What is Midgut Malrotation?
Midgut malrotation is a condition that occurs when the part of the digestive tract, that appears during early development in the womb, doesn’t rotate properly. This condition can either appear very suddenly, at irregular intervals, or you may not show any symptoms at all. If this malrotation leads to the intestine twisting, it becomes a surgical emergency that needs immediate attention.
Normally, as a baby grows in the womb, their small intestines rotate around a major blood vessel supplying the intestines, called the superior mesenteric artery (SMA). This happens between the fourth and eighth week of pregnancy. During this time, the intestines protrude through a structure called the yolk stalk, which later turns into the umbilicus or the belly button. While this process happens, the intestines become longer and rotate in a counterclockwise direction by 90 degrees, then get pulled back into the abdomen. Inside the abdomen, they rotate a further 180 degrees in the same direction.
Midgut malrotation can happen in different ways:
* Non-rotation: this happens when the intestines do not rotate at all.
* Incomplete rotation: this is when the intestines do not rotate completely.
* Reverse rotation: this is when the intestines rotate in the opposite direction.
* Anomalous fixation of the mesentery: the mesentery connects your intestines to the wall of your abdomen, and this happens when it attaches in an abnormal way.
What Causes Midgut Malrotation?
When there are changes in the BCL6 gene, it affects the normal functioning of the pathways that are important for the correct placement of parts of your digestive system. This can result in the abnormal location of the cecum (a pouch at the beginning of the large intestine) and the formation of fibrous or thick bands extending from the cecum to the back of your abdominal cavity. This extends over the duodenum (the first part of the small intestine) and can create a spot that can potentially get blocked.
The shortened section, or mesentery, of the misplaced intestines forms a sort of stem around which the intestines may twist, leading to a condition known as volvulus. This twisting can then interfere with the blood supply to the intestines, causing them to become starved of oxygen and nutrients, a condition called ischemia.
Risk Factors and Frequency for Midgut Malrotation
Mid-gut malrotation is a condition with a rate of about 1 in every 6,000 live births. Because many of these situations cause no symptoms, the actual number could be even higher. The most common kind of these conditions is “nonrotation,” seen in about 2 out of every 1,000 scans of the upper digestive system.
Among these deviations, malrotation with bowel volvulus—twisted intestine—is the most serious. As a result, mid-gut malrotation was typically considered a problem that shows up in the first few years of life. One third of the cases occur within the first month of life, 60% within the first year, and over 75% by the age of five. Only a very small number of cases—between 0.2% and 0.5%—show up in adults, and of these, only 15% present with a twisted intestine.
- Total cases of mid-gut malrotation are seen in about 1 out of every 6,000 live births.
- Most common type is nonrotation, seen in 2 in every 1,000 scans of the upper digestive system.
- Severe cases often involve a twisted intestine.
- Commonly presents itself in infancy, often within the first month of life.
- Only a small percentage of cases arise in adults, amongst which even fewer involve a twisted intestine.
- Associated with a number of birth defects, including heart disease, hernias, abdominal wall defects, certain types of intestinal blockages, esophageal issues, biliary obstruction, and complex anal malformations such as VACTERL.
- Affects boys twice as often as girls.
Signs and Symptoms of Midgut Malrotation
Malrotation, a condition that affects the position of a person’s intestines, presents differently based on a person’s age and how rapidly the symptoms appear. If the symptoms are acute, meaning they appear suddenly, they may include vomiting. This vomiting is often characterized by green or fluorescent yellow color, also known as bilious. However, note that sometimes the vomit may not have this color (nonbilious). If a child under one year old vomits this way, it can be a signal of a blockage in their digestive system, possibly due to malrotation leading to a twist in their intestines, also known as a volvulus. This situation might occur because their intestines can move around more than usual, causing them to twist around the main artery that supplies them with blood, compromising their blood flow.
The abdomen may look bloated, but this is not a common symptom in acute presentations of this condition, especially in young infants. As time passes, other symptoms like unstable vital signs, inflammation of the abdomen lining (or peritonitis), and blood in the feces due to decreased blood flow to the intestines leading possibly to tissue death can occur. These symptoms are most common especially if the intestines get twisted (volvulus).
In older children and adults, the signs of malrotation can vary and might overlap with symptoms of chronic or intermittent abdominal pain. Vomiting may also occur but it may not be characterized by the green or fluorescent yellow color (bilious).
Testing for Midgut Malrotation
If a child or a patient suspected of having intestinal malrotation with twisting (volvulus) is stable, they should undergo an evaluation using medical imaging to confirm the diagnosis.
