Omental infarction occurs when there is ischemia to the greater omentum. This can be idiopathic or secondary to various conditions. It is an uncommon cause of acute abdomen, with vague symptoms.
Omental infarction (OI) is a condition where the greater omentum is subjected to ischemic damage due to interrupted blood flow. It is rare and often characterized by right lower quadrant abdominal pain [1]. One in one thousand laparotomies performed is secondary to acute abdomen arising from OI.
OI can be classified into primary and secondary [2]. In primary disease, the exact pathogenesis is unknown. There is a greater incidence of OI on the right hand side, and literature suggests that the reason lies in abnormal vasculature, stemming from embryonic factors, making it particularly vulnerable to congestion and decreased blood flow [3]. This is often referred to as primary idiopathic segmental OI [4]. In some cases the omentum first twists around itself, which then leads to OI. Conditions that predispose to omental torsion are obesity, adhesions, increased peristalsis, intra abdominal masses, and increased abdominal pressure [5]. Obesity is thought to increase the risk of torsion because of the additional fat tissue that disrupts the arterial blood supply and increases the weight of the omentum [6]. Males are more affected by idiopathic OI than females. OI has been known to occur in children as well, notably those who are obese. Secondary OI results from various medical conditions such as trauma, surgery, vascular disease and hypercoagulable states.
Because of its uncommon occurrence and non specific presentation, OI is frequently misdiagnosed, as clinicians suspect more common causes of acute abdomen, namely appendicitis, acute cholecystitis, peptic ulcer disease and so on [7]. Constitutional symptoms such as fever, as well as gastrointestinal upset (nausea, vomiting, diarrhea) are usually absent. Right sided guarding may be elicited [3].
As the clinical picture is unreliable in diagnosis, more emphasis has been placed on imaging modalities. Because of their improved availability, accuracy, and thus detection rate, fewer exploratory laparotomies are being done [2] [8]. Furthermore, this may explain the apparent increased incidence of omental infarction, added to more awareness of the condition by physicians [9]. Radiology is thus paramount, as it confirms the diagnosis and influences management.
In primary omental OI, abnormalities are likely to be present in the right lower quadrant, whereas secondary OI mostly appears at the site of the causative injury. The distinction between idiopathic omental infarction, and infarction secondary to torsion can only be definitively made intra-operatively.
Imaging: