Congential defects

Question 1

What is a congenital defect

Answer 1

this means that it is present at birth

Question 2

describe the statics of congenital defects

Answer 2

• Around 20% of live births have some defect
• 75% are minor anomalies – not immediately life threatening – does not require intervention immediately
• 25% are major structural anomalies- not compatible outside the uterus require some

Question 3

what is a minor anomaly

Answer 3

75% are minor anomalies – not immediately life threatening – does not require intervention immediately

– Approx 15%
– Anomaly does not usually require intervention
– Causes minimum handicap
– Children with 1 minor anomaly have 3% chance of a having a major malformation

Question 4

what is a major anomaly

Answer 4

• 25% are major structural anomalies- not compatible outside the uterus require some
  – Approx 6% (3% live births plus 3% diagnosed later)
  – Anomaly that requires medical/surgical treatment
  – Causes significant handicap

Question 5

what is the leading cause of infant mortality

Answer 5

congenital defects

Question 6

what are the causes of congenital defects

Answer 6

• Genetic/chromomse (13-15%) - down syndrome
• Drugs (7-10%) – acne medication (Accutane) and thalidomide
• Environmental (7-10%) – infectious agents (rubella, CMV, Zika) chemical agents alcohol

Question 7

what is the name of an acne medication that can cause congenital defect

Answer 7

Accutane – vitamin A retinoic acid – gets stored in fat and has toxic levels of vitamin A that can pass across the placenta

Question 8

what is the percentage of causes of congenital defects that we do not know about

Answer 8

• 70% of all birth defects we don’t know what the cause is or it is multifactorial

Question 9

what has the USA and 77 other countries done to reduce the risk of not enough folic acid intake

Answer 9

• USA and 77 countries fortify flour and cereals to increase general population intake

Question 10

what does not enough folic acid cause

Answer 10

neural tube defects such as ..

• spina bifida
• skull bone doest form

Question 11

why is it important to take folic acid before you become pregnant

Answer 11

• usually don’t find out till you miss a period by that point around 28 days has gone this means that you miss the important formation steps of the baby

Question 12

what week is the embryo stage too and form

Answer 12

3-8 weeks

Question 13

what weeks are the foetal stage to and from

Answer 13

9-38 weeks

Question 14

what is the foetal period

Answer 14

foetal period is a growth period and the embryonic period is a patterning stage

Question 15

name some examples of major congenital defects

Answer 15

• anencephaly
• cleft lip and cleft palate
• omphalocele
• gastroschesis
• hypospadias
• phocomelia
• spina bifida
• talipes equinovarus

Question 16

name some examples of minor congenital defects

Answer 16

• auricular ear tag or pit
• supernumerary nipples
• cryptorchidism
• syndactyly
• rocker bottom feet
• polydactyly
• overlaying digits
• micropensi

Question 17

what is anencephaly

Answer 17

• The uterus is contracting and the physical movement of the brain against the wall of the uterus can dmage the brain and lead to significant brian damage
• They can survive for a couple of years and it depends on how much of the brain has been damaged
• They have a face but know skull

Question 18

what is Hypospadias

Answer 18

• It is a problem of the male external genital not closing properly
• Opening of the urethra hasn’t closed down the shaft of the penis
• It needs surgical correcting

Question 19

what is cryptorchidism

Answer 19

• Undescending testes
• Most spontaneously correct within 3 months
• Undescended testis incidence 7.6:1000
• Cryptorchidism 1-4% of live male births, most spontaneously correct within 3 months
• Still undescended in 1% at 1 year of age.
• 20x increased risk of developing testicular malignancy
• It also potentially leads to male infertility as well

Question 20

what does cryptorchidism lead to infertility

Answer 20

• In the scrotum the testes is one to two degrees cooler but if it is stuck in the body cavity it gets heated up and this can lead to infertility

Question 21

how does holoprosencephaly vary

Answer 21

• This is loss of midline structrues down the midline

- Can vary from mild to sever

Question 22

what can cause holoprosencephaly

Answer 22

• Can be genetic or environmental (alcohol consumption)

Question 23

where can we detect cleft lip and cleft palate

Answer 23

• We can detect these earlier and do surgery to correct them in uterus
• Better regenertative capacity in utero
• Better diagnostic tools for earlier detection

