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Torsion of the root of the mesentery — Clinical Guidelines

Overview

Torsion of the root of the mesentery, also known as mesenteric torsion or mesenteric volvulus, is a rare but life-threatening condition characterized by the twisting of the mesenteric vessels around the root of the mesentery, leading to acute ischemia and potentially necrosis of the bowel segment supplied by the affected vessels. This condition predominantly affects middle-aged and elderly individuals, often presenting acutely with severe abdominal pain, nausea, vomiting, and signs of systemic inflammatory response. Early recognition and prompt intervention are critical due to the high mortality rate associated with delayed treatment. Understanding this condition is vital for clinicians to avoid misdiagnosis and ensure timely surgical intervention, particularly in patients presenting with acute abdominal emergencies 1.

Pathophysiology

Mesenteric torsion occurs when the mesentery, the connective tissue suspending the small intestine from the posterior abdominal wall, twists around its axis, typically due to abnormal mobility or anatomical variations. This twisting obstructs the mesenteric vessels, leading to compromised blood flow and subsequent ischemia. The ischemia can rapidly progress to bowel infarction if not promptly addressed. The underlying mechanisms often involve predisposing factors such as adhesions from previous surgeries, inflammatory processes, or anatomical anomalies that destabilize the mesentery. Over time, these factors can lead to localized hypercoagulability or altered blood flow dynamics, culminating in the acute twisting event. The resultant ischemia triggers a cascade of cellular damage, including inflammation and potential necrosis, which can extend beyond the initially affected segment if not intervened upon swiftly 1.

Epidemiology

Mesenteric torsion is exceedingly rare, with incidence rates not well-documented in large population studies due to its sporadic nature. Available data suggest it predominantly affects middle-aged and elderly individuals, though cases in younger populations have been reported. There is no clear sex predilection noted in the literature. Geographic and specific risk factor distributions are not extensively detailed, but predisposing factors such as prior abdominal surgeries and inflammatory conditions are recognized. Trends over time are similarly limited, with most reports being case series rather than population-based studies, making definitive temporal trends difficult to ascertain 1.

Clinical Presentation

Patients with mesenteric torsion typically present acutely with severe, diffuse abdominal pain that may localize to the periumbilical region or right lower quadrant. Nausea, vomiting, and signs of peritoneal irritation such as rebound tenderness and guarding are common. Systemic symptoms like fever, tachycardia, and hypotension may indicate a more severe systemic inflammatory response or sepsis. Atypical presentations can include vague abdominal discomfort or even vague gastrointestinal symptoms mimicking other acute abdominal conditions. Red-flag features include rapid deterioration, shock, and signs of bowel perforation or peritonitis, necessitating urgent diagnostic evaluation to rule out mesenteric torsion 1.

Diagnosis

The diagnosis of mesenteric torsion is challenging due to its rarity and nonspecific initial presentation. The diagnostic approach involves a combination of clinical suspicion, imaging, and sometimes exploratory surgery. Key diagnostic criteria and tests include:

Clinical Suspicion: High index of suspicion based on acute onset of severe abdominal pain, particularly in patients with a history of abdominal surgery.

Imaging:

- CT Abdomen: Often the first imaging modality, looking for signs of bowel wall thickening, pneumatosis intestinalis, portal venous gas, and mesenteric fat stranding indicative of ischemia. - Mesenteric Venous Thrombosis: May mimic mesenteric torsion; differentiation often requires careful assessment of imaging findings.

Labs: Elevated inflammatory markers (e.g., CRP, WBC count) support an acute inflammatory process but are non-specific.

Differential Diagnosis:

- Acute Appendicitis: Localized pain, tenderness in the right lower quadrant. - Gastrointestinal Bleeding: Hemodynamic instability without clear abdominal signs. - Mesenteric Ischemia from Other Causes: Consider thromboembolic events or arterial occlusions based on imaging and clinical context 1.

Management

Initial Management

Stabilization: Immediate resuscitation with intravenous fluids, monitoring of vital signs, and support of hemodynamics.

Surgical Consultation: Urgent consultation with a surgeon is essential due to the high risk of bowel necrosis.

Definitive Treatment

Exploratory Laparotomy: Primary intervention to assess and untwist the mesentery, repair any necrotic bowel segments, and address underlying causes.

