Faecal peritonitis

A 67-year-old male patient who underwent a low anterior resection (LAR) due to a rectal carcinoma T3N0Mx four days before, presents with generalised abdominal pain, fever and haemodynamic instability.

CT examination with gastrograffin oenema and intravenous contrast showed:
-LAR postoperative findings.
-Gastrograffin leakage to presacral space adjacent to the suture.
-Intraperitoneal contrast distant from the suture in the mesentery and left paracolic gutter with contrast and faecal material levels, due to intra abdominal leakage from the external drainage catheter.
-Abundant pneumoperitoneum and subcutaneous emphysema in pelvis and paraespinal area.

Peritonitis is defined as an inflammation of the peritoneum due to several causes such as infections, inflammatory process, vascular pathology, tumours or postsurgical. Peritonitis secondary to gastrointestinal perforation is usually produced by a poly-microbial infection. [1].
The severity of the infection depends on the site of the perforation.
The clinical onset is variable from asymptomatic (in elderly patients, patients with previous antibiotic or corticosteroid treatment) to acute and sudden abdominal pain with fever, nausea and vomiting, tachycardia, hypotension, even septic shock. The mortality rate of large bowel perforation is between 20-40%. [1]
The diagnosis is based on clinical symptoms although there are helpful CT findings [1, 2] such as peritoneum thickening that enhance after intravenous contrast administration and stranding of the mesenteric fat with or without ascitis. Less frequently, well-defined collections, mesenteric vessels engorgement and paralytic ileus due to inflammatory changes can be founded [2, 3].
If there are previous surgical treatments, we must consider wound dehiscence or anastomotic leakage as the cause of the peritonitis.
In colorectal surgery, the anastomotic leakage is the most frequent and serious complication (between 2-5% is accepted) [4, 5]. In anterior rectal resection this percentage increases to 24%. [6] The mortality rate is as high as 45% [7] so an early diagnosis is needed.
Anastomotic leakage also causes intra-abdominal accumulation of purulent or faecal material that can lead to abscess or faecal peritonitis, resulting in abdominal sepsis [4, 5]. The main treatment is surgical approach with the aim of draining the abdominal cavity and to control the infection. Empirical antibiotic therapy is used in early stages. [1]
In order to avoid postsurgical complications like haematoma, fluid collections or abscess formation, it has been standard practice to place prophylactic drainage in the abdominal or pelvic cavity after colorectal anastomosis, but late studies show that routine use of prophylactic drainage may not decrease those postsurgical complications. [8]
In our patient, the drainage catheter was positioned in the first surgery as prophylactic management. Four days after the surgery he developed fever, abdominal pain and haemodynamic instability, so abdominal CT was performed and an anastomotic leakage was diagnosed. The drainage catheter was removing faecal content from the presacral space and spreading it through the abdominal cavity causing wide faecal peritonitis.
The patient underwent a new surgery and left terminal colostomy was performed.