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MFM Exampro Questions > Prenatal diagnosis > Flashcards

Prenatal diagnosis Flashcards

1
Q

Frequency of abnormalities in LIVEBORNS

A

Chromsomal abnormality: 0.5%
Mendelian disorder: 1%
Polygenic/multifactorial: 1%
unknown etiology: 2-3%

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2
Q

Recurrent risk after birth of child with chromosomal abnormality?

A

T21 1.5%
or the maternal age related risk, whichever is higher

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3
Q

Recurrence risk for children with NTD

A

Recurrence Risk:
o For mother with NTD: 5%
o For couple with previous affected child: 2-3%
o For couple with 2 affected children: 6-10%

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4
Q

Microarray analysis

A
  • to find small deletions or duplications (copy number variants)
  • Case presentation:
    o Amnio = 46 XX, t(9;14)(p23;q23)
    o Apparently balanced translocation between chromosome 9 and 14
    o Parents have normal karyotype
  • Microarray analysis can detect abnormalities below the level of detection of a routine karyotype, as well as whole chromosome abnormalities
  • May detect CNV of unknown significance
  • CANNOT detect balanced translocations, inversions, low level mosaicism, or point mutations
  • Most beneficial when US identifies anomaly
  • With IUFD/stillborn  cells won’t grow in culture for karyotype, but can be assed by microarray
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5
Q

What can microarrays NOT detect

A

Balanced rearranagement

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6
Q

Chance of multifactorial inheritance with cleft lip?

A

1-5%

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7
Q

What are considerations of ultrasound? Based on thermal and mechanical effects?

A
  • Thermal bioeffects refer to heat generated within or around cells exposed to ultrasound
  • Mechanical effects refer to potential impact on tissue from phsiical forces generated by ultrasound waves, such as radiation, streaming, free radicals, and cavitation
  • ODS (output display standard) – an approximation of risk of thermal injury is the therma index (TI); and the standard for mechanical mechanisms is the mechanical index (MI)
  • A low risk of thermal or miechanical bio effects is seen with TI or MI value of < 1, and if ultrasound machine is capable of producing output levels of greater than 11, then either the TI or MI must be displayed on the screen
  • Recommended scanning time with TI 0.5-1 = < 60 minutes; if TI 1-1.5 = < 30 min
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8
Q

Microarray diagnoses and anomalies

A

Microarrays analysis detects clinically relevant deletions or duplications in 6% of fetuses with structural anomaly and normal karyotype

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9
Q

Acrania/anencephaly, recurrent risk

A

 Lethal, multifactorial, IDDM, antiepileptic drugs
 r/o spina bifida
 5-6% recurrence risk

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10
Q

Ventriculomegaly

A

o VM: most common associated anomaly is spina bifida; if cyst, could be DW
 Shrinkage of CP at 14 weeks(dialted VS with small CP)
 Posterior horn > 10mm
 (mom’s trial – fetal surgery for OSB – decreased need for shunting; more babies walking without assistance; but increased PTB rate and uterine dehiscence)

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11
Q

Agenesis of the corpus callosum

A

 Dilated posterior horns
 Absent CSP
 If isolated, normal outcome in 90% of cases
 Tear drop/wide posteriorly
 CC is formed at 22 weeks

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12
Q

Holoprosencephaly

A

single ventricle; fusion of thalami; midline defects (cyclopia, clefts, proboscis)
 Recurrence: 6%
 Dx: semilobar = separate ventricles except frontal horns

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13
Q

Hydrancephaly

A

: fluid filled cranium; no cortex liquefied brain
 Work up: thrombophilia – thrombosis of internal carotids can cause this

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14
Q

Porencephaly

A

o Porencephaly: result of infarct
 Communicates with lateral ventricles; arachnoid cysts does NOT communicate
 One or more cystic cavities communicating with ventricles (infarction or hemorrhage)
 Prognosis: related to size and location of lesion; development may be normal

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15
Q

Schizencephaly

A

clefts connecting the lateral ventricles with sub-arachnoid space – absent CSP
 Occluded MCA thrombophilia
 Prognosis: severe neurodevelopmental delay

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16
Q

Schizencephaly

A

clefts connecting the lateral ventricles with sub-arachnoid space – absent CSP
 Occluded MCA thrombophilia
 Prognosis: severe neurodevelopmental delay

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17
Q

Arachnoid cyst

A

o Arachnoid cyst: not communicating with ventricles; one or more cystic cavities
 No blood flow
 Prognosis: related to mass effect; development may be normal (80%)

