Generality
The omphalocele is a congenital anatomical defect, marked by the failed closure of the abdomen and the consequent protrusion, through an opening at the umbilical level, of one or more abdominal organs (intestine, liver, stomach, spleen etc.).
From: //en.wikipedia.org/wiki/Omphalocele
In a more than fair number of cases, the omphalocele represents a clinical sign of specific chromosomal alterations, such as those that induce trisomy 13 or trisomy 18.Furthermore, the correlation between omphalocele and congenital defects of the heart and / or neural tube is frequent.
Doctors can diagnose the omphalocele already during prenatal life, by means of some special tests.
The only viable therapy is a surgical one and consists of the reintegration of the extra-abdominal organs into their ideal cavity.
What is the omphalocele?
The omphalocele is a congenital defect of the abdominal wall, characterized by the protrusion, through a more or less wide opening at the umbilical level, of the main organs of the abdomen (ie liver, intestine, stomach etc.).
Generally, around these protruded organs, there is a thin and transparent serous membrane, very similar to a sack, which derives from an exfoliation of the peritoneum . This bag is usually intact.
According to the doctors, the confalocele is a particular type of hernia .
A hernia is the outflow of a bowel, or part of it, from the cavity that normally contains it (NB: the word viscera indicates a generic internal organ).
Causes
Short introduction: in normal conditions, up to about the tenth (X) week of pregnancy, the fetus's intestine resides outside the abdomen, just outside the navel. Afterwards, the abdominal cavity absorbs it, through a process of fusion of the abdominal muscular wall.
At the origin of the omphalocele there is a wrong development, during fetal life, of the abdominal muscles. These elements, in fact, rather than merge with each other and absorb the intestine, remain separate and give rise to a real opening on the belly.
As the pregnancy continues and the size of the fetus enlarges, even abdominal organs such as the stomach or liver gradually tend to protrude and find themselves, in a completely abnormal way, outside the abdomen.
As we will see, there are cases of omphalocele more serious than others.
ONFALOCELE AND CHROMOSOMIC ANOMALIES
In a fair number of cases (approximately 15%), the unbalanced coincides with the presence of some specific chromosomal anomalies .
Chromosomal abnormalities are serious genetic conditions, characterized by numerical and sometimes even structural alterations of chromosomes, ie the cellular elements in which DNA resides.
This coincidence has led doctors and experts to believe that the two circumstances are closely connected with each other, with the unclear to represent a clinical manifestation of the present chromosomal anomaly.
The chromosomal anomalies that most frequently determine, in those who carry them, the presence of omphalocele are trisomy 18 (or Edwards syndrome ), trisomy 13 (or Patau syndrome ) and Beckwith-Wiedemann syndrome .
What are trisomy 18 and trisomy 13? Some details
Geneticists speak of trisomy when the genetic makeup of an individual has three chromosomes of the same type, that is a triad of homologous chromosomes, rather than a pair (as it normally should be). Therefore, if the total number of chromosomes in every single cell of a healthy person is 46, the total number of chromosomes in every single cell of a person with trisomy is 47.
Trisomies are part of those genetic anomalies known as aneuploidies, that is, variations in the chromosome number.
Trisomy 18 and trisomy 13 carriers have three copies of the autosomal chromosome 18 and three copies of the autosomal chromosome 13, respectively.
In both cases, their health conditions are very serious and often incompatible with life. In fact, if death did not take place already in prenatal age, it is very likely to come shortly after birth.
Both trisomy 18 and trisomy 13 are responsible for characteristic physical alterations (especially at the facial level) and include, as the only known risk factor, the advanced age of the mother.
Epidemiology
According to some estimates by the US Center for Disease Prevention and Control (CDC), in the United States, the annual frequency of the omalocele is 2-2.5 cases per 10, 000 new births.
Still according to the same research, the mortality rate linked to this abdominal wall defect would be about 25%.
Symptoms and Complications
To learn more: Omphalocele symptoms
The characteristic sign of the ompalocele is the extra-abdominal (ie external to the abdomen) presence of the organs that normally should be inside the abdominal cavity.
Not all omphaloceles are serious in equal measure. Their severity depends on the size of the opening on the abdomen and how many organs protrude outside it.
Therefore, the doctors consider a small (or of contained gravity) an omphalocele characterized by the protrusion of the intestine alone; while they consider a large (or high gravity) an omphalocele characterized by the protrusion of the intestine, the liver, the spleen etc.
OTHER SIGNS
Often, the abdominal cavity of children with omphalocele is much smaller than it actually should be. As will be seen in the chapter on therapy, this represents a problem when the doctor intervenes surgically.
COMPLICATIONS
Being in fact deprived of protection (NB: the peritoneum does not provide a particularly efficient defense), the abdominal organs that are outside the belly can:
- Easily develop an infection. Infections are particularly frequent when the peritoneum is broken.
- Easily receive pinches or backfires. All this can damage the affected organ and cause a huge and very dangerous leakage of blood.
