Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Transfusion Science > Haemolytic Disease of the Newborn and Foetus > Flashcards

Haemolytic Disease of the Newborn and Foetus Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is Haemolytic Disease of the Newborn and Foetus

A

A condition in which the life span of foetal red cells is reduced by the action of specific antibodies derived from the mother by placental transfer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What led to a dramatic decrease in HDN cases after the 1970s

A
  • Routine antenatal care including:
  • screening of all expectant mothers to find those whose pregnancy may be at risk of HDN
  • giving preventative tx accordingly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The disease involves (3)

A
  1. Maternal alloimmunisation -> produces antibody
  2. Transplacental passage of IgG antibody to the foetus
  3. Sensitisation and destruction of foetal cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of immune system do newborns have

A

Primitive immune system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What keeps the foetus alive while they have their primitive immune system

A

The transport of the mothers antibodies across the placenta and into the fetal circulation. This occurs as their immune system matures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a major cause of HDN

A

An incompatibility of the Rh blood group between the mother and foetus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which pregnancies are at risk of HDN

A

Ones in which a Rd D- mother becomes preggers with a Rh D+ foetus (child inherited D+ antigen from father)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the Rh D- mother’s immune response to a Rh D+ foetus

A

The mothers immune response to the fetal D antigens is to form anti D antibodies against it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of antibodies are tha anti D antibodies and what does this mean

A

IgG antibodies. These type of antibodies can cross the placenta and be delivered to the fetal circulation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is ABO incompatibility less severe than Rh incompatibility

A

Fetal rbcs express less of the ABO blood group antigens compared with adult levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When may some foetal cells pass into the maternal blood system (2)

A
  1. At delivery
  2. Occasionally during pregnancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Initially, what type of antibody is the maternal anti D antibody and can it cross the placenta

A

Initially, the anti D antibody is of the IgM type, this cannot cross the placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens in subsequent pregnancies after the formation of the IgM anti D antibodies

A

A repeat pregnancy with a Rh D+ child stimulates the rapid production of type IgG anti D antibodies which can cross the placenta into the foetal circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Once in foetal circulation what does the anti D antibody do

A

Attach to the Rh D antigens found on the foetal rbcs. This marks them to be destroyed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What determines the nature of HBN to be mild, moderate or severe

A

The rate of haemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What occurs in mild cases

A
  • The small increase in red cell haemolysis is tolerated by the foetus
15
Q

Symptoms (2) and tx of newborns with mild cases of HDN

A
  1. Mild anaemia
  2. Jaundice
    Both of these may resolve w/o tx
16
Q

What happens when there is an increased rate of haemolysis

A
  • Bilirubin may remain low during pregnancy as placenta can remove bilirubin from the foetal circulation
  • Post delivery the neonate’s immature liver is unable to metabolise the increased bilirubin accumulated in their blood
  • Within 24 hrs bilirubin may rise and enter the brain, causing kernicterus
17
Q

What is kernicterus and its prognosis

A

Kernicterus is a potentially fatal condition that leaves permanent neurological damage in the babies that survive.

17
Q

Complications of HDN (6)

A
  1. Anaemia -> in foetus & neonate
  2. Jaundice -> elevated bilirubin
  3. Kernicterus -> seen in jaundice infants where bilirubin crosses into the brain and attaches and damages the brain tissue
  4. Hydropic -> bloated w fluid
  5. Hydrops foetalis -> watery foetus suffering from oedema bloated w fluid
  6. Erythroblastosis foetalis -> large no.s of nucleated rbcs in foetal peripheral blood
17
Q

Testing of the mother (4 methods)

A
  1. Previous history -> of transfusions, pregnancies, infants affected by HDN
  2. ABO and Rh testing -> all Rh D- mothers must be identified
  3. Antibody screen -> should be performed using the IAT to detect IgG antibodies in the mother
  4. Antibody identification -> if antibody screen is positive, need to determine the identity of the antibody and its clinical significance
18
Q

How many times must antenatal mothers be blood grouped

A

At least twice

19
Q

What is performed to determine if a Rh+ mother has been sensitised to the Rh D antigen

A

An antibody screen is performed on her plasma

20
Q

What is given to unsensitised mothers to reduce the risk of future sensitisation

A

Anti-D Ig

21
Q

What does Anti D Ig do

A

Mops up any foetal rbcs that may have leaked into the mother’s circulation

22
Q

When do Rh- mothers receive anti D Ig (2)

A
  1. At about 28 wks gestation, which is about when the foetal rbcs start expressing the D antigen
  2. A few wks before labour begins (Risk of feto-maternal hemorrhage is high)
23
Q

When is the final dose of anti D Ig given

A

After the baby has been delivered if the baby is Rh +

24
Q

How is the father tested

A

By doing a Rhesus genotype, which predicts the chances of having a Rh + baby

25
Q

What are the chances of a Rh+ baby with a father who is homozygous DD

A

100% chance of foetus being Rh+

26
Q

What are the chances of a Rh+ baby with a father who is heterozygous Dd

A

50% chance of foetus being Rh+

27
Q

How can the level of haemolysis in the foetus be measured

A

The level of bilirubin in the amnion can be measured and is indicative of the level of haemolysis in the foetus

28
Q

What other ways is the foetus tested (4)

A
  1. Foetal blood sampling for blood group
  2. Direct Coombs test
  3. Hb (anaemia)
  4. Bilirubin (jaundice)
29
Q

What is the Doppler ultrasound used to test for in the foetus

A

Non invasive technique for measuring oedema and anaemia in the foetus

30
Q

How is the neonate (newborn) tested

A
  1. Cord blood taken (representative of neonatal sample)
  2. ABO and Rh of infant
  3. Direct Coombs test -> see if maternal antibody has attached to infant’s cells in utero
  4. Hb level to assess anaemia
  5. Bilirubin level to assess jaundice
31
Q

Management & tx of foetus with suspected HDN

A
  1. Intrauterine blood transfusions
  2. Early delivery solution to Hydropic baby -> prematurity has risks
    3.Phototherapy -> aids w excretion of bilirubin
  3. Top up blood transfusions post delivery
  4. Immediate exchange transfusion post delivery -> alleviate the hyperbilirubinaemia, correct anaemia

Transfusion Science (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions