Malrotation is a birth defect that occurs when the intestines do not correctly or completely rotate into their normal final position during development. People born with malrotation may develop symptoms and complications, most often when they are babies but sometimes later in life. Some people with malrotation never develop symptoms or complications.

The lower gastrointestinal (GI) tract is the last part of the digestive tract. The lower GI tract consists of the large intestine and the anus.

The large intestine absorbs water and changes the waste products of the digestive process from liquid into formed stool. The large intestine includes

• the appendix, a finger-shaped pouch attached to the cecum
• the cecum, the first part of the large intestine, which is connected to the end of the small intestine
• the colon, which has four sections: the ascending colon, the transverse colon, the descending colon, and the sigmoid colon
• the rectum, the lower end of the large intestine leading to the anus

The anus is a 1-inch opening at the end of your digestive tract through which stool leaves your body. The anus includes the sphincter muscles—muscles that open and close and allow you to control bowel movements.

Experts are not sure how common malrotation is because not all people with malrotation develop signs or symptoms. Some studies suggest that about 1 in 500 people have malrotation.

Malrotation is most commonly diagnosed in babies. Up to 80 percent of babies with malrotation are diagnosed in the first month of life.

Experts don’t know what causes malrotation. However, genes or changes in genes—called mutations—may play a role.

If you or your child has signs or symptoms of malrotation or its complications, you should seek medical help right away.

Common signs of malrotation in babies younger than age 1 include

• vomiting, often with bile in the vomit, which makes it green in color
• failure to thrive
• pain or tenderness in the abdomen
• bloating of the abdomen
• bleeding from the rectum or passing bloody stools

In children older than age 1 and adults, common signs and symptoms include

• pain in the abdomen
• vomiting
• nausea
• diarrhea
• bloating
• constipation
• bleeding from the rectum or passing bloody stools
• failure to thrive in children

If malrotation and its complications cut off blood flow to the intestines and cause shock, symptoms may include

• confusion or unconsciousness
• fast heart rate
• pale skin
• sweating

Children with malrotation may have other birth defects, including defects of the

• gastrointestinal (GI) tract
• wall of the abdomen
• heart
• biliary tract
• pancreas

Malrotation can cause volvulus, or twisting, of the small intestine. Malrotation can also cause intestinal obstruction due to bands of mesentery—the tissues that hold the intestines in place—pressing against the duodenum. These problems can lead to serious and life-threatening complications such as

• lack of blood flow to the blocked part of the intestine and death of the blood-starved tissues
• a perforation, or hole, in the wall of the intestine
• peritonitis, an infection of the lining of the abdominal cavity
• sepsis, a serious illness that occurs when the body has an overwhelming immune system response to an infection
• shock

Doctors diagnose malrotation based on medical and family history, a physical exam, and imaging tests.

Physical exam

During a physical exam, a doctor will check for signs of pain, tenderness, or bloating or visible swelling of the abdomen and may listen to sounds inside the abdomen using a stethoscope. A doctor may also check for signs of shock, such as a rapid pulse or low blood pressure.

Imaging tests

Doctors may use the following imaging tests to diagnose malrotation

• x-rays, which use a small amount of radiation to create pictures of the inside of the body
• lower GI series, which uses x-rays and a chalky liquid called barium to view the large intestine
• upper GI series, which uses x-rays and barium to view the upper GI tract, including the small intestine
• ultrasound, which uses sound waves to create an image of organs

Doctors treat malrotation and its complications with surgery. During surgery, the surgeon may

• divide any bands of tissue in the abdomen that are causing complications or might in the future
• change the position of the intestines to lower the risk of future complications
• untwist any volvulus
• remove any parts of the intestines damaged by volvulus
• remove the appendix, since malrotation can make it difficult to diagnose appendicitis if the patient develops this condition in the future