Diseases of the peritoneum

1. Big picture

The peritoneum is a large, highly reactive serous membrane. Its diseases usually present in one of three exam patterns:

1. Acute peritonitis → abdominal pain, guarding, sepsis → surgical emergency until proven otherwise.
2. Ascites-related peritoneal disease → fluid accumulation, infection, malignancy, tuberculosis, chylous/bloody ascites.
3. Peritoneal tumors/infiltration → peritoneal carcinomatosis, mesothelioma, lymphoma → progressive ascites, weight loss, abdominal distension.

The examiner wants a safe sequence:

Acute abdomen/peritonitis?
        ↓
ABC + sepsis management + broad-spectrum antibiotics
        ↓
CT abdomen if stable
        ↓
Urgent source control if secondary peritonitis

For cirrhotic ascites:

New/worsening ascites or hospitalized cirrhotic patient
        ↓
Diagnostic paracentesis
        ↓
Ascitic PMN ≥250/mm³ = spontaneous bacterial peritonitis
        ↓
Immediate antibiotics ± albumin

AASLD guidance covers ascites, spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome; diagnostic paracentesis and prompt treatment of SBP are central management principles. ([aasld.org][1])

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