eMedicine Specialties > Radiology > Pediatrics

Midgut Volvulus

Janet R Reid, MD, FRCP(C), Associate Professor of Radiology, Section Head of Pediatric Radiology, Children's Hospital of Cleveland Clinic

Updated: Jul 27, 2007

Introduction

Background

Midgut volvulus is a condition in which the intestine has become twisted as a result of malrotation of the intestine during fetal development. Malrotation of the intestine occurs when the normal embryologic sequence of bowel development and fixation is interrupted. The malrotated bowel is prone to torsion, which can lead to midgut volvulus.

Pathophysiology

Development of the human gut takes place during the first months of fetal life. In normal embryos, physiologic herniation of the gut through the umbilicus at 6 weeks’ gestation is accompanied by a 270° counterclockwise rotation of the developing intestine around the superior mesenteric artery (SMA). By 10-12 weeks, the intestine returns to the abdomen and assumes its normal adult anatomic position. Normal small bowel mesentery has a broad attachment stretching diagonally from the duodenojejunal junction (DJJ), in the left upper quadrant, to the cecum, in the right lower quadrant. This point of attachment at the DJJ is called the ligament of Treitz.

Malrotation is most commonly caused by incomplete rotation of the intestine (<270° of counterclockwise rotation, occurring in weeks 5-12). Malrotation disorders can be divided into 3 categories:

• Nonrotation (0° to 90° of counterclockwise rotation, occurring before 6 weeks)
• Reverse rotation (abnormal rotation between 90° and 180°, causing obstruction or reversal of the normal duodenal/SMA relationship, occurring in weeks 6-10)
• Malrotation most often associated with malfixation (between 180° and 270° of counterclockwise rotation, occurring after 10 weeks)

The small bowel may be in the right abdomen; however, this finding is not reliable. Often, the large bowel is in the left abdomen.

Malrotation predisposes patients to 2 problems: midgut volvulus and small bowel obstruction.

Frequency

United States

Although malrotation is estimated to occur in 1 in 500 live births, the actual frequency of malrotation is unknown because many asymptomatic patients probably never present to a physician.

International

Incidence is the same as in the United States.

Mortality/Morbidity

• Midgut volvulus: The close proximity of the cecum to the duodenum is associated with a narrow stalk of mesentery around which the gut may twist, resulting in midgut volvulus (see Image 1). Accompanying superior mesenteric vascular compromise (first venous, followed by arterial) can lead to life-threatening ischemia of the small bowel and gangrenous necrosis. Mortality associated with midgut volvulus is at least 15%, and there is a high incidence of short gut syndrome, total parenteral nutrition dependence, and resultant cirrhosis.
• Duodenal obstruction: Coiling of the duodenum with the ascending colon produces complete or partial duodenal obstruction. Ladd bands are abnormal peritoneal reflections that cross the duodenum and pass to the undersurface of the liver or posterior abdominal wall; they cause duodenal obstruction in some patients.

Race

No racial predilection is seen.

Sex

No gender predilection is seen.

Age

In approximately 60% of patients, malrotation presents by 1 month of age. Another 20-30% of patients present at 1-12 months of age. Malrotation may remain clinically "silent" for some time and can present at any age.

Anatomy

In malrotation, the following relationships may be observed in the gut:

• The DJJ is low and to the right of the normal location (see Image 3).  
• The proximal small bowel (jejunum) is in the right upper quadrant.  
• The cecum is in the upper and/or left abdomen.  
• The large bowel is in the left abdomen.  
• Other associated anomalies are seen around the ampulla of Vater.

Presentation

In neonates, malrotation with midgut volvulus classically presents with bilious vomiting and high intestinal obstruction (see Image 2). While most neonates with bilious vomiting do not have midgut volvulus, this diagnosis must be ruled out.

Older children with malrotation may manifest a failure to thrive, chronic recurrent abdominal pain, malabsorption, or other vague presentations. The older the child is, the less readily identifiable is the clinical presentation. Nonrotation of the intestine may be asymptomatic and is an incidental finding on upper GI series performed for other reasons.

Associated anomalies are seen in approximately 60% of patients and include congenital heart disease with heterotaxy (abnormal positioning and arrangement of the abdominal organs, such as the spleen, liver, and major blood vessels; right-sided or left-sided isomerism) (see Image 7). Malrotation is almost always present in patients with congenital diaphragmatic hernia and abdominal wall defects, such as omphalocele and gastroschisis. Also, malrotation is more common with imperforate anus, duodenal atresia, duodenal web, stenosis, preduodenal portal vein, annular pancreas, and biliary atresia.

