Intestinal obstruction secondary to a transmesocolic internal hernia: a case report and review of the literature.

INTRODUCTION AND

IMPORTANCE

Acute intestinal obstruction is a common surgical emergency, most often caused by postoperative adhesions, strangulated external hernias, or tumors. Internal hernias are rare (0.6-5.8% of cases) but carry a high risk of strangulation and intestinal ischemia. Transmesocolic hernias, arising from small bowel loops herniating through congenital or acquired mesocolic defects, are an uncommon subtype, with paraduodenal hernias being more frequent. Preoperative diagnosis is challenging due to nonspecific symptoms, but contrast-enhanced abdominal CT is the gold standard for detecting abnormal bowel positioning, mesenteric mass effect, and signs of wall compromise. We report a case of transmesocolic internal hernia causing bowel obstruction in a young patient and review the literature regarding its epidemiology, diagnosis, and management.

CASE PRESENTATION: A 20-year-old male smoker presented with a 4-day history of occlusive syndrome and epigastric gurgling. Examination revealed a slightly distended abdomen with peri-umbilical tenderness, and laboratory tests showed an elevated C-reactive protein level. Contrast-enhanced CT demonstrated small bowel obstruction due to strangulation by a pseudo-sac on the right side, suggestive of a transmesenteric internal hernia, with early signs of bowel compromise, including parietal thickening and moderate fluid effusion. Intraoperative findings revealed approximately 2.9 m of ileal loops herniated through the transverse mesocolon, with a 50-cm segment inflamed and nonviable. An extended ileocecal resection of the affected segment was performed, preserving 2.9 m of healthy small intestine, followed by repositioning of the bowel and a manual end-to-end ileocolonic anastomosis.

CLINICAL DISCUSSION: Internal hernias are a rare cause of small bowel obstruction, with transmesocolic hernias being less frequent than paraduodenal hernias. They result from small bowel loops herniating through congenital or acquired mesocolic defects, carrying a high risk of vascular compromise. Clinical presentation is often nonspecific, with intermittent pain and subocclusive episodes preceding acute obstruction. Contrast-enhanced CT is the diagnostic modality of choice, identifying abnormal bowel loops, mesenteric vessel displacement, and signs of bowel wall compromise. Definitive treatment is surgical, including reduction of herniated bowel, assessment of viability, and closure of the defect; bowel resection is required if ischemia or necrosis is present. Early diagnosis and prompt intervention are critical, as morbidity and mortality correlate with delay and the extent of necrosis. Transmesocolic hernias, although rare, should be suspected in cases of obstruction without prior abdominal surgery, and timely imaging and surgery can reduce the need for extensive resections.

CONCLUSION

Internal transmesocolic hernias are rare but potentially serious causes of intestinal obstruction, often challenging to diagnose preoperatively due to nonspecific symptoms. Contrast-enhanced abdominal CT is essential for detecting suggestive features and guiding timely surgical intervention. Definitive treatment is surgical, involving reduction of herniated loops and closure of the mesocolic defect; segmental resection, such as ileocecal resection, is required in cases of irreversible intestinal injury to prevent septic complications and optimize prognosis.