Intestinal malrotation is a birth defect involving a malformation of the intestinal tract; it occurs while a fetus is forming in its mother's uterus.
As a fetus grows in its mother's uterus before birth, different organ systems develop and mature. The digestive tract starts off as a straight tube from the stomach to the rectum. Initially, it is located in the fetus' abdomen, but, for a short time, part of the intestine moves into the umbilical cord.
At about the 10th week of pregnancy, the intestine leaves the umbilical cord and re-enters the abdomen. At that point, the intestine makes two turns and is no longer a straight tube.
Malrotation occurs when the intestine does not make these turns as it should.
In addition, intestinal malrotation causes the cecum (the end of the small intestine) to develop abnormally. The cecum is normally located in the lower-right side of the abdomen. With malrotation, the cecum and the appendix (which is attached to the cecum) stay in the upper-right side of the abdomen. Bands of tissue called Ladd's bands form between the cecum and the intestinal wall and can create a blockage in the duodenum (the beginning of the small intestine).
A volvulus occurs after birth as a result of intestinal malrotation. The intestine becomes twisted, causing an intestinal blockage. This twisting can also cut off the blood flow to the intestine, and the intestine can be damaged.
Intestinal malrotation occurs in one out of every 500 live births in the United States. Malrotation occurs equally in boys and girls. However, more boys become symptomatic by the first month of life than girls.
The majority of children with malrotation develop symptoms within their first year of life. Intestinal malrotation is most often recognized in infancy, as most infants develop symptoms of acute bowel obstruction within the first week of life. Malrotation is rarely seen in older children, and when it does occur, symptoms may be absent or intermittent. Some people who have malrotation go through their entire life without having any symptoms and are never diagnosed. Others may not have symptoms until adolescence or adulthood.
Up to 70% of children with intestinal malrotation also have another congenital malformation, including the one or more of the following:
- Digestive system abnormalities
- Cardiac abnormalities
- Abnormalities of the spleen
- Abnormalities of the liver
A child with malrotation is likely to experience a twisting of the intestine known as a volvulus. This will cause an obstruction, preventing food from being digested normally and dehydration to occur. The blood supply to the twisted part of the intestine also may be cut off, which can lead to the death of that segment of the intestine.
Ladd's bands, formed between the cecum and the intestinal wall, also may create a blockage in the duodenum, preventing food from being digested.