Intestinal Malrotation

Intestinal malrotation is a congenital anomaly that results from failure of the GI tract to undergo normal rotation around the mesenteric vessels during embryologic development. This condition can result in several anatomic patterns characterized by abnormal location and attachments of the abdominal cavity’s intestines. These anomalies can be clinically silent or present with a number of complications, the most catastrophic of which is midgut volvulus. Intestinal malrotation usually presents in infancy as an acute onset of bilious vomiting. Definitive diagnosis is established with the upper GI series and the treatment is emergent surgery.

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Overview

Definition

Intestinal malrotation is a failure of the GI tract to undergo normal rotation around mesenteric vessels during embryogenesis.

Epidemiology

  • Asymptomatic malrotation is present in ~ 1 in 500 births.
  • Symptomatic malrotation (midgut volvulus) occurs in 1:6000 neonates.
  • 30% will present by 1st month, and 58% by 1 year of life.
  • Boys = Girls
  • Up to 62% will have another congenital anomaly:
    • Congenital diaphragmatic hernia (most common)
    • Congenital heart disease
    • Omphalocele
    • Gastroschisis
    • Intestinal/esophageal/biliary atresia
    • Anorectal malformations
    • Meckel’s diverticulum

Etiology

  • Failure of normal 270° counterclockwise rotation of the GI tract during the 4th–8th week of embryological development around the superior mesenteric axis.
  • Resulting in abnormal intestinal attachments and anatomic positions
  • A spectrum of rotational abnormalities can result.

Pathophysiology

Malrotation represents a spectrum of rotational abnormalities. The 2 most common abnormalities are complete nonrotation and incomplete rotation.

Complete non-rotation

  • Small bowel is on the right and colon is on the left.
  • If the mesentery has a narrow base, clockwise twisting may result in midgut volvulus.
  • When the mesenteric base is wide, there is not a high risk for volvulus.

Incomplete rotation

  • Cecum is in the mid-upper abdomen.
  • Cecum fixated to the right lateral abdominal wall with Ladd’s bands (peritoneal attachments).
  • Ladd’s bands cross the duodenum and may cause extrinsic compression.
  • This configuration can also result in midgut volvulus as well as internal hernias.

Midgut volvulus

  • Twisting of the mesentery of malrotated small intestine
  • Small bowel obstruction and ischemia will result.
  • An acute presentation in infants most commonly results in a surgical emergency, but chronic/subacute cases can also occur in older individuals.

Clinical Presentation

Malrotation (without volvulus)

  • Mostly asymptomatic
  • Duodenal obstruction (from Ladd’s bands):
    • Forceful bilious vomiting
    • Sometimes non-bilious, if obstructed proximally to the ampulla of Vater

Midgut volvulus

  • Infants and young children:
    • Bilious vomiting 
    • Abdominal distension/tenderness: variable
    • Late signs (indicating bowel ischemia): 
      • Hematochezia or rectal bleed
      • Hematemesis
      • Hypotension
      • Pale skin with diaphoresis
      • Tachycardia 
  • Older children/adults:
    • Insidious onset
    • Intermittent abdominal pain and vomiting (bilious or nonbilious)
    • Failure to gain weight due to malabsorption 
    • Chronic diarrhea

Internal hernias

  • Can also present with intermittent abdominal pain/vomiting
  • Intermittent constipation
  • Diagnosis is often missed/delayed

Diagnosis

History

  • Acute onset of bilious vomiting in infants
  • Older children:
    • Failure to thrive/failure to gain weight
    • Chronic abdominal pain/vomiting/diarrhea
    • Acute onset of abdominal pain and vomiting

Physical exam

  • Abdominal tenderness (may be difficult to elicit in infants)
  • Abdominal distention (variable)
  • Signs of infant distress:
    • Crying
    • Tachypnea
    • Drawing up of knees to the abdomen
  • Signs of dehydration
    • Dry mucous membranes
    • Sunken fontanelles
  • Lethargy
  • Late signs indicating ischemia/perforation:
    • Peritonitis/rigid abdomen
    • Hematochezia
    • Fever
    • Tachycardia/hypotension

Laboratory studies

  • Nonspecific
  • CBC:
    • Leukocytosis
    • Anemia (in chronic cases)
  • Chemistry:
    • Contraction alkalosis, electrolyte abnormalities from vomiting
    • Acidosis, elevated lactate: signs of bowel ischemia

Imaging

Should only be performed in stable patients. Patients with hemodynamic instability/sepsis/peritonitis should proceed to emergent surgery.

