Acute Abdomen: Acute Peritonitis

Usually generalized in response to perforation of an abdominal viscus
In most cases the ones we will see with acute abdomen are acute suppurative peritonitis.


  • Inflammation of the peritoneum causes a localised pain.

  • Peritoneum lines the abdominal cavity and organs.

  • Inflammation caused by Infection, Chemical causes or mechanical.

  • Acute or Chronic Peritonitis (See topic).

  • Septic and Aseptic, Primary and secondary.

Causes of acute peritonitis

  • Perforated Duodenal ulcer and gastric acid leak.

  • Appendix abscess and rupture of pus into abdomen.

  • Diverticular abscess and rupture with faeces and pus leak.

  • Perforated gall bladder and bile leak.

  • Perforation of ischaemic gut with faeces leak.

  • Trauma – stabbing with bowel or other organ perforation.

  • Operative – colonic polypectomy with faeces leak.

  • Uterine perforation with instrumentation and spread of infection.

  • Infected peritoneal dialysis catheters cause Chronic Peritonitis (See topic).

  • Spontaneous bacterial peritonitis in those with cirrhosis.

  • Typhoid perforations.

  • Chronic Peritonitis usually TB .


  • Gram-negative: Escherichia coli, Klebsiella pneumoniae, Bacteroides.

  • Gram-positive: Streptococcus pneumoniae.

  • Tuberculous: See chronic peritonitis.


  • Acute onset of abdominal pain or referred pain to shoulder from diaphragm.

  • Abdomen is tender and rigid and hard like a board. There is guarding.

  • Bowel sounds reduced or absent and patient looks awful.

  • May be Tachycardia, fever and hypotension and signs of complications.


See Acute Abdomen.
Sepsis, SIRS, Septic shock, AKI, ARDS, Ileus, Death.


  • ABCS as needed. Oxygen if low stats. Stabilize.

  • IV fluids, Nil by mouth, IV Broad spectrum antibiotics.

  • IV analgesia as needed e.g. Morphine 5-10 mg IV + Antiemetic.

  • Urgent Surgical referral for assessment for laparotomy.

  • Surgical management of Acute Peritonitis is key.

  • Delays only to allow resuscitation and achieving volume status.

  • Antibiotic cover e.g. Tazocin or Gentamicin or Amoxycillin/Metronidazole.

  • Removal of infarcted tissue or perforated bowel.

  • Repair of any viscus perforation.

  • Removal of infective foci or drainage.

  • Peritoneal lavage is performed.