Peritonealiinflammation

Peritonealiinflammation, or peritonitis, is inflammation of the peritoneum, the serous membrane lining the abdominal cavity. It can be primary (spontaneous bacterial peritonitis, often in people with advanced liver disease), or secondary to intra-abdominal pathology such as a perforated viscus, bowel obstruction, or abdominal trauma. A related form occurs in people undergoing peritoneal dialysis, where catheter-associated infection leads to peritoneal inflammation.

Causes and pathophysiology. The most common triggers are infectious agents, including Gram-negative and Gram-positive bacteria and, less often, fungi. Chemical irritation from pancreatitis, biliary or gastrointestinal leakage, or autoimmune processes can also produce peritoneal inflammation. The inflammatory response involves recruitment of neutrophils and other leukocytes, release of cytokines, and accumulation of protein-rich fluid in the peritoneal cavity, which can disrupt normal peritoneal function and lead to systemic symptoms in more extensive cases.

Clinical features. Patients typically present with abdominal pain and tenderness, often with guarding or rebound, fever, nausea, vomiting, and sometimes an ileus. In peritoneal dialysis patients, cloudy dialysis effluent is a common clue. The illness may be localized or diffuse, and signs of systemic illness such as tachycardia or hypotension can occur in severe cases.

Diagnosis. Evaluation includes clinical assessment, laboratory tests, and analysis of ascitic or dialysis effluent. A key diagnostic criterion is an elevated neutrophil count in the peritoneal fluid (for example, >250 cells/µL). Cultures of the fluid help identify the causative organism. Imaging (ultrasound or CT) may be used to detect intra-abdominal sources or complications.

Management. Immediate empirical antibiotic therapy is essential for suspected peritonitis. In community-acquired cases, broad-spectrum antibiotics with activity against enteric organisms are used; in peritoneal dialysis-associated peritonitis, intraperitoneal antibiotics are common. If secondary peritonitis due to perforation or abscess is suspected, surgical intervention is often required. Treatment is adjusted based on culture results and clinical response.

Prognosis and prevention. Outcome depends on the underlying cause, timeliness of treatment, and patient comorbidity. Prevention focuses on early recognition, appropriate antimicrobial therapy, and, in PD patients, strict aseptic technique and prompt management of catheter infections.