ASSOCIATED DEFECTS
Often, children with omphalocele are born with heart defects and neural tube defects (ie the embryonic structure from which the central nervous system originates).
These alterations can be the result of the associated chromosomal anomalies, described above, or of other causes, in many cases, unknown.
The simultaneous presence of omphalocele and other defects in other systems or systems reflects a very serious, deadly health condition within a few days (if not also in the prenatal phase).
| Percentage of cases of omphalocele with heart defects and neural tube defects. | |
Type of defect | Percentage |
| Congenital heart defects Congenital neural tube defects | 50% 40% |
Diagnosis
At birth, the diagnosis of omphalocele is quite simple. The newborn, in fact, presents clear and unequivocal signs.
In the prenatal phase, on the other hand, doctors may notice the presence of the abdominal defect through a normal ultrasound scan.
In these situations, the ultrasound examination must be followed by more thorough checks, which serve to establish the gravity and characteristics of the omphalocele, any other congenital anomalies and the chromosomal structure of the fetus.
To clarify all these aspects, the doctors resort to:
- Level II ultrasound
- Fetal echocardiography
- Amniocentesis and / or fetal karyotype
LEVEL ECOGRAPHY
Level II ultrasound is a more precise examination of simple prenatal ultrasound (level I ultrasound). In fact, it provides very clear images of the fetal organs (and their possible anomalies) and allows to understand how the development of the fetus is proceeding inside the uterus.
FETAL ECOCARDIOGRAPHY
Fetal echocardiography is a normal ultrasound of the heart, which allows us to analyze the anatomy, function and rhythm of the heart of the fetus. Therefore, it is useful to clarify if the newborn has cardiac alterations associated with the unbalanced.
Its execution belongs to a doctor specialized in fetal and pediatric cardiology.
AMNIOCENTESIS
Amniocentesis consists in the collection, by transabdominal route, of a small amount of amniotic fluid.
Contained inside a bag (amnios or amniotic sac), the amniotic fluid is the fluid that surrounds and protects the fetus during its uterine development.
After collection (NB: in general, doctors practice amniocentesis between the 16th and 18th week of pregnancy), the analysis laboratory carries out various tests on the sample obtained, including a check of the chromosome kit.
Therefore, amniocentesis allows us to understand if the omphalocele is associated with some particular chromosomal alterations.
FETAL CARIOTYPE
The fetal karyotype is an evaluation test of the chromosomal outfit of the highly specific fetus (NB: higher grade than amniocentesis), which allows to accurately probe all the chromosomes of a collected cell sample.
This makes it possible to identify the smallest chromosomal alterations, which a less precise examination, such as amniocentesis, is not always able to identify.
IN CASE OF PRENATAL DIAGNOSIS
If the diagnosis of omphalocele occurs in the prenatal phase, the mother must undergo periodic monitoring, through which the doctor observes the progress of the pregnancy.
It is not excluded that the unbalanced regress spontaneously during gestation.
Treatment
The treatment of the omphalocele is exclusively of a surgical type and has the final purpose of reinserting the organs that reside outside it inside the abdomen.
The possibility of applying this therapy depends mainly on two factors:
- The gravity of the unbalanced . The more serious it is, the more difficult the intervention.
- Congenital anomalies that accompany the omphalocele . The more and more serious they are, the more care and attention they need to pay to the little patient.
ONFALOCELE OF SLIGHT AND ISOLATED GRAVITY
If the omphalocele is small (for example, when only the intestine is outside the abdomen) and is not associated with other diseases, doctors are likely to successfully complete the reintegration procedure.
In general, the operation is never immediate, but always occurs after a short period of time after birth. During this time, the surgeon who will operate the child will cover the deflex with a special synthetic material.
From the executive point of view, the intervention is quite delicate and requires considerable competence and experience on the part of the entire medical staff.
Reasons for good chances of success
Re-inserting an organ only is simpler than reinserting two or more.
Furthermore, infants with mild omphalocele often have an abdominal cavity of normal size and not smaller than normal. Thanks to this, the feasibility of the operation is greater.
SERIOUS ONFALOCELE AND VERY SERIOUS
If the omphalocele is severe or very serious, because associated with other congenital defects, doctors generally have little chance of successfully treating (or even simply intervening on) the protrusion of the abdominal organs.
The reasons are different. First of all, most of the newborns in this state have a very small abdominal cavity, which does not guarantee the space that the extra-abdominal organs need. Secondly, congenital defects, such as congenital anomalies, are situations that make it contraindicated to perform a surgical operation.
Sometimes, it may happen that there are no bases for operating only in the first years of life. In these circumstances, the doctors choose to postpone the intervention to childhood, in the hope that in the meantime the abdomen will expand its internal space.
What is the type of birth in case of severe or very serious omphalocele?
In the case of severe or very serious omphalocele, the doctors resort to a delivery by cesarean section, because it is less dangerous for both the mother and the fetus.
Prognosis
According to what was said in the previous chapter dedicated to therapy, the prognosis of the omphalocele depends on its severity and the associated diseases.
