Omphalocele
Encyclopedia
An omphalocele is a type of abdominal wall defect
in which the intestine
s, liver
, and occasionally other organ
s remain outside of the abdomen
in a sac because of a defect in the development of the muscles of the abdominal wall.
, protrudes in the midline, through the umbilicus
(navel).
It is normal for the intestines to protrude from the abdomen, into the umbilical cord, until about the tenth week of pregnancy
, after which they return to inside the fetal abdomen.
The omphalocele can be mild, with only a small loop of intestines present outside the abdomen, or severe, containing most of the abdominal organs. In severe cases surgical treatment
is made more difficult because the infant's abdomen is abnormally small because it had no need to expand to accommodate the developing organs.
The presence of an omphalocele is often associated with cardiac defects.
. Genetic counseling
and genetic testing
such as amniocentesis
is usually offered during the pregnancy.
(Trisomy 13).
is a similar birth defect, but in gastroschisis the umbilical cord is not involved and the lesion is usually to the right of midline. Parts of organs may be free in the amniotic fluid, and not enclosed in a membranous (peritoneal) sac. This condition is less commonly associated with other defects than omphalocele.
Other related syndromes are Pentalogy of Cantrell
, Beckwith-Wiedemann, and OEIS Complex.
Abdominal wall defect
An infant born with an abdominal wall defect has an abnormal opening on the abdomen. This often causes the intestines and other organs to form outside of the body.There are two main types of abdominal wall defects - omphalocele and gastroschisis....
in which the intestine
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
s, liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
, and occasionally other organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...
s remain outside of the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
in a sac because of a defect in the development of the muscles of the abdominal wall.
Presentation
The sac, which is formed from an outpouching of peritoneumPeritoneum
The peritoneum is the serous membrane that forms the lining of the abdominal cavity or the coelom — it covers most of the intra-abdominal organs — in amniotes and some invertebrates...
, protrudes in the midline, through the umbilicus
Navel
The navel is a scar on the abdomen caused when the umbilical cord is removed from a newborn baby...
(navel).
It is normal for the intestines to protrude from the abdomen, into the umbilical cord, until about the tenth week of pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
, after which they return to inside the fetal abdomen.
The omphalocele can be mild, with only a small loop of intestines present outside the abdomen, or severe, containing most of the abdominal organs. In severe cases surgical treatment
Abdominal surgery
The term abdominal surgery broadly covers surgical procedures that involve opening the abdomen. Surgery of each abdominal organ is dealt with separately in connection with the description of that organ Diseases affecting the abdominal cavity are dealt with generally under their own names The term...
is made more difficult because the infant's abdomen is abnormally small because it had no need to expand to accommodate the developing organs.
The presence of an omphalocele is often associated with cardiac defects.
Screening
An omphalocele is often detected through AFP screening or a detailed fetal ultrasoundUltrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
. Genetic counseling
Genetic counseling
Genetic counseling or traveling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning...
and genetic testing
Genetic testing
Genetic testing is among the newest and most sophisticated of techniques used to test for genetic disorders which involves direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene products as enzymes and other proteins and for microscopic...
such as amniocentesis
Amniocentesis
Amniocentesis is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for...
is usually offered during the pregnancy.
Causes
Some cases of omphalocele are believed to be due to an underlying genetic disorder, such as Edward's syndrome (Trisomy 18) or Patau SyndromePatau syndrome
Patau syndrome, also known as trisomy 13 and trisomy D, is a chromosomal abnormality, a syndrome in which a patient has an additional chromosome 13 due to a nondisjunction of chromosomes during meiosis. Some are caused by Robertsonian translocations...
(Trisomy 13).
Related conditions
GastroschisisGastroschisis
Gastroschisis represents a congenital defect characterized by a defect in the anterior abdominal wall through which the abdominal contents freely protrude. There is no overlying sac and the size of the defect is usually less than 4 cm...
is a similar birth defect, but in gastroschisis the umbilical cord is not involved and the lesion is usually to the right of midline. Parts of organs may be free in the amniotic fluid, and not enclosed in a membranous (peritoneal) sac. This condition is less commonly associated with other defects than omphalocele.
Other related syndromes are Pentalogy of Cantrell
Pentalogy of Cantrell
Pentalogy of Cantrell is a rare syndrome that causes defects involving the diaphragm, abdominal wall, pericardium, heart and lower sternum.It was characterized in 1958.An locus at Xq25-26 has been described....
, Beckwith-Wiedemann, and OEIS Complex.
External links
- The Brown Fetal Treatment Program - Providence, Rhode Island at Brown UniversityBrown UniversityBrown University is a private, Ivy League university located in Providence, Rhode Island, United States. Founded in 1764 prior to American independence from the British Empire as the College in the English Colony of Rhode Island and Providence Plantations early in the reign of King George III ,...
- Fetal Treatment Center: Omphalocele at UCSF