Question 24

what is congenital diaphragmatic hernia

Answer 24

• The diaphragm separate the thoracic from abdominal cavity, but in some babies it doesn’t and there is a defect in the diaphragm that allows the liver and the gastrointestinal loops to go into the thoracic cavity
• The lungs still need to form
• Intestines can push the heart and lungs across, this constricts the left and right lung from being able to develop

Question 25

how do you repair congenital diaphragmatic hernia

Answer 25

- Repairs can be done with simple sutures or for large defect a synthetic patch such as Gor-tex, polytetrafluoroethylene (Teflon), Dacron and tendon. - In utero repair via laproscopy can allow lungs to develop

Question 26

what is gastroschsis

Answer 26

- This is split belly where the abdomen body wall hasn’t closed and you have loops of the intestine that fall out into the ammonitic sac, it is toxic and up against the uterine wall

Question 27

how is gastroshciss repaired

Answer 27

- Gastroschisis reduction of bowel back into the abdomen may not be possible initially without undue tension. - A prosthetic silo is gradually tightened, and after a few days can be removed

Question 28

what happens in week one of fertilisation

Answer 28

- Fertilisation in ampulla region of uterine tube within 24 hours of ovulation - 3 days after fertlsiation – ball of cells morula - Then you start cell division and become a zygote until 3 days after fertilisation you become the morula - They still continue to divide and form a blastocyst

Question 29

describe how the blastocyte impacts

Answer 29

- The blastocyst hatches from the zona pellucida which allows implantation - this prevents any sperm getting in and happens around day 5 - Blastocyst implants to the endometrium around day 6 - The cells around the outside become the placenta

Question 30

what happens in week 2

Answer 30

Trophoblast differentiates into 2 layers Embryoblast differentiates into 2 layers 2 cavities formed -

Question 31

what are the two layers that the trophoblast differentiates into in week 2

Answer 31

Trophoblast differentiates into 2 layers - Syncytioblast - Cytotrophoblast - These are mutil nucleated cells that form the vili and push around and form the placenta proper

Question 32

what are the two layers that the embryoblast differentiates into in week 2

Answer 32

Embryoblast differentiates into 2 layers - Epiblast dorsally - Hypoblast ventrally - Comes from the inner cell mass and forms two layers the epiblast and hypoblast this forms the primordial germ cells

Question 33

what are the two cavities formed in week 2

Answer 33

2 cavities formed - Amniotic cavity dorsal to epiblast - Yolk sac cavity ventral to hypoblast

Question 34

what is a hydatitidform mole

Answer 34

- Molar pregnancy - These are where there is no embryo and just placenta because the syncytioblast only come from the placenta - The placenta comes from the paternal genes and the placenta is thereof reforms when you have a anucular egg and then undergo cell division but they all come from the father - Or you have two sperm that go into the a nucular and produce 46 XX or 46 - Whole of the uterus is filled with the placenta - Moles are generally lagre and composed of grape like clusters of swollen chorionic villi

Question 35

what is a partial hydatirfomr

Answer 35

- Two sperm fertilise one egg so there are 69 chromosmes - So there are two lots of paternal genes that fomr more placenta but maternal genes that give the embryo - Some evidence of embryonic development can be found - Karyotype usually triploid - 69XXX, 69XXY, 69XYY

Question 36

what happens in week three

Answer 36

• Two layers transformed by gastrulation into three germ layers – Ectoderm – Mesoderm – Endoderm – But everything comes from the epiblast, in the midline running down there are invaginations, everything streams into the middle and goes underneath and into the three layers, the cells that invaginate and move in and round happen in the midline this establishes the three germ layers and the body axis, decides where the head is and the body is, body axis is determined during gastrulation • Establishes body axes – Cranial / caudal – Dorsal / ventral – Left / right

Question 37

what does the ectoderm form

Answer 37

nervous system and skin

Question 38

what does the mesoderm form

Answer 38

muscle, connective tissue, bone

Question 39

what does the endoderm form

Answer 39

gut

Question 40

what is Milagros carron

Answer 40

- Epiblast cells stop invaginating too soon, insufficient mesoderm is produced - It is often associated with kidney and gastrointestinal defects so few survive to have the legs separated

Question 41

what is situs inerversus

Answer 41

* Situs inversus 0.01% of population | * Complete reversal of organs in body cavity,