Intestinal atresia is any

congenital A birth defect is an abnormal condition that is present at childbirth, birth, regardless of its cause. Birth defects may result in disability, disabilities that may be physical disability, physical, intellectual disability, intellectual, or dev ...

malformation of the structure of the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

that causes

bowel obstruction Bowel obstruction, also known as intestinal obstruction, is a mechanical or Ileus, functional obstruction of the Gastrointestinal tract#Lower gastrointestinal tract, intestines which prevents the normal movement of the products of digestion. Ei ...

. The malformation can be a narrowing (

stenosis Stenosis () is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). ''Stricture'' as a term is usually used when narrowing ...

), absence or

malrotation Intestinal malrotation is a congenital anomaly of rotation of the midgut. It occurs during the first trimester as the fetal gut undergoes a complex series of growth and development. Malrotation can lead to a dangerous complication called volvulus, ...

of a portion of the intestine. These defects can either occur in the

small Small means of insignificant size Size in general is the Magnitude (mathematics), magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to three geometrical measures: length, area, or ...

large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the Digestion, digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces befor ...

Symptoms and signs

The most prominent symptom of intestinal atresia is

bilious Bile (from Latin ''bilis''), also known as gall, is a yellow-green/misty green fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is primarily composed of water, is produced ...

vomiting soon after birth. This is most common in

jejunal The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialized for the absorption by enterocytes of small nutrient molecules which have been previo ...

atresia. Other features include abdominal distension and failure to pass

meconium Meconium is the earliest stool of a mammalian infant resulting from defecation. Unlike later feces, meconium is composed of materials ingested during the time the infant spends in the uterus: intestinal epithelial cells, lanugo, mucus, am ...

. The distension is more generalised the further down the bowel the atresia is located and is thus most prominent with ileal atresia. Inability to pass stool is most common with

duodenal The duodenum is the first section of the small intestine in most vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest p ...

or jejunal atresia; if stool is passed, it may be small, mucus-like and grey. Occasionally, there may be

jaundice Jaundice, also known as icterus, is a yellowish or, less frequently, greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving ...

, which is most common in jejunal atresia. Abdominal tenderness or an abdominal mass are not generally seen as symptoms of intestinal atresia. Rather, abdominal tenderness is a symptom of the late complication meconium peritonitis. Before birth, excess amniotic fluid (

polyhydramnios Polyhydramnios is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in about 1% of pregnancies. It is typically diagnosed when the amniotic fluid index (AFI) is greater than 24 cm. There are two clini ...

) is a possible symptom. This is more common in duodenal and

oesophageal atresia Esophageal atresia is a congenital medical condition (birth defect) that affects the alimentary tract. It causes the esophagus to end in a blind-ended pouch rather than connecting normally to the stomach. It comprises a variety of congenital anat ...

Cause

The most common cause of non-duodenal intestinal atresia is a vascular accident

in utero The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more fertilized eggs until bir ...

that leads to decreased intestinal

perfusion Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ (anatomy), organ or a tissue (biology), tissue, usually referring to the delivery of blood to a capillary bed in tissue. Perfusion may also refer t ...

and

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

of the respective segment of bowel. This leads to narrowing, or in the most severe cases, complete obliteration of the intestinal lumen. In the case that the

superior mesenteric artery In human anatomy, the superior mesenteric artery (SMA) is an artery which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the ...

, or another major intestinal

artery An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

, is occluded, large segments of bowel can be entirely underdeveloped (Type III). Classically, the affected area of bowel assumes a spiral configuration and is described to have an "apple peel" like appearance; this is accompanied by lack of a dorsal mesentery (Type IIIb). An inherited form – familial multiple intestinal atresia – has also been described. This disorder was first reported in 1971. It is due to a mutation in the gene TTC7A on short arm of

chromosome 2 Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 million base pairs and representing almost ei ...

(2p16). It is inherited as an autosomal recessive gene and is usually fatal in infancy. Ileal atresia can also result as a complication of

ileus. A third of infants with intestinal atresia are born prematurely or with

low birth weight Low birth weight (LBW) is defined by the World Health Organization as a birth weight of an infant of or less, regardless of gestational age. Infants born with LBW have added health risks which require close management, often in a neonatal inten ...

