Duodenal Atresia – The Congenital Defect in Newborns
Duodenal Atresia is a rare anomaly that occurs between 1 in 10,000 to 1 in 6,000 live births. It occurs in the small intestine, obstructing the free flow of fluid and nutrients along the digestive tract of the fetus. It can sometimes be associated with other problems like Down syndrome or heart defects. But if not, the condition is easily treatable with no further complications or consequences to the child.
What Is Duodenal Atresia?
The duodenum is the first part of the small intestine and its opening, the lumen, remains open when the fetus is developing in the womb. This opening facilitates the free flow of food and fluids through the digestive tract for fetal development. In duodenal atresia, there is a malformation of the lumen, i.e. it is either absent or completely closed off, thus obstructing the flow. This blockage, or atresia, results in polyhydramnios — an abnormal accumulation of amniotic fluid as it is not being swallowed and digested by the fetus. This can subsequently present complications during pregnancy. Therefore, diagnosis and treatment of this congenital condition are necessary.
Types of Duodenal Atresia
Duodenal Atresia can manifest in the form of duodenal growth failure, annular pancreas, anomalies of the biliopancreatic tract or choledochal cysts. It may be classified into two types:
1. Partial Duodenal Atresia
In partial duodenal atresia, there is an incomplete closure of the lumen characterized by a mucosal diaphragmatic membrane with an intact muscle wall. This type of duodenal atresia is referred to as a duodenal diaphragm.
2. Complete Duodenal Atresia
Complete duodenal atresia can occur either due to duodenal “webs” or the absence of a part of the duodenum. In the former case, there is a short fibrous cord connecting the two ends of the blocked duodenum. These cords are known as duodenal webs as they form a web-like membrane at the point of obstruction. Other times, there is a complete separation between two parts of the duodenum due to the absence of a segment of the duodenum.
What Are the Causes of Duodenal Atresia?
The exact causes of duodenal atresia are not known, but it is believed that it could be a result of genetic factors which cannot be controlled by the parents. If both the parents have the same trait of the same defective recessive gene, which is then inherited by the fetus, it will have the disorder. However, if it gets one normal gene and one defective gene, it usually will not show symptoms but will become a carrier of the disorder.
It could also be due to blood vessel defects in the embryo, which result in decreased blood supply in the duodenum. This will cause the duodenum to be absent, closed off or develop an overgrowth of cells that obstruct the lumen.
Another cause of the anomaly is Down syndrome. 1/3rd of the babies born with duodenal atresia is diagnosed with Down syndrome. When a child is born with three copies of chromosome 21 instead of two, they have a condition called trisomy 21, commonly referred to as Down syndrome. This condition causes physical and intellectual disabilities which include duodenal atresia, heart abnormalities, or problems with vision and hearing. However, despite the additional complicating factors, duodenal atresia can be treated, and children with Down syndrome can grow up to live long and healthy lives.
What Are the Symptoms of Duodenal Atresia?
Signs of duodenal atresia in a child can be noticed prior to childbirth. Since the condition can cause complications during pregnancy and also put the child at risk, it is of utmost importance to look out for the following signs and symptoms.
Duodenal atresia is not easily detectable during pregnancy, signs of it appear on a prenatal ultrasound. However, these signs are usually nonspecific, like a dilated stomach.
1. Double Bubble
Double bubbles are an indicator of duodenal atresia that can be easily spotted on an ultrasound or an X-ray. In a fetus with duodenal atresia, fluid doesn’t flow through the intestinal tract but only accumulates in the stomach and the duodenum due to the obstruction of the lumen. The first bubble is the image of the fluid-filled stomach, and the second bubble is the fluid-filled duodenum.
In the course of a normal pregnancy, excessive amniotic fluid in the womb is swallowed and digested by the fetus. But a baby with duodenal atresia finds it difficult to swallow it. So the fluid begins to accumulate in the amniotic sac, causing the uterus to become enlarged. This condition is referred to as duodenal atresia polyhydramnios and if severe, can put the mother at the risk of early delivery.
The symptoms of duodenal atresia post-birth may vary, depending upon the severity of the blockage. They may increase or decrease, sometimes not appearing for weeks, months or even years.
1. Abdominal Swelling
Post-birth, the baby may exhibit a distended or swollen upper abdomen due to the accumulation of fluids in the stomach and the duodenum that has been blocked.
After birth, the baby may vomit bile, which is the yellow-green secretion arising from the liver. The vomit, in some cases, can consist of clear or light brown granular matter. Duodenal atresia vomiting typically occurs a few hours after birth and will be severe and in large amounts.
3. Absence Of Bowel Movements
The newborn will initially excrete meconium stools, i.e. dark-coloured stools that contain the matter that lines the intestines when the fetus is developing in utero. However, they may fail to do so, or after the passing of the first few meconium stools, the baby may become constipated and resist treatment.
A fetus with duodenal atresia is unable to digest the necessary amount of nutrients for growth. This may cause the baby to measure small when it is born. Sometimes, babies may also have heart disease, abnormalities in the anus, rectum, small intestine, oesophagus or the genitourinary system (i.e., organs of the reproductive and urinary system). Physical and intellectual challenges are usually a result of Down syndrome.
