Hughes, Heather DO; McGerald, Genevieve DO; Daniel, Reethamma MD; Kutin, Neil MD
A 3-year-old girl presented to the emergency department complaining of abdominal pain for three days. The pain was constant and mainly located over the right lower quadrant. The symptoms had increased in severity over the past day. The patient also presented with nausea, loose bowel movements, and anorexia. Her medical history revealed hypothyroidism but no previous surgical history.
Tenderness of the entire abdomen was noted with the point of maximal tenderness in the right lower quadrant. Rebound tenderness was also noted. A laboratory analysis demonstrated no significant abnormalities. Abdominal computed tomography revealed inflammatory changes around the cecum with focal fluid collection without visualization of the appendix, highly suspicious for acute appendicitis.
The patient underwent surgery for appendicitis, but during surgery, the surgeon observed torsion of the omentum with areas of hemorrhage and infarction. The vasculature was congested, suggesting omental torsion and infarction. The omentum and appendix were removed. The postoperative period was uneventful, and she was discharged from the hospital without complication. The pathologist confirmed the diagnosis of omental infarction with no pathologic evidence of appendicitis.
Omental infarction is a rare condition and difficult to diagnose preoperatively. She subsequently was found to be the youngest case of omental infarction in the literature. Omental infarction is an infrequent cause of abdominal pain, presenting mainly in the third to fifth decades of life. Fewer cases are reported in children. The youngest documented case of omental infarction is age 5, largely because of the absence of omental fat in children. The omentum twists around its axis, compromising vascularity and resulting in extravasation and necrosis.
Children with omental infarction classically present with acute onset of right-sided abdominal pain and tenderness, and the tenderness is localized in most patients. The presumed diagnosis in children is usually appendicitis. Omental infarction can mimic various other causes of an acute abdomen, and physicians should generally include this in their differential diagnosis of pediatric patients with abdominal pain. Unfortunately, the symptoms and clinical findings do not present in any characteristic pattern that suggests the diagnosis. The differential diagnosis should include not only appendicitis but cholecystitis, cecal diverticulitis, and other disease. Omental infarction has an incidence of 0.0016-0.37 percent in pediatric patients with abdominal pain. (Gac Med Mex 2007;143(1):17.)
It is not possible to distinguish omental infarction from appendicitis clinically. Because CT is being used more frequently to investigate acute abdominal pain in children, knowing the characteristic imaging features of omental infarction is important in making the diagnosis preoperatively and in distinguishing omental infarction from acute appendicitis. The CT scan shows an infarcted omentum as an area of high-attenuated fat containing hyperattenuated streaks just beneath the parietal peritoneum with thickening of the overlying anterior abdominal wall in cases of omental torsion. (Abdom Imaging 2004;29:502.)
Another finding can be a whirling pattern of the mesentery or fluid accumulation within the abdomen. Unfortunately, all of these findings also can be observed in various other disease processes. Acute appendicitis was the initial diagnosis made in this patient. The CT findings were not diagnostic of omental infarction, and the final diagnosis was established intraoperatively.
Theories regarding the causes of omental infarction include anomalous arterial supply to the omentum, kinking of veins associated with increased intra-abdominal pressure, or vascular congestion after large meals. (Radiology 1992;185:169.) Childhood obesity has recently been identified as a predisposing factor. Other precipitating factors include trauma, coughing, sudden change in body position, and compression between the liver and the anterior abdominal wall. (Principles of Surgery. 5th ed. New York, NY: McGraw-Hill, 1989: 1495.)
Pathologic findings include congestion, hemorrhage, fat necrosis, and varying degrees of inflammatory cell infiltration. Segmental omental infarction is a self-limited, benign condition that may resolve spontaneously in most patients. The inflammatory response resolves with retraction and fibrosis leading to complete healing or autoamputation. (Radiology 1992;185:169; Australas Radiol 2000;44:212; J Comput Assist Tomogr 1993;17:379.) Reported complications include adhesions with bowel obstruction and abscess formation. (J Comput Assist Tomogr 1993;17:379; Am J Gastroenterol 1980;74:443.)
Although some surgeons promote conservative treatment, many believe that laparoscopic excision is the treatment of choice. After the infarcted omentum is removed, the child's clinical symptoms resolve quickly and the risk of abscess formation or other problems, such as bowel obstruction caused by adhesions, is reduced. Recovery after removal is rapid and uneventful in most patients.