Duodenal atresia is the congenital absence or complete closure of a portion of the lumen of the

duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...

. It causes increased levels of amniotic fluid during pregnancy ( polyhydramnios) and intestinal obstruction in newborn babies. Newborns present with bilious or non-bilous vomiting (depending on where in the duodenum the obstruction is) within the first 24 to 48 hours after birth, typically after their first oral feeding. Radiography shows a distended stomach and distended duodenum, which are separated by the pyloric valve, a finding described as the double-bubble sign. Treatment includes suctioning out any fluid that is trapped in the stomach, providing fluids intravenously, and surgical repair of the intestinal closure.

Signs and symptoms

History and physical examination

During pregnancy, duodenal atresia is associated with increased

amniotic fluid The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products betwee ...

in the uterus, which is called polyhydramnios. This increase in amniotic fluid is caused by the inability of the fetus to swallow the amniotic fluid and absorb it in their digestive tract. After birth, duodenal atresia may cause abdominal distension, especially of the upper abdomen.

Bilious Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile ...

or non-bilious vomiting, depending on the position of the atresia in relation to the Ampulla of Vater, commonly occurs within the first day of life.

Associated conditions

Approximately 20–40 percent of all infants with duodenal atresia have

Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...

and 50% have a congenital cardiac anomaly. Approximately 8% of infants with Down syndrome have duodenal atresia.

Diagnosis

Imaging

Antenatal

Antenatal ultrasonography allows for earlier detection and diagnosis of duodenal atresia. The duodenum is not typically filled with fluid on imaging, however if fluid is visualized on ultrasound, this may suggest duodenal atresia as it causes obstruction and fluid may not pass distal to the atretic area. Early diagnosis of duodenal atresia provides time for clinicians to provide prenatal counseling and prepare for postnatal management.

Postnatal

The diagnosis of duodenal atresia is usually confirmed by

radiography Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeut ...

. An

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

of the abdomen is the first step in evaluation. The x-ray should be obtained after placement of a

nasogastric tube Nasogastric intubation is a medical process involving the insertion of a plastic tube (nasogastric tube or NG tube) through the nose, down the oesophagus, and down into the stomach. Orogastric intubation is a similar process involving the inserti ...

(feeding tube), evacuating the stomach and filling 40-50 ml of air to demonstrate two large air filled spaces, the so-called "double bubble" sign. The air is trapped in the stomach and proximal duodenum, which are separated by the

pyloric sphincter The pylorus ( or ), or pyloric part, connects the stomach to the duodenum. The pylorus is considered as having two parts, the ''pyloric antrum'' (opening to the body of the stomach) and the ''pyloric canal'' (opening to the duodenum). The ''pylori ...

, creating the appearance of two bubbles visible on x-ray. Since the closure of the duodenum is complete in duodenal atresia, no air is seen in the distal duodenum. Note that the double bubble sign is typically pathologic however it is not specific for duodenal atresia and may indicate other pathologies such as annular pancreas or midgut volvulus. A limited

upper gastrointestinal series An upper gastrointestinal series, also called a barium swallow, barium study, or barium meal, is a series of radiographs used to examine the gastrointestinal tract for abnormalities. A contrast medium, usually a radiocontrast agent such as barium ...

using barium contrast can be used to differentiate between duodenal atresia and midgut volvulus.

Causes

The cause of duodenal atresia is not known. Dr.

Julius Tandler Julius Tandler (February 16, 1869 – August 25, 1936) was an Austrian physician and Social Democratic politician, whose research secured him a lasting place in the history of anatomy. His main claim to fame was his ambition to introduce a compr ...

hypothesized in 1900 that the etiology of duodenal atresia was due to occlusion of the duodenal lumen and failure to re-canalize during embryological development. Research surrounding duodenal atresia in recent years has switched focus to the fibroblast growth factor pathway in mouse models as Tandler’s original hypothesis was unable to account for the different types of duodenal atresia.

Diagnosis

Classification

Duodenal atresia is classified into 3 types: * Type 1: the most common form of duodenal atresia, making up 92% of cases. A web made of mucosa and submucosa obstructs the duodenal lumen however there are no defects in the muscle coat. * Type 2: rarest form of duodenal atresia, making up 1% of cases. The proximal and distal ends of the duodenum are atretic and separated but are connected by a cord (mesentery still intact). * Type 3: makes up 7% of duodenal atresia cases. The ends of the duodenum are atretic without any tissue attachment (mesentery defect).

Management

Early treatment includes removing fluids from the stomach via a

, and providing fluids

intravenously Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

. The definitive treatment for duodenal atresia is surgery (duodenoduodenostomy or duodenojejunostomy), which may be performed openly or

laparoscopically Laparoscopy () is an operation performed in the abdomen or human pelvis, pelvis using small Surgical incision, incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few ...

. The surgery is required but not immediately urgent - a 24 to 48-hour delay is permissible to facilitate transport, further evaluation and fluid resuscitation. The initial repair has a 5 percent morbidity and mortality rate. Nasogastric suction is typically continued post-operatively and patients can be transitioned to small oral feeds once nasogastric tube output decreases significantly or stops completely.

Complications

Prognosis is usually very good, although complications are more likely to occur when there are serious congenital anomalies. Complications from surgical repair include

Peptic ulcer disease Peptic ulcer disease (PUD) is a break in the inner lining of the stomach, the first part of the small intestine, or sometimes the lower esophagus. An ulcer in the stomach is called a gastric ulcer, while one in the first part of the intestines ...

Gastroesophageal reflux disease Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

Cholecystitis Cholecystitis is inflammation of the gallbladder. Symptoms include right upper abdominal pain, pain in the right shoulder, nausea, vomiting, and occasionally fever. Often gallbladder attacks (biliary colic) precede acute cholecystitis. The pain l ...

Esophagitis Esophagitis, also spelled oesophagitis, is a disease characterized by inflammation of the esophagus. The esophagus is a tube composed of a mucosal lining, and longitudinal and circular smooth muscle fibers. It connects the pharynx to the stomach; s ...

Megaduodenum Megaduodenum is a congenital or acquired dilation and elongation of the duodenum with hypertrophy of all layers that presents as a feeling of gastric fullness, abdominal pain, belching, heartburn, and nausea with vomiting sometimes of food eaten 2 ...

Blind loop syndrome Blind loop syndrome (BLS), also known as stagnant loop syndrome, is a state that occurs when the normal bacterial flora of the small intestine proliferates to numbers that cause significant derangement to the normal physiological processes of dig ...

, and anastomotic leak. Late complications may occur in about 12 percent of patients with duodenal atresia, and the mortality rate for these complications is 6 percent.

Epidemiology

Duodenal atresia occurs in 1 in every 10,000 live births and is the most common intestinal atresia, constituting up to 60% of intestinal atresias.

References

External links

{{Congenital malformations and deformations of digestive system Gastrointestinal tract disorders Congenital disorders of digestive system