Makindo Medical Notes

⚠️ Peritonitis = inflammation of the peritoneum (the serous membrane lining the abdominal cavity). It is a surgical emergency in most cases, as untreated infection can lead to sepsis and death. 👉 Causes include perforation, infection, trauma, or secondary to peritoneal dialysis.

📖 About

• Inflammation of the peritoneum caused by bacterial or chemical irritation.
• May be localised (around the source, e.g. perforated appendix) or generalised (diffuse contamination).
• Primary (spontaneous) peritonitis occurs without a clear source – classic in cirrhotics with ascites.
• Secondary peritonitis = due to intra-abdominal catastrophe (e.g. perforation, trauma, abscess).

⚡ Causes

• 🕳️ Perforated viscus: duodenal ulcer, perforated appendix, diverticulitis, bowel perforation, malignancy.
• 🦠 Infection: spontaneous bacterial peritonitis (SBP) in cirrhosis; peritoneal dialysis-related peritonitis.
• 💉 Trauma: blunt or penetrating abdominal trauma, post-op leaks.
• 🧪 Chemical: bile, blood, gastric acid, pancreatic enzymes in peritoneum.

🩺 Clinical Features

• Severe abdominal pain + tenderness (often sudden onset).
• 🔒 Guarding and rigidity (“board-like abdomen”).
• ❌ Rebound tenderness (pain on release of pressure).
• 🤢 Nausea, vomiting, anorexia.
• 🌡️ Fever, tachycardia, hypotension → progressing to sepsis and shock.
• Absent bowel sounds (paralytic ileus).

🔎 Investigations

• 🧪 Bloods: FBC (↑ WCC), CRP, U&E, LFTs, clotting, cultures.
• 🧪 Ascitic tap (if cirrhotic): neutrophils >250/mm³ = diagnostic of SBP.
• 📸 Imaging:
  • Upright CXR: free air under diaphragm (perforation).
  • Abdominal X-ray: dilated loops, free air.
  • CT abdomen: localises source, free fluid, abscess.

🚑 Management

• 🔴 Resuscitation first: ABC, IV fluids, oxygen, NG tube, urinary catheter.
• 💉 Broad-spectrum IV antibiotics (cover Gram-negative + anaerobes).
• 🔪 Surgery (laparotomy/laparoscopy) for most secondary causes (perforation, abscess drainage).
• SBP in cirrhotics: cefotaxime or ceftriaxone IV → secondary prophylaxis with oral norfloxacin/co-trimoxazole.
• Peritoneal dialysis peritonitis: intraperitoneal antibiotics, catheter management.
• Post-op: intensive monitoring, sepsis bundle, nutritional support.

⚠️ Complications

• Sepsis and septic shock 🚨
• Multi-organ failure (renal, respiratory, cardiovascular)
• Intra-abdominal abscesses
• Adhesions → bowel obstruction
• Death if untreated (mortality high in elderly/cirrhotics)

🎯 Prognostic Factors

• Age (elderly worse prognosis)
• Underlying cause (perforated ulcer vs SBP)
• Delay to surgery
• Comorbidities (cirrhosis, renal failure, diabetes)

🛡 Prevention

• Proton pump inhibitors for high-risk ulcer patients.
• Good peritoneal dialysis technique (sterile precautions).
• SBP prophylaxis in cirrhotics with low ascitic protein or previous SBP.

📚 Exam Pearls

• SBP: ascitic neutrophils >250/mm³ = diagnostic.
• Rigid, silent abdomen = classic generalised peritonitis.
• CXR showing free gas under diaphragm = perforated viscus until proven otherwise.
• Management is resuscitation + antibiotics + urgent surgery (except SBP).
• Mortality in cirrhotics with SBP can be 30–40% despite treatment.