Perforated bowel

Perforation is a hole that develops through the wall of a small or large intestine from insult or injury to the mucosa of the bowel wall. Perforated colon is a potentially life threatening complication that may result from a variety of disease processes ¹. Common causes of bowel perforation include trauma, instrumentation, obstruction, inflammation, infection, malignancy, ischemia, and invasive procedure. This resulting in the spilling of air and digestive contents into the peritoneal cavity. These contents can range from highly acidic gastric contents in more proximal bowel perforation, to fecal material from a more distal area of perforation. Patients presenting with abdominal pain and distension, especially in the appropriate historical setting, must be evaluated for perforated colon as delayed diagnosis can be life-threatening due to the risk of developing infections such as peritonitis ². Management includes stabilizing the patient while making the surgical consultation. Even appropriately managed, bowel perforation can lead to increased morbidity and mortality from post repair complications such as adhesions and fistula formation ³.

Perforated bowel causes

Bowel perforations can be separated based on their anatomic locations, but many causes are overlapping:

• Small bowel: Erosion from duodenal ulcerations, tumor, infection or abscess, Meckel’s diverticulum, hernia with strangulation, inflammatory bowel disease/colitis, mesenteric ischemia, foreign body, obstruction, medication/radiation related, iatrogenic, blunt or penetrating abdominal trauma
• Large bowel: Tumor, diverticulitis, infection or abscess, colitis, foreign body, obstruction, volvulus, iatrogenic, blunt or penetrating abdominal trauma ⁴

Perforated bowel can be caused by a variety of factors. These include:

• Appendicitis
• Cancer
• Crohn disease
• Ulcerative colitis
• Diverticulitis
• Bowel blockage
• Chemotherapy agents
• Increased pressure in the esophagus caused by forceful vomiting

It may also be caused by surgery in the abdomen or procedures such as colonoscopy.

In children, bowel perforation is most likely to follow abdominal trauma. The incidence of bowel perforation is 1% to 7% in pediatric trauma patients.

In adults, ulcerative disease represents the most common etiology of bowel perforation, with duodenal ulcers causing 2- to 3-times the rate of perforation than gastric ulcers do. Perforation secondary to diverticular disease represents up to 15% of cases. In the geriatric population, perforated appendicitis represents the most common cause of perforation.

The overall incidence of perforation from colonoscopy has been reported on average around 2% with higher rates during colonoscopy requiring therapeutic interventions ⁵.

Perforated bowel symptoms

Perforation of the intestine causes the contents to leak into the abdomen. This causes a severe infection called peritonitis.

Symptoms may include:

• Severe abdominal pain
• Chills
• Fever
• Nausea
• Vomiting
• Shock

Lower chest or abdominal pain after recent instrumentation from endoscopy/colonoscopy or laparoscopic/open surgical procedure should raise high suspicion for this diagnosis. Previous medical, surgical, and social history to include a history of a prior hernia, bowel obstruction, known or suspected malignancy, foreign body insertion or ingestion, abdominal trauma, and regular medication use (NSAIDs, corticosteroids, and chemotherapy are the most common) should be elicited. The patient is likely to complain of pain and distension in the abdomen that is worsening. Patients may describe a pain-free period before the worsening of their pain, and this can represent decompression of an inflamed or injured area directly following the perforation.

Diffuse spillage of air and intestinal contents may make the pain difficult to localize during focused abdominal examination, but palpation is likely to identify tenderness. Patients usually have nausea and vomiting. As the situation progresses, peritoneal signs such as guarding and rigidity may develop. Vital signs may be normal, especially in early presentation; however, tachycardia, tachypnea, fever, and other signs of sepsis are likely to develop ⁶.

When perforation occurs at the tumor site, peritoneal contamination is usually localized; when perforation is located proximal to the tumor site, the fecal spread results in diffuse peritonitis and septic shock ⁷. In this setting, physical examination reveals an acutely ill patient characterized by fever, tachypnea, tachycardia and confusion.

