Chapter 17 “Free Air” in a 72-Year-Old Female (Case 7)
| Perforated ulcer | Perforated diverticulitis | Perforated cancer |
| Perforated small bowel obstruction | Anastomotic breakdown | Perforated cecum |
PATIENT CARE
Clinical Thinking
• Try to elicit peritoneal findings (involuntary guarding and rebound). Peritoneal findings in a patient with free air mandate operative exploration.
• Medications may mask abdominal findings, and many elderly patients are often on multiple medications. Medications may also be causative: pay particular attention to narcotics, nonsteroidal anti-inflammatory drugs, and steroids.
• When in a consulting situation, check whether previous physicians may have given narcotics early on in the hospital course.
• Although many patients with abdominal pain frequently get fast-tracked to CT, the dx of peritonitis does not require sophisticated imaging. In fact, the oral contrast ingested and the delays in obtaining the CT often do more harm than good. A complete hx and physical examination, prompt resuscitation, and timely operative intervention will provide the best care for these patients.
History
• Perforated ulcer is often preceded by a hx of ulcer disease. Patients may describe a variable time of vague upper abdominal pain and then pinpoint (the exact time of perforation) when the pain became much more intense. They may also relate a hx of arthritis or other disease for which they take NSAIDs.
• Perforated cancer may be suspected with a hx of change in bowel habits, melena, anemia, or recent obstructive symptoms.
• Patients with a perforated cecum usually have an antecedent hx consistent with a more distal large bowel obstruction or a prolonged and significant ileus.
Physical Examination
• VS: Perforated viscus is commonly accompanied by fever. Hypotension can be associated with fluid depletion or sepsis.
• Although the tenderness is likely to be diffuse, it may be greater in the epigastrium of patients with perforated ulcer, in the RLQ in patients with perforated appendicitis and perforated cecum, or in the LLQ in patients with perforated diverticulitis.
Tests for Consideration
| $35 |
| Clinical Entities | Medical Knowledge |
|---|---|
| Perforated Peptic Ulcer | |
| PΦ | Ulcer disease is due to acid hypersecretion or loss of the mucosal barrier function of the stomach. Infection with Helicobacter pylori often plays a role. Loss of mucosal barrier is seen in patients taking NSAIDs or steroids. Perforation occurs with continued acid exposure, and can occur in either the stomach or duodenum. |
| TP | Patients typically can state exactly when the perforation occurred. The peritonitis is initially a chemical peritonitis, and patients lie still. They often relate that the drive to the hospital was exquisitely painful and that they “felt every bump.” |
| Dx | Upper abdominal pain, peritonitis, and free air on plain radiography are key diagnostic features. Posterior perforations may be more difficult to diagnose, and may present with back pain and air outlining the psoas shadow. RLQ pain occurs after several hours as the irritating gastric or duodenal contents spill down the right colic gutter. |
| Tx | Tx includes fluid resuscitation and closure of the perforation. Acid reduction can be achieved with medication or surgery. See Sabiston 46, Becker 26. |
| Perforated Diverticulitis | |
| PΦ | Perforated diverticulitis begins with an occlusion of a colonic diverticulum by feces. |
| TP | Ongoing obstruction results in perforation of the diverticulum, often with resulting abscess formation or dissemination of feces throughout the abdomen. |
| Dx | The dx is based on antecedent hx of LLQ pain and cramping followed by generalized abdominal pain associated with free air. Often the dx is suspected but not certain until laparotomy. Diagnostic features include LLQ or lower midline tenderness with peritonitis. |
| Tx | Tx includes broad-spectrum antibiotics and resection of the involved segment of intestine. An ostomy is often required as resection and re-anastomosis should not be performed in the presence of significant peritoneal soilage and the absence of an adequate bowel prep. See Sabiston 50, Becker 25. |
| Perforated Cecum | |
| PΦ | When the large bowel is obstructed distally or when there is a process that profoundly distends the cecum (e.g., ileus, Ogilvie’s syndrome), the cecum will be the portion of the bowel most at risk for perforation. According to the Law of Laplace, the intraluminal pressure required to stretch the wall of a hollow tube is inversely proportional to its diameter. The largest diameter in the colon is the cecum; hence, the cecum requires the least amount of pressure to increase in size. As the wall tension of the cecum increases, ischemia with longitudinal splitting of the serosa and perforation can occur. |
| TP | There is usually a hx of antecedent large bowel obstruction (a distal obstructing lesion) or a significant colonic ileus as in Ogilvie’s syndrome. |
| Dx | Cecal perforation, like other viscous perforations, presents with peritonitis and “free air.” Specific dx of a perforated cecum may not be made until the time of laparotomy. |
| Tx | Tx includes broad-spectrum IV antibiotics due to fecal peritonitis and resection of the cecum. The decision for ileostomy or primary re-anastomosis (ileocolostomy) depends on the degree of peritoneal soilage and the patient’s overall status. See Sabiston 50, Becker 14. |
| Perforated Cancer | |
| PΦ | Perforated cancer occurs when cancer obstructs the colonic lumen, resulting in colonic obstruction and subsequent perforation. |
| TP | The hx is variable depending on the site of perforation; it is most common in the descending and sigmoid colon. Often a hx of increasing constipation with decreasing stool caliber is present. |
| Dx | The dx may not be made until the time of laparotomy. Chronic anemia due to occult blood loss may provide a preoperative clue. |
| Tx | Tx includes broad-spectrum IV antibiotics due to fecal peritonitis and resection of the involved segment of intestine with the formation of an ostomy. A careful intraoperative assessment of the rest of the abdomen, particularly the rest of the colon and the liver, for metastatic disease is necessary. See Sabiston 50, Becker 21. |
| Perforated Small Bowel Obstruction | |
| PΦ | Perforated small bowel obstruction is most often due to adhesions that cause a complete obstruction with build-up of air and fluid, resulting in perforation. |
| TP | The patient usually complains of nausea, vomiting, constipation or obstipation, and abdominal pain. |
| Dx | Dx is made by an antecedent hx of obstruction, abdominal distention, a previous abdominal operation, and free air. An obstructive pattern may or may not be present on plain abdominal radiography. |
| Tx | Tx is preoperative IV antibiotics and laparotomy with small bowel resection and anastomosis. See Sabiston 48, Becker 25. |
| Anastomotic Breakdown | |
| PΦ | Anastomotic breakdown is a breakdown of a sewn or stapled anastomosis anywhere in the GI tract. Causes include tension, poor blood supply, and poor technique. |
| TP | The breakdown most often becomes evident 4 to 7 days after the operation, although the patient often has a low-grade fever and more pain than expected for a few days prior to the development of free air. |
| Dx | Dx is based on hx, physical examination, and radiographic imaging. As a certain amount of free air is expected after laparotomy, CT may be required to help identify anastomotic problems. |
| Tx | Tx includes broad-spectrum IV antibiotics and reoperation, which would likely include creation of an ostomy for fecal diversion. See Sabiston 15. |
| “Free Air” Not Associated with Viscus Perforation | |
| PΦ | (See the Zebra Zone.) Air can enter the peritoneal cavity from the chest by tracking along the mediastinum and retroperitoneum, and from the female genital tract via the fallopian tubes. |
| In general, however, “free air” should be considered to connote a perforated viscus until proven otherwise. | |