An abdominal x-ray has some usage limitations for diagnosing a blocked intestine. A sign on the x-ray known as the double-bubble could suggest a blockage, where an air-filled stomach and the upper part of the small intestine show up without much gas in the rest of the intestine. Remember, however, that this sign isn’t always definitive. X-ray is about 69% sensitive (meaning it catches 69% of actual cases) and 57% specific (meaning it correctly excludes 57% of non-cases).
An Upper GI series, which is a set of x-rays of the upper digestive system, is pretty good for this diagnosis – with a sensitivity of 93%, specificity of 77%, and accuracy of 86%. But this is only for stable patients. Normal results show that the small intestine has crossed the midline in the abdomen. If the patient has malrotation, the ligament of Trietz may show up on the right side of the abdomen instead of the left, and there might also be a corkscrew-shaped small intestine or evidence of a volvulus.
If the Upper GI series doesn’t give a clear result, or the patient’s symptoms continue to be unclear, the doctors might follow up with a barium enema (lower GI series). This is generally limited to stable or chronic patients who are not actively vomiting.
An ultrasound, meanwhile, is not typically used to rule out malrotation. It’s about 88% sensitive and 96% specific in diagnosing intestinal obstructions. Ultrasound might show unusual positions of the superior mesenteric vein (SMV) and the superior mesenteric artery (SMA), or other signs of malrotation such as the twisting of blood vessels, known as the ‘whirlpool’ sign.
A CT scan might be used to investigate an absence of the duodenum (a part of the small intestine) in its usual position behind the peritoneum, the membrane that covers the organs in the abdomen. The scan may also show abnormal positioning of the SMA/SMV, or offer more evidence of the ‘whirlpool’ sign.
An MRI, however, is not usually used in an emergency setting where a volvulus is suspected. It could be useful when it’s better to avoid using x-rays or CT scans, such as in a pregnant patient.
In cases of heterotaxy syndrome, children who don’t have symptoms are recommended to get screened for intestinal malrotation. On the other hand, children born with gastroschisis, omphalocele, or congenital diaphragmatic hernia don’t usually need routine screening for malrotation unless they show symptoms such as abdominal pain, feeding intolerance, and vomiting.
Laboratory tests may also be required. An elevated or reduced white blood cell count can indicate systemic inflammation or sepsis. Blood cell counts (CBC) may also reveal a lower or higher than normal blood count which could be due to blood loss or fluid depletion. An increase in lactate levels or metabolic acidosis could be due to any bowel tissue not getting enough oxygen, and vomiting can also lead to acidosis due to loss of gastric acid. The complete metabolic panel may reveal changes due to this condition, like increased levels of potassium or changes in sodium, chloride, bicarbonate levels. If possible, these imbalances should be corrected before any surgical interventions.
Treatment Options for Midgut Malrotation
When a baby has symptoms like vomiting green bile or experiencing a sudden blockage in their stomach or gut, it could be a sign of intestinal malrotation. This condition can be harder to spot in older kids and adults because stomach pain can happen inconsistently. The doctor determines if a patient has this condition by looking at their symptoms and doing tests. If there’s a risk of the intestines tearing and causing an infection in the abdomen (peritonitis), urgent treatment will be required.
If the patient is stable, tests like x-rays or scans can confirm the diagnosis. If intestinal malrotation is causing a twist in the gut (volvulus) or a blockage in the bowel, the doctor will insert a tube through the nose or mouth to suction out fluids from the stomach. The patient will also receive treatment to correct any imbalances in body fluids and salts, and they’ll be given broad-spectrum antibiotics to prevent infections prior to surgery.
In the case of an emergency twist in the gut, the best option is urgent surgery. The aim of the surgery is not to correct the malrotation, but to prevent any future twists from happening. This procedure is known as a Ladd procedure. Here, the surgeon will unravel any twists, clear any bands of tissue that may cause a blockage, and rearrange the intestines within the abdomen. The appendix is also removed during this process.
There’s some disagreement among medical experts about whether this surgery should be done through small incisions using a camera (laparoscopic) or through a bigger incision (open surgery). While studies show that both methods work, the laparoscopic method might not be as good at preventing future twists.
In certain cases where surgery is not urgent, laparoscopy can be very useful. This approach is particularly helpful in planned surgeries or in older children and adults. Appendectomy, or removal of the appendix, is usually done for two reasons: firstly, the location of the appendix can make it harder to identify and treat appendicitis and secondly, the blood vessel supplying the appendix can get damaged while clearing the bands of tissue.