Doctors check for the signs mentioned above using the diagnosis methods mentioned below. Learn below how exactly the diagnosis is made.
How Is Duodenal Atresia Diagnosed?
Duodenal atresia can be diagnosed during pregnancy. Signs of the condition may be seen during the routine 20-week antenatal ultrasound; however, they usually become visible during the third trimester. If there are signs of duodenal atresia during the pregnancy, like an enlarged uterus (due to polyhydramnios) or a double bubble in the ultrasound, several diagnostic techniques can be employed. They may also be used in genetic testing/screening to confirm if there is a chance the child may have Down syndrome.
The Fetal ultrasound is obtained on performing high-resolution ultrasonography which is a non-invasive diagnostic test. Reflective sounds are used to create a picture of the baby inside the womb, and these images show the fetus’ intestinal tract and other organs. The test is also used to detect polyhydramnios to check for the risk of early delivery.
Fetal echocardiography also referred to as an echo, is a non-invasive high-resolution ultrasound procedure performed by a pediatric cardiologist (heart specialist) to check for heart abnormalities. Congenital heart defects can be common among babies suffering from duodenal atresia or even Down syndrome.
Amniocentesis is a test where a sample of amniotic fluid is removed from the amniotic sac. A small needle is placed through the abdomen and into the amniotic sac, and the fluid sample is collected. Since the fluid surrounds the baby, it contains cells of the baby, thus facilitating analysis of its chromosomes. It is used to check for genetic disorders and chromosomal conditions.
A determinative diagnosis of duodenal atresia is undertaken only after the baby is born. A duodenal atresia X-ray is taken to verify the diagnosis.
Treatment of Duodenal Atresia
Duodenal atresia, even if diagnosed prior to the birth of the baby, cannot be treated until after the baby is born. However, some precautions can be taken to cut the risks of complications during childbirth. Here’s how the condition is dealt with before and after childbirth.
Though duodenal atresia is treated after the birth of the child, certain interim modalities have to be undertaken to lower the risk of complications during birth. Measures have to be taken to prevent the risk of preterm labour due to polyhydramnios. These prenatal preventive treatment measures involve close monitoring of the fetus and the mother. The uterus is frequently measured, and its size and internal pressure are evaluated. An amnioreduction can be carried out to remove the excess of amniotic fluid. Additionally, other complicating factors like Down syndrome and heart disease are also identified.
The goal of preventive measures prior to childbirth is to ensure a normal vaginal delivery as close as possible to the due date. However, even if the delivery is normal, the baby requires specialized medical interventions which are provided in the neonatal intensive care unit (NICU). Breastfeeding or bottle-feeding milk to the baby is not possible, so a nasogastric tube is inserted into the child’s stomach via the mouth or nose. Fluids are provided through the tube, and the trapped air is removed as it cannot pass through the digestive tract. Nutrients are fed intravenously. An x-ray and echocardiogram test to definitively ascertain the presence of duodenal atresia and heart defects is carried out before moving forward with treatment.
Surgery can be an option to treat the condition after childbirth. Since the newborn is in a delicate state, medication practitioners need to take utmost care during and after the surgery. Read on to know more about it.
Before The Surgery
A surgery, either open or laparoscopic, is performed two-three days after birth to fix the atresia. Duodenal atresia repair of all forms of the condition is accomplished with the same procedure. General anaesthesia is first administered to the baby. Then, the blocked end of the duodenum is opened and connected to the remainder of the small intestine at the point of obstruction. There are seldom any complications in the procedure.
After The Surgery
The baby is returned to the NICU and put on a ventilator for a few days while his heart rate, breathing, and oxygen levels are monitored. For two to three weeks after the procedure, nutrition is provided intravenously until the bowels heal and begin to function normally. Once the baby is able to consume food from a bottle or through breastfeeding, and there are no signs of further complications, he will be discharged from the hospital.
Outlook for Children With Duodenal Atresia
Duodenal atresia prognosis is excellent when the condition occurs without any associated problems; the survival rate is 95%. There are rarely any complications during the procedure. Potential immediate complications after, like leaking from the repaired bowel connections, bleeding or infections inside the abdomen or wound, are extremely rare but they can be operated and rectified. There may be chances of dehydration, abdominal swelling, problems with intestinal motility or gastroesophageal reflux. However, it is more likely that a baby with congenital duodenal atresia, once operated on, will be able to live a completely normal life, without needing long-term or follow-up treatment. But, if the condition is accompanied with other congenital defects like Down syndrome, the outlook varies, depending upon the severity of the problem.
Duodenal atresia is a congenital defect in a fetus, resulting in an obstruction in the digestive tract. It can be treated after the baby is born by performing a simple surgical procedure. With proper precaution and care, complications can be avoided so that the child can go on to lead a healthy life without further treatment. However, in instances where the condition is supplementary to other problems like Down syndrome or heart defects, there are long-term effects that require further treatment.