Fig. 1
Malrotation and midgut volvulus. In normal development, the midgut is fixed to the retroperitoneum and the mesentery has a wide base. In malrotation, the narrow base of mesentery can undergo volvulus, and requires repair with the Ladd’s procedure (Source: Christopher Coppola)
(c)
Situs inversus: with suits inversus and heterotaxy, there is often malrotation and non-fixation. Other abnormalities may be present such as asplenia and central globular liver. Of note, when situs inversus is present, volvulus will usually occur with a counter-clockwise rotation of the midgut, which differs from the volvulus when the organs are on the usual side of the body.
(d)
There is much variation in malrotation between individual patients. Different segments of the midgut may be free to undergo volvulus and sometimes there is partially complete fixation of the bowel. As an example, even if the cecum is located in the right lower quadrant, it does not guarantee that the proximal gut has undergone normal fixation. Some abnormalities of fixation can cause kinked or tortuous arrangements of the duodenum which can result in obstruction.
(e)
Malrotation is often called the “ubiquitous anomaly” because it frequently accompanies other congenital abnormalities. Conditions where the midgut does not return to the abdomen during gestation, such as diaphragmatic hernia, gastroschisis, and omphalocele, will usually involve malrotation and non-fixation of gut.
2.
Clinical presentation:
(a)
The typical presentation of malrotation is bilious vomiting. It is essential that this history is elicited from the child’s parents. They should be asked the color of vomitus, and if it is present on clothing or a towel it can be inspected. Any account of bilious vomiting should raise the possibility of malrotation with volvulus and requires immediate evaluation.
(b)
The child may have a scaphoid abdomen resulting from proximal obstruction of the intestine at the duodenum. Inability to pass stomach contents past this point keeps the intestine empty. If vomiting has gone on for a prolonged period, the patient will be dehydrated, anuric, and lethargic or in hypovolemic shock.
3.
Diagnosis: there are many causes for bilious vomiting from infectious to neoplastic, but the cause that must be rapidly excluded is malrotation. Upper gastrointestinal series is the most accurate method to determine if it is present.
(a)
Upper gastrointestinal series: a radiologist experienced in determining rotation of bowel should be consulted. Barium contrast gives the best definition, but water soluble contrast can be used if there is a chance of perforation, to avoid the irritation caused by extravasated barium. If the child is awake, he or she can drink the contrast from a bottle, otherwise, it can be instilled via a nasogastric tube.
(i)
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There are three criteria for normal rotation of gut. If any of them are absent, the child has malrotation.
1.
Passage of duodenum from left to right, then back again.
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