The abdomen may be diffusely tender or may present localized tenderness, guarding, or rebound tenderness. Bowel sounds are usually absent. The toxic symptoms of peritonitis are usually delayed, but are considered an ominous sign ⁸. Leukocytosis and neutrophilia, elevated amylase levels and lactic acidosis suggest perforation or necrosis ⁹. The suspicion of large bowel obstruction or perforation is based on aspecific symptoms, signs and laboratory findings: adjunctive diagnostic tests are mandatory, whenever available.

Perforated bowel complications

Early

Hemodynamic instability leading to hypoperfusion, shock, and multi-organ system failure, infection (whether local abscess formation, peritonitis, or systemic bacteremia)

Late

Delayed wound healing, postoperative adhesions leading to bowel obstruction, fistula formation, and hernias ¹⁰.

Perforated bowel diagnosis

When the clinical scenario is suggestive of bowel perforation, abdominal ultrasound or abdominal plain X-ray should be used as first screening imaging tests. Bedside abdominal ultrasound, performed by a trained physician or surgeon, has higher sensitivity and same specificity of abdominal plain X-ray ¹¹; moreover, it reduces the mobilization of a critically-ill patient. One of the limitations of the abdominal ultrasound and of the abdominal plain X-ray is the risk of false negatives of pneumoperitoneum, when a small amount of intraperitoneal free air is present, such as in the case of early perforation at the tumor site (see Table 1).

CT scan is the best imaging technique to evaluate large bowel obstruction and perforation ⁷. Despite contrast enema shows acceptable sensitivity and specificity, abdominal CT scan, with high sensitivity and specificity, has the absolute advantage to provide the clinician with an optimal grade of information, in particular regarding the complications of cancer-related large bowel obstruction. Moreover, it is possible to stage the neoplastic disease and to identify synchronous neoplasms. Due to this multifaceted profile, CT scan represents the imaging test of choice in current clinical practice; if CT is available, the water-soluble contrast enema can be considerate obsolete. For obstructive left colon carcinoma, self-expandable metallic stent, when available, offers interesting advantages as compared to emergency surgery; however, the positioning of self-expandable metallic stent for surgically treatable causes carries some long-term oncologic disadvantages, which are still under analysis.

Table 1. Comparison of imaging studies for confirmation and site of bowel perforation

	Confirmation of perforation		Site of perforation
	Sensitivity	Specificity	Sensitivity	Specificity
Abdominal plain X-ray	53%	53%	not stated	not stated
Abdominal ultrasound	92%	53%	not stated	not stated
Colonic enema	not stated	not stated	not stated	not stated
CT scan	95%	90%	not stated	90%

[Source ⁷ ]

Labs may include a complete blood count, basic metabolic panel, liver function tests, lipase, amylase, and inflammatory markers such as C-reactive protein (CRP). However, common findings such as a leukocytosis or elevated amylase or elevated CRP (C-reactive protein) level are non-specific for diagnostic purposes.

Perforated bowel treatment

Treatment of a patient with suspected bowel perforation involves establishing intravenous (IV) access and initial hemodynamic management, especially if the patient presents with any signs or symptoms concerning for sepsis or shock. Initiation of broad-spectrum antibiotics aimed at gram-negative and anaerobic organisms is essential and should be initiated early. For suspected distal perforation of the intestinal tract, nasogastric decompression should be performed, and the patient made NPO (nothing by mouth).

If the patient is hemodynamically stable and there is no concern for peritonitis, such as in the case of a spontaneously contained perforation, the option for non-surgical management with antibiotics and observation may be pursued in consultation with the surgical team.

Localized abscess formation may be amenable to drainage by interventional radiology.

Most cases will progress to require direct investigation via laparoscopic or open (laparotomy) exploration. This allows for primary repair as well as infection control measures. Minimally invasive exploration and repair are often successfully performed. However, it should be noted that exploratory laparotomy is the surgical intervention of choice for any signs of clinical deterioration or hemodynamic instability ¹².

