MALROTATION
Introduction
Malrotation is a structural anomaly of the GI tract resulting from improper sequence of events in the embryological development of the gut, which predisposes the bowel to twist around its mesentery resulting in a condition known as volvulus.
Epidemiology
- Occurs between 1/200 – 1/500 live births
- Majority of children with malrotation present before one month of age with volvulus.
Embryology
- By the 5th week of development, the developing gut lengthens disproportionately to the growth of the abdomen forming the primary intestinal loop, which herniates through the umbilicus and rotates 90¼ counterclockwise by the 6th week.
- By the tenth week, midgut retracts to the abdomen, and rotates an additional 180¼.
Pathophysiology
- Malrotation refers to impaired rotational process of the midgut as it returns from outside of the abdominal cavity (extracoelomic phase of development) to the abdominal cavity.
- The impaired rotational process could be non-rotation or partial rotation and/or combination of both which results in abnormal fixation of the cecum to the right abdominal wall and obstruction of duodenum by bands of peritoneum called Ladd bands.
- Malrotation results in narrow and long base of mesentery which predisposes bowel to twist around it; this condition is known as volvulus.
- Often volvulus occurs about the superior mesenteric artery axis, which results in ischemia of regions supplied by the artery, from duodenum to the splenic flexure.
Presentation
- Signs of bowel obstruction
- Bilious vomiting in the neonate is an indication of malrotation until proven otherwise
- Diffuse abdominal pain, dull and aching in quality – but pain is a symptom that is difficult to identify in infants.
- Gastrointestinal bleeding (sign of ischemic necrosis - associated w/ volvulus)
- Failure to thrive
Diagnosis
- Clinical symptoms – bilious vomiting, inconsolable neonate/infant, GI bleed, FTT
- Radiological findings
- dilated stomach and proximal duodenum on X ray
- Gold standard – upper GI study with contrast
- Doppler ultrasound.
Management
- Volvulus is a surgical emergency, delay in untwisting bowel can lead to ischemic necrosis
- Ladd procedure - divide peritoneal (Ladd) bands which obstruct the duodenum, separate the duodenum and jejunum to the right side of the abdomen and the colon to the left side of the abdomen.
- The goal is to minimize risk of future volvulus by widening base of mesentery.
- Appendectomy is also always performed to eliminate appendicitis as a potential diagnosis in future episodes of abdominal pain
Prognosis
- Intestinal function prognosis depends on the severity of the ischemic insult.
- Children who had large amounts of bowel resected require intravenous nutrition.
Differential Diagnosis
- In neonates – necrotizing enterocolitis
- In older infants – intussusception.
- In older children and adults – intussusception, appendicitis.
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