The patients of peritonitis usually present with abdominal pain, moderate fever and gastrointestinal disturbances (such as vomiting and constipation). In primary bacterial peritonitis, there may be a history of liver disease along with blood in the vomitus or black stools. Secondary bacterial peritonitis often has a more acute onset.

The physical examination of the abdomen shows marked tenderness. There may be distention, rigidity and rebound tenderness. Abdomen does not move with respiration and the bowel sounds are absent.

The following investigations are helpful in establishing the diagnosis of peritonitis.

• Complete blood count: Complete blood count will show leukocytosis or leukopenia.
• Examination of ascitic fluid: Ascitic fluid is obtained by paracentesis. There is an increased cellularity. Gram stain can be used to visualize the bacteria. Culture is also positive for around 70% of the cases [7]. The amount of protein, glucose, lactate dehydrogenase and amylase in the ascitic fluid is also abnormal [8].
• Abdominal imaging: Imaging of the abdomen by radiography, ultrasonography and computerized tomography (CT) can help detect any pathology that is responsible for the development of secondary bacterial peritonitis.

Primary bacterial peritonitis is treated by antibiotic therapy [9]. The drugs commonly used include cefotaxime, ceftriaxone, ampicillin and quinolones. No specific drug is better than the other. Supportive treatment is also provided. Lactulose is given to prevent the development of hepatic encephalopathy.

In secondary bacterial peritonitis, in addition to antibiotic therapy, the control of the source of the infection is also essential. Surgery may be required for the treatment of the cause (e.g. if there is perforated peptic ulcer, perforated appendix, perforated colon and so on). The antibiotic therapy should cover both aerobic and anaerobic organisms. Piperacillin-tazobactam is often used.

In tertiary bacterial peritonitis, the source of infection should be cured. The drug used should be in accordance with the culture report. Abdominal washout with open laparotomy may also be needed.

Peritonitis generally has a poor prognosis. The mortality rate in primary bacterial peritonitis is up to 30%. However, there is a high incidence of recurrence. By 6 months, recurrence is seen in up to 43% of the cases and by 1 year, in 69% of the cases. There is a 50-70% mortality in recurrent cases. This high mortality is due to the development of complications such as gastrointestinal bleeding and renal dysfunction [4] [5].

In secondary bacterial peritonitis, the mortality is associated with the etiology. Perforation of the stomach or colon implies a particularly poor prognosis whereas appendicitis has the lowest risk of mortality.

Prompt diagnosis and treatment improves the prognosis in all types of peritonitis. Host related factors also play a key role in determining the outcome of these infections [6].

Each type of peritonitis has its own etiology.

Primary bacterial peritonitis

Primary bacterial peritonitis is most commonly related to ascites due to liver cirrhosis [1]. The notable risk factors include large volume ascites and ascites with a protein content greater than 1 g/dL [2]. Ascites originating from disorders of the heart and kidneys, or due to any neoplastic condition can also lead to bacterial peritonitis. The following organisms are commonly responsible for the infection.

• Escherichia coli
• Klebsiella
• Streptococcus species
• Pseudomonas
• Proteus

Secondary bacterial peritonitis

Secondary bacterial peritonitis is due to any preexisting infectious source in the abdomen. It results from causes such as acute appendicitis, cholecystitis, pancreatitis, perforated peptic ulcer and perforated bowl. Pelvic inflammatory disease can also cause peritonitis. The causative organisms include:

• Escherichia coli
• Klebsiella
• Proteus
• Streptococcus species
• Enterococcus species
• Bacteroides
• Clostridium species

Tertiary bacterial peritonitis

The causative organism in tertiary bacterial peritonitis is often the same as that of secondary bacterial peritonitis. Malnutrition, massive blood transfusion and infection with antibiotic resistant organisms greatly increases the chance of developing bacterial peritonitis [3].

Primary bacterial peritonitis is a common complication of cirrhosis in both adults and children. It occurs in as many as 10 to 30% of the patients with cirrhosis and associated ascites. The highest incidence of primary bacterial peritonitis in children is seen at two stages; one is the neonatal period and the other is the age of 5 years.

In all types of peritonitis, the pathology starts with the contamination of the peritoneum by bacteria. In primary bacterial peritonitis, bacteria enter the ascitic fluid by translocation whereas in secondary bacterial peritonitis, they infect the peritoneum from any preexisting source in the viscera. There is inflammation of the peritoneum with exudations of serum, fibrin, cells and pus.

Up to 22% of the patients of cirrhosis with gastrointestinal hemorrhage develop primary bacterial peritonitis. Therefore, primary bacterial peritonitis can be prevented by the use of prophylactic antibiotic therapy in the patients of cirrhosis associated with gastrointestinal hemorrhage [10].

Tertiary bacterial peritonitis can be prevented by ensuring adequate control of the source of infection and the treatment of etiology of secondary bacterial peritonitis.

Peritonitis is the acute inflammation of peritoneum - the serous membrane that lines the walls and invests the viscera of the abdomen. Both the parietal and visceral components of the peritoneum are involved. Peritonitis has the following types:

• Primary bacterial peritonitis: Primary bacterial peritonitis occurs commonly in the case of ascites associated with cirrhosis. It refers to the infection of previously sterile ascitic fluid without any other detectable source of infection.
• Secondary bacterial peritonitis: Secondary bacterial peritonitis refers to the infection of the peritoneum from any infected visceral source.
• Tertiary bacterial peritonitis: Tertiary bacterial peritonitis is the recurrent infection of the peritoneum despite adequate treatment.

Peritonitis is the infection of the membrane that covers the abdominal walls and organs. It usually results from liver failure or from preexisting sources of infection in the organs. It is a serious disease and often leads to death if not treated promptly. The treatment consists of the administration of antibiotics and supportive care.

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