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18
Q

Encephalocele

A

o Encephalocele: skull defect (75% occipital); herniated brain tissue
 Diff dx: meckel gruber; amniotic band syndrome
 Prognosis: depends on amount of brain tissue; 80% are impaired)

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19
Q

Meningocele

A

o Meningocele: skull defect with no herniated brian tissue
 Prognosis good

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20
Q

Vein of Galen

A

o AV malformation: Vein of Galen
 Midline cystic tubular structure posterior to the thalamus with blood flow
 3rd trimester MR should be done
 Prognosis:
* Alive and well (35%); alive and MR (15%); Overall PND rate (55%)

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21
Q

Intracranial tumors

A

o Intracranial tumors: usually distorted intracranial anatomy; prognosis usually poor
 Craniopharyngioma
 Teratoma
 Undifferentiated tumor

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22
Q

Intracranial hemorrhage

A

o Intracranial hemorrhage: r/o AIT (50%)
 Test mom for anti platelet antibodies

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23
Q

Cleft lip

A

o If have cleft lip: have 75% chance of having cleft palate
 Worse prognosis = bilateral cleft

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24
Q

Nuchal fold vs cystic hygroma and diagnoses associations

A
  • Nuchal fold/nuchal edema – think T21
  • Septated cystic hygroma – think 45 XO
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25
Q

Cystic hygroma

A
  • Cystic hygroma:
    o Multiseptated cystic masses; intact skull and spine
    o Hydrops present in 80%
    o Prognosis good if isolated
26
Q

Fetal goiter

A
  • Fetal goiter: if hypothyroid: thyroxine injected into amniotic sac
    o If hyperthyroid: PTU/Tapozole for mom
    o Enlarged thyroid below level of larynx; poly in 3rd trimester
    o r/o maternal grave’s disease; 80% are hypothyroid
    o prognosis: good if euthyroid at birth
27
Q

CHAOS

A
  • CHAOS (congenital high airway obstruction Syndrome)
    o Prepare for EXIT – c/s; use of relaxants; delivery of head to the shoulders – allow enough time for bronchosopic evaluation of airway and tracheostomy placement
28
Q

Sacrococcygeal teratoma

A
  • Sacrococcygeal teratoma: huge vascular teratoma from the top of the sacrum; intact spine
    o w/u: rule out AV shunting, CHF, hydrops
    o prognosis: perinatal morality (50%) due to PTD or hydrops
    o without surgery, malignant transformation (80% by 4 months)
    o 1st sign of CHF = pericardial effusion, then ascites
29
Q

Hemivertebrae

A
  • Hemivertebrae
    o r/o VATER, Klippel-Feil, Noonan’s , sirenomelia/caudal regression, Carco-Levin
30
Q

Congenital diaphragmatic hernia

A
  • CDH: 95% are left sided
    o Left: mediastinal shift to the R
     Absence of normally placed stomach
     Liver in chest (50%)
    o Right: mediastinal shift to the left; GB in the chest; normally placed stomach
    o Portal vessels in the chest
31
Q

4CV cardiac anomalies

A
32
Q

TEF

A
  • TE Fistula/Esophageal atresia:
    o Absent stomach; poly
    o Dilated proximal esophageal pouch
    o Survival 95% if isolated
33
Q

BPS

A
  • Pulmonary sequestration:
    o White lesion (lower lobes or upper abdomen); feeding vessel from aorta
    o Diff dx: CCAM type III
    o Prognosis: good if isolated; poor if hydrops
34
Q

Abdominal anomalies- Duodenal atresia

A
  • Duodenal atresia:
    o Associated anomalies 20% (*cardiac); performe fetal echo)
    o Prognosis: good
35
Q

Abdominal anomalies- Duodenal atresia

A
  • Duodenal atresia:
    o Associated anomalies 20% (*cardiac); performe fetal echo)
    o Prognosis: good
36
Q

Diagnosis of fetal SBO

A
  • SBO: more than 2 fluid filled areas in the abdomen; peristalsis
    o Diff dx: meconium illeus, volvulus, Hirschsprung, abdominal cysts
    o r/o T 21; the higher the obstruction, the more the poly
37
Q

Body stalk anomaly

A
  • Body Stalk: omphalocele, severe kyphoscoliosis and a rudimentary UC; liver attached to placenta
38
Q

GU- renal agenesis

A
  • Renal agenesis: anhydramnios (by 16 weeks); no bladder; flattened adrenals; absent renal arteries
    o Work up: renal ultrasound of parents (15% have unilateral renal agenesis)
    o Prognosis: recurrence 3% (unless syndromic)
39
Q

