GIT Anomaly
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Transcript of GIT Anomaly
GASTROINTESTINAGASTROINTESTINAL TRACT L TRACT
ANOMALIESANOMALIES
ObjectivesObjectives Describe the development of the digestive system Detail the malformations of the midgut Describe the sonographic findings of the
gastrointestinal system Describe the normal development of the stomach
and the importance of it’s sonographic visualization
Detail the fetal hepatobiliary system Describe situs inversus List the abnormalities of the gastrointestinal tract
and their sonographic findings
EmbryologyEmbryology
Foregut– Esophagus– Stomach & duodenum– Liver & Biliary system– Pancreas– Spleen
Midgut– Small intestines – Colon supplied by
the SMA Hindgut
– Structures supplied by the IMA
EmbryologyEmbryology Stomach forms at about 4 weeks Descends into abdomen from initial
position at about 7 weeks Abdominal wall muscles develop at
about 11 weeks Stomach can be seen on ultrasound
at about 9 weeks
EsophagusEsophagus Embryology
– Esophagus & trachea develop from common structure
– Partitioned by tracheo-esophageal septum Separate tracts form - 3-5 weeks
Fluid can be seen in esophagus– Fetal swallowing is normal
Esophageal AtresiaEsophageal Atresia Incomplete formation of the esophagus > 90% have a fistula between trachea &
esophagus (TEF) No sex preference
Esophageal AtresiaEsophageal Atresia Associated
anomalies– Heart– Chromosomes– GI– GU– VACTERL
Vertebral defect Anorectal
malformation Cardiac defect TracheoEsophageal
fistula Renal anomaly Limb defects
Prognosis– 22-75% mortality
if detected in utero
– Long term sequelae common Strictures Aspiration Recurrent TEF Feeding difficulties Esophageal
dysmotility nearly 100%)
Esophageal AtresiaEsophageal Atresia Ultrasound findings
– Most types have connection from mouth to stomach
Small amount of fluid may be seen in stomach
Follow-up on all fetuses with small stomach
Look for esophageal pouch (expands with swallowing)
– Polyhydramnios– IUGR late 2nd and 3rd
trimester
Polyhydraminos
Small stomach
bubble
Imaging Fetal BowelImaging Fetal Bowel
Duodenal AtresiaDuodenal Atresia
Lack of normal canalization leading to partial or complete obstruction
Most common small bowel obstruction: 1:5000 to 1:10,000 (Callen2008)
– Jejunal atresia nearly as common Unknown etiology Can result from
– Membrane across lumen– Annular pancreas– Occlusion of SMA
Duodenal AtresiaDuodenal Atresia
Associated anomalies– 30% of DA fetuses have trisomy 21– 50-70% of DA have other anomalies
Vertebral GI Heart Occasionally renal
– Overall mortality 15-40%– 95% survival if isolated with immediate
surgical treatment
Duodenal AtresiaDuodenal Atresia Ultrasound findings
– “double bubble” sign Stomach &
duodenum Seen in all
types of small bowel obstruction
– Polyhydramnios
Atresia & stenosis of small bowel and colon are less common
Obstruction usually results from vascular insult
Duodenal AtresiaDuodenal Atresia Differential diagnosis includes
Choledochal cyst Liver cyst
Jejunal, Ileal AtresiaJejunal, Ileal Atresia Best diagnostic clue:
– Hyperperistalsis within small bowel loops highly suggestive of obstruction
– Dilated, fluid-filled loops of bowel– Rarely presents as a cyst-like mass– Polyhydramnios
Associated with other GI anomalies Sensitivity for US detection near 100%
Bowel ObstructionBowel Obstruction
Exact location of dilatation may be hard to determine
Prognosis– Depends on
Site of obstruction Length of normal bowel Associated anomalies Presence/absence of perforation
– Lower obstructions have better outcome
Echogenic BowelEchogenic Bowel Controversy over what is considered echogenic
– Appears more echogenic with higher frequency transducer
Has been associated with– Cytomegalovirus (CMV) & Parvovirus– Severe IUGR & unexplained intrauterine demise– Trisomy 21– Bowel obstruction– Cystic fibrosis
Echogenic bowel suggests bowel compromise. In approximately one third of fetuses with echogenic bowel on prenatal ultrasonography, a malformation of the GI tract is later confirmed.
