Abdominal wall defects are a type of

congenital defect A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...

that allows the stomach, the intestines, or other organs to protrude through an unusual opening that forms on the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

. During the development of the fetus, many unexpected changes occur inside the womb. Specifically, the stomach, intestines, or other organs begin to develop outside the fetus' abdomen through the abnormal hole in the abdomen and, as development progresses, the abdominal wall eventually encloses these organs. In some cases of defect either the umbilical opening is too oversized or has developed improperly which allows the organs to remain outside or to squeeze through the

abdominal wall In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls. There is a common set of layers covering and forming all the walls: the deepest being the ...

. There are two main types of abdominal wall defects that result due to the changes during development. They are

omphalocele Omphalocele or omphalocoele also called exomphalos, is a rare abdominal wall defect. Beginning at the 6th week of development, rapid elongation of the gut and increased liver size reduces intra abdominal space, which pushes intestinal loops out of ...

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 ba ...

. Gastroschisis develops when the abdominal wall does not completely close, and the organs are present outside of the infant's body. Omphalocele occurs when some of the organs protrude through the muscles of the abdomen in the area surrounding the umbilical cord. Omphalocele can be either minor, with only some of the organs exposed, or severe, with most, if not all of the abdominal organs being exposed.

Presentation

Complications

Concerns that arise due to abdominal wall defects can be threatening and require immediate and intensive medical care. Some infections may persist for long periods of time and lead to serious complications, such as feeding problems, which can cause the infant to require several surgeries. Since these complications can be severe, it is recommended that parents work closely with a team of physicians throughout the duration of the treatment. After the treatment is completed, children with abdominal wall defects may need additional help. Additional services are usually necessary for with omphalocele and the associated chromosomal abnormalities and birth defects that also arise. Treatments in these cases are long-term and focus on the physical and developmental difficulties that the children will endure. The parents may find this process difficult and need assistance in dealing with the process by a service that is provided by the healthcare team.

Cause

Out of all of the causes of birth defects information about a great number is still unknown. As of 2004, the reason that abdominal wall defects occur has yet to be determined or understood. The symptoms that the mother may present that would indicate the development of the defect and unnoticeable . Most cases of abdominal wall defects have been found to be sporadic and have no relationship with the history of the disorder within the family. Th
EPA is aware
that a common herbicide called

Atrazine Atrazine is a chlorinated herbicide of the triazine class. It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn), soybean and sugarcane and on turf, such as golf courses and residential lawns. Atrazine's primary manu ...

causes abdominal wall defects as well as other birth defects and cancer. Atrazine has been banned in the EU since 2004, yet is still commonly used in the US despite the evidence of harm. Atrazine affects the drinking water supply, most predominantly in the midwest. The Center for Disease Control and Prevention did a study on the relationship between Atrazine and abdominal wall defects: "Gastroschisis and omphalocele are congenital abdominal wall defects (AWD). Atrazine and nitrates are common agricultural fertilizers" and concluded: "Indiana has significantly higher rates of AWD bdominal wall defectscompared with national rates. Increased atrazine levels correlate with increased incidence of AWD."

Diagnosis

Before birth, openings in the abdomen can usually be detected by a detailed

ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...

AFP screening Alpha-fetoprotein (AFP, α-fetoprotein; also sometimes called alpha-1-fetoprotein, alpha-fetoglobulin, or alpha fetal protein) is a protein that in humans is encoded by the ''AFP'' gene. The ''AFP'' gene is located on the ''q'' arm of chromosome 4 ...

. In addition to the ultrasound or AFP scanning, it is also necessary for children with this defect to be checked for other birth defects because genetic disorders are usually associated with some of the abdominal wall defects. In looking for other genetic disorders that may be associated, Genetic counseling and further genetic testing, such as

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 n ...

, are offered.

Treatment

Abdominal wall defects can be treated surgically if there are no accompanying anomalies. The surgical procedure also called

repair/closure or

repair/closure is not overcomplicated. The organs are normal but are misplaced. However, if the abdominal cavity is too small or when the organs are too large or swollen to close the skin, it may be difficult to fit all the

viscera In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...

into the small abdominal cavity. In such cases, the surgeon will place a covering pouch generally made of

silastic Silastic (a portmanteau of 'silicone' and 'plastic') is a trademark registered in 1948 by Dow Corning Corporation for flexible, inert silicone elastomer. Composition The Silastic trademark refers to silicone elastomers, silicone tubing and some cr ...

, commonly called a ''silo'' (because it's shaped like an agricultural silo), over the abdominal organs on the outside of the infant.Abdominal Wall Defects
by Sajani Shah MD, at M&M Conference at

SUNY Downstate Medical Center SUNY Downstate Health Sciences University (Downstate) is a public medical school and hospital in Brooklyn, New York. It is the southernmost member of the State University of New York (SUNY) system and the only academic medical center for hea ...

. Feb 24, 2006. The silo serves to conserve heat and prevent infection. The silo is spring-loaded so that the device can be attached to the inside of the abdominal wall without sutures. The top of the silo is secured in a way that causes it to stand upright, so that the bowels are gradually coaxed into the abdominal cavity by gravity. This process can take up to a week, and final closure may be performed a few weeks later. More surgery may be required to repair the abdominal muscles at a later time.

Prognosis

If there are no other defects, the prognosis after surgical repair of this condition is relatively good. However, 10% of those with more severe or additional abnormalities die from it. The organs themselves are fully functional; the difficulty lies in fitting them inside the abdomen. The condition is, in fact, a

hernia A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. Groin herni ...

requiring only replacement and strengthening of the passageway through which it occurred. After surgery, increased pressure in the stretched abdomen can compromise the function of the organs inside.

Incidence

Abdominal wall defects, specifically the main two types, gastroschisis and omphalocele, are rare, occurring in about one out of every 5000 births. There is no difference in prevalence between boys and girls. Birthing individuals who are below the age of twenty are almost four times as likely to have an offspring that has developed an abdominal wall defect compared to those in their late twenties and older.

References

External links

{{Congenital abdominal wall defects Congenital disorders of musculoskeletal system