study guide chapter 60-62 Flashcards
Which abnormality has a significantly narrower chest diameter?
asphyxiating thoracic dystrophy.
Several syndromes may be associated with this finding, including thanatophoric dwarfism
In the presence of oligohydramnios, resultant pulmonary hypoplasia may be seen with a reduction in overall thoracic size.
What is the most important determinant for fetal viability?
Adequacy of pulmonary development single most important determinant for fetal viability
Sonographic evaluation of a normal fetal thorax?
Normal thoracic cavity is symmetrically bell shaped:
Ribs form lateral margins
Clavicles form upper margins
Diaphragm forms lower margin
Size:Thorax normally slightly smaller than abdominal cavity
Ratio (thoracic circumference to abdominal circumference) reported to remain constant throughout pregnancy (0.94 ± 0.05)
sono:
Fetal lungs appear homogeneous on sonography, with moderate echogenicity
Early in gestation, lungs similar to or slightly less echogenic than liver
As gestation progresses, trend is toward increased pulmonary echogenicity relative to liver
To evaluate normal fetal thorax:
Transverse, coronal, and/or parasagittal Evaluate chest: Size, shape, symmetry Evaluate heart: Position, size, rate, pericardial fluid Evaluate pulmonary texture Centrally positioned mediastinum
Chest circumference measurements made in transverse plane at level of?
Chest circumference measurements made in transverse plane at level of four-chamber view of heart
Fetal breathing..
Fetal breathing becomes more prominent in second and third trimesters
Mature fetus spends almost one-third of its time breathing
Fetal breathing movements documented if characteristic seesaw movements of fetal chest or abdomen sustained for at least 20 seconds
Fetal breathing movements considered absent if no such fetal activity noted during 20-minute observation period
Fetal respiration may vary in response to maternal activities and substance ingestion
Stimulated by increased sugar doses and decreased by smoking
degree of cardiac axis?
45?
Apex of heart should be directed toward spleen
Base of heart lies horizontal to diaphragm
Abnormalities associated with pulmonary hypoplasia?
pulmonary hypoplasia is:
Caused by decrease in number of lung cells, airways, and alveoli, with resulting decrease in organ size and weight
Most commonly occurs from prolonged oligohydramnios or secondary to small thoracic cavity as result of structural or chromosomal abnormality
Look for chromosome anomalies, renal anomalies, intrauterine growth restriction, premature rupture of membranes, masses within thoracic cavity
Prognosis grave; 80% die after birth
sonographic findings in CCAM?
Is a multicystic mass within the lung.
Consists of primitive lung tissue and abnormal bronchial and bronchiolar-like structures. CCAM is one of the bronchopulmonary foregut malformations
sono:
Type I:(macrocystic) Single or multiple large cysts 2 cm in diameter; good prognosis after resection of affected lung
Type II: Multiple small cysts, <1 cm in diameter, echogenic; high incidence 25% of other congenital anomalies (renal, gastrointestinal)
Type III: Large, bulky, noncystic lesions producing mediastinal shift; poor prognosis
Usually only one lobe affected
Associated polyhydramnios and anasarca have poor prognosis
Types of diaphragmatic hernias?
Sporadic defect; occurs in 1:2000 to 1:5000 births
herniation through foramen of:
Bochdalek:
Most common type of diaphragmatic defect occurs posteriorly and laterally in diaphragm
foramen of Morgagni:
May occur anteriorly and medially in diaphragm, through foramen of Morgagni, and may communicate with pericardial sac
In anteromedial defects, heart may be normally positioned but surrounded by pleural fluid, while fetal stomach may be located in its normal position in abdomen
What lung cyst is the most common?
Bronchogenic Cysts
Occur as result of abnormal budding of foregut
Lack any communication with trachea or bronchial tree
Typically occur within mediastinum or lung
Infrequently found inferior to diaphragm
The severity of pulmonary hypolasia depends on what?
Severity depends on when pulmonary hypoplasia occurred during pregnancy and its severity and duration
Other factors, such as pulmonary fluid dynamics, fetal breathing movements, and hormonal influences, may contribute
The supernumerary lobe of the lung? sono?
pulmonary sequestration:
Extrapulmonary tissue present within the pleural lung sac or connected to the inferior bordr of the lung with its own pleural sac.
Extra lung tissue nonfunctional; receives its blood supply from systemic circulation
Arterial supply usually from thoracic aorta, with venous drainage into vena cava
sono:
Echogenic solid mass resembling lung tissue
Rarely occurs below diaphragm
Associated with hydrops and polyhydramnios, diaphragmatic hernia, gastrointestinal anomalies
Normal intra-abdominal anatomy
If you see pleural fluid what should you look at?
Pleural Effusion (Hydrothorax): Most common reason is chylothorax occurring as right-sided unilateral collection of fluid secondary to malformed thoracic duct. Hydramnios often accompanies chylothorax resulting from esophageal compression
May result from immune causes(e.g., Rh hemolytic disease), nonimmune causes, or from CHF
Effusions may also occur in fetuses with chromosomal abnormalities (e.g., trisomy 21) or in fetus with cardiac mass
Once discovered, careful search for lung, cardiac, and diaphragmatic lesions should be attempted
Evaluation for signs of hydrops should be performed
Correlation with clinical parameters warranted to exclude immunologic causes of pleural effusions
Congenital bronchial atresia is most commonly located where?
