|Year : 2013 | Volume
| Issue : 2 | Page : 46-48
Omental infarction: A misleading cause of an acute abdomen
Robinson George1, Kukku Leopold1, Krishnan Prasad1, Veena Nair2
1 Department of General and Laparoscopic Surgery, Sree Narayana Institute of Medical Sciences, Cochin, Kerala, India
2 Department of Radiodiagnosis, Sree Narayana Institute of Medical Sciences, Cochin, Kerala, India
|Date of Web Publication||15-Jan-2014|
Department of Surgery, Sree Narayana Institute of Medical Sciences, Cochin 683 594, Kerala
Source of Support: None, Conflict of Interest: None
Omental infarction is a rare cause of an acute abdomen. Depending on the site of infarction, it can mimic conditions such as appendicitis, cholecystitis and diverticulitis. Before computed tomography, the diagnosis was made intraoperatively. We report a case of a young man who was treated conservatively following diagnosis using radiologic means, for its rarity and merits of a similar conservative approach in future cases.
Keywords: Appendicitis, computed tomography, omental infarction, omental torsion
|How to cite this article:|
George R, Leopold K, Prasad K, Nair V. Omental infarction: A misleading cause of an acute abdomen. Saudi Surg J 2013;1:46-8
| Introduction|| |
Omental infarction (OI), described 100 years ago  has an unknown etiology. , The incidence of OI is estimated to be around 0.1% of all laparotomies performed.  There are probably around 50 cases reported in the literature. Most patients present with right-sided abdominal pain (90%) and affects males more (ratio 2:1). , It has been postulated that the right side of the omentum is more prone to infarction due to greater length and mobility.  Other authors have attributed its occurrence to a different embryonic origin of the right side of the omentum with congenitally anomalous fragile blood vessels. , This condition occurs mainly in people in their fourth and fifth decades  and a significant proportion of cases have also been described in the pediatric population (15%).  This is unique because initially the diagnosis was appendicitis and found to be OI after the appropriate imaging was performed.
| Case Report|| |
A 27-year-old obese male engineer with a body mass index (BMI) 30 presented with complaints of sudden onset, cramping right lower quadrant pain with radiation to right flank. Any movement aggravated the pain and was associated with anorexia, vomiting and fever. There was no past surgical or medical history.
Abdominal examination revealed right iliac fossa and right flank tenderness. Rebound tenderness and Rovsing's sign were positive. Routine investigations showed leucocytosis and microscopic hematuria in urinalysis. He was put on antibiotics and analgesics, recovered in 2 days and discharged since he was not willing for surgery. The diagnosis at this time was subacute appendicitis. Unfortunately, he returned the very same evening with severe pain in the right flank and hypochondrium.
This dissociated picture between severity of pain and clinical features left us riddled. A contrast enhanced computed tomography (CT) abdomen, performed the next day, showed increased density and fat stranding in omental fat in the right upper and lower quadrant, clearly suggestive of OI [Figure 1] and [Figure 2].
|Figure 1: Computed tomography sagittal view showing a focal area of hyperattenuating omental fat stranding (red arrow)|
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|Figure 2: Computed tomography axial view showing the hyperattenuation and pericolonic adhesions|
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Patient was closely observed and managed with intravenous fluids, antibiotics and nil per oral. His abdominal pain gradually resolved and was discharged 5 days later.
| Discussion|| |
OI is a rare cause of acute abdomen, with incidence of less than 4 cases/1000 cases of appendicitis.  The incidence of OI is estimated to be around 0.1% of all laparotomies performed.  Low incidence and non-specific presentation contribute to OI being misconstrued for appendicitis, peptic ulcer disease, cholecystitis, pancreatitis, among other abdominal pathology. ,,, Morbidity offset by a harmless recovery with OI, rationalized mandatory surgery in earlier reports.  More recent literature queries exploration, as improvements in accuracy and accessibility of CT imaging diagnosis have been made. 
Infarction can be isolated or successive to omental torsion. Bush is credited with citing the very first case of OI associated, with hemorrhaging into the greater omentum caused by a traumatic event  and Eitel, the first case of torsion associated OI, a few years later in 1896. 
Pathogenesis in relation to blood supply disruption in OI is unknown. In lieu of a preponderance for right side presentations, , it has been hypothesized that the right half of the omentum consists of anatomically altered vasculature, less tolerant of spontaneous venous stasis and thrombosis secondary to stretching of omental veins. , An elevated BMI has been of particular interest, especially cases reporting idiopathic OI in obese children. It is hypothesized that fat accumulation in the omentum can impede the distal right epiploic artery. 
Understanding abdominal innervation will help to decipher clinical presentation. Parietal peritoneum of the anterior abdominal wall shares somatic innervations with overlying muscle and skin. Hence, irritation will precipitate localized tenderness and muscle contraction, guarding, through efferent pathways, via afferent connections on the parietal peritoneum. Owing to its surface area and proximity to the anterior wall and coupled with extensive manoeuvrability, diseased greater omentum can irritate parietal peritoneum in many locations across the entire anterior abdomen: Which is why greater omentum is a strong candidate for causing multi foci, site specified pain, mirroring our patient's presentation. 
Recognition of omental pathology radiographically has improved immensely over the last 2 decades.  Hyperattenuated streaks and heterogenous fatty mass with a capsule, located between anterior abdominal wall and colon is the best diagnostic clue to diagnosis.  Definitive differentiation between OI and torsion related infarction can only be made surgically, although discerning between them does not change management.
Presently, no definitive course of action for managing OI exists. Accurate recognition of pathology on CT means diagnosis can be attained without exploration and in turn conservative management has become a viable option. This approach utilizes analgesics and antibiotics with optimal fluid management in the first instance.  Fragoso et al., reasons that, the risks associated with conservative management are theoretical, with no reported cases to date. 
The authors recommending surgical management, a laparascopic approach is favored, affording thorough abdominal exploration and omental necrosectomy.  Removing devitalized omentum reduces a "theoretical" risk of secondary peritoneal abscess formation. 
As of present, no study shows a difference in outcome following surgery or conservative management. After CT imaging, Itenberg et al. advocate close monitoring of a patient in the first 24-48 h, refrain from considering surgery until deterioration in any symptom, sign or clinical marker.  We decided on a conservative approach since the symptoms abated and the patient was not ready for an intervention. Most of the OI's can be managed conservatively as per literature.
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[Figure 1], [Figure 2]