fetal Anomalies Part III

Fetal Abdomen

Normal fetal stomach

Visualized as early as 9 weeks GA, but more reliably at 13 weeks; fluid-filled structure in LUQ of fetus.

Situs inversus

Condition where the stomach and heart are reversed; total situs inversus has a right-sided stomach and heart

Partial situs inversus

has a right-sided stomach and left-sided heart.

Partial situs inversus is most commonly associated with

congenital heart defects and other anatomical anomalies.

Esophageal Atresia

Condition characterized by failure to visualize stomach, often indicated by polyhydramnios or non-visualization after an empty stomach is ruled out. When the stomach and esophagus aren’t connected

Failure to visualize the stomach in the LUQ may be due to

normal but empty stomach, displacement of the stomach into the chest or umbilical cord, non-production of amniotic fluid, esophageal atresia, microgastria

The most common form of esophageal atresia presents with

tracheoesophageal fistula to the distal esophageal segment. The stomach may have fluid, but it is less than normal

With esophageal atresia the stomach may be visualized

as two parallel echogenic lines

Fetal pancreas

seen between the left kidney and stomach

Fetal GB

can be seen at 14-16 wks gestation

Fetal gallstones

are echogenic foci with acoustic shadowing within the fetal gallbladder

Fetal Gb sludge

its usually a precursor to gallstones and presents as echogenic material without shadowing

Fetal gall stones and/or GB sludge will usually

be resolved 6 weeks after birth

fetal choledochal cysts

congenital cysts of the biliary tree are most commonly seen in the CBD

Differential diagnoses for fetal choledochal cysts include

biliary atresia with cystic dilation

In a normal fetus which liver lobe will be larger

the left lobe

Fetal hepatomegaly is usually seen

in fetuses with hemolytic diseases

Fetal liver hemangiomas may be seen as

echogenic small structures in the liver

fetal splenomegaly is seen in

fetuses with CMV- herpes

Physiologic midgut herniation

when bowel herniates into the base of the umbilical cord during early fetal development as early as 8 wks. It will usually return to its normal place by 11 wks

When will the colon be seen

after 22 weeks

Duodenal obstruction

Most common cause of small bowel obstruction in the fetus, associated with conditions like trisomy 21.

Duodenal atresia is associated with

the double bubble sign

Double bubble sign

produced by large obstructed stomach and distended prox duodenal segment

Duodenal atresia

it is important to show the continuity of the dilated duodenal segment with the stomach to r/o other cystic structures

What will the stomach bubble contain?

rugae

Duodenal atresia is associated with

trisomy 21, cardiac abnormalities, and esophageal atresia

What is the most common fetal bowel obstruction

atresia of the small bowel

What are most common sites for small bowel atresia

the proximal and distal jejunum and ileum

What causes increases mortality rate

multiple atresias, meconium ileus, peritonitis, and gastroschisis

In atresia of the small bowel, the bowel loops will

have an internal diameter >7mm and strong peristalsis

When is polyhydramnios common in atresia of the small bowel

when the obstruction is at or above the level of the prox jejunum

Short bowel syndrome

is a malabsorption disorder caused by an extensive resection of the small intestine or congenital conditions that result in inadequate intestinal length. This condition leads to severe nutrient deficiencies and requires careful management.

VACTERL complex

A rare congenital condition involving multiple defects including vertebral, anal, cardiac, tracheoesophageal, renal, and limb defects.

Meconium Ileus

Obstruction and dilation of ileum occurring from thick, sticky meconium often related to cystic fibrosis.

Sonographic appearance of meconium ileus

it appears similar to jejunal or ileal atresia- small bowel loops are dilated

Meconium ileus may result in

bowel perforation or volvulus

Meconium peritonitis

is an inflammation of the peritoneum caused by the leakage of meconium into the abdominal cavity, often associated with meconium ileus.

What causes meconium peritonitis

when volvulus, jejunal, or ileal atresia, or meconium ileus perforates the small bowel

Meconium peritonitis presents with

immediate ascities

Inflammation from meconium peritonitis may cause

calcifications of along the surface of the bowel or peritoneum

Hirschsprung’s disease

the cause of functional bowel obstruction

Hirschsprung’s disease may present with

polyhydramnios, and multiple dilated loops of bowel

Echogenic Bowel

Bowel that appears echogenic as pregnancy progresses due to meconium; abnormal if seen early in the second trimester past 14 weeks

For a diagnoses of echogenic bowel

it must be the same the echogenic as the iliac bones

Anorectal atresia

is a congenital condition where the anal opening is missing or blocked, which can lead to intestinal obstruction.

Gastroschisis

Right-sided, para-umbilical defect causing free-floating loops of bowel in amniotic fluid.

Increased AFP, echogenic bowel and IUGR together are associated

a high risk of perinatal morbidity

Omphalocele

Midline defect where intra-abdominal contents herniate into the umbilical cord, covered by a membrane.

Pentalogy of Cantrell

failure of fusion of the lateral folds in the thoracic region, failure of the development of the transverse septum of the diaphragm

Pentalogy of Cantrell consists of

an anterior diaphragmatic hernia, midline abdominal wall defects, cardiac anomalies, defect of the diaphragmatic pericardium, and lower sternal defect

Pentalogy of Cantrell can be associated with

chromosomal abnormalities, craniofacial vertebral abnormalities, 2vc and ascites

Limb body wall complex is AKA

body stalk anomaly

Limb body wall complex may result from

amniotic band syndrome

Limb body wall complex

a rare anomaly caused by the failure of the closure of the ventral body wall

Limb body wall complex will present with at least 2 of the following

limb defects, anterior body defects, exencephaly or encephalocele with or without facial defects

Bladder Exstrophy

Failure of mesenchymal cells to migrate, causing a protruding mass from lower abdominal wall, often in males.

Bladder exstrophy is associated with

narrow thorax, clubfeet, renal anomalies, hydrocephaly, ascites

OEIS complex

Persistence of infraumbilical cloacal membrane, interfering with normal anterior abdominal wall closure and failure of the separation of the urogenital septum from the rectum. one hole for rectum, vagina, and urethra, resulting in a single opening.

Anomalies associated with OEIS complex include

CNS, GU, anomalous genitalia, limb defects, 2vc, closed spinal defects, omphalocele, and renal agenesis