Pulmonary anomaly that resuls from focal obliteration of segment of the bronchial lumen.
Most common in left upper lobe
Appears on ultrasound as echogenic pulmonary mass lesion
mortality rate at birth for a fetus with a diaphragmatic hernia is?
high (75%)
What is diaphragmatic hernia associated with?
pulmonary hypertension, pulmonary hypoplasia or chromo
Hydrops usually not present with left-sided congenital diaphragmatic hernias unless associated fetal malformations are present
Presence of pulmonary hypoplasia and pulmonary hypertension is real issue that results from size of hernia
Pulmonary arteries become hypertrophied and thickened, resulting in pulmonary hypertension that after birth leads to persistent fetal circulation
if pleural fluid what could happen?
Shift of mediastinal structures
Compression of heart
Inversion of diaphragm
compression of lungs
rupture of amnion that leads to entanglement or entrapment of fetal parts to the sticky chorion?
Amniotic band syndrome
Defect in the lower abdominal wall and anterior wall of the urinary bladder?
Cloacal exstrophy
Anomaly with large cranial defects, facial cleft, large body wall defects and lib abnormalities?
limb-body wall complex
Opening in the layers of the abdominal wall with evisceration of the bowel to the right of the umbilical cord?
Gastroshisis
Small bowel always found in herniation
Other organs that may be involved in herniation: Large bowel Stomach Portions of genitourinary system Liver
If you have an omphalocele with scoliosis?
When scoliosis is found, consider limb-body wall complex (or body-stalk anomaly), a lethal disorder
This disorder also includes severe cranial defects, facial clefts, extensive abdominal wall defect of the chest, and abdomen and limb defects.
Abnormal fusion of the amnion and chorion extends as a sheet from the cord and adheres to the fetus and placenta
If an omphalocele is low what should you consider?
When low omphalocele is observed, consider bladder or cloacal exstrophy.
Results in exstrophy of bladder in which two hemibladders are separated by intestinal mucosa
Other anomalies may include anal atresia, spina bifida, and lower-limb defects
What does beckwith-wiedemann syndrome include?
coexistwnce of and omphalocel, macroglossia and visceromegaly
Gastroschisis is from astrophia of what vessel?
right umbilical vein
most common abdominal wall defects?
omphalocele, umbilical hernia, and gastroschisis
critical part of the process of closing the abdominal wall?
In sixth week, process called folding helps embryo transform itself into cylindrical shape
This transformation is critical part of process of closing abdominal wall
normal hernia of bowel to allow what?
permits development of intraabdominal organs and allows necessary bowel rotation
Umbilication hernia of bowel occurs during eighth week of development as midgut extends to extraembryonic coelom in proximal portion of umbilical cord
Midgut grows faster than abdominal cavity at this stage because of increased size of liver and kidneys
Herniation develops
Intestines return to abdominal cavity by 12th week of gestation
omphalacele
When bowel loops fail to return to abdomen, bowel-containing omphalocele occurs
Membrane consisting of peritoneum and amnion forms omphalocele sac encasing herniated organs
Ascites may coexist with omphalocele
Hydramnios found in one third of fetuses
Associated anomalies include: Complex cardiac disease Gastrointestinal Neural tube Genitourinary tract anomalies
Chromosomal anomalies occur in 35% to 60% of omphaloceles
five defects of pentalogy of cantrell?
omphalocele ectopic heart lower sternum anterior diaphragm diaphragmatic pericardium
prognosis of an infant with gastroschisis?
good prognosis
Free-floating herniated small bowel
Large bowel, stomach, gallbladder, urinary bladder, pelvic organs may be involved
A high omphalacele is the primary finding in what condition?
pentalogy of cantrell
Limb–Body Wall Complex defects more common on what side?
Occurs with fusion of amnion and chorion
Amnion does not cover umbilical cord normally
Extends as sheet from margin of cord
Is continuous with both body wall and placenta
Left-sided body wall defects three times more common than right-sided defects
Is associated with:
Large cranial defects
Facial cleft
Body wall complex defects involving thorax
Body wall complex defects involving abdomen
Limb defects
common anomilies associated with gastrischsis?
When organs other than small or large bowel seen, body stalk anomalies should be suspected
or none?
membrane of omphalacele is made up of?
Membrane consisting of peritoneum and amnion forms omphalocele sac encasing herniated organs
What does the umbilical vein drain?
placenta???
After birth, umbilical vein collapses and becomes ligamentum teres hepatis
In fetus, umbilical vein courses cephalically in free, inferior margin of falciform ligament
Joins umbilical portion of left portal vein at caudal margin of left intersegmental fissure of liver
the hepatic bud enlarges and the right umbilical vein atrophy during what week?
7th
A fetus with partial situs inversus demonstrates what?
condition in which only the heart or the abdominal organs are reversed.
