chapter 61-Anterior Abdominal Wall Flashcards
What are the two most common anterior abdominal wall defects?
Omphalocele and gastroschisis
What are the less common abdominal wall defect?
ectopia cordis, limb-body somplex and cloacal exstrophy
At what week gestation is the embryo flat disk like?
5th week
when the embryo is flat disk like what are the three layers it consist of?
- ectoderm
- mesoderm
- endoderm
In the 6th week what is the process called that helps the embryo transform itself into a cylindrical shape?
the folding process
what week of development does the umbilical herniation of the bowel occur?
8th week
What causes the midgut to grow faster than the abdominal cavity early in development?
increased size of the liver and kidney and herniation develops
What week gestation does the intestines return to the abdominal cavity?
12 th week
what transformation is the critical part of the process of closing the abdominal wall?
intestines to return to abdominal cavity
The growth of the neural tube causes what?
it causes the embryo to fold at the caudal end, incorporating part of the yolk sac as the hindgut.
what does the hindgut turn into?
cloaca
what weeks does the fetal bowel normally migrates into the umbilical cord from the abdominal cavity.
8th to 12th week
Normal embryologic herniation of the bowel permits the development of?
the intrabdominal organ and allow necessary bowel rotation
herniation permits the bowel to ?
rotate around the superior mesenteric artery
Because of the lack of space within the abdominal cavity and the large feta liver and kidneys, this forces the bowel?
from the abdomen and into the extraembryonic coelom of the umbilical cord
It is important to image ________ and________ to evaluate for the presence of absence of defects.
cord insertion and anterior abdominal wall
What questions should be asked when evaluating the abdominal wall?
- is a limiting membrane present
- What is the relation of the umbilical cord to the defect?
- Which organs are involved?
- Is the bowel normal in appearance?
- Are other fetal malformations evident?
What are the tree most common abdominal wall defects?
- omphalocele
- gastroschisis
- umbilical hernia
The incidence of omphaloceles is roughly ___ in ______ live births
1 in 4000
when does omphalocele develop?
when there is a midline defect of the abdominal muscles, fascia and skin that results in herniation of the intrabdominal structures into the base of the umbilical cord
Omphalocele is cover by a membrane that consist of?
amnion and peritoneum
With omphalocele ____ level might be slightly _____ or within _____ _____
AFP; elevated; normal limits
Omphaloceles are characterized as what two types?
- Those that contain the liver within the sac
2. Those that contain a variable amount of bowel without liver
sonographic signs of omphalocele:
- central abdominal wall defect with evisceration of the bowel or a combination of liver and bowel into the base of the umbilical cord
- Membrane consisting of the peritoneum and amnion forms the omphalocele sac
- A normal cord instertion suggest hernia
_________ is found in 1/3 or fetuses with omphalocele
hydramnios
What are the associated anomalies of omphalocele?
- complex cardiac disease
- gastro intestional
- neural tube
- genirourinary tract (polycystic kidneys with a small omphalocele may indicate trisomy 13)
Omphalocele may occur concurrently with?
diaphragmatic hernia
when omphalocele with scoliosis is found consider ?
limb body wall complex
What is limb body wall complex?
a letal disorder which includes severe cranial defects, facial clefts, extensive abdominal wall defect of the chest, and abdomen and limb defects
Amniotic band syndrome may represent?
milder form of limb body wall complex and be predicted by amniotic band that entangle or amputate fetal parts
When organomegaly and macroglossia are observed. What else is suspected?
Beckwith-Wiedemann syndrome
When a low omphalocele is observed consider?
bladder or cloacal exstrophy
what is considered when a large omphalocele, diaphragmatic hernia, ectopia cordis and other heart defects are observed?
