chapter 63 fetal abdomen Flashcards
fetal organs are well formed by the ___
2nd trimester
forms when intestines return normally to abdominal cavity & herniate either prenatally or postnatally through an inadequately closed umbilicus
umbilical hernia
how does a hernia differ from omphalocele?
hernia is covered by subcutaneous tissue & skin, omphalocele is only covered by subcutaneous tissue.
most common malformation of the midgut
meckel’s diverticulum
usually a small finger-like sac about 5cm long, projects from the border of the ileum
meckel’s diverticulum
remnant of the proximal part of the yolk sac that fails to degenerate and disappear during the early fetal period
meckel’s diverticulum
most fetuses older than ____ should have fluid in their stomach
16 weeks
if fluid is not seen in the stomach, the stomach should be reevaluated in ______
20-30 minutes
if an echogenic mass is seen in the fetal stomach, in a patient with clinical or sonographic evidence of an abruption, this could possibly be:
a hematoma associated with intraamniotic hemorrhage
normal esophagus can be visualized in the thorax during the :
2nd and 3rd trimesters
visualization of the umbilical cord site must be made to rule out:
- omphalocele
- gastroschisis
- hernia
- mass formation
after birth the umbilical vein collapses and forms the _____
ligamentum teres
because the fetus is capable of swallowing sufficient amounts of amniotic fluid in the 1st trimester, the stomach may be visualized by approximately ____
11-weeks
meconium begins to accumulate in the distal part of the small intestine after ____
15-16 weeks
distinction of large bowel from small bowel is possible after ____
20 weeks
small bowel is slightly ______ compared to the liver
hyperechoic
after _____, normal peristalsis is increasingly observed
27 weeks
colon can be identified at the:
end of the 2nd trimester
colon appears:
long, tubular, hypoechoic structure with well-defined walls
colon does/doesn’t have peristalsis like small bowel:
doesn’t
after 14 weeks, meconium appears ____ compared to fetal liver
hypoechoic
Meconium ____ in echogenicity closer to term
increases
liver ____ in fetuses with Rh-isoimmunization
enlarges due to increased production of blood(hematopoiesis)
sonographically, most liver tumors appear
solid and hypoechoic
about ___% of benign and malignant liver tumors are calcified
5%
reversal of thoracic and abdominal organs
situs inversus
prognosis in patients with total situs inversus
good/normal
prognosis of patients with partial situs inversus
high mortality rate
partial situs inversus is diveded into:
Aspenia
Polysplenia
partial situs inversus: Asplenia:
- absent spleen
- stomach and galbladder are more midline
- liver is more central
- abnormal positioning of aorta/IVC on same side
partial situs inversus: Asplenia mortality rate:
95%
partial situs inversus: Polysplenia:
- absent gallbladder
- interuption of IVC
- more than one spleen, located along greater curvature of stomach(right side)
partial situs inversus: Polysplenia mortality rate:
80%
cardiac malformations occur ____% in asplenia
99%
cardiac malformations occur ____% in polysplenia
90%
true ascites is seen within the ____ and in the spaces between _____
peritoneal recesses
small bowel loops
true ascites outlines the ___
falciform ligament
sonolucent band near the fetal anterior abdominal wall, is commonly seen in routine OB exams over 18 weeks
psuedoascites
pseudoascites never outlines the ____
falciform ligament
agenesis of the gallbladder occurs in approximately ___% of patients with biliary atresisa
20%
spleen may _____ in fetuses with Rh-isoimmunization
enlarge
GI malformations are important to detect before birth to help prevent:
- dehydration
- bowel necrosis
- respiratory difficulties
develops when portion of bowel grows, infarcts, and then doesn’t develop completely(GI)
atresia
bowel loops above the atresia ____
enlarge
bowel loops below the atresia ____
narrow
atresia results in
hydramnios
congenital blockage of the espophagus
esophageal atresia
results from faulty separation of the foregut into its respiratory & digestive components
esophageal atresia
esophageal atresia most commonly occurs with ____
fistula/tracheoesophageal fistula
combination of ____ and _____ over repeated exams suggest esophageal atresia
polyhydramnios and absent stomach
most common anomaly seen with esophageal atresia:
anorectal atresia
blockage of duodenal lumen by a membrane:
duodenal atresia
amniotic fluid fails to move past the obstruction in the duodenum and backs up into the duodenum and stomach. This creates the ____ sign
double-bubble sign
duodenal atresia often exists with _____ pancreas
annular pancreas
which trisomy is associated with duodenal atresia?
trisomy 21
AFP is _____ due to faulty swallowing in duodenal atresia
elevated
double-bubble sign most commonly results from:
duodenal atresia
atresia of the ____ or _____, or both, is slightly more common than duodenal atresia
jejunum or ileum
atresia of the jejunum/ileum is most often caused by
vascular accident
blockage of the jejunum and ileum appears as:
multiple cystic structures proximal to the cite of atresia
the more distal the obstruction(bowel) the ___ severe the hydramnios
less
the dilated bowel loops can be isolated, or associated with other anomalies:
- ascites
- meconium peritonitis
this is the earliest manifestation of cystic fibrosis
meconium ileus
presence of thick overproduced meconium in the distal ileum
meconium ileus
meconium ileus sonographically appears:
tiny echogenic reflections in the peristalsic small bowel
other conditions, besides meconium ileus, that are associated with echogenic bowel
- cytomegalovirus
- trisomy 21
complex disorder of the bowel and genitourinary tract. imperforate anus is found with this
anorectal atresia
occurs when a membrane covers the anus, preventing expulsion of meconium
imperforate anus–anorectal atresia
hirschsprung’s disease AKA:
megacolon
abnormal innervation of large intestines
hirschsprung’s disease/megacolon
sonographic appearance of hirschsprung’s disease(megacolon)
- dilated bowel loops
- difficult to diagnose prenatally
arises when fetus has sterile chemical peritonitis secondary to in-utero bowel perforation
Meconium peritonitus
sonographic appearance of meconium peritonitis:
- calcifications on peritoneal surfaces or in scrotum
- may cause psuedocyts
- ascites fluid may be echogenic
with hyperechoic bowel, bowel is compared to the brightness of ____
bone
hyperechoic bowel is usually seen in the ____ trimester
2nd trimester
true ascites is always ___
abnormal
fluid collects between 2 leaves of unfused omentum, results in cystic appearance in abdomen:
ascites
ascites prognosis with non-immune hydrops:
poor
cystic masses of the abdomen can result in compression of other organs, creating:
- hydronephrosis
- hydroureter
- fetal hydrops