Abdominal X-ray:

  • Should be performed to rule out perforation in infants
  • May show double-bubble sign (duodenal obstruction)

Upper GI series (UGI):

  • Gold standard in hemodynamically stable patients 
  • The duodenojejunal segment (ligament of Treitz) is to the right of the midline.
  • Duodenum has a “corkscrew” appearance (indicates volvulus).
  • Dilated duodenum in cases of extrinsic compression or volvulus.

Ultrasound:

  • Twisting of the superior mesenteric vein and the mesentery around the superior mesenteric artery is known as the “whirlpool” sign.
  • Abnormal superior mesenteric artery/vein relationship 
  • Abnormal position of 3rd portion of the duodenum
  • Dilated duodenum
  • Normal ultrasound does not rule out malrotation.

Management

Preoperative management

  • Fluid resuscitation/electrolyte correction
  • Nils per os (nothing by mouth)
  • Intravenous antibiotics to cover bowel flora
  • Nasogastric tube insertion for gastric decompression

Ladd’s procedure

Emergent laparotomy:

  • Performed for all cases of midgut volvulus.
  • Procedure consists of:
    • Counterclockwise reduction of midgut volvulus 
    • Division of Ladd’s bands
    • Broadening of the mesentery (open folded mesentery like a book and divide congenital adhesions)
    • Positioning the colon on left side and the entire small bowel on the right side to prevent any future recurrence of volvulus 
    • Appendectomy
    • Resection of any necrotic bowel if present, possibly with stoma creation

Elective/prophylactic Ladd’s procedure:

  • Should be performed in incidentally detected/asymptomatic intestinal malrotation 
  • Can be performed laparoscopically in the absence of volvulus
Ladd’s procedure

Ladd’s procedure:
Untwisting of the bowel and division of Ladd’s bands. Small bowel is placed on the right and the colon is on the left side of the abdomen.

Image by Lecturio.

Prognosis

  • Overall mortality after surgery: 3%–9%
  • Mortality is near 0% for otherwise healthy children with no ischemia, but the mortality rate can increases if:
    • Intestinal necrosis
    • Prematurity
    • Associated congenital anomalies
  • Risk of recurrent volvulus: 2%–8%
  • If a large segment of the small intestine needs to be resected because of necrosis, short-gut syndrome may result.

Differential Diagnosis

  • Duodenal atresia and stenosis: a congenital condition where there is an absence of normal duodenal lumen. This condition can present with recurrent vomiting, feeding intolerance, and failure to thrive. Abdominal X-ray shows a characteristic double bubble sign and a gasless distal bowel. Management relies on surgical correction.
  • Hypertrophic pyloric stenosis: a hypertrophy of the pyloric sphincter muscle in infants. This condition presents after the 1st 3 weeks of life with projectile nonbilious vomiting. Diagnosis is made with ultrasound, and treatment is surgical pyloromyotomy.
  • Intussusception: a condition in which 1 part of the intestine telescopes into another, usually resulting in bowel obstruction. Patients present with colicky abdominal pain, vomiting, and sometimes bloody (or currant-jelly) stools. Diagnosis in children is frequently established with ultrasound. Treatment in children typically involves non-operative reduction with an enema, with surgery being reserved for complicated cases.

References

  1. Bensard D.D. (2018). Intestinal Malrotation. Medscape. Retrieved February 17, 2021, from https://emedicine.medscape.com/article/930313-overview
  2. Brandt M.L. (2019). Intestinal malrotation in children. UpToDate. Retrieved February 17, 2021, from https://www.uptodate.com/contents/intestinal-malrotation-in-children
  3. Filston H.C., Kirks D.R. (1981). Malrotation – the ubiquitous anomaly. J Pediatr Surg. 16(4 Suppl 1), 614. 
  4. Townsend C.M. Jr., Beauchamp R.D., Evers B.M., Mattox K. L. (2004). Sabiston Textbook of Surgery. 17th ed. (2109–2110).

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