Mannheim Peritonitis Index (MPI)
Predicts severity and mortality risk in peritonitis using eight clinical and intra-operative factors
For use by health professionals only. The MPI provides population-level risk estimates and should support, not replace, surgical judgement, sepsis management, and ICU decision-making. Scoring assumes a diagnosis of secondary/generalised peritonitis and intra-operative confirmation.
Enter patient and intra-operative details
Component points:
• Age: – |
Sex: – |
Organ failure: – |
Malignancy: –
• Duration >24h: – |
Non-colonic origin: – |
Diffuse peritonitis: – |
Exudate: –
Total MPI score (0–47): –
Risk band: Not yet calculated
Enter all fields above, then click “Calculate MPI” to see the total score and an approximate mortality risk band (low / intermediate / high).
Classical MPI scoring: age >50 years (5), female (5), organ failure (7), malignancy (4), duration >24 h (4), origin not colonic (4), diffuse peritonitis (6), exudate: clear (0), cloudy/purulent (6), fecal (12). MPI ≤20 is typically associated with very low mortality (~0–5%), 21–29 with intermediate mortality, and ≥30 with high mortality (~40–60%+) in many published series. Local outcomes may differ.
The Mannheim Peritonitis Index (MPI) is a disease-specific scoring system designed to predict the risk of death in patients with peritonitis (usually secondary/generalised peritonitis after hollow viscus perforation).
It was developed in the 1980s by Wacha and Linder from a large cohort of patients with purulent peritonitis, where 20 potential risk factors were analysed and 8 were found to be independently prognostic. These 8 factors were weighted and combined into a single score – the MPI.
Components and scoring of the Mannheim Peritonitis Index
For each risk factor present, points are assigned; their sum is the MPI score (0–47):
- Age > 50 years – 5 points
- Female sex – 5 points
- Organ failure (renal, pulmonary, shock, etc., by standard definitions) – 7 points
- Malignancy – 4 points
- Duration of peritonitis > 24 h before surgery – 4 points
- Origin of sepsis not colonic – 4 points
- Diffuse / generalised peritonitis – 6 points
- Type of exudate in peritoneal cavity
- Clear – 0 points
- Cloudy / purulent – 6 points
- Fecal – 12 points
The higher the MPI, the more severe the peritonitis and the higher the mortality risk. In multiple studies and meta-analyses, MPI has shown good predictive value and is simple to apply intra-operatively.
Interpreting MPI scores (approximate)
Many studies group patients into three risk strata, for example:
- MPI ≤ 20 – Low risk: mortality typically ~0–5%
- MPI 21–29 – Intermediate risk: mortality often ~10–25%
- MPI ≥ 30 – High risk: mortality frequently ≥40–60%
These percentages are cohort-dependent: modern peri-operative and ICU care can improve survival, but the trend (higher MPI → higher mortality) is consistent.
MPI is best used to:
- Identify high-risk patients needing early aggressive resuscitation and ICU-level care
- Support audit and research
- Help in risk counselling (along with other clinical information)
It should not be used in isolation to decide whether to operate or to limit treatment.