If the guts are twisted (midgut volvulus), the surgeon will move the intestines out of the abdomen to untwist them and then assess if the intestines are healthy. If there’s doubt about whether the intestines are viable or not, the surgeon may postpone the decision to remove them. In such cases, a second surgery might be done after 12-24 hours, once the patient’s health is stabilized.
After untwisting the intestine, the surgeon will check for any other blockages caused by bands of tissues. If any obstructions are detected, they are carefully removed to prevent damage to major blood vessels. Then, the surgeon will put everything back in the right place. Finally, they will insert a tube through the nose to the gut to check for any internal blockages.
What else can Midgut Malrotation be?
When a person is suspected of having an issue known as midgut malrotation, it can often appear like many other stomach or bowel problems. Here are some other illnesses that doctors would consider before making a diagnosis:
- Newborn bowel obstruction: This condition can prevent a newborn from passing their first poop, or meconium, within the first 48 hours. It can be caused by multiple issues such as duodenal atresia, jejunoileal atresia, meconium ileus, Hirschprung’s disease, small left colon syndrome, or an annular pancreas.
- Congenital Band: This is a medical term for a type of internal scar tissue that isn’t connected to any current issues inside the belly (like past operations, leftover embryonic tissue, inflammation, peritonitis, etc.).
- Intestinal volvulus: This is a condition that happens when your intestine twists around itself.
- Necrotizing enterocolitis: A serious condition usually seen in premature babies, where portions of the bowel undergo tissue death.
- Neonatal sepsis: This is a severe blood infection that occurs in newborns.
- Pediatric gastroesophageal reflux: Commonly known as acid reflux, this happens when stomach acid frequently flows back into the tube connecting your mouth and stomach.
- Intussusception in older infants: This is a serious condition where part of the intestine slides into an adjacent part, much like folding a part of a telescope.
The diagnosis needs careful consideration by the physicians to ensure the right course of treatment.
What to expect with Midgut Malrotation
Patients with a condition called midgut malrotation usually have a good chance of recovery, if they don’t have additional problems, such as a twisted intestine (midgut volvulus), damaged tissue due to inadequate blood supply (necrosis), being smaller than expected for their stage of pregnancy (small for gestational age), being born early (premature delivery), or other abnormalities.
The risk of death after surgery for malrotation can be between 3 to 9 percent. There are factors that can increase this risk, such as having a volvulus, being premature, or having associated health conditions.
During surgery for malrotation, the surgeon typically widens the base of a fold of tissue in the abdomen that connects the intestine to the abdominal wall (the mesentery) to reduce the risk of the intestine twisting again (recurrent volvulus). However, the chance of experiencing recurrent volvulus is estimated to be between 2 and 8 percent.
Possible Complications When Diagnosed with Midgut Malrotation
Common complications after general surgery can include conditions such as a twisted intestine happening again, blockage in the small intestine due to scar tissue formed after surgery, infections at the site of the wound, blood clots in major veins, and pneumonia caused by the placement of a nasogastric tube (a tube inserted through the nose into the stomach to release gas and fluid).
Unfortunately, losing a large part of the bowel can cause other problems like short bowel syndrome and vitamin deficiencies.
For those with short bowel syndrome, treatments often include drugs to control diarrhea, nutritional therapy, which involves eating small but protein-rich meals and increasing hydration. They may also need vitamin and mineral supplements and in some cases, may require parenteral nutrition – a method of getting nutrition into your body through your veins. This is usually needed when the remaining part of the bowel is too short or still healing. In extreme cases, a procedure to reconstruct the bowel or bowel transplantation may be considered as the last option.
Common Complications:
- Twisted intestine recurring
- Small intestine blockage due to scar tissue
- Infections at the wound site
- Blood clots in major veins
- Pneumonia
- Short bowel syndrome
- Vitamin deficiencies
Treatments for Short Bowel Syndrome:
- Medications to control diarrhea
- Nutritional therapy
- Hydration
- Vitamin and mineral supplements
- Parenteral nutrition (if necessary)
- Bowel reconstruction or transplantation (last resort)
Preventing Midgut Malrotation
The patient and their family need to understand that there is a risk of the twisting issue, known as volvulus, happening again, which could need more surgery. It’s important to know that this is a very serious condition that can be life-threatening. The family also needs to be made aware that surgery doesn’t fix the issue of the intestines being in the wrong place (malrotation), but it does help reduce the risk of the intestines twisting again.