Diagnosis

Intestinal atresias are often discovered before birth; either during a routine sonogram which shows a dilated intestinal segment due to the blockage, or by the development of

(the buildup of too much amniotic fluid in the uterus). These abnormalities are indications that the fetus may have a bowel obstruction which a more detailed ultrasound study can confirm. Infants with stenosis instead of atresia are often not discovered until several days after birth. Some fetuses with bowel obstruction have abnormal chromosomes. An

amniocentesis Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is ...

is recommended because it can determine not only the sex of the baby, but whether or not there is a problem with the chromosomes. If not diagnosed ''in utero'', infants with intestinal atresia are typically diagnosed at day 1 or day 2 after presenting with eating problems, vomiting, and/or failure to have a bowel movement. Diagnosis can be confirmed with an X-ray, and typically followed with an

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 bariu ...

lower gastrointestinal series A lower gastrointestinal series is a medical procedure used to examine and diagnose problems with the human colon of the large intestine. Radiographs (X-ray pictures) are taken while barium sulfate, a radiocontrast agent, fills the colon via ...

, and ultrasound.

Classification

By location

Intestinal atresia may be classified by its location. Patients may have intestinal atresia in multiple locations. *

Duodenal atresia Duodenal atresia is the congenital absence or complete closure of a portion of the lumen (anatomy), lumen of the duodenum. It causes increased levels of amniotic fluid during pregnancy (polyhydramnios) and intestinal obstruction in newborn babies. ...

– malformation of the

duodenum The duodenum is the first section of the small intestine in most vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest p ...

, part of the intestine that empties from the stomach, and first section of the small intestine * Jejunal atresia – malformation of the

jejunum The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialized for the absorption by enterocytes of small nutrient molecules which have been pr ...

, the second part of the small intestine extending from the duodenum to the ileum, that causes the jejunum to block blood flow to the colon * Ileal atresia – malformation of the

ileum The ileum () is the final 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 posterior intestine or distal intestine may ...

, the lower part of the small intestine * Colon atresia – malformation of the colon Malformations may also occur along multiple portions of the intestinal tract; for instance a malformation that occurs along or spans the length of the jejunum and the ileum is termed jejunoileal atresia.

By malformation

Intestinal atresia can also by classified by the type of malformation. The classification system by Bland-Sutton and Louw and Barnard (1955) initially divided them into three types. This was later expanded to five by Zerella and Grosfeld et al.

= Type I

= In type I, there is a wall (

septum In biology, a septum (Latin language, Latin for ''something that encloses''; septa) is a wall, dividing a Body cavity, cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Hum ...

) or membrane at some point in the bowel, leading to dilation of the bowel on the nearer side and a collapse of the bowel on the latter side. Bowel length is not usually affected in this type.

= Type II

= In type II, there is a gap in the bowel, and either end of the remaining intestine is closed off and connected to the other by a fibrous cord that runs along the edge of the

mesentery In human anatomy, the mesentery is an Organ (anatomy), organ that attaches the intestines to the posterior abdominal wall, consisting of a double fold of the peritoneum. It helps (among other functions) in storing Adipose tissue, fat and allowi ...

. The mesentery remains intact.

= Type IIIa

= Type IIIa is similar to type II, but the mesentery is defective (there is a V-shaped gap), and the bowel length may be shortened.

= Type IIIb

= In type IIIb, also known as the "apple peel" or "Christmas tree" deformity, the atresia affects the jejunum, and the intestine is often malrotated with most of the mesenteric arteries absent. The remaining ileum, which is of varying length, survives on a single mesenteric artery, which it is twisted around in a spiral form. The term apple-peel intestinal atresia is generally reserved for when it affects the jejunum, while Christmas tree intestinal atresia is used if it affects the duodenum. It may affect both, however.

= Type IV

= Type IV involves a combination of all the other types and takes the appearance of a string of sausages. The length of the bowel is always shortened, but the last part of the ileum is usually not affected, as in type III. This type usually affects the nearest end of the jejunum, but the far end of the ileum may instead be affected.

