Intra-abdominal Infection

Diverticulitis / Appendicitis / Perforation / Abscess / Peritonitis

• CC: Abdominal pain, fever

• PP: Localized tenderness, rebound/guarding, N/V, anorexia, diarrhea/constipation

• PN: No urinary symptoms, no GI bleed, no chest pain/SOB unless present

• pertinent SHx: EtOH, tobacco, drug use, prior abdominal surgery

• Etiology: GI source infection from microperforation, perforation, abscess, appendicitis, diverticulitis, ischemia, or post-op leak

• risk factors: Older age, immunosuppression, malignancy, recent surgery, IBD, diverticulosis, diabetes

• initial DATA: CBC, CMP, lactate if septic, lipase, UA, blood cultures if febrile/septic, CT A/P with IV contrast

• pending DATA: Blood cultures, abscess/drain cultures, surgical findings

• prior data: Prior abdominal imaging, colonoscopy, surgical history

• MEDS: Steroids, immunosuppression, anticoagulation, recent antibiotics

• COURSE:

Plan:

• NPO initially

• IV fluids, electrolyte repletion

• Antibiotics:

  • Stable: Ceftriaxone 2 g IV daily + Metronidazole 500 mg q8h

  • Broader/severe: Piperacillin-tazobactam

  • ESBL/MDR/septic shock: Meropenem

• CT A/P with IV contrast

• Surgery consult if appendicitis, perforation, peritonitis, ischemia, obstruction, uncontrolled source

• IR consult if drainable abscess

• Trend CBC/CMP/lactate if septic, abdominal exam, fever curve

• Pain/nausea control

• Advance diet as tolerated after improvement/source control

• PO step-down:

  • Augmentin 875 mg BID

  • OR Ciprofloxacin 500 mg BID + Metronidazole 500 mg TID

• Duration:

  • After adequate source control: often ~4 days

  • No source control/complicated: usually 5–7+ days depending response