Peritonitis natural history

Peritonitis Main Page
Patient Information
Overview
Causes
Classification Spontaneous Bacterial Peritonitis Secondary Peritonitis
Differential Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Shivani Chaparala M.B.B.S [2]

Overview

With treatment, patients usually do well. Without treatment, the outcome is usually poor. However, in some cases, patients do poorly even with prompt and appropriate treatment.

Natural History

Spontaneous bacterial peritonitis presents as a complication of ascites which can be due to cirrhosis , heart failure or renal failure. Untreated disease leads to complications and has a poor prognosis. If properly treated, typical cases of surgically correctable peritonitis (e.g. perforated peptic ulcer, appendicitis, and diverticulitis) have a mortality rate of about <10% in otherwise healthy patients, which rises to about 40% in the elderly, and/or in those with significant underlying illness, as well as in cases that present late (after 48h). If untreated, generalized peritonitis is almost always fatal.

Complications

• Sepsis
• Encephalopathy
• Liver failure
• Renal failure
• Tense ascites
• Coma
• Death
• Sequestration of fluid and electrolytes, as revealed by decreased central venous pressure, may cause electrolyte disturbances, as well as significant hypovolaemia, possibly leading to shock and acute renal failure.
• A peritoneal abscess may form (e.g. above or below the liver, or in the lesser omentum).
• Sepsis may develop, so blood cultures should be obtained.

• The fluid may push on the diaphragm and cause breathing difficulties
• Development of abscess is the leading cause of persistent infection and development of tertiary peritonitis.
• The majority of abscess formation occurs subsequent to secondary peritonitis.The risk of abscess increases to 10-30% in cases of preoperative perforation of the hollow viscus, significant fecal contamination of the peritoneal cavity, bowel ischemia, delayed diagnosis and therapy of the initial peritonitis, and the need for reoperation, as well as in the setting of immunosuppression.
• Tertiary peritonitis: the incidence of tertiary peritonitis in patients requiring ICU admission for severe abdominal infections may be as high as 50-74%.

Prognosis

• Peritonitis is a frequent cause of morbidity.The prognosis greatly depends on the degree of intra-abdominal contamination, the severity of underlying disease, the immune response of the host and associated organ dysfunction.Associated mortality rates vary from < 1% to > 60%. In the studies that reported spontaneous bacterial peritonitis, the median mortality was 43.7%, 31.5% at 1 month and 66.2% at 12 months. The overall mortality rate is high—up to 30% during hospitalization and up to 70% by 1 year. Mortality may be predicted by the 22/11 model: MELD score greater than 22 and peripheral white blood cell count higher than 11,000/mcL. Patients with cirrhosis and septic shock have a high frequency of relative adrenal insufficiency, which if present requires administration of hydrocortisone. In survivors of bacterial peritonitis, the risk of recurrent peritonitis may be decreased by long-term norfloxacin, 400 mg orally daily; ciprofloxacin (eg, 500 mg orally once or twice a day), although with recurrence the causative organism is often resistant to fluoroquinolones; or trimethoprim-sulfamethoxazole (eg, one double-strength tablet five times a week). In high-risk cirrhotic patients without prior peritonitis (eg, those with an ascitic protein less than 1.5 g/dL and serum bilirubin greater than 3 mg/dL (51.3 mcmol/L), serum creatinine greater than 1.2 mg/dL (99.96 mcmol/L), blood urea nitrogen 25 mg/dL or more (9 mmol/L or more), or sodium 130 mEq/L or less [130 mmol/L or less]), the risk of peritonitis, hepatorenal syndrome, and mortality for at least 1 year may be reduced by prophylactic norfloxacin, 400 mg orally once a day. In patients hospitalized for acute variceal bleeding, oral norfloxacin (400 mg orally twice a day) or intravenous ceftriaxone (1 g per day), which may be preferable, for 7 days reduces the risk of bacterial peritonitis.

Predictors for poor prognosis in SBP include:

• Older age
• Higher Child-Pugh scores
• Nosocomial origin
• Encephalopathy
• Elevated serum creatinine and bilirubin
• Ascites culture positivity
• Presence of bacteremia and
• Infections with resistant organisms.

The prognosis risk of peritonitis may be stratified using the Mannheim's Peritoneal index score (MPI) as shown below:

Riskfactor	Score
Age >50 years	5
Female sex	5
Organ failure	7
Malignancy	4
Origin of sepsis not colonic	4
Diffuse generalized peritonitis	6
Preoperative duration of peritonitis >24h	4
Intraperitoneal exudates Clear Cloudy, purulent Fecal	0 6 12

Assessment of the prognosis of patients with peritonitis using MPI

• For a score of 27, the sensitivity was 66.67%, specificity was 100%, and positive predictive value for mortality is 100% at an accuracy of 94%.

Assessment of severity of peritonitis using MPI
Score	Mortality rate	Morbidity rate
<21	0%	13.33%
21-27	27.28%	65.71%
>27	100%	100%

Factors that were found to be independently significant factors in predicting the mortality:

• Duration of pain for >24 h
• Organ failure on admission
• Female sex and
• Feculent exudate
• Early prognostic evaluation of abdominal sepsis is useful in the assessment of the severity of the disease and to select high-risk patients for early surgical reintervention.