Asplenia (absence of spleen):
Abnormally positioned stomach and gallbladder
More centrally positioned liver
Abnormal positioning of aorta and IVC on same side
Polysplenia represented as transposition of liver, spleen, stomach, and absence of gallbladder. Interruption of IVC and azygos vein directly posterior to heart and in front of spine. At least two spleens present along greater curvature of stomach. Heart block common in polysplenia syndrome
if you see evidence of a double bubble with tri 21 what is the condition?
Duodenal Atresia
Sonographic appearance termed “double bubble sign”
Hydramnios almost always seen with duodenal atresias later in pregnancy
Most cases found distal to ampulla and often coexist with annular pancreas
About 30% of fetuses with duodenal atresia have trisomy 21 (Down syndrome)
Cardiovascular anomalies frequent; fetal echocardiography invaluable in excluding cardiac lesions
Anomalies occur in approximately 50% of infants with duodenal atresia
Fetus with dialated loops of echogenic bowel should be evaluated for what?
Meconium Ileus
Normal small bowel may appear echogenic during second trimester of pregnancy.
Other fetal conditions associated with echogenic small bowel (cytomegalovirus and trisomy 21)
Meconium peritonitis may occur secondary to perforation of obstructed bowel.
Inflammatory response occurs because of leakage of bowel contents, which may cause fibrosis of tissue and calcifications.
where is the spleen visualized?
Imaged on transverse plane posterior and to left of fetal stomach
Spleen, like liver, may enlarge in fetuses with Rh-immune disease
cause of areas of echogenicty in the fetal abdomen?
Meconium Ileus: dialated and echo bowel
Anorectal Atresia: dilated colon and calcified meconium
cystic growth of the common bile duct?
choledochal cyst
haustral folds can be found in which of the following structures?
colon
one of the sacculations of the colon caused by longitudinal bands that are shorter than the gut
A remnant of the proximal part of the yolk sac?
Meckel’s diverticulum
Is the most common malformation of midgut
Usually small fingerlike sac, about 5 cm long, projects from border of ileum
normal sono apearance of the esophagus during 2nd and 3rd tri?
Normal esophagus can be visualized in thorax during second and third trimesters as two or more parallel echogenic lines (“multilayered” pattern)
Sometimes possible to see fluid in esophagus as fetus swallows amniotic fluid
when you can diff small bowel and large?
20weeks
know about fetal stomach
Most fetuses older than 14 to 16 weeks should have fluid in their stomach
transposition of liver, stomach, absent of gb and multi spleens
polysplenia
sonolucent band near the fetal anterior abdominal wall from the abdominal wall muscles in the fetus over 18 weeks?
pseudoascites
most reliable criteria for dialated bowel loops?
Normal diameter of small bowel lumen ≤5 mm, with length of 15 mm near term
Normal measurements of colon diameter range from 3 to 5 mm at 20 weeks to 23 mm or larger at term
causes of double bubble?
Duodenal atresia Duodenal stenosis Annular pancreas Ladd’s bands Proximal jejunal atresia Malrotation Diaphragmatic hernia
coexisting anomolies with Esophageal Atresia?
Coexisting anomalies common in 50% to 70% of fetuses with esophageal atresia
Most commonly observed anomaly is anorectal atresia and VACTERL
Growth restriction present in 40% of cases
Chromosomal trisomies (18 and 21) reported
Fistula may not be present and fluid will not reach stomach; stomach will not be visualized by ultrasound
Combination of polyhydramnios and absent stomach over repeated studies may be suggestive of esophageal atresia
Will not be diagnosed in majority of cases because of tracheoesophageal fistula
Upper neck sign has been observed as additional finding
hindgut Derivatives
Derivatives of hindgut: Left part of transverse colon Descending colon Sigmoid colon Rectum Superior portion of anal canal Epithelium of urinary bladder Most of urethra
All of structures supplied by inferior mesenteric artery
choledochal cyst sono:
close prox to neck of GB
ovoid RUQ
cyst entering bile duct
absence of peristalsis
if you see peritoneal calcifications at 30 weeks what does it indicate?
Meconium Peritonitis
Calcifications seen on peritoneal surfaces or in scrotum via processus vaginalis
Ascitic fluid may be echogenic.
Is unusual to see calcification in meconium ileus in fetus with cystic fibrosis
VACTERL is a group of anomalies association with what?
Anorectal Atresia
Presents as complex disorder of bowel and genitourinary tract
Imperforate anus is disorder that occurs when membrane covers anus, prohibiting expulsion of meconium
May present as part of VACTERL association or in caudal regression
Prognosis poor with anorectal atresia because of associated anomalies
fetal liver:
Hemopoiesis (blood formation) begins during sixth week
Accounts for large size of liver between seventh and ninth weeks of development
By 12th week, bile formation by hepatic cells has begun
Accounts for 10% of total weight of fetus at 11 weeks and 5% of total weight at term
Left lobe of liver larger than right in utero secondary to greater supply of oxygenated blood
describe situs inversus
heart and abd organs are completely reversed
complex disorder of the bowel and genitourinary tract
anorectal atresia
