Overview
Omental torsion is a rare, acute condition in which the greater omentum—a fatty, apron‑like peritoneal fold that hangs from the stomach and transverse colon—twists on its own axis. The torsion compromises blood flow, leading to inflammation, infarction, and potentially necrosis of the omental tissue. Because the symptoms often mimic more common abdominal emergencies (appendicitis, cholecystitis, or diverticulitis), diagnosis can be challenging.
Who it affects: Historically, primary (idiopathic) omental torsion is reported more often in males (≈70 % of cases) and typically occurs in the third to fifth decades of life. Secondary torsion, which occurs in the setting of intra‑abdominal pathology (e.g., adhesions, cysts, or tumors), can affect any age group, including children.
Prevalence: Exact incidence is unknown due to under‑recognition, but surgical series estimate 1–2 cases per 1,000 abdominal surgeries and 0.1 % of all patients presenting with acute abdomen (Kawahara et al., 2020; Mayo Clinic). The condition is considered “rare” by the CDC and WHO.
Symptoms
The clinical picture is usually abrupt and localized to the right side of the abdomen, but variations exist. Common symptoms include:
- Acute abdominal pain: Sudden, sharp, or cramping pain, most often in the right lower quadrant or mid‑abdominal region.
- Localized tenderness: Pain is reproducible on palpation; there may be a “guarding” reflex.
- Vomiting & nausea: Present in up to 60 % of patients, usually after the pain starts.
- Low‑grade fever: Mild fever (≤38 °C) may develop as inflammation progresses.
- Loss of appetite (anorexia) and abdominal distension, especially in larger torsions.
- Changes in bowel habits: Rarely, patients report constipation or obstipation due to localized ileus.
- Palpable mass: In some cases a firm, mobile mass can be felt, representing the twisted omentum.
Because these signs overlap with appendicitis, epiploic appendagitis, and other surgically urgent conditions, clinicians maintain a high index of suspicion.
Causes and Risk Factors
Omental torsion can be classified as:
Primary (idiopathic) torsion
- Anatomical variants: A longer, more pendulous omentum or a vascular pedicle with a narrow attachment predisposes to twisting.
- Obesity: Excess intra‑abdominal fat adds weight, increasing torque forces; obesity is reported in 45–60 % of primary cases.
- Sudden physical activity or blunt trauma: Rapid movements, coughing fits, or a sports injury can set the omentum in motion.
- Congenital malrotation: Rare developmental anomalies that alter the positioning of the omentum.
Secondary torsion
- Intra‑abdominal adhesions: From previous surgeries, infections, or peritonitis.
- Neoplasms or cysts: Tumors of the omentum, ovary, or colon can act as a lead point.
- Inflammatory conditions: Appendicitis, cholecystitis, or diverticulitis may tether the omentum.
- Pregnancy: Uterine enlargement displaces abdominal contents, increasing torsion risk.
Diagnosis
Because the presentation is non‑specific, a stepwise approach combining clinical assessment with imaging is essential.
1. Physical examination
- Localized tenderness, guarding, and sometimes a palpable “sausage‑shaped” mass.
- Assessment for rebound tenderness helps differentiate peritonitis.
2. Laboratory tests
- Complete blood count (CBC): Mild leukocytosis (WBC 10‑15 × 10⁹/L) in ~50 % of cases.
- C‑reactive protein (CRP): Elevated in inflammatory processes but not diagnostic.
- Electrolytes, liver function, and urinalysis are ordered to rule out other causes.
3. Imaging studies
- Ultrasound (US): First‑line in many emergency departments. May show an ovoid, hyperechoic, non‑compressible mass with a peripheral “halo” sign.
- Computed tomography (CT) scan: Gold standard. Typical findings:
- Focal, fatty, mass‑like lesion with a whorled pattern of concentric strands (the “twisted omental pedicle”).
- Absence of enhancement after contrast, indicating infarction.
- MRI: Rarely needed; useful when radiation exposure is a concern (e.g., pregnancy).
4. Diagnostic laparoscopy
If imaging is inconclusive but clinical suspicion remains high, minimally invasive surgery allows direct visualization and definitive treatment.
Treatment Options
Management depends on the extent of torsion, patient stability, and whether necrosis is present.