Echogenic BowelEchogenic Bowel Highly operator dependant High frequency transducers falsely
increase bowel echogenicity Differential Diagnosis
– Meconium peritonitis– Anal atresia– Swallowed debris (10% from swallowed
blood)
Fetal GallstonesFetal Gallstones
Gallbladder lies more anterior in the abdomen than the stomach
Echogenic foci with shadowing can be seen
Usually resolve in first year of life
Infectious ProcessesInfectious Processes
Bowel PerforationBowel Perforation
Incidence of bowel perforation 3.3:100,000
Many possible causes Meconium peritonitis
– Distension from obstruction (any kind) can cause perforation of small intestine
– Leakage of meconium into abdomen– Chemical peritonitis– Inflammatory response may seal over perforation
forming a pseudocyst (meconium pseudocyst)
Bowel PerforationBowel Perforation
Meconium Cyst/Pseudocyst– Result of bowel perforation– Hyperechogenic cyst, resolving through
pregnancy Primary/Idiopathic perforation (95%)
– No obstruction– Appear early (first and early 2nd trimester)– Spontaneous sealing – Favorable outcome
Secondary perforation– Intestinal obstruction– Occurs late in pregnancy– Intra-abdominal calcifications
Meconium PeritonitisMeconium Peritonitis Sonographic findings
– Hyperechogenic bowel – main marker– Intraperitoneal echogenic material– Ascites– Dilated bowel loops– Meconium pseudocysts – Intraperitoneal calcifications– Polyhydramnios
Meconium PeritonitisMeconium Peritonitis
Prognosis– Perforation may seal over
May form pseudocyst
– Serious condition – Management depends on cause &
evolution of pathology
Meconium IleusMeconium Ileus Obstruction and dilatation of the ileum
– Caused by impaction of thick meconium – Nearly always found in fetuses with cystic
fibrosis– Can progress to meconium
peritonitis/pseudocyst if perforation occurs
Meconium PeritonitisMeconium Peritonitis
Pseudocyst
**
VolvulusVolvulus Bowel loop twisted on it’s
mesentery, resulting in vascular compromise– Dilated, non-peristalsing bowel loop– Single “kinked” loop very suggestive
Differential diagnosis– Jejunal/ ileal atresia– Intussusception
Cystic Lesions of the Cystic Lesions of the AbdomenAbdomen
Choledochal CystCholedochal Cyst Congenital cystic dilatation of biliary
system (choledochal cyst) Ducts may be dilated Cystic structures seen in fetal
abdomen anterior to right kidney
Choledochal CystCholedochal Cyst
**
Liver CystLiver Cyst
*
Stomach
Enteric Duplication CystEnteric Duplication Cyst May be cystic (80%) or tubular (20%) Best diagnostic clue: Thick-walled cyst Generally anechoic but can be echogenic Rarely bowel dilatation Excellent prognosis Differential diagnosis
– Ovarian cyst– Mesenteric cyst– Choledochal cyst– Meconium pseudocyst
Mesenteric CystsMesenteric Cysts Represent obstructed lymphatic
drainage Lymphangioma Sonographic findings
– Mid-line cystic lesion– May be multisepated or unilocular– Solid appearance if hemorrhage present
Malignancy rare
Hepatic CalcificationsHepatic Calcifications Liver-associated calcifications Determination of intraparenchymal vs
capsular Acoustic shadowing may or may not be
present Isolated, single hepatic calcifications
generally of no consequence Multiple calcifications more likely to be
associated with abnormal karyotype (T21,T18,T13)
Hepatic CalcificationsHepatic Calcifications
Ovarian CystsOvarian Cysts
*Bladder
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