What are the clinical features, diagnosis, and treatment of intestinal malrotation?

Intestinal Malrotation: Clinical Features, Diagnosis, and Treatment

Clinical Features

Intestinal malrotation results from failure of the normal 270° counterclockwise rotation of the midgut during embryonic development, creating a narrow-based mesentery that predisposes to life-threatening midgut volvulus. 1, 2, 3

Presentation by Age Group

Neonates and Infants:

• Bilious vomiting within the first 2 days of life is the hallmark presentation and constitutes a surgical emergency 4, 1, 5
• Abdominal distension due to proximal intestinal obstruction 1, 5
• Failure to pass meconium or abnormal meconium passage 1
• More than half of cases present during the first month of life 6

Adults (0.2-0.5% of all cases):

• Recurrent abdominal pain from chronic partial obstruction 7, 3, 8
• Acute abdomen with vomiting when volvulus occurs 7, 8
• May be discovered incidentally during laparotomy for other indications (occurred in 58% of one adult series) 8

Critical Complication: Midgut Volvulus

• Occurs in approximately 68% of symptomatic patients 6
• Leads to intestinal ischemia, necrosis, sepsis, and death if untreated 9, 7
• One-third of patients with volvulus develop ischemic intestine requiring resection 6

Diagnosis

Upper GI series is the reference standard for diagnosing malrotation, with 96% sensitivity. 4, 5

Imaging Modalities in Order of Preference

1. Fluoroscopy Upper GI Series (Gold Standard):

• The key diagnostic finding is abnormal position of the duodenojejunal junction (ligament of Treitz) 4, 5
• Sensitivity of 96% with false-positive rate of 2% and false-negative rate of 7% 4
• "Corkscrew sign" from dilated duodenal segments at different levels 7
• Meticulous technique is essential as redundant duodenum, bowel distension, and jejunal position can cause misinterpretation 4

2. CT Scan (Especially for Adults and Acute Presentations):

• Demonstrates the "whirlpool sign" - twisted mesentery around the superior mesenteric artery and vein 7
• Shows dilated bowel segments with air-fluid levels 7
• Most accurate method for adults presenting with acute symptoms 7

3. Ultrasound (Adjunctive Role):

• The "whirlpool sign" (clockwise wrapping of SMV and mesentery around SMA) is specific for midgut volvulus 4, 5
• Can assess SMV position relative to SMA, though normal relationship does not exclude malrotation (21% false-positive, 2-3% false-negative) 4
• Bowel gas obscures vessels in up to 17% of cases 4

4. Plain Abdominal Radiographs (Limited Value):

• Normal radiographs do NOT exclude malrotation 4, 5
• May show nonspecific bowel gas patterns 4

5. Contrast Enema (Not Recommended as Initial Study):

• Up to 20% false-negative rate 4
• 15% of normal infants have high mobile cecum causing false-positives 4

Treatment

For symptomatic patients or those with known malrotation, surgical intervention with the Ladd procedure is the definitive treatment and should be performed urgently to prevent catastrophic volvulus. 5, 9, 6

Immediate Management Algorithm

If Acute Presentation with Suspected Volvulus:

1. Urgent surgical consultation immediately - this is a surgical emergency 5
2. Fluid resuscitation 5
3. Nasogastric tube for bowel decompression 5
4. Broad-spectrum antibiotics if perforation or ischemia suspected 5
5. Proceed directly to operating room - do NOT delay for extensive imaging 6

Surgical Approach: The Ladd Procedure

The four-step Ladd procedure includes: 6

1. Evisceration and inspection of the mesenteric root
2. Counterclockwise derotation of midgut volvulus
3. Lysis of Ladd's bands with straightening of duodenum along right abdominal gutter
4. Inversion-ligation appendectomy and placement of cecum in left lower quadrant 6

Surgical Approach Options:

• Open laparotomy remains standard, especially in acute presentations 6, 8
• Laparoscopic approach is feasible in stable patients with low complication rates 8
• Bowel resection required if ischemia/necrosis present (occurs in 33% of volvulus cases) 6

Prophylactic Surgery Controversy

For asymptomatic infants with incidentally discovered malrotation, prophylactic Ladd procedure should be strongly considered given the catastrophic consequences of volvulus. 9

Evidence supporting prophylactic approach:

• Zero reoperations in prophylactic group vs. 26% in symptomatic group 9
• 39% of symptomatic patients had volvulus at surgery, 4.3% had bowel necrosis 9
• Faster recovery: 5 days to full feeds vs. 7.4 days, 8 days to discharge vs. 11 days 9
• No mortality in prophylactic group 9

Outcomes and Prognosis

Pediatric patients:

• Mortality rate of 4.5% when bowel resection required 6
• Excellent outcomes when diagnosed and treated promptly 6

Adult patients:

• Low complication rates (25%): wound infection, delayed gastric emptying, adhesive ileus 8
• Recurrence rate approximately 17% 8
• No mortality in elective cases 8

Critical Pitfalls to Avoid

• Never dismiss bilious vomiting in a neonate as benign - assume malrotation with volvulus until proven otherwise 4, 1, 5
• Do not rely on normal plain radiographs to exclude malrotation 4, 5
• Do not delay surgery for extensive imaging workup when volvulus is clinically suspected 5, 6
• Recognize that up to 15% of UGI studies may be false-positive or false-negative due to technical factors 4
• In adults, maintain high index of suspicion even with vague chronic symptoms 7, 3, 8