Preferred Examination

The diagnostic test of choice in a child with possible malrotation, with or without midgut volvulus, is an upper GI series.

Limitations of Techniques

In most patients with malrotation, an upper GI series is easy to perform and, in experienced hands, is easy to interpret, with the following exceptions:

• With complete duodenal obstruction, an upper GI series does not differentiate between the causes of proximal intestinal obstruction. In such cases, surgical exploration is indicated.
• A redundant duodenum, seen in some normal individuals, can be confused with malrotation. A careful following of the barium shows a normal DJJ; if uncertainty exists, barium can confirm normal rotation if the cecum is seen in the right lower quadrant.

Differential Diagnoses

Duodenal Atresia
Gastroesophageal Reflux
Hypertrophic Pyloric Stenosis
Necrotizing Enterocolitis

Other Problems to Be Considered

Malrotation without midgut volvulus
Duodenal stenosis
Duodenal web
Annular pancreas

Radiography

Findings

Abdominal radiographs are frequently performed in children with abdominal symptoms. In cases of simple malrotation, radiographs may appear normal.

In midgut volvulus, the classic radiographic finding is a partial duodenal obstruction (dilation of both the stomach and proximal duodenum, with a small amount of distal bowel gas). Complete obstruction of the duodenum may also be found. Less frequent, but more ominous, signs are a gasless abdomen, ileus, or a distal small bowel obstruction with multiple dilated loops and air-fluid levels. A normal abdominal film does not exclude malrotation.

An upper GI series is the preferred diagnostic test for malrotation with midgut volvulus and must be performed, unless a delay in surgical treatment will compromise outcome (as in the case of a moribund child). The upper GI series is performed with barium administered either orally or through a nasogastric tube. The normal DJJ lies to the left of the left-sided spinal pedicle at the level of the duodenal bulb on a true frontal view. The duodenal C-sweep courses posteriorly, inferiorly, anteriorly, and then superiorly.

The findings of a malrotation on upper GI series include the following:

• The DJJ is displaced downward and to the right on frontal view.  
• The duodenum has an abnormal course on lateral view.  
• Abnormal positioning of the jejunum (lying on right side of abdomen) should alert the physician to the possibility of a malrotation, but this finding should not be relied upon to either make or exclude the diagnosis.

In malrotation with midgut volvulus, the findings also include the following:

• A dilated, fluid-filled duodenum  
• A proximal small bowel obstruction  
• A "corkscrew" pattern (proximal jejunum spiraling downward in the right- or mid-upper abdomen in midgut volvulus, which is rare) (see Image 6)  
• Mural edema and thick folds

Degree of Confidence

In malrotation without midgut volvulus, the degree of confidence on plain radiographs is low. Radiographs are rarely normal in malrotation with midgut volvulus, increasing the degree of confidence in this clinical scenario.

An upper GI series provides a high degree of confidence in the diagnosis of malrotation with midgut volvulus.

False Positives/Negatives

Radiographic false negatives: Normal radiographs are common with malrotation.

Radiographic false positives:

• Findings in midgut volvulus are nonspecific and can be seen in other conditions that may cause ileus or ischemia, such as acute pyelonephritis, appendicitis, and necrotizing enterocolitis.
  
• Duodenal obstruction, seen in midgut volvulus and malrotation, is also seen with duodenal stenosis, duodenal web, annular pancreas, preduodenal portal vein, and duodenal atresia.
  
• Upper GI series sensitivity is 85-95%, with a higher specificity (false positives are rare). Although a DJJ low and to the right of normal is a sensitive indicator of malrotation, this finding can also occur secondary to distended bowel, masses, and splenomegaly, especially in children younger than 4 years, whose mesenteric attachments are not as well fixed as they are in later years. Scoliosis makes it difficult to rule out malrotation because the normal bony landmarks are lost.

Computed Tomography

Findings

See Ultrasound.

Magnetic Resonance Imaging

Findings

Diagnosis of malrotation with midgut volvulus on fetal magnetic resonance imaging (MRI) has been reported.¹ In practice, this is a difficult diagnosis to make, and MRI is not recommended in infants suspected of having malrotation with midgut volvulus.

Ultrasonography

Findings

The "whirlpool sign" on color Doppler ultrasonography shows mesentery and flow within the SMV wrapping around the SMA (in a clockwise direction), suggesting, but not entirely specific for, malrotation with midgut volvulus (see Image 8). A dilated, fluid-filled duodenum is frequently seen in patients who have obstruction without volvulus.