Guidelines on the management of large bowel perforation, obstructive left colon carcinoma, and obstructive right colon carcinoma were released on August 13, 2018, by the World Society of Emergency Surgery ⁷.

When diffuse peritonitis occurs in cases of cancer-related colon perforation, the priority is control of the sepsis source. Medical treatments including appropriate fluid resuscitation, early antibiotic treatment and management of co-existing medical conditions according to international guidelines must be delivered to all patients at presentation.

To establish the effectiveness of antimicrobial prophylaxis for the prevention of surgical wound infection in patients undergoing colorectal surgery, a Cochrane review was published in 2014 including 260 trials and 68 different antibiotics ¹³. The review found high-quality evidence, showing that prophylaxis with antibiotics covering aerobic and anaerobic bacteria prior to elective colorectal surgery reduces the risk of surgical wound infection.

Generally, patients with intestinal obstruction with no systemic signs of infections present a risk of surgical site infections similar to patients undergoing elective surgery; in general, antibiotic prophylaxis is sufficient.

In the case of perforation at the tumor site, resection consists of formal resection with or without anastomosis, with or without stoma.

In the case of perforation proximal to the tumor site, resection consists of simultaneous tumor resection and management of proximal perforation. A subtotal colectomy may be required depending on the condition of the colon wall,

The Hartmann procedure should be preferred to simple colostomy because colostomy appears to be associated with longer hospital stay, multiple operations, and no decrease in morbidity. Loop colostomy should be reserved for unresectable tumors in severely ill patients who cannot undergo major surgical procedures or general anesthesia.

Resection and primary anastomosis should be the preferred option for uncomplicated malignant left-sided large bowel obstruction in the absence of other risk factors. Patients with high surgical risk are better managed with the Hartmann procedure.

Total colectomy should not be preferred over segmental colectomy in the absence of cecal tears or perforation, evidence of bowel ischemia, or synchronous right colonic cancers, because the former does not reduce morbidity and mortality, and it is associated with higher rates of impaired bowel function.

Laparoscopy cannot be recommended for emergency treatment of obstructive left colon carcinoma; it should be reserved for favorable cases in specialized centers.

Locally advanced rectal cancers are better treated with a multimodal approach, including neoadjuvant chemoradiotherapy. If there is acute obstruction, avoid resection of the primary tumor, and a stoma should be created.

If right-sided colon cancer is causing acute obstruction, the preferred option is right colectomy with primary anastomosis. A terminal ileostomy with colonic fistula is an alternative if primary anastomosis is considered unsafe.

For unresectable right-sided colon cancer, a side-to-side anastomosis can be performed between the terminal ileum and the transverse colon (internal bypass); as an alternative, a loop ileostomy can be created.

For right-sided obstruction, right colectomy with terminal ileostomy should be considered the procedure of choice, and severely unstable patients should be treated with a loop ileostomy.

For right-sided perforation, right colectomy with terminal ileostomy should be considered the procedure of choice, and if an open abdomen has to be considered, stoma creation should be delayed.

For left-sided obstruction, the Hartmann procedure should be considered the procedure of choice, and severe unstable patients should be treated with loop transverse colostomy.

For left-sided perforation, the Hartmann procedure should be considered the procedure of choice, and if an open abdomen has to be considered, stoma creation should be delayed.

In patients with perforation/obstruction due to colorectal lesions, an open abdomen should be considered if abdominal compartment syndrome is expected, and bowel viability should be reassessed after resection. Open abdomen should be closed within 7 days.

In patients with colorectal carcinoma obstruction and no systemic signs of infection, antibiotic prophylaxis is recommended that mainly targets gram-negative bacilli and anaerobic bacteria because of potential bacterial translocation. Prophylactic antibiotics should be discontinued after 24 hours or 3 doses.

Perforated bowel prognosis

The patient’s medical state before the perforation occurs best predicts general prognosis. In patients without multiple comorbidities, the outcomes are more favorable. Management of the underlying etiology is key to preventing further episodes ¹⁴.

References

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