**5. Role of X-ray abdomen and CT scan in confirming the diagnosis**

Plain radiography remains the most frequently ordered examination in patients with suspected perforation. Pneumoperitoneum is present in the rupture of any hollow viscous. It may also be observed following recent abdominal surgery, paracentesis, and pneumatosis intestinalis. Benign pneumoperitoneum may rarely develop following endoscopy due to transmural passage of insufflated air without bowel perforation [15]. Plain radiography can detect about 55–85% of patients with pneumoperitoneum [16]. It can detect as little as 1–2 ml of free air [17]. Upright lateral chest radiograph has better sensitivity than upright postero-anterior chest radiograph [18]. Upright positions including left lateral decubitus are uncomfortable in critically ill patients in the emergency setting. In such patients supine decubitus anteroposterior view of the thorax and anteroposterior or lateral view of the abdomen are generally requested [19].

Free air can be visualized in different shapes, sizes, and locations in the abdominal cavity. On upright postero-anterior chest or abdominal radiography, free air is visualized as a translucent crescent below the diaphragm (**Figure 1**). These free-air signs can be categorized as bowel-related, right-upper-quadrant, peritoneal ligament- related, or other signs [20]. Rigler sign is the visualization of both sides of the bowel wall in a supine abdominal radiograph (**Figure 2**). The presence of normal gas

#### **Figure 1.**

*X-ray abdomen showing A-Giant pneumoperitoneum appearing as an air-fluid level in the peritoneal cavity. B-pneumoperitoneum on the left side may be confused with fundal gas.*

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Figure 3.
X-ray chest showing Chilaiditi sign.
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in the bowel lumen, as well as free extraluminal gas, makes the bowel wall outline nicely visible. It is seen when a large quantity of free gas is present in the abdomen. Hyperlucent liver sign is also seen in a supine radiograph. Intraperitoneal free air may outline the various peritoneal ligaments making them visible along their course giving rise to various signs: falciform ligament sign, ligamentum teres sign, "inverted V" sign, urachus sign, etc. [20]. Along with it air in the subcutaneous tissue can also be visualized. Pneumoperitoneum is often absent in the perforation of the retroperitoneal duodenum. A confusing picture related to pneumoperitoneum is the Chilaiditi sign. It is the interposition of the bowel, commonly colon, between the right

**113**

**Figure 5.**

*Flowchart for the diagnosis of small bowel perforation.*

**Figure 4.**

*patient as shown in* **Figure 1.**

*Early Recognition and Management of Small Bowel Perforation*

hemidiaphragm and the liver. It can be falsely diagnosed as pneumoperitoneum. Features that are suggestive of Chilaiditi sign are gas between liver and diaphragm and haustra in the gas suggesting that it is bowel and not free air (**Figure 3**) [21]. Although plain radiography is good modality in suspected cases of hollow viscus

perforation, ultrasonography can be helpful in certain scenarios because of the absence of radiation exposure, bedside availability, no pre-procedural preparation, and speed. It can be used in pregnant females and sick patients. It can detect free fluid in the abdomen and rule out other causes of acute abdominal pain. It may not help in the early period of perforation when the amount of free fluid is scant for detection. Computed tomography (CT) scan is very sensitive and specific for perforation of the gastrointestinal tract (80–100%) [22]. It is more sensitive than plain radiography for small or retroperitoneal perforations. In addition to free air, it can also detect the location and size of perforation and any fluid collection. Direct CT signs of intestinal perforation are free gas and extra-luminal leak of oral contrast (**Figure 4**) [23]. Indirect signs include misty mesentery, fluid collection, bowel wall thickening, and extra-luminal fecal matter [24]. In a prospective study of 85 patients, the MDCT images confirmed the site of gastrointestinal tract perforation in 73 (86%) patients.

*CECT abdomen showing big pneumoperitoneum anteriorly and left side intra-abdominal collection. Same* 

*DOI: http://dx.doi.org/10.5772/intechopen.96435*

#### *Early Recognition and Management of Small Bowel Perforation DOI: http://dx.doi.org/10.5772/intechopen.96435*

hemidiaphragm and the liver. It can be falsely diagnosed as pneumoperitoneum. Features that are suggestive of Chilaiditi sign are gas between liver and diaphragm and haustra in the gas suggesting that it is bowel and not free air (**Figure 3**) [21].

