Idiopathic Segmental Infarction is relatively rare. The occurrence of infarction is unrelated to trauma, torsion, cardiovascular disease, adhesions, or other intra-abdominal pathological conditions. It is an acute vascular disease of the omentum with an unknown cause, also referred to as spontaneous omental infarction or hemorrhagic infarction of the greater omentum.

bubble_chart Pathogenesis

Many scholars have proposed various theories to explain the mechanism of disease. It is generally believed that venous distension or abnormal venous return, the heavy membrane pulling on blood vessels leading to elongation and/or injury to the inner membrane, grade I trauma, increased abdominal pressure, and anatomical variations of the membrane can all contribute to thrombosis in the membrane. The infarction typically occurs at the free edge of the right-sided membrane. The lesion mass is triangular in shape, usually with a diameter of about 6–8 cm, and may sometimes extend to surrounding tissues and the parietal peritoneum. Microscopic examination reveals thrombosis in the membrane's arteries and veins, along with infiltration of multinucleated cells and round cells.

bubble_chart Clinical Manifestations

It is commonly seen in well-nourished men aged 20 to 30, with males being 2.5 times more likely than females, and is closely related to obesity. Patients present with persistent and severe right-sided abdominal pain, with pain in the lower right abdomen accounting for about three-quarters of cases, significantly worsening during activity. Nausea and vomiting are uncommon, but fever may occur. Examination reveals localized abdominal tenderness, rebound tenderness, and muscle rigidity, with tenderness often found at McBurney's point and its surrounding area in the lower right abdomen. An abdominal mass or localized fullness may be palpable. Hypersensitivity of the skin is a characteristic sign of this condition. White blood cell counts are normal or slightly elevated.

Due to symptoms such as abdominal pain, tenderness and muscle rigidity in the right lower abdomen, and signs of peritoneal irritation, along with elevated peripheral white blood cell count, it is often misdiagnosed as acute appendicitis or even acute cholecystitis. B-ultrasound may reveal a small amount of ascites, and abdominal puncture might yield bloody ascites. The condition is often confirmed only during emergency laparotomy for acute abdomen. Many patients are misdiagnosed with acute appendicitis, and it is only noticed during surgery when bloody serous effusion is found in the abdominal cavity. The infarcted area may form a firm, red, or purplish-black mass.

bubble_chart Treatment Measures

The involved omentum tissue should be widely excised.

bubble_chart Prognosis

The prognosis of this disease is good.

bubble_chart Differentiation

Differential diagnosis includes acute appendicitis and acute cholecystitis.