Bowel Resection: Depending on the extent of necrosis, partial or segmental bowel resection may be necessary.

Mesenteric Revascularization: Ensuring adequate blood supply to remaining viable bowel segments.

#### Specific Steps and Considerations

Fluid Resuscitation: Aggressive fluid therapy to maintain perfusion pressure.

Antibiotics: Broad-spectrum antibiotics to cover for potential sepsis.

Monitoring: Continuous monitoring of lactate levels, hemodynamic parameters, and abdominal signs for progression or complications.

Contraindications: Conservative management is contraindicated due to the high risk of mortality associated with delayed surgical intervention 1.

Complications

Common complications include:

Bowel Necrosis and Perforation: Risk increases with delayed diagnosis and intervention.

Systemic Sepsis: Secondary to bowel necrosis or inadequate resuscitation.

Chronic Abdominal Pain: Post-surgery, due to adhesions or residual ischemia.

Management Triggers:

Persistent Elevated Lactate Levels: Indicative of ongoing ischemia.

Worsening Hemodynamic Instability: Requires immediate surgical reevaluation.

Clinical Signs of Peritonitis: Suggests bowel perforation and necessitates urgent surgical intervention 1.

Prognosis & Follow-up

The prognosis for mesenteric torsion is heavily dependent on the rapidity of diagnosis and intervention. Early surgical correction can significantly improve outcomes, with mortality rates decreasing with prompt treatment. Prognostic indicators include the extent of bowel necrosis, patient's preoperative condition, and timeliness of surgical intervention. Follow-up typically involves:

Short-term Monitoring: Regular assessments of bowel function, nutritional status, and signs of complications.

Long-term Monitoring: Periodic imaging and clinical evaluations to monitor for adhesions, bowel function, and overall recovery.

Recommended follow-up intervals may vary but generally include:

Initial Postoperative Weeks: Frequent visits (weekly to biweekly).

Subsequent Months: Monthly visits for several months, tapering off based on recovery progress 1.

Special Populations

Elderly Patients

Elderly patients are at higher risk due to comorbid conditions and potentially slower physiological responses. Careful preoperative assessment and optimization of comorbidities are crucial.

Postoperative Surgery History

Patients with prior abdominal surgeries are at increased risk due to potential adhesions contributing to mesenteric instability. Preoperative imaging and surgical planning should account for these factors 1.

Key Recommendations

Prompt Surgical Consultation: In patients presenting with acute severe abdominal pain, especially with signs of systemic inflammatory response, consider mesenteric torsion until ruled out (Evidence: Expert opinion) 1.

Imaging with CT Abdomen: Utilize CT abdomen with contrast to evaluate for signs of mesenteric ischemia, including bowel wall thickening and pneumatosis intestinalis (Evidence: Moderate) 1.

Urgent Exploratory Laparotomy: For confirmed or highly suspected cases, immediate exploratory laparotomy is recommended to assess and manage torsion (Evidence: Strong) 1.

Resuscitation and Monitoring: Aggressive fluid resuscitation and continuous monitoring of hemodynamic parameters and lactate levels (Evidence: Strong) 1.

Broad-Spectrum Antibiotics: Administer broad-spectrum antibiotics to cover for potential sepsis (Evidence: Moderate) 1.

Address Underlying Causes: During surgery, address any underlying causes such as adhesions or anatomical anomalies contributing to mesenteric instability (Evidence: Expert opinion) 1.

Postoperative Care: Close postoperative monitoring for signs of bowel necrosis, sepsis, and other complications (Evidence: Moderate) 1.

Follow-up Imaging: Consider follow-up imaging to assess for complications like adhesions or residual ischemia (Evidence: Expert opinion) 1.

Multidisciplinary Approach: Involve gastroenterology, critical care, and surgical specialists in the management plan (Evidence: Expert opinion) 1.

Educate on Risk Factors: Educate patients with prior abdominal surgeries about the increased risk and signs prompting urgent medical attention (Evidence: Expert opinion) 1.

References

1 MacNeil SD, Liu K, Garg AX, Tam S, Palma D, Thind A et al.. A Population-Based Study of 30-day Incidence of Ischemic Stroke Following Surgical Neck Dissection. Medicine 2015. link

Torsion of the root of the mesentery