Peritonitis: inflammation of the abdominal lining — causes, signs, and care

Causes and mechanisms

The condition may arise when bacteria, fungi, chemicals or irritant fluids enter the peritoneal space. Common pathways include a tear or perforation in the gastrointestinal tract, leakage from an inflamed organ, or spread from the bloodstream. Typical underlying problems include:

• Perforation of the abdomen from trauma or bowel ulcer
• Ruptured appendix and other intra‑abdominal infections
• Severe pancreatitis causing enzymatic irritation
• Pelvic inflammatory disease spreading upward
• Ascites with secondary infection, often in the setting of cirrhosis

Clinical features and diagnosis

Patients usually present with sudden, severe and worsening abdominal pain, guarding or rigidity, fever, nausea and reduced appetite or weight loss over time. Physical exam often shows abdominal tenderness and signs of peritoneal irritation. Diagnosis combines clinical assessment with blood tests, imaging such as CT or ultrasound, and sometimes sampling of peritoneal fluid.

Treatment and prognosis

Treatment depends on cause and severity. Immediate management frequently includes intravenous fluids, pain control and broad‑spectrum antimicrobial therapy (antibiotics) targeted when cultures are available. Many patients require surgical intervention to repair perforations, remove infected tissue, or drain abscesses. With prompt treatment outcomes are favorable; untreated peritonitis can lead to sepsis and organ failure.

Prevention and notable facts

Prevention focuses on timely care for abdominal infections and injuries, appropriate management of chronic liver disease with ascites, and safe surgical and catheter techniques. Peritonitis can be primary (spontaneous bacterial) or secondary to another intra‑abdominal event; recognizing the distinction guides treatment choices.