PCKD (Potter Type I)

A

o Large, echogenic kidneys; may have oligo and nonvisualized bladder, may not be diagnosed until 24 wk
o r/o meckel gruber – polycystic kidneys and omphalocele
o amnio CVS with microarray
o recurrence = 25%

40
Q

Multicystic kidney disease (Potter type II)

A
  • Multicystic kidney disease (Potter type II)
    o Kidneys replaced by multiple non-communicating cysts of variable sizes; nonvisualized bladder if bilateral; oligo (if bilateral)
    o Rule out associated anomalies (cardiac, chromosome, renal agenesis)
    o Good prognosis if unilateral
41
Q

Adult polycystic kidney disease (Potter Type III)

A
  • Adult polycystic kidney disease (Potter type III)
    o US usually normal
    o Large kidneys with non-communicating cysts of variable sizes
    o 30% have cysts in liver, pancrease, splee, lungs
    o Cerebral aneurysms (20%)
    o Diff dx: mendelian disorders; genetic syndromes
    o Work up: amnio/cvs for microarray
     r/o tuberous sclerosis, Jeune syndrome, sturge-weber syndrome, meckel gruber, zellweger syndrome
    o Recurrence = 50%
42
Q

Candidates and considerations for in utero shunting for uropathies

A
  • Consideration for in –utero shunting:
    o Potential candidates:
     Bilateral mod-sev hydronephrosis and normal cortical echogenicity
     Severe megacystitis and decreasing AFV or oligo
     Normal levels of urinary Na, Ca, and b2 microglobulin
    o Poor prognostic criteria:
     Bilateral multicystic or echogenic kidneys suggestive of renal dysplasia
     Anhydramnios
     High urinary Ca, Ca, and b2 microglobulin levels
43
Q

Limb anomalies

A
44
Q

Poor prognostic factors for skeletal dysplasia

A

FL/AC < 0.16
Small (bell shaped) thorax
Short ribs
Marked bowing
Cloverleaf skull

45
Q

Differential for club food

A

Idiopathic
Spina bifida
T18
Pena-Shokier
ABS
Arthrogryposis
Skeletal dysplasis

46
Q

Thanatophoric dysplasia (type I and II) – 3rd trimester diagnosis

A

o Severe shortening of the limbs
o Narrow thorax
o Large head with prominent forehead
o Telephone receiver femurs (type I)
o Cloverleaf-shaped cranium (type II)

47
Q

Achondroplasia (3rd trimester)

A

o Heterozygous:
 Limb shortening (after 22 weeks)
 Microcephaly
 Frontal bossing
 Normal intelligence and life expectancy
o Homozygous:
 Small thorax – lethal

48
Q

Overall risk of congenital anomalies in newborns

A

3-5%

49
Q

Principles of teratogens

A

Teratogens:
- An agent which acts on developing embryo or fetus to create a structural abnormality or a deviation from normal morphology or function
- Principle 1: susceptibility depends on genotype of conceptus and how it interacts with environmental factors
o Classic: fetal hydantoin syndrome: related to metabolic defect in fetus
- Principle 2: susceptibility of conceptus to teratogens varies with developmental stage at time of exposure
o When does embryonic period of development end and fetal period begin?
 At the end fo the 10th completed week after menstruation
o “fetal period effects”
 May have substantial effect in CNS leading to altered behavior in life
 Differences may not even be recognizable until long after birth
- Principle 3: Teratogenic agents act non-randomly on developing cells and tissues
- Principle 4: final manifestations of abnormal development are death, malformation, IUGR< and altered function
o Largely dependent on which stage of development exposure occurred
- Principle 5: For an adverse effect to cocur, an agent must reach conceptus
o Placental passage
o Large molecules (MW > 1000) do not easily cross the placenta
- Principle 6: amount of abnormal development increases in degree with dosage of agent exposed
o May vary from no effect to lethal with same agent

50
Q

FDA categories

A
  • A: controlled studies in women fail to demonstrate risk to fetus
  • B: either animal studies have not demonstrated a fetal risk but there are no controlled studies in pregnant women OR animal studies show adverse effect that was not confirmed in controlled studies in women
    o Tylenol, narcotics, prednisone
  • C: animal studies show adverse effects AND there are no controlled studies in women OR studies in women and animals are not available
    o Phenergan, lorazepam
  • D: posistive evidence of human fetal risk but benefits may be acceptable
    o ACE I, PTU, warfarin, valproic acid, lithium, magnesium sulfate
  • X: studies have shown fetal risk in pregnant women clearly outweight any possible benefit
    o DES, danazol, thalidomide, isoretinoin
51
Q

