ultrasound anomalies

Question 1

non-immune hydrops

Answer 1

-any causes of fetal hydrous not caused by RBC alloimmunization
-1/1500-1/3800 births
+up to 35% discovered incidentally on ultrasound

Question 2

hydrops

Answer 2

refers to abnormal fluid buildup in 2 or more locations

Question 3

ascites

Answer 3

fluid buildup in the abdomen

Question 4

cardiovascular hydrops

Answer 4

• most common mechanism (17-35%)

- due to increased central venous pressure

Question 5

chromosomal abnormality associated hydrops

Answer 5

• 7-16% of cases

- can be due to cardiac anomalies, lymphatic dysplasia abnormal myelopoeisis, etc

Question 6

infection associated hydrops

Answer 6

• 5-7%
• can be due to anemia, anoxia, endothelial cell damage, and increased capillary permeability
• CMV, too, parvo, syphilis, herpes, rubella, coxsackie virus, leptospirosis, trypanosome cruzi

Question 7

twin-twin transfusion associated hydrops

Answer 7

• 3-10%

- due to hyper___emia and increased central venous pressure

Question 8

aneuploidy and hydrops

Answer 8

• monosomy X (42-67% cases)
• Trisomy 21 (23-30%)
• Trisomy 13, 18, 12

Question 9

syndromic hydrops

Answer 9

• Noonan
• Pena-Shokeir syndrome
• myotonic dystrophy
• multiple pterygium syndrome
• skeletal dysplasias

Question 10

pena-shokeir syndrome

Answer 10

• caused by mutations of the DOK7 and RAPSN genes
• can cause IUGR, joint contractures, pulmonary hypoplasia, and facial anomalies
• also called fetal akinesia deformation sequence

Question 11

metabolic conditions and hydrops

Answer 11

• galactosialidosis
• GM1 gangliosidosis
• sialidosis
• MPS IVA
• Farber disease
• most of these not evaluated prenatally, as they aren’t what we worry about most with hydrops

Question 12

parvo pathogenesis

Answer 12

affects bone marrow by preferentially infecting and replicating inside erythroid cells
-see hand and neck depression
-incredibly anemic baby with hydrops starting 2-4w post-maternal infection
+usually starts with ascites
*10% risk of fetal hydrous after maternal infection (which is usually mild)

Question 13

parvo treatment

Answer 13

transfusion at 19-22w usually helps the fetal bone marrow recover and baby will be okay

Question 14

MCA doppler

Answer 14

looks at blood vessel in fetal brain to show how fast blood is being shunted and therefore how anemic the fetus is
+higher doppler values indicate more significant anemia

Question 15

PUBS

Answer 15

-used to be used to study hematocrit levels and find out if baby is anemic
-now used to transfuse following MCA
+use dense pellet of high crit irradiated O negative blood to transfuse

Question 16

estimated fetal weight

Answer 16

• BPD
• HC
• abdominal circumference
• femur length

Question 17

PUBS risk

Answer 17

• failure of procedure and continued anemia in fetus
• ROM, preterm labor or delivery
• typically done after 18w & before 34w to avoid problems

Question 18

ultrasound

Answer 18

screening method completed at different times in pregnancy to identify possible issues or differences, monitor growth and fluid levels as well as guide additional procedures and further care

Question 19

level II anatomy scan

Answer 19

• typically done between 18-22w to allow for further follow-up and timing of results
• in depth look at head, face, neck, chest, abdomen, spine, extremities and genitalia

Question 20

early anatomy

Answer 20

completed transvaginally around 14w for cases suspicious of abnormality or family history
-followed up by later scans

Question 21

intracardiac echogenic focus (EIF, IEF)

Answer 21

• soft marker with possible increased risk for Down syndrome
• identified commonly in left ventricle
• sometimes not reported anymore because it does not impact function
• ethnic variation-more common in Asian population

Question 22

pylectasis

Answer 22

-dilation of the renal pelvis
-more common in males
-can be indicative of a GU structural anomaly
+if greater than 4mm at anatomy followup at 28w-new cutoff 7mm
-slightly increased risk for Down syndrome, but less concerning if isolated

Question 23

absent/hypoplastic nasal bone

Answer 23

-echogenic line within the bridge of fetal nose
-significant risk of Down syndrome
+51x more likely, BUT can be familial and ethnic (if Caucasian could be 132x more likely, if Afro-Carribean only about 8.5x more likely)
+typically not associated with other conditions

Question 24

hypoplastic nasal bone cutoff

Answer 24

less than 5th percentile indicates abnormal

Question 25

echogenic bowel

Answer 25

• increases risk for aneuploidy (LR=6), and CF
• can be seen in cases of fetal infection (namely CMV)
• can also be associated with bowel malformations or rupture as well as intra-amniotic bleeding

Question 26

CF risk with echogenic bowel

Answer 26

2% if parental carrier status unknown

Question 27

CPC incidence

Answer 27

-seen in 1% of all pregnancies and 50% of trisomy 18 pregnancies
+Tri18 LR=7
*however it is rare for Tri18 to only be seen with this finding

Question 28

CPC

Answer 28

-relatively common abnormality seen within fetal brain ventricles in area that makes CSF
-in the absence of a karyotypic abnormality there is no association with fetal abnormality or developmental problems
+often times NIPS is first line testing now
-rarely can look similar to intracranial hemorrhage

Question 29

increased nuchal fold

Answer 29

• abnormal measurement at posterior fossa at 18-24w
• increases risk for DS (LR=17-especially if found before 20w), cardiac anomalies, single gene disorders such as skeletal dysplasias, Noonan, multiple pterygium syndrome
• fetal echo recommended as follow-up

Question 30

club foot

Answer 30

• 1 in 1000 live births, typically isolated with good prognosis
• can be related to positional factors (oligo, multiple gestation, uterine anomalies such as fibroids)
• can be a sign of neurological, muscle or connective tissue disorders including >50 genetic conditions

Question 31

omphalocele

Answer 31

• herniation of abdominal contents into umbilical cord
• 50% risk of chromosome abnormality
• increased need for c-section delivery

Question 32

gastroschisis

Answer 32

-intestines protrude into amniotic fluid without covering-typically to the right of cord
-usually sporadic and not due to karyotypic abnormality
+typically due to a vascular event that occurred
-seen more commonly in young mothers, particularly smokers
-usually prognosis is fine, some risk for IUFD, but fine if survive to birth-can sometimes need surgical resection

Question 33

skeletal dysplasias

Answer 33

-more than 300 types caused by single gene abnormalities
+makes pin-pointing type difficult prenatally, though some have characteristic features
+if detected in 1st or 2nd tri likely lethal, non-lethal present later or postnatally
-X-rays and autopsy can help determine recurrence risks

Question 34

identifying skeletal dysplasia on ultrasound

Answer 34

-measuring long bones (humerus & femur)
+on anatomy making sure these & digits are present
+if these are short or oddly shaped measure all 12
-looking at shape of the head
-measuring chest circumference/size

Question 35

preaxial extra digits

Answer 35

more concerning from genetics POV than post-axial which is more likely to be isolated or familial
-polydactly more common in AA populations and can be inherited in AD fashion

Question 36

clefting

Answer 36

• 1/1000 live births

- typically isolated, but can be part of 300+ syndromes