Developmental Pathology 1

Question 1

Define embryo, fetus, newborn(neonate) and infant.

Answer 1

embryo: conception until end of week 8
fetus: weeks 9 until birth
newborn: first month of extrauterine life
infant: first year of life

Question 2

Contrast developmental age and gestational age.

Answer 2

Developmental age: conception until birth or intrauterine demise
Gestational age: from LMP until removal or delivery of conceptus

Question 3

List the time frames for blastogenesis, organogenesis and phenogenesis.

Answer 3

blastogenesis: first 4 weeks (developmental fields develop)
organogenesis: end of week 4 to end of week 8- primitive organs form
phenogenesis- end of week 8 until birth (38th)- vulnerable to defects

Question 4

Contrast intrinsic v. extrinsic abnormalities.

Answer 4

intrinsic: cell/organ development that is inherently abnormal from the beginning– malformations and dysplasias

extrinsic abnormalities: external forces alter development– deformations, disruptions

Question 5

Oligohydramnios, malformed uterus, liomyomata, major CNS defects cause what type of congenital malformation.

Answer 5

deformation: abnormal form or position of a body part caused by mechanical force (extrinsic, occurring during phenogenesis)

Question 6

Which direction due talipes calcaneovalgus and talipes equnovarus point?

Answer 6

valgus- points toward midline

varus- points away from the midline

Question 7

Describe the Potter sequence as an example of a sequence.

Answer 7

Potter sequence results from oligohydramnios, oligohydramnios due to renal agencies

oligohydramnios results in pulmonary hypoplasia, altered facies, positioning defects of hands and feet, breech presentation (all due to fetal compression)

Question 8

List 4+ factors that can cause congenital malformations.

Answer 8

genetic: either chromosomal or single gene mutation
environmental factors (teratogens)
multifactorial
undetermined (most)

Question 9

Contrast the phenotypes of autosomal trisomies: Down Syndrome, Edward’s syndrome and Patau Syndrome.

Answer 9

Down Syndrome 21 : epicanthic folds, leukemias, dementia
Edwards 18: micrognathia (small jaw), overlapping fingers
Patau 13: polydactyly, palate (clef), puny eyes (microphthalmia)

Question 10

Teratogenic induced anomalies are typically ____.

Answer 10

disruptions (usually before 8weeks)

Question 11

List 5+ examples of drug/chemical teratogens.

Answer 11

thalidomide- limb defects via down regulation of wingless (WNT signaling)

folate antagonists

hormones (esp. androgenic)

valproic acid- disrupts homeobox HOX TF proteins for limb- vertebral-craniofacial development

retinoid acid- interrupts TGF-B signaling- cleft lip/palate

warfarin
alcohol- pre and postnatal growth retardation, facial anomalies, CNS dysfunction

maternal diabetes: large for gestational age and hypoglycemia post birth

Question 12

Name the TORCHS infections.

Answer 12

toxoplasmosis
rubella
cytomegalovirus
herpes simplex
syphilis

(all except herpes are transplacental)

Question 13

Common organs affected by TORCHES include (3)?

Answer 13

1. eyes: retinitis in too or cataracts in rubella
2. heart defects: PDA in rubella
3. deafness

Question 14

When is a fetus most susceptible to toxoplasmosis and what are the results of infection?

Answer 14

risk of transmission increases with gestational age, more severe malformations with early infection

results in periventricular calcifications and chorioretinitis

Question 15

When is a fetus most susceptible to rubella and what are the results of infection?

Answer 15

transmission risk earliest in pregnancy (1st trimester)

results in cataracts, heart defects (PDA), defense, and mental retardation

Question 16

CMV infection in the ____ trimester results in what?

Answer 16

second trimester: mental retardation, microcephaly, deafness, hepatosplenomegaly

preterm delivery or fetal death with stillbirth

**characterized by chronic violates and viral intranuclear inclusions (owl eye)

Question 17

Describe two different phenotypes of herpes simplex virus infection (herpes neonatorum).

Answer 17

limited: SEM disease- skin, eyes and mucous membranes affected in severe desquamating skin disease

disseminated infection is often fatal and involves the liver and brain

Question 18

Contrast early and late congenital syphilis infections.

Answer 18

early (infantile): snuffles (nasal congestion), blouse skin rash, hepatomegaly, skeletal abnormalities (saddle nose, saber shin)

late (tardive): after two years
Hutchinson triad: notched centra incisors, interstitial keratitis (blindness), deafness

Question 19

What are the effects of early radiation exposure of a developing fetus?

Answer 19

high doses in 1st trimester is worst: microcephaly, blindness, skull defects, spina bifida, cleft palate, others