Pentalogy of Cantrell
What is gastroschisis?
an opening in the layers of the abdominal wall with evisceration of the bowel and infrequently,k the stomach and genitourinary organs but rarely the liver
Gastroschisis is a periumbilical defect that nearly always is located to the ______ of the ________
right; umbilicua
It is thought that gastroschisis is a consequence of?
atrophy of the right umbilical vein or a disruption of the omphalomesenteric artery
Where are gastroschisis defects located?
small and are located next to the normal cord insertion
T or F The insertion of the umbilical cord is normal in fetuses with gastroschisis
True
T or F small bowel is always found in the herniation
True
What other organs are involved with gastroschisis?
large bowel, stomach, genitourinary and rarely liver
AFP levels are significantly _______ in gastro. comparted with imphalocele because of ___________.
higher; exposed bowel
T or F Gastroschisis is found more in women
False; men
Ischemia with gastroschisis may cause?
bowel perforation or meconium peritonitis
What % of infants die when diagnosed with gastroschisis in which ischemia and gangrene of the bowel were present?
50
How should the infant be delivered with gastroschisis and why?
cesarean to prevent bowel damage and contamination from vaginal deliver
What is the prognosis for the infant with uncomplicated gastoschisis?
Excellent
Sonographer may be able to detect gastroschisis after _____ weeks of gestation?
12
Sonographic finding of gastroschisis
- cord normally inserted into abdominal wall, defect always to the right of cord insertion
- edges of bowel are irregular and free floating w/o covered membrane
- multiple loops of bowel may be seen outside the abd. cavity in the area of the cord
Sono. appearance of gastroschisis
- Right paraumbilical defect of abdominal wall, rarely a left side defect
- free floating herniated small bowel, large bowel, stomach, gallbladder, urinary bladder, and pelvic organs may be involved. (when organs other thatn small or large bowel are seen, body stalk anomalies should be suspected
A herniated bowel may be mildly dilated with?
bowel wall thickening
Notably dilated bowel may suggest?
infarction or bowel atresia
what is amniotic band syndrome?
rupture of the amnion, which leads to entrapment or entanglement of the fetal parts by the sticky chorion
Early entrapment by amniotic bands may lead to ?
severe craniofacial defects and internal malformation
Late amniotic band entrapment may lead to?
amputation or limb restriction
What is beckwith-wiedemann syndrome?
a rare group of disorder having in common the coexistence of omphalocele, macroglassia, and visceromegaly
Sono finding of Beckwith-Widedmann syndrome?
presence of omphalocele, growth acceleration, macroglossia dn visceromegaly
With B. W. syndrome what may be present in the third trimester?
polyhydramnios
Bladder exstrophy is characterized by?
a defect in the lower abdominal wall and anterior wall of the urinary bladder
Bladder exstrophy anomaly may be ____ or _____
mild or severe
In bladder exstrophy the everted bladder becomes exposed on?
the lower abdominal wall
T of F ; With bladder extrophy, the normal urinary bladder is not visible upon sono. evaluation
True
Pentalogy of Cantrell is rare and is the association of?
- a cleft or defect in the distal sternum
- diaphragmatic defect
- midline anterior ventral wall defect (most often omphalocele)
- defect of the apical pericardium with communication intothe peritoneum
- ectopic heart
What is the usual primary findings of Pentalogy of Cantrell?
high or superumbilical omphalocele
What happens if a diaphragmatic defect is large enough to produce a diaphragmatic hernia?
displacement of the heart and mediastinum should be observed, but the sternal and pericardial defects are not well seen
the exposed heart present outside the chest wall through a cleft sternum?
ectopia cordis
What is the most dramatic finding of ectopic cordis?
heart outside the thoracic cavity; a portion of all the heart may protrude through the defect in the sternum
what is a cleft sternum?
partial or absent wouthout ectopia cordis, and is typically a superior or total cleft
In cleft sternum; dramatic pulsations of the anterior chest wall occur from the heart beating against the ________ without the presence of the __________ to protect it.
chest, sternum
sonographic appearance of PoC; ectopic cordis and cleft sternum;
heart may be seen to lie outside the normal thoracic cavity or bulge through the defective sternum
-common to see pericardian and pleural effusion
-
what is limb body wall complex?
associated with large cranial defects; facial cleft; body wall complex defects involving the thorax, abdomen, or both; and limb defect
left side body wall defects are _____ times more common than right side defects
3
what are some other anomalies with limb body wall complex?
scoliosis and various internal malformations
Limb body wall complex occurs with the fusion of ?
amnion and chorion