Treatment

Fetal and neonatal intestinal atresia are treated using

laparotomy A laparotomy is a surgical procedure involving a surgical incision through the abdominal wall to gain access into the abdominal cavity. It is also known as a celiotomy. Origins and history The first successful laparotomy was performed without ...

after birth. If the area affected is small, the surgeon may be able to remove the damaged portion and join the intestine back together. In instances where the narrowing is longer, or the area is damaged and cannot be used for period of time, a temporary

stoma In botany, a stoma (: stomata, from Greek language, Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the Epidermis (botany), epidermis of leaves, stems, and other organs, that controls the rate of gas exc ...

may be placed. The infant is usually given intravenous fluid hydration, and a nasogastric or orogastric tube may be used to aspirate the contents of the stomach. The nutritional administration is maintained after surgery until the bowel can resume normal function.

Prognosis

Mekoniumzyste bei terminaler Ileumatresie - Roe 001

Prognosis is usually good if treated with surgery in infancy. The main factor in mortality is the availability of care and appropriate

parenteral nutrition Parenteral nutrition (PN), or intravenous feeding, is the feeding of nutritional products to a person intravenously, bypassing the usual process of eating and digestion. The products are made by pharmaceutical compounding entities or standard ph ...

after surgery until the bowel can resume normal function. The most common complication is pseudo-obstruction at the site of surgery due to pre-existing intestinal dysmotility. This can usually only be treated by non-surgical methods. If the atresia is not treated, the bowel may become

perforated A perforation is a small hole in a thin material or web. There is usually more than one perforation in an organized fashion, where all of the holes collectively are called a ''perforation''. The process of creating perforations is called perfor ...

ischemic Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

. This can lead to abdominal tenderness and meconium peritonitis, which can be fatal.

Epidemiology

Intestinal atresia occurs in around 1 in 3,000 births in the United States. The most common form of intestinal atresia is duodenal atresia. It has a strong association with Down syndrome. The second-most common type is ileal atresia. 95% of congenital jejunoileal obstructions are atresias; only 5% are stenoses. Prevalence of jejunoileal atresia is 1 to 3 in 10,000 live births. It is weakly associated with

cystic fibrosis Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that impairs the normal clearance of Sputum, mucus from the lungs, which facilitates the colonization and infection of the lungs by bacteria, notably ''Staphy ...

intestinal malrotation Intestinal malrotation is a congenital anomaly of rotation of the midgut. It occurs during the first trimester as the fetal gut undergoes a complex series of growth and development. Malrotation can lead to a dangerous complication called volvulus, ...

, and

gastroschisis Gastroschisis is a birth defect in which the baby's intestines extend outside of the abdomen through a hole next to the belly button. The size of the hole is variable, and other organs including the stomach and liver may also occur outside the b ...

. The frequencies of each type from Louw and Barnard's classification are as follows: * Type I: 19–23% of cases (mean: 20.6%) * Type II:10–35% of cases (mean: 25.3%) * Type IIIa: 15%–46% of cases (mean: 30%) * Type IIIb ("apple-peel" type): 4–19% of cases (mean: 8.8%) * Type IV: 6–32% of cases (mean: 15.9%). (Note: the mean percentages total higher than 100% due to rounding.)

History

Ileal atresia was first described in 1684 by Goeller. In 1812,

Johann Friedrich Meckel Johann Friedrich Meckel (17 October 1781 – 31 October 1833), often referred to as Johann Friedrich Meckel, the Younger, was a German anatomist born in Halle. He worked as a professor of anatomy, pathology and zoology at the University of Halle, ...

reviewed the topic and speculated on an explanation. In 1889, English surgeon John Bland-Sutton proposed a classification system for intestinal atresia and suggested that it occurs at areas that are obliterated as part of normal development. In 1900, Austrian physician Julius Tandler first put forward the theory that it may be caused by lack of recanalisation during development. The vascular ischemic cause of non-duodenal atresia was confirmed by Louw and Barnard in 1955 and was repeated in later studies. It had first been proposed by N. I. Spriggs in 1912.

References

External links

{{Congenital malformations and deformations of digestive system Congenital disorders of digestive system Rare diseases