Although plain radiography is good modality in suspected cases of hollow viscus perforation, ultrasonography can be helpful in certain scenarios because of the absence of radiation exposure, bedside availability, no pre-procedural preparation, and speed. It can be used in pregnant females and sick patients. It can detect free fluid in the abdomen and rule out other causes of acute abdominal pain. It may not help in the early period of perforation when the amount of free fluid is scant for detection.

Computed tomography (CT) scan is very sensitive and specific for perforation of the gastrointestinal tract (80–100%) [22]. It is more sensitive than plain radiography for small or retroperitoneal perforations. In addition to free air, it can also detect the location and size of perforation and any fluid collection. Direct CT signs of intestinal perforation are free gas and extra-luminal leak of oral contrast (**Figure 4**) [23]. Indirect signs include misty mesentery, fluid collection, bowel wall thickening, and extra-luminal fecal matter [24]. In a prospective study of 85 patients, the MDCT images confirmed the site of gastrointestinal tract perforation in 73 (86%) patients.

#### **Figure 4.**

*Endoscopy in Small Bowel Diseases*

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**Figure 3.**

*X-ray chest showing Chilaiditi sign.*

**Figure 2.** *Rigler sign.*

in the bowel lumen, as well as free extraluminal gas, makes the bowel wall outline nicely visible. It is seen when a large quantity of free gas is present in the abdomen. Hyperlucent liver sign is also seen in a supine radiograph. Intraperitoneal free air may outline the various peritoneal ligaments making them visible along their course giving rise to various signs: falciform ligament sign, ligamentum teres sign, "inverted V" sign, urachus sign, etc. [20]. Along with it air in the subcutaneous tissue can also be visualized. Pneumoperitoneum is often absent in the perforation of the retroperitoneal duodenum. A confusing picture related to pneumoperitoneum is the Chilaiditi

sign. It is the interposition of the bowel, commonly colon, between the right

*CECT abdomen showing big pneumoperitoneum anteriorly and left side intra-abdominal collection. Same patient as shown in* **Figure 1.**

**Figure 5.** *Flowchart for the diagnosis of small bowel perforation.*

Furthermore, the logistic regression showed that extra-luminal air, segmental bowel wall thickening, and focal defect of the intestinal wall were strong predictors of the site of perforation [25].

Signs present in plain radiography are also seen in scout view in CT. When contrast is contraindicated, then even plain CT is of help, in diagnosing perforation. The European Society of Gastrointestinal Endoscopy (ESGE) recommends that clinical features suggestive of perforation after an endoscopy should be rapidly and carefully evaluated and documented with a CT scan [26]. See flowchart for the diagnosis of intestinal perforation (**Figure 5**).

### **6. Resuscitation, supportive measures, and preparation for surgery**

Evaluation and resuscitation should go hand in hand. The intravascular fluid deficit should be corrected considering systemic diseases in acutely ill patients. Warmed crystalloids (normal saline or lactated Ringer solution) should be started using wide-bore IV cannula. Fluid therapy should be guided according to physical signs (pulse rate, blood pressure), urine output, lactate levels, CVP, etc. Patients who are not responsive to adequate fluid therapy should be started on vasopressors. Nasogastric tube insertion prevents aspiration in patients with altered mental status and the elderly. Foley's catheterization is needed to measure urine output.

Parenteral analgesics (tramadol, paracetamol, NSAID, etc) should be started in an adequate dose in combination, keeping in mind the renal function of the patient. We generally avoid diclofenac in bowel repair as animal studies have shown an increased risk of post-surgery leak [27]. Broad-spectrum antibiotic therapy (piperacillin + tazobactum or meropenem, etc. along with metronidazole) should be started to control on-going sepsis. The antibiotics can later be continued as indicated or changed according to culture and sensitivity.

The anesthetic evaluation would include the American Society of Anesthesiologists (ASA) classification system to stratify patients according to the degree of perioperative risks [28]. Thromboprophylaxis should be started in high-risk patients that include mechanical devices (thromboembolic deterrent stocking and pneumatic compression boots) and drugs (heparin and LMWH) [29]. Risk factors for deep vein thrombosis include increased age, obesity, chronic diseases (diabetes, COPD, malignancy), corticosteroid therapy, and past or family history of thromboembolic disease. Written consent for surgery is taken and the patient and the family should be explained about the possibility of multiple staged surgeries, temporary stomas, postoperative ICU care, and expected complications of surgery.
