Disease in Embryology

Question 1

when is the first screening of the foetus and what usually occurs

Answer 1

undertaken at 10 - 14 weeks CRL 45- 84mm
calculates due date and current gestational age
have maternal blood sample to test for T21 (downs) T18 Edwards and T13 Patau

Question 2

what happens to likelihood of foetus having a cognitive disease with age of mother

Answer 2

increases

T21 most common then T18 then T13

Question 3

what is a nuchal translucency and what’s normal

Answer 3

thickness of the skin at the back of the neck normal is less than 3.5 mm
may have lost of fluid which could show problems

Question 4

when is the only range of times you can do a nuchal translucency

Answer 4

between 10 - 14 gestation

when the fetal lymphatic system is developing and peripheral resistance of the placenta is high

Question 5

what happens after 14 weeks and of gestation in regards to nuchal translucency

Answer 5

lymphatic system is developed draining away excess fluid

any abnormalities casing fluid accumulation would be undetected

Question 6

what are the causes of T21 and how common is it

Answer 6

non-disjunction (92%) or translocation (4%)

92% of affected pregnancies are terminated

1 in 800 people have it

Question 7

what are the typical physiological consequences of T21

Answer 7

congenital heart disease 40%
intellectual disability 
physical characteristics - small chin, shorter stature, sleep apnoea 
visual problems 80% (eg cataracts)
hearing problems 90% (eg otitis media)

Question 8

what is T18 and how common is it

Answer 8

Edwards syndrome
non-disjunction
1 - 3-5000

Question 9

what is the prognosis and clinical consequences of T18

Answer 9

60% die in utero
lifespan 5-15 days
microcephaly, cleft lip, clenched hand or fist

Question 10

what is T13 and how common is it

Answer 10

patois syndrome
non-disjunction or translocation
1 in 5-10,000

Question 11

what is the prognosis of T13

Answer 11

60% die in utero 
5-15 days alive 
severe mental disability 
seizures 
facial clefts

Question 12

what is anencephaly and what is the prognosis

Answer 12

failure of fetal skull formation
exposure of brain contents to pressure effects
100% mortality
98% detection rate in frist trimester

Question 13

what is the GIT derived from and in what week

Answer 13

endoderm
foregut - oesophagus - upper duodenum
midgut duodenum to 2/3 along transverses colon
hindgut 1/3 transverses colon to rectum

Question 14

what happens to the midgut in 6th week gestation

Answer 14

midgut protrudes through umbilical cord and undergoes 270 rotation clockwise process is completed by the 12th week

Question 15

what happens if herniation remains after 12 weeks

Answer 15

gastroschisis

omphalocele

Question 16

what is gastroschisis

Answer 16

4 in 1000
herniation of intestinal contents most commonly bowl
may include liver and stomach
corrected through surgery after birth

Question 17

what is omphalocele

Answer 17

1 in 4000
associated with higher rates of genetic defects
umbilical cord involvement
poorer outcome than gastroschisis

Question 18

what specific conditions are screening for in the second trimester

Answer 18

detailed examination of the heart and brain
spina bifida
cleft
cardiac diseases

Question 19

what diseases are only 50% likely to be detected

Answer 19

serious cardiac anomalies
transposition of great arteries
AVSD
hypo plastic left heart syndrome

Question 20

which condition has the highest detection rate

Answer 20

anencephaly

Question 21

which system develops the earliest

Answer 21

nervous system in week 3

but is also the last to be completed

Question 22

describe the basic formation of the nervous system

Answer 22

develops from the neural plate folding to become the neural tube

Question 23

what is the incidence of spina bifida and what causes it

Answer 23

1 in 500 to 1 in 2000
mostly isolated but can be genetic
failure of vertebral arches to close

Question 24

which are the common regions affect by spina bifida and what’s the treatment

Answer 24

lumbar 75% and 15% sacral
folic acid supplementation
sodium valproate

Question 25

what are the clinical consequences of spin bifida

Answer 25

dependant upon location 
leg weakness 
bladder and bowel incontinence 
sexual dysfunction 
risk of developmental delay

Question 26

what causes cleft lip

Answer 26

failure of fusion in week 12

Question 27

how common is cleft lip and what are midline clefts associated with

Answer 27

1 in 1000
60% are isolated
midline - associated with higher rates of genetic conditions