Resuscitation and operative preparation occur simultaneously.
Keep fasting, establish large bore IV access, correct hypovolaemia and major electrolyte abnormalities and insert a urinary catheter in significant sepsis.
Start enteric Gram negative and anaerobic coverage.
A practical regimen is:
Ceftriaxone 2 g IV every 24 hours plus metronidazole 500 mg IV every 12 hours.
For septic shock, healthcare associated infection or substantial resistant organism risk:
Piperacillin tazobactam 4.5 g IV every 8 hours by extended infusion, adjusted for renal function.
Free ileal perforation with peritonitis requires surgery.
At operation, inspect the entire small bowel because more than one perforation may exist, particularly with typhoid disease.
A small isolated perforation with healthy surrounding bowel may be debrided and closed transversely.
Segmental ileal resection with primary anastomosis is preferred when perforations are multiple or clustered, the surrounding bowel is severely inflamed, the defect is large or tissue viability is uncertain.
Severe shock, gross contamination, poor tissue perfusion or major bowel oedema increases anastomotic failure risk and may justify temporary diversion or staged reconstruction.
When tuberculosis or Crohn disease is suspected, send tissue for histology and microbiology.
After adequate source control, routine prolonged treatment for secondary bacterial peritonitis is unnecessary. Approximately 4 days is usually sufficient, although treatment directed at the underlying disease such as enteric fever or tuberculosis follows its own required duration.
