TNM: a simple classification system for complicated intra-abdominal sepsis after acute appendicitis.

Background: Delayed diagnosis in case of acute appendicitis (AA) could lead to complicated intra-abdominal sepsis (IAS). Grading systems are not commonly employed in the clinical practice, because they are too complicated or too specific. Therefore, we suggest grading the severity of complicated IAS after AA with a simple system: TNM, an acronym borrowed by cancer staging where T indicates temperature, N neutrophils, and M multiple organ failure (MOF). This prospective observational study evaluates the predictive value of the TNM score on mortality of patients with complicated IAS after AA.

Methods: Sixty-eight patients with complicated IAS after AA were treated. Three classes of attributes were chosen: temperature (T), neutrophils count (N), and MOF (M). After defining the categories T (T0-T4), N (N0-N3) and M (M0-M2), these were grouped in stages (0-IV). Variables analyzed for their possible relation to death were age, sex, temperature, neutrophils count, preoperative organ failure, immunocompromised status, stage (0-IV). Odds ratios were calculated in a univariate and multivariate analysis.

Results: TNM staging was: one patient stage 0; 16 patients at stage I; 26 patients at stage II; 16 patients at stage III; nine patients at stage IV. Death occurred in 15 patients (22%). Neutrophil count, preoperative organ failure, immunocompromised status, stages III-IV were potential predictors of postoperative death in univariate analysis; only stage IV was significant independent predictor of postoperative mortality in multivariate analysis.

Conclusions: TNM classification is very easy to use; it helps to define the mortality risk and is useful to objectively compare patients with sepsis.