Intestinal Malrotation: Pathophysiology, Imaging Features, Diagnosis, and Management

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Introduction

Intestinal malrotation is a rare but clinically significant congenital anomaly of intestinal rotation and fixation. Although typically diagnosed in infancy, it can occasionally present in adulthood with atypical features such as chronic abdominal pain, intermittent vomiting, or even life-threatening midgut volvulus. This article provides a comprehensive overview based on the latest global literature, while integrating illustrative radiographic and CT images for accurate interpretation.

Case Summary

A 59-year-old woman presented with chronic abdominal pain. Radiographs and CT scans revealed abnormal positioning of the small and large intestines, with features consistent with intestinal malrotation.

Imaging Findings from the Case

[Figure 1] Simple abdomen X-ray (A: Erect, B: Supine):

Dilated colonic loops clustered in the left hemiabdomen, with small bowel loops predominantly in the right hemiabdomen.
Interpretation: Suggestive of abnormal intestinal positioning consistent with malrotation.

[Figure 2] Coronal CT:

Demonstrates small bowel predominantly on the right and colon on the left. The duodenum fails to cross the midline at the expected ligament of Treitz. 

Interpretation: Findings strongly suggest intestinal malrotation.


[Figure 3] Axial CT:

Small bowel loops occupy the right abdomen; superior mesenteric vein (SMV) is seen abnormally positioned left to the superior mesenteric artery (SMA).
Interpretation: Reversal of SMA-SMV relationship is a hallmark feature of malrotation.


[Figure 4] Sagittal CT:

The duodenum does not cross posteriorly between the aorta and SMA, instead showing an abnormal anterior course.
Interpretation: Confirms failure of normal duodenal rotation.

Pathophysiology

Intestinal malrotation arises from arrested embryonic rotation of the midgut. Normally, the midgut undergoes a 270° counterclockwise rotation around the superior mesenteric artery during fetal development. In malrotation, this process halts prematurely, resulting in:

  • Abnormal fixation of the small and large bowel.

  • Malposition of the duodenojejunal junction and cecum.

  • Predisposition to midgut volvulus due to a narrowed mesenteric base.

Associated anomalies: omphalocele, gastroschisis, diaphragmatic hernia, annular pancreas, duodenal atresia/stenosis, asplenia and polysplenia syndromes.

Epidemiology

  • Incidence: approximately 1 in 200–500 live births.

  • Symptomatic cases: 1 in 6000 births.

  • Male predominance (M:F ≈ 2:1).

  • Most cases are diagnosed in infancy, but rare cases may remain silent until adulthood, often presenting with nonspecific abdominal symptoms.

Clinical Presentation

  • Infants: bilious vomiting, abdominal distension, failure to thrive.

  • Adults: chronic abdominal pain, intermittent nausea, malabsorption, weight loss, or acute abdomen due to midgut volvulus.

  • Complications: bowel ischemia, necrosis, life-threatening sepsis if volvulus occurs.

Imaging Features

Fluoroscopy (Upper GI series) – Gold standard

  • Failure of duodenum to cross midline.

  • Duodenojejunal junction located right of midline.

  • C-loop of duodenum abnormal in configuration.

  • Cecum malpositioned (often midline or left-sided).

CT Findings

  • Small bowel: predominantly right-sided.

  • Colon: displaced to the left.

  • Ligament of Treitz: absent or abnormally positioned.

  • Whirlpool sign: twisted mesenteric vessels (SMA & SMV) suggestive of volvulus.

  • SMV position: abnormally left of the SMA.

Radiography

  • Non-specific bowel gas pattern, but clustering of bowel loops in abnormal locations may suggest malrotation.

Differential Diagnosis

  • Duodenum inversum (unusual duodenal course).

  • Redundant/wandering duodenum.

  • Chronic adhesive small-bowel obstruction.

  • Superior mesenteric artery syndrome.

Diagnosis

Diagnosis requires integration of imaging and clinical suspicion.

  • Upper GI contrast series is the best modality in children.

  • CT is highly valuable in adults, especially when complications such as volvulus are suspected.

Treatment

The Ladd procedure remains the gold standard:

  1. Reduction of midgut volvulus (if present).

  2. Division of Ladd bands.

  3. Broadening of mesenteric base.

  4. Placement of small bowel on the right, colon on the left.

  5. Appendectomy (to avoid future diagnostic confusion).

In adults with asymptomatic malrotation, surgical correction is debated but often recommended due to the lifelong risk of volvulus.

Prognosis

  • With timely surgical correction: excellent long-term outcomes.

  • Delayed diagnosis in volvulus cases may lead to massive bowel necrosis, high morbidity, and mortality.

  • Adults with chronic malrotation may continue to experience mild symptoms even after surgery, but risk of volvulus is eliminated.

Quiz

Q1. Which embryological failure leads to intestinal malrotation?

A. Failure of midgut herniation

B. Failure of 270° counterclockwise midgut rotation

C. Failure of hindgut fixation

D. Failure of cloacal septation

Q2. On CT, which vascular relationship is abnormal in intestinal malrotation?

A. SMV right of SMA (normal)

B. SMV left of SMA

C. Aorta anterior to SMA

D. Portal vein anterior to SMV

Q3. The gold standard imaging study for diagnosing malrotation is:

A. Plain radiography

B. CT abdomen

C. Upper GI series with contrast

D. MRI enterography

Q4. What is the definitive surgical procedure for intestinal malrotation?

A. Whipple’s procedure

B. Hartmann’s procedure

C. Ladd procedure

D. Roux-en-Y reconstruction

Q5. Which of the following anomalies is associated with malrotation?

A. Omphalocele

B. Gastroschisis

C. Diaphragmatic hernia

D. Asplenia/Polysplenia syndromes

E. All of the above

Answer & Explanation

1. Answer: B. Explanation: Normal midgut rotation is 270° counterclockwise. Arrest leads to malrotation.

2. Answer: B. Explanation: SMV abnormally lies to the left of SMA in malrotation.

3. Answer: C. Explanation: Upper GI series provides the most reliable diagnostic signs.

4. Answer: C. Explanation: Ladd procedure is the standard treatment.

5. Answer: E. Explanation: All listed anomalies are associated with intestinal malrotation.

References

  1. P. I. Abbas, H. A. Dickerson, and D. E. Wesson, "Evaluating a management strategy for malrotation in heterotaxy patients," J. Pediatr. Surg., vol. 51, no. 5, pp. 859–862, 2016.

  2. G. E. Ballesteros, A. T. Ayats, C. D. Feliubadaló, C. M. Martínez, and A. C. Tarragó, "Intestinal malrotation — volvulus: Imaging findings," Radiologia, vol. 57, no. 1, pp. 9–21, 2015.

  3. M. P. Federle and S. J. Kraus, "Malrotation," STATdx.com. Accessed: Feb. 13, 2018.

  4. K. Graziano, S. Islam, R. Dasgupta, et al., "Asymptomatic malrotation: Diagnosis and surgical management," J. Pediatr. Surg., vol. 50, no. 10, pp. 1783–1790, 2015.

  5. R. E. Smith, L. J. Dufour, and P. T. Houck, "CT diagnosis of midgut malrotation in adults," Radiographics, vol. 39, no. 5, pp. 1458–1470, 2019.

  6. J. E. Nehra and J. Goldstein, "Intestinal malrotation: Clinical presentation and surgical management," Surg. Clin. North Am., vol. 97, no. 1, pp. 147–159, 2017.

  7. M. A. Torres and J. Ziegler, "Malrotation of the intestine," World J. Surg., vol. 43, no. 7, pp. 1780–1790, 2019.

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