Pneumoperitoneum - Causes, Symptoms, Diagnosis, and Treatment

What Is the Peritoneal Cavity?

The space between the parietal and visceral peritoneum is called the peritoneal cavity. The parietal and visceral layers line the peritoneal cavity, and this lining attaches and protects the vital organs. The structures bound by the peritoneal cavity are called retroperitoneal and intraperitoneal.

Boundaries of the peritoneal cavity are as follows:

• Vertebrae.

• Pelvic floor.

• Diaphragm.

The peritoneal cavity is further divided into the greater and lesser peritoneal cavities. The peritoneal cavity differs in both sexes due to different pelvic organs. The chances of the peritoneal cavity being infected are rare due to mucous plugs at the external opening. Still, the entrapment of the air or excessive fluid in the peritoneal cavity is most common.

What Is Pneumoperitoneum?

Pneumoperitoneum is a medical term used to describe the presence of free air in the abdomen or air in the peritoneal cavity, which is a space within the abdominal cavity. The most common cause of this condition is the rupture or discontinuation of the abdominal lining. This can be due to post-surgical complications or due to some other nonsurgical causes.

In cases where the cause is unknown or differs from abdominal lining discontinuation, such conditions are spontaneous pneumoperitoneum. Pneumoperitoneum can also result even when the peritoneal lining is intact. Some cases include introducing air into the peritoneum through the female vagina. It is commonly observed after intercourse. It has been observed that not every case of bowel perforation leads to pneumoperitoneum. Some of the perforations are insignificant and heal on their own. Abdominal surgeries in almost every case present with postoperative pneumoperitoneum, but this condition heals within three to four days.

What Are the Causes of Pneumoperitoneum?

The potential causes of pneumoperitoneum can be listed as follows:

• Perforated duodenal ulcer.

• Perforated peptic ulcer.

• Ruptured diverticulum (the pouch that lines the digestive system gets ruptured).

• Necrotizing enterocolitis (gastrointestinal disease affecting neonates).

• Malignancy.

• Ischemic bowel (intestinal disorder).

• Laparotomy (abdominal surgical procedure).

• Laparoscopy (diagnostic test of the abdomen).

• Post-endoscopic bowel trauma (abdominal trauma).

• Peritoneal infections (infection of the abdominal lining).

• Bronchopleural fistula (the infectious connection between the bronchial tree and pleural space).

• Vaginal insufflation (vaginal infection).

• Vaginal douching (intravaginal cleansing).

• Postpolypectomy syndrome (abdomen infection).

• Severe coughing.

The above-listed causes can be divided into surgical and nonsurgical causes based on the etiology of the disease.

What Are the Signs and Symptoms of Pneumoperitoneum?

The most common signs and symptoms presented by the patients are as follows:

• Abdominal pain.

• Vomiting.

• Abdominal distension.

• Constipation or diarrhea.

• Tachycardia.

• Fever.

• Hypotension.

Some of the symptoms differ according to the site of perforation, for example:

• Duodenal Ulcer Perforation: The pain in patients with perforation is in the epigastric region and lasts for a concise duration, but the abdomen is tender on palpation.

• Appendicular Perforation: In such cases, the patients have a classical presentation with pain originating in the periumbilical region and episodes of vomiting and fever. On examination, the guardian is noted.

• Small Bowel Perforation: These patients have a history of fever and chronic pain in the lower abdomen. This different site of origin and pain location helps diagnose the condition and provide appropriate treatment.

How Is Pneumoperitoneum Diagnosed?

The pneumoperitoneum can be diagnosed radiographically as the gas entrapment is noted as a radiolucent patch on the radiograph. Conventional X-rays help diagnose the condition but have been reported to be misdiagnosed in cases where the amount of gas enclosed is less; therefore, computed tomography is used and considered a standard diagnostic method.

To confirm diagnosis following signs are noted on the radiographs, and the severity and the presence of the disease are confirmed based on the diagnostic criteria, which are also called diagnostic signs and are as follows:

• Saddlebag or Mustache Sign: When the air or gas is noted in the midline or below the central tendon, radiographs taken in the supine position are termed a saddlebag sign.

• Rigler's sign: Cases in which the air is noted to outline both sides of the bowel wall are termed the Rigler sign.

• Lucent Liver Sign: It is observed when the liver loses its radiopacity due to the accumulation of air anterior to the liver.

• Football Sign: When the abdominal cavity is filled by gas is termed a football sign and is observed in cases with large pneumoperitoneum, it is most commonly seen in children with iatrogenic gastric perforations and Hirschsprung's disease.

• Silvers Sign or Falciform Ligament Sign: This is observed when the gas surrounds the Falciform ligament.

What Is the Differential Diagnosis for Pneumoperitoneum?

Some other disorders or radiographic errors can present as pseudo pneumoperitoneum.

Some of such conditions are as follows:

• Subphrenic abscess (infection surrounding the diaphragm).

• Chilaiditi syndrome, where the bowel is compressed between the diaphragm and liver.

• Atelectasis (lung collapse) at the base of the lung can cause radiographic artifacts.

• Connective tissue disorders.

• Acute appendicitis (inflammation of the appendix).

• Intraabdominal abscess.

• Inflammatory bowel disease (chronic intestine inflammation).

What Is the Use of Pneumoperitoneum in Medicine?

The pneumoperitoneum is created before laparoscopic surgeries, which is one of the essential diagnostic methods in many critical patients to visualize adequately and carry out operative manipulations if required. This procedure is carried out using carbon dioxide gas as it is highly diffusible and has a rapid rate of absorption and excretion; these properties of carbon dioxide reduce postoperative complications making it safe to use. Laparoscopy is less invasive and is preferred over other surgical diagnostic procedures.

How Is Pneumoperitoneum Treated?

Pneumoperitoneum can be treated based on its underlying cause. Gastrointestinal perforation is considered one of the most common surgical emergencies and requires immediate medical attention. Some cases of pneumoperitoneum, like post-laparoscopic pneumoperitoneum, heal independently within seven to ten days.

Some of the most common treatment modalities include:

• Surgery for the repair of the perforations.

• Antibiotic therapy.

• Pain relieving medications.

• Lifestyle and food habit modifications.

• Adequate rest.

Conclusion:

Pneumoperitoneum is a condition in which there is free accumulation of air in the abdomen. The most probable cause of pneumoperitoneum is the breach in the continuity of the peritoneal lining. Other causes include air inclusion through the vaginal opening in females after sexual intercourse, which is diagnosed radiographically with the help of ultrasound, X-ray, or computed tomography. In some cases, pneumoperitoneum is also caused by postoperative abdominal surgeries but is cured on its own within three to four days. Still, some conditions are more severe and require medical attention, surgery, or treatment with antibiotics.