Subphrenic Abscess

  • Etiology: Occurs 1–3 weeks post-op (e.g., splenectomy, gastrectomy, cholecystectomy) or post-peritonitis.
  • Presentation
    • Persistent fever, RUQ/LUQ pain, referred shoulder pain (Kehr sign), hiccups
    • Sympathetic pleural effusion (dullness, decreased breath sounds at base).
      • Not infection.
      • Localized infection in the subphrenic space causes intense inflammation of the adjacent diaphragmatic peritoneum.
      • This inflammation increases the vascular and lymphatic permeability of the diaphragm.
  • Diagnosis:
    • Initial: CXR (shows elevated hemidiaphragm, pleural effusion, subdiaphragmatic air-fluid level) or US.
    • Best: CT abdomen/pelvis w/ IV contrast showing fluid collection w/ peripheral rim enhancement.
  • Management:
    • First-line: Broad-spectrum IV Abx (e.g., Zosyn) + percutaneous drainage (CT/US-guided).
    • Second-line: Surgical drainage if percutaneous drainage fails, fluid is multiloculated, or pt is hemodynamically unstable.
  • Complications: Sepsis, peritonitis, transdiaphragmatic spread (empyema).