Duodenal atresia overview

# Overview
Duodenal atresia is the congenital absence or complete closure of a portion of the lumen of the duodenum. Intestinal atresia, including duodenal atresia, may be classified into four subtypes: Type I, Type II, Type III, and Type IV. Type I is the most common subtype which involves the complete mucosal membrane, with muscularis and serosa remaining intact. The prevalance of duodenal atresia is 0.1 to 0.4 per 100000. It commonly affects neonates and has a male to female ratio of 2 to 1. The symptoms of duodenal atresia usually develop in the first 48 hours of life, and start with symptoms such as bilious vomiting in 80% of the cases. Prognosis is generally very good, and the survival rate of patients with duodenal atresia is approximately 90%.

# Historical Perspective
In 1900, J. Tandler reported duodenal stenosis due to failure of recanalization of duodenum during fetal development in pregnancy. In 1961, Thomas Santulli and William Blanc described the figure 8 formation of small bowel, which is described as apple-peel intestinal atresia. In 1936, William Ladd developed a surgical procedure to correct the duodenal malrotation.

# Classification
Intestinal atresia, including duodenal atresia, may be classified into four subtypes: Type I, Type II, Type III, and Type IV. Type I is the most common subtype which involves the complete mucosal membrane, with muscularis and serosa remaining intact.

# Pathophysiology
It is thought that duodenal atresia is the result of failure of neural cell migration during the 8th to 10th week of duodenal re-canalization. It is associated with down syndrome, vertebral defects, anal anomalies, esophageal atresia, annular pancreas, malrotation, renal abnormalities, cardiac causes, and mandibulofacial anomalies.

# Causes
The cause of duodenal atresia has not been identified.

# Differentiating duodenal atresia from Other Diseases
Duodenal atresia must be differentiated from other diseases that cause persistent vomiting, and feeding difficulties, such as volvulus, jejuno-ileal atresia, malrotation, and meconium ileus. It is differentiated based on imaging.

# Epidemiology and Demographics
The prevalance of duodenal atresia is 0.1 to 0.4 per 100000. It commonly affects neonates and has a male to female ratio of 2 to 1.

# Risk Factors
The most potent risk factor in the development of duodenal atresia is down syndrome. Other risk factors include annular pancreas, and VACTERL syndrome.

# Screening
There is insufficient evidence to recommend routine screening for duodenal atresia. However, screening for down syndrome may show duodenal atresia during pregnancy.

# Natural History, Complications, and Prognosis
The symptoms of duodenal atresia usually develop in the first 48 hours of life, and start with symptoms such as bilious vomiting in 80% of the cases. Prognosis is generally very good, and the survival rate of patients with duodenal atresia is approximately 90%.

# Diagnosis

## Diagnostic Criteria
Duodenal atresia does not have a diagnostic study of choice. However, abdominal x-ray and ultrasound can confirm duodenal atresia.

## History and Symptoms
The hallmark of duodenal atresia is bilious emesis with in the first 48 hours of life. A positive history of persistent emesis and feeding difficulties is suggestive of duodenal atresia. The most common symptoms of duodenal atresia include bilious emesis, persistent emesis, and feeding difficulties.

## Physical Examination
Common physical examination findings of duodenal atresia include abdominal distension, dehydration, and restlessness.

## Laboratory Findings
Laboratory findings consistent with the diagnosis of duodenal atresia include polyhydramnios on prenatal ultrasound, hypokalemia, and hyperchloremia.

## Electrocardiogram
There are no ECG findings associated with duodenal atresia.

## X-ray
An abdominal x-ray may be helpful in the diagnosis of duodenal atresia. Findings on the abdominal x-ray diagnostic of duodenal atresia include double bubble sign which is indicative of gas present in the stomach and absent in the distal small intestine.

## Ultrasound
Ultrasound may be helpful in the diagnosis of duodenal atresia. Findings on ultrasound suggestive of duodenal atresia include polyhydramnios in pregnancy, and air fluid levels in the stomach with absent gas in the distal colon. Echocardiography can be performed to check for cardiac defect in infants with associated down syndrome.

## CT scan
The CT scan findings associated with duodenal atresia are similar to the abdominal x-ray and ultrasound findings.

## MRI
The MRI findings associated with duodenal atresia are similar to the abdominal x-ray and ultrasound findings.

## Other Imaging Findings
Barium swallow study can be performed post operatively in duodenal atresia to make sure there is no leak in the anastomosis.

## Other Diagnostic Studies
There are no other diagnostic studies associated with duodenal atresia.

# Treatment

## Medical Therapy
There is no medical treatment for duodenal atresia. Medical management to consider in duodenal atresia in preparation for surgery are orogastric decompression of the stomach, fluid resuscitation, broad-spectrum antibiotics, and vitamin K.

## Surgery
Surgery is the mainstay of treatment for duodenal atresia. A nasogastric or orogastric tube should be inserted to decompress the abdomen. A laparotomy or laparoscopy can be performed to correct duodenal atresia. Surgical procedures include duodenoduodenostomy, and duodenojejunostomy.

## Primary Prevention
There are no established measures for the primary prevention of duodenal atresia.

## Secondary Prevention
Effective measures for the secondary prevention of duodenal atresia include prenatal ultrasound, postnatal abdominal x-ray and ultrasound, and surgical repair.