Degree of Confidence

The moderate-to-low degree of confidence associated with ultrasonography and CT necessitates an upper GI series to confirm the diagnosis.

False Positives/Negatives

Ultrasonography and CT have false-negative rates of approximately 30% and false-positive rates as high as 20%.

Nuclear Imaging

Findings

Nuclear medicine techniques do not provide sufficient resolution to confidently diagnose midgut volvulus; therefore, nuclear medicine is not a recommended imaging modality for the diagnosis this condition.

Angiography

Findings

Angiographic abnormalities with chronic volvulus have been well described, and they include proximal occlusion of the SMA, a "barber-pole sign" (whirling SMA and its branches), extensive collateral vessels, and thickening of the small bowel folds.

Angiography is not used to diagnose acute midgut volvulus.

Degree of Confidence

The degree of confidence is high, but this examination is rarely indicated.

False Positives/Negatives

Few false positives or false negatives are seen with angiography.

Intervention

Medicolegal Pitfalls

• A false-negative diagnosis of malrotation with midgut volvulus can lead to delays in the diagnosis and, possibly, death or severe morbidity.  
• A false-positive diagnosis can lead to an unnecessary laparotomy and a delay in obtaining the correct diagnosis.  
• The highest sensitivities and specificities with upper GI series are in pediatric centers where operators with experience and pediatric expertise perform the examinations. If the upper GI results are in question, the examination should be repeated through a nasogastric feeding tube or the study should be continued to determine the position of the cecum.

Multimedia

Media file 1: Malrotation with midgut volvulus shows torsion around the narrow mesenteric stalk.

Media file 2: Supine radiograph in a newborn with midgut volvulus shows a high intestinal obstruction.

Media file 3: Upper GI series shows malrotation without midgut volvulus in an infant with vomiting but without failure to thrive. The duodenojejunal junction is low and to the right of the spine on this frontal view.

Media file 4: Upper GI series shows malrotation with midgut volvulus. An incomplete duodenal obstruction and dilation of the first and second portions are seen, as is the "corkscrew sign."

Media file 5: Upper GI series shows malrotation with midgut volvulus in a lateral view.

Media file 6: Upper GI series shows the "corkscrew sign" in a frontal view (same patient as in Image 5).

Media file 7: Upper GI series and a small bowel study show malrotation without midgut volvulus in a patient with complex congenital heart disease and heterotaxy. Note the small bowel in the right abdomen.

Media file 8: Ultrasound with color Doppler ultrasonography shows malrotation with midgut volvulus demonstrating the "whirlpool sign." The superior mesenteric vein (SMV) in this patient wraps around the superior mesenteric artery (SMA).

Media file 9: CT scan shows the abnormal relationship of the superior mesenteric vein (SMV) to the superior mesenteric artery (SMA). The SMV should lie to the right of the SMA in this adolescent with undiagnosed malrotation without volvulus (V=SMV, A=SMA).

References

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Keywords

malrotation with midgut volvulus, nonrotation, reverse rotation, malrotation

Contributor Information and Disclosures

Author

Janet R Reid, MD, FRCP(C), Associate Professor of Radiology, Section Head of Pediatric Radiology, Children's Hospital of Cleveland Clinic
Janet R Reid, MD, FRCP(C) is a member of the following medical societies: American Association for Women Radiologists, American Society of Neuroradiology, Ohio State Medical Association, Radiological Society of North America, Royal College of Physicians and Surgeons of Canada, and Society for Pediatric Radiology
Disclosure: Nothing to disclose.

Medical Editor

Henrique M Lederman, MD, PhD, Consulting Staff, Department of Radiology, The Children's Hospital of Philadelphia; Professor of Radiology and Pediatric Radiology, Chief, Division of Diagnostic Imaging in Pediatrics, Federal University of Sao Paulo, Brazil
Henrique M Lederman, MD, PhD is a member of the following medical societies: Society for Pediatric Radiology
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

Managing Editor

David A Stringer, BSc, MBBS, FRCR, FRCPC, Professor, National University of Singapore; Head, Diagnostic Imaging, KK Women's and Children's Hospital, Singapore
David A Stringer, BSc, MBBS, FRCR, FRCPC is a member of the following medical societies: British Columbia Medical Association, Canadian Association of Radiologists, European Society of Paediatric Radiology, Ontario Medical Association, Radiological Society of North America, Royal College of Physicians and Surgeons of Canada, Royal College of Radiologists, and Society for Pediatric Radiology
Disclosure: None None None

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

John Karani, MBBS, FRCR, Consulting Staff, Department of Radiology, King's College Hospital, London
Disclosure: Nothing to disclose.

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