Intestinal Malrotation: Pathophysiology, Causes, Symptoms, Treatment, Prognosis

Intestinal Malrotation is a pathological condition which results due to an underdeveloped intestine. This condition usually begins in the first trimester around the 10th week in pregnancy. Intestinal Malrotation develops as a result of the intestines not being able to develop in their normal position in the abdomen. Intestinal Malrotation is suspected in a newborn baby when the baby experiences a medical condition called as volvulus characterized by twisting of the intestines resulting in intestinal obstruction, which causes the food not to get digested appropriately. The part of the intestine which gets twisted does not get adequate supply of blood which causes that particular segment of the intestine to get necrotic. Necrosis of a segment of the intestine is a serious medical condition and requires immediate medical attention. It is estimated that in the United States approximately 1 in every 600 babies born have Intestinal Malrotation with symptoms observed within the first year of life. Majority of cases of Intestinal Malrotation are diagnosed within the first week of life itself.

As stated, Intestinal Malrotation is caused due to underdeveloped intestines where the intestines are not fixed at their normal positions in the abdomen. To better understand the pathophysiology of Intestinal Malrotation, it is imperative to understand the anatomy of the abdomen, especially the position of the intestines, under normal circumstances.

Normally, the digestive tract is made from the foregut, midgut, and hindgut. The foregut is the anterior part of the digestive tract and starts at the mouth and carries on till the duodenum. From here, the midgut starts and this is where the intestines develop. The hindgut includes the colon and the rectum. Together, these three form the digestive tract of an individual. The development of the digestive tract in the fetus takes place in three stages, stage I beginning between the 5th and the 10th week into pregnancy. During this period normal rotation takes place with the superior mesenteric artery acting as the axis around which rotation takes place. The duodenojejunal loop is located superior to the superior mesenteric artery in a perpendicular position and rotates at a straight angle in an anticlockwise direction. With Intestinal Malrotation, the duodenojejunal loop does not lie in its anatomic position to the left of the superior mesenteric artery. This results in the mesentery forming a narrow base causing malrotation in the midgut or midgut volvulus.

The state II of development of the digestive tract begins at approximately 10th week of pregnancy. During this time, the bowel comes back to the abdominal cavity. As it returns to its normal position, the duodenojejunal loop rotates by an additional 90 degrees and lies on the left of the superior mesenteric artery. If Intestinal Malrotation occurs in the second stage, there is incomplete rotation which causes obstruction of the duodenum. Based on how much rotation is complete prior to the arrest of rotation the base of the mesentery becomes narrow resulting again in midgut volvulus.

The stage III development starts from the 11th week of pregnancy till the baby is delivered. Under normal circumstances, in this stage the cecum descends to the right lower quadrant but in cases of Intestinal Malrotation, there is development of herniated pouch due to the mesentery of the colon and the duodenum do not get completely fixed to the retroperitoneum. This results in the descending left mesocolon to not get completely fixed and may cause the bowel to strangulate as in this case the small intestine tends to push out through the unfixed area resulting in mesocolic hernia.

The root cause of Intestinal Malrotation remains unknown although some studies suggest a familial occurrence of this disease.

The first and foremost sign of Intestinal Malrotation is abdominal pain and cramping as the bowel is unable to push the food through the obstruction caused by the malrotation. To identify abdominal pain or cramping in newborns there are certain telltale signs like the baby will cry whenever the legs are pushed in the upward direction, will stop crying all of the sudden for a few minutes and then start crying again. This will be the pattern followed again and again. Some of the other symptoms of Intestinal Malrotation are:

• Frequent greenish tinged vomiting
• Abdominal swelling
• Paleness of skin
• Decreased appetite
• No urine output
• Irregular bowel movements
• Blood in stools
• Fever
• Lethargy.

In order to diagnose Intestinal Malrotation, the treating physician will perform a detailed physical exam to look for abdominal swelling or paleness of skin. The physician may also order certain tests like

• Abdominal X-rays: This may be done to look for intestinal obstruction
• X-rays Utilizing Barium Enema: In this procedure barium is inserted in the intestine through anus and x-rays are taken which will show the obstruction clearly due to the barium
• Abdominal CT: A CT scan may be performed to look for obstruction in the intestines.

Intestinal Malrotation is a medical condition which requires emergent treatment as if left untreated the twisted segment of the intestine may become necrotic due to lack of appropriate blood supply which may be life threatening. Intestinal Malrotation is treated with surgery. Treatment begins with administering IV fluids to keep the baby hydrated. Antibiotics are administered to avoid infections during procedure. The volvulus is repaired by first correcting the twisted part of the intestine and looking for any damage and repairing it. If there is no significant damage to the twisted portion then it is untwisted and replaced back in the abdomen in its normal position. Another procedure is performed about 24 hours post the first procedure to look at the status of the intestine. If any part of the intestine is found to be damaged then that part of the intestine is removed.

In cases where significant portion of the intestine becomes damaged then a large part of the intestine is removed and the remaining part may not be able to be connected together. In this situation, a procedure called as colostomy is performed in which an opening is made in the abdomen and the two ends of the intestine are brought out through the opening and stool that is passed is collected in a bag called as the colostomy bag. This may be permanent or temporary depending on the status of the intestine.

Even though surgery is needed to repair Intestinal Malrotation, most of the babies who undergo this procedure have normal growth and development post treatment. In case of babies having volvulus due to Intestinal Malrotation also do not have permanent problems if treated early enough.

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