Metabolic conditions that cause anomalies

A
  • DM:
    o Risk of anomalmies of poorly controlled is 11%
    o NTD, CHD, renal/GI, skeletal/sacral
    o HbA1c 10% - 25% risk of anomaly
  • Phenylketonuria: inborn error of phenylalanine hydroxylase leading to toxic accumulation of phenylalanine
    o Treated from infancy with dietary restriction
    o Normal growth and development
    o If off diet prior to conception, toxic levels will affect fetus
     Causes microcephaly and MR
     Complex cardiac defects
    o Autosomal recessive; check FOB status
    o Recommend against aspartame in pregnancy because of high phe content
52
Q

Mercury

A
  • Mercury:
    o Convered in muscle to methylmercery
    o Fetal neurologic damage with psychomotor retardation
    o Fish consumption of coated grains/contaminated fish
    o Largest amount in large predator fish
    o Canned tuna has less; usually limit to 2 cans/week in pregnancy
53
Q

Lead

A
  • Lead: risk for IUGR and MR
    o Lead levels should be < 25 micrograms/dl; ideally less than 10
54
Q

Fetal alcohol syndrome

A
  • IUGR, MR, microcephaly, short palpebral fissures, smooth philthrum and thin upper lip, CHD, small 5th fingernail
  • Effects seen with 2 drinks/day
  • No lower limit to exposure known
55
Q

Fetal hydantoin syndrome

A
  • Growth delay, MR, wide anterior fontanel, metopic ridging, hypertelorism, broad flat nasal bridge, bowed upper lip, cleft lip and palate, hypoplastic distal phalanges and nails, hirsutism
  • Affects 10% of fetuses exposed to dilantin
  • Dilatin metabolized to dilantin epoxide; fetuses homozygous deficient for dilantin epoxide hydrylase have fetal dilantin syndrome; can be diagnosed through parental carrier status and amnio
  • Tiny nails
  • Valproic acid: 1% risk for NTD
56
Q

Fetal Warfarin syndrome

A

Fetal Warfarin syndrome:
- Exposure during 6-9 weeks; 1/3 affected
- Appearance: nasal hypoplasia nd depressed nasal bridge; stippling of epiphyses, fingernail/fingertip hypoplasia, LBW, MR

57
Q

Retinoic embryopathy

A

Retinoic Embryopathy:
- Isotretinoin (Accutane) exposure: 35% embryopathy if used > 2 weeks post conception
- Appearance: abnormalities of 1st and 2nd pharyngeal arches surrounding 1st pharyngeal cleft
- Microtia (small ears), anotia, micrognathia, hypertelorism, conotruncal cardiac defects, hydrocephalus, microcephaly

58
Q

Fetal thalidomide syndrome

A
  • Marketed for morning sickness in 50’s; no abnormalities in animal testing
  • Malformation produced in tissues of mesodermal origin related to time of ingestion; single dose produced syndrome
  • Affects: long bone development; limb reductions
    o External ear abnormalities, normal intelligence, fusion of fingers
  • Absolute risk: 20% of those exposed
  • Phocomelia – hand and feet close to the trunk (no long bones)
59
Q

Effects of tetracycline

A
  • Tetracycline: adverse effect on fetal teeth and bones
    o Medication complexes with calcium orthophosphate; leads to bright yellow teeth
    o Teeth undergo calcification at 5 months; use after causes staining of enamel
60
Q

Effects of tetracycline

A
  • Tetracycline: adverse effect on fetal teeth and bones
    o Medication complexes with calcium orthophosphate; leads to bright yellow teeth
    o Teeth undergo calcification at 5 months; use after causes staining of enamel
61
Q

Substance use and fetal risks

A

Illicit Drug use:
- Marijuana: mild growth delay
- Opiates: increased risk for IUGR and risk for IUFD
- Amphetamines: cleft lip/palate, IUGR
- LSD: no anomalies
- PCP: postnatal irritability
- Cocaine: no pattern, but increased risk of:
o Genitourinary anomalies
o Cardiac anomalies
o CNS anomalies
o Ophthalmologic anomalies
o Limb anomalies
o Related to vasospasm and hypoxia
o Maternal effects: increased risk of elevated HR/BP; abruption, PPROM, LBW, previa

MFM Exampro Questions (17 decks)

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