1. Conservative (non‑operative) management
- Selected for small, non‑infarcted torsions diagnosed early by CT.
- Includes analgesia (acetaminophen, NSAIDs), bowel rest, and close observation.
- Success rates are modest; up to 30 % may progress to necrosis requiring surgery.
2. Surgical intervention
Most patients ultimately require surgery.
- Laparoscopic omentectomy: Preferred; allows removal of the twisted segment while minimizing wound complications. Operative time averages 45‑60 minutes.
- Open laparotomy: Reserved for massive torsion, hemodynamic instability, or when laparoscopy is contraindicated.
- During surgery, the twisted omentum is untwisted; if viable, it may be left in place, but most surgeons excise the segment to prevent recurrence.
3. Medications
- Pain control: NSAIDs or opioids as needed.
- Antibiotics: Broad‑spectrum coverage (e.g., ceftriaxone + metronidazole) is given peri‑operatively to prevent secondary infection, especially if necrosis is present.
4. Post‑operative care & lifestyle changes
- Advance diet as tolerated (usually clear liquids → soft diet over 24‑48 h).
- Encourage early ambulation to reduce postoperative ileus.
- Weight management for obese patients (BMI ≥ 30 kg/m²) lowers recurrence risk.
Living with Omental Torsion
Most patients recover fully after surgery, but a few practical tips help ensure a smooth return to daily life.
- Follow‑up appointments: Usually within 1‑2 weeks post‑op to assess wound healing and discuss pathology results.
- Gradual activity increase: Light walking beginning day 1; avoid heavy lifting (>10 kg) for 4‑6 weeks.
- Nutrition: A balanced diet rich in fiber and lean protein supports healing and weight control.
- Monitor for recurrence: Although rare (<5 % after excision), report any new, sudden abdominal pain promptly.
- Psychological support: Acute abdominal emergencies can be stressful; consider counseling if anxiety about future episodes persists.
Prevention
Because primary torsion is often linked to modifiable factors, the following measures may reduce risk:
- Maintain a healthy weight: Aim for BMI < 25 kg/m² through diet and regular exercise (150 min/week moderate activity).
- Avoid sudden, forceful abdominal strain: Use proper body mechanics when lifting; warm‑up before vigorous sports.
- Manage chronic cough or constipation: Treat underlying respiratory or gastrointestinal conditions to limit repetitive intra‑abdominal pressure.
- Post‑surgical care: If you have a history of abdominal surgery, adhere to physiotherapy regimens that minimise adhesion formation.
Complications
If left untreated, twisted omentum can progress to irreversible ischemia and necrosis, leading to several serious outcomes:
- Peritonitis: Infection of the peritoneal cavity, presenting with high fever, diffuse abdominal rigidity, and sepsis.
- Abscess formation: Localized pus collection may require drainage.
- Hemorrhage: Vascular tearing within the omentum can cause intra‑abdominal bleeding.
- Intestinal obstruction: Large necrotic masses can kink adjacent bowel loops.
- Septic shock: Rare but life‑threatening; mortality reported up to 6 % in delayed cases (World Journal of Emergency Surgery, 2022).
When to Seek Emergency Care
- Sudden, severe abdominal pain that worsens over minutes to hours.
- Persistent vomiting (more than 2 episodes) or inability to keep fluids down.
- High fever (≥38.5 °C) or chills.
- Rapid heart rate (tachycardia) or low blood pressure (dizziness, fainting).
- Abdominal swelling, rigid “board‑like” abdomen, or a palpable mass.
- Signs of shock: pale skin, rapid shallow breathing, confusion.
References
- Mayo Clinic. “Omental torsion.” Accessed May 2026. https://www.mayoclinic.org.
- Kawahara N, et al. Primary omental torsion: a review of 46 cases. Surg Today. 2020;50(3):281‑287.
- Benson J, et al. CT findings of omental torsion: diagnostic accuracy and pitfalls. Radiology. 2021;298(2):456‑464.
- World Journal of Emergency Surgery. “Outcomes of delayed treatment of omental torsion.” 2022;17(1):12.
- National Institutes of Health (NIH). “Obesity and surgical complications.” 2023. https://www.nih.gov.
- Cleveland Clinic. “Acute abdomen – differential diagnosis.” 2024. https://my.clevelandclinic.org.