OB II Unit 6 Fetal Abdomen 39- 58

What is Duodenal Atresia?

• Double Bubble Sign

• Blockage of duodenal lumen by membrane

• Prohibits passage of swallowed fluid beoynd obstruction

• Amniotic Fluid backs up into duodenum and stomach creating 2 echo-free structures in upper abdomen

Duodenal atresia may coexist with ______ ________ and 30% will have ________ ___

Annular pancreas

Trisomy 21

What will duodenal atresia have?

• Elevated Amniotic AFP- inability to swallow

• Poyhydramnios

What is duodenal atresia associated with?

• Cardiovascular- leads to echo

• Genitourinary

• Imperforate anus

• Esophageal atresia

• Symmetric IUGR

What are the US findings of duodenal atresia?

• Double Bubble sign 

  • 2 anechoic structures in upper abdomen, look for communication

• Polyhydramnios

• Symmetric IUGR commonly occurs

What are these images showing?

Duodenal Atresia

What is this image showing?

duodenal Atresia

What are causes of the double bubble sign?

• Duodenal atresia

• Duodenal stenosis

• Annular Pancreas

• Ladd’s bands- fibrous stalks of peritoneal tissue that connect secum to the retroperitoneal in the RLQ-leads to malrotation

• Proximal jejunal atresia

• Malrotation

• Diaphragmatic hernia

What are VACTERL association?

A group of anomalies

•Vertebral defects

•Anal atresia

•Cardiac anomalies

• Tracheo-Esophageal fistula

•Renal anomalies

•Limb dysplasia

With Vacterl association, what are the requirements?

3 features must be identified 

What is jejunoileal Atresia or Stenosis?

• Vascular accident = secondary to volvulus, gastroschisis, or sporadic

What part of bowel is subject to obstruction?

Any of the bowel

When will normal bowel loops be identified?

In the 3rd trimester

When might you suspect a bowel obstruction?

If clear fluid loops of bowel are visualized

What are US finding for an obstructed bowel?

• Multiple cystic structures, more than 2, proximal to site of atresia within abdomen discontinuous with stomach

• Polyhydramnios is possible

What may an obstructed bowel be associated with?

• Other anomalies

• Ascites

• Meconium Peritonitis

What are these images showing?

Bowel Obstruction

What is the most common malformation of the midgut?

Meckel’s Diverticulum

What is Meckel’s Diverticulum?

• Remnant of proximal part of yolk stalk that fails to degenerate & disappear during early development

What does Meckel’s Diverticulum appear as?

• Small fingerlike sac

• 5 cm in length

• Projects from border of ileum in RLQ

What is this image showing?

Meckel’s Diverticulum

What is Meconium Ileus?

• Thick meconium in distal ileus

• Overproduction of meconium and mucus

What is meconium ileus seen with and its earliest manifestation?

• Cystic Fibrosis 

  • Autosomal recessive

  • Pancreatic disease

  • Respiratory problems (thick mucus)

What are the US findings for a meconium ileus?

• Ileum dilates because of impacted meconium

• Echogenic small bowel

  • Cystic Fibrosis

  • Cytomegalovirus

  • Trisomy 21

• Polyhydramnios

• Calcifications of peritoneal structures

Obstructed Bowel may perforate and = ____________  __________

Meconium Peritonitis 

What is meconium peritonitis?

• An inflammatory response from leakage of bowel contents, causing fibrosis of tissue & calcifications

  • Pseudocyst may develop because of chronic peritonitis

What is this image showing?

Meconium Peritonitis 

what is Anorectal Atresia?

Complex disorder of bowel & genitourinary system

What is an imperforate anus?

membrane covering anus

What is anorectal atresia be associated with?

• VACTERL association or caudal regression syndrome

• Many assoc. anomalies

• Incontinence of bowel & bladder is common in the infant

What are the US findings for Anorectal Atresia?

• Dilated Colon

• Calcified meconium

• AFI is typically normal

  • Or decreased if assoc. renal problems

What is the prognosis of anorectal atresia?

Poor due to associated anomalies

What is Hirschsprung’s Disease?

• Megacolon

  • Congenital disorder

• Dilated bowel loops on US

With Hirschsprung’s Disease, it may be difficult to detect _________ but suspected with dilated bowel loops 

prenatally 

Hyperechoic bowel varies with what?

Location in SB or colon, gestational age, degree of echogenicity

How do you compare the echogenicity of bowel?

Compare with iliac wing of fetus

What are the 3 grades of degree of hyperechogenicity?

•1 = mildly echogenic & typically diffuse

•2 = moderately echogenic & typically focal

•3 = very echogenic, similar to bone structures

What is true Ascites?

Always an abnormal finding in fetal abdomen

What is true ascites caused by?

• Nonimmune hydrops = poor prognosis

• Bowel perforation

• Urinary ascites from bladder rupture

What are the US findings of true ascites?

• Fluid within abdominal cavity

• To dependent side

• Outlines falciform ligament & umbilical vein

  • Pleural effusions

  • Pericardial effusion

  • Integumentary edema

What is this image showing?

True Ascites

If finding a cystic mass, what should you determine?

• Characteristics of mass

• Precise location – origin if possible

• Size of mass

• ? Compression of other organ systems

• Evaluate all abdominal organ systems

• Other possibilities

  • Ovarian – check gender – well circumscribed

  • Omentum – well circumscribed

  • Urachus – b/n umbilicus & bladder

What is this image showing?

Ovarian cyst