viscus perforation who underwent surgery in a tertiary care centre. Patients were grouped into three categories after calculating their MPI score based on disease severity - MPI <21, between 21 and 29 and >29 and followed up until discharge or death. Mortality and mortality rates were calculated and data analysed. Results: In 175 patients with secondary peritonitis, a bimodal distribution was noted with peaks in age groups of 20–30 (20.6%) and 50–60 (19.4%). Appendicular perforation dominated in the age groups 10–40, followed by gastric perforation in the 50–80 groups. Males were 70.9% and females 29.1%. The majority had appendicular perforation (37.7%) followed by stomach (30.9%) and duodenum (18.3%). Patients with MPI score <21 had 0% mortality, score 21–29 had 4.5% mortality and >29 had mortality of 87% (P < 0.001). Patients with morbidity such as surgical site infection (SSI), pneumonia, enterocutaneous fistula had an MPI score > 29 (P < 0.001). For the MPI score of 25, sensitivity was 78% and specificity was 84.86%, with a positive likelihood ratio of 7.93 and a negative likelihood ratio of 0.303. Conclusion: There is a bimodal distribution of secondary peritonitis with peaks in age groups of 20–30 and 50––60 years. There is a male preponderance and a statistically significant association of MPI with mortality in secondary peritonitis and morbidity like SSI s, pneumonia and enterocutaneous fistula.