Brainscape's Knowledge GenomeTM

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


See full index

MLSCI 270 > HDFN & RhIg > Flashcards

HDFN & RhIg Flashcards

1
Q

HDFN

A
  • maternal red cell antibodies (IgG) crss placenta and attach to fetal cells causing hemolysis
  • anemia in fetu
  • increase in erythropoiesis (Erythroblastosis fetalis)
  • mild to severe depending on antibody identity and concentration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

factors of maternal Ab production (5)

A
  • amount of blood (0.5 mL vs 25 mL
  • immunogenicity of antigen (D vs Fya)
  • previous exposure (primary vs secondary)
  • maternal immune response (responder vs. non-responder)
  • ABO compatibility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

severe cases of HDFN (in utero)

A
  • profound anemia
  • hepatosplenomegaly
  • hypoproteinemia
  • cardiovascular failure (heart enlarged bc decrease in RBC mass)
  • “Hydrops fetalis” severe edema = infant dies in utero
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

severe cases of HDFN (postpartum)

A
  • anemia
  • hyperbilirubinemia
    > unconjugated bilirubin increases = Kernicterus
  • hemolysis continues postpartum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

kernicterus

A

brain damage

  • unconjugated bilirubin crossed BBB
  • cerebral palsy-like effect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why don’t we see jaundice in fetus?

A

bc bilirubin in amniotic ac ad mom is getting rid of it so jaundice only seen in newborn

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

these blood groups are not associated with HDFN

A

Lewis
P
I (babies = i)

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

most common blood group associated with HDFN

A

ABO

  • mild or subclinical
  • first pregnancy can be affected
  • IgG ABO antibodies (anti-A,B)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

disease at birth for ABO HDFN

A
  • no anemia or mild
  • no jaundice, but bilirubin increases
  • spherocytes on smear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is RhIg?

A
  • human source anti-D
    > acquired from pooled plasma with anti-D
    > anion exchange column chromatography
    > solvent detergent (destroys lipid enveloped viruses) and ultrafiltration steps (removes non-enveloped viruses)
    > lyophilized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how is RhIg delivered?

A

intravenous (IV) or intramuscular (IM)

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

mechanism of action RhIg

A

used for prevention of anti-D production in pregnancy when given to Rh neg females

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

mechanism of RhIg is not fully understood but may involve inhibiting the adaptive immune system by: (3)

A
  • masking epitope of D antigen
  • increasing rate of removal of D pos infant cells by opsonization (removal by spleen)
  • FcyRIIB receptor inhibition of B cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

who gets RhIg? and when?

A
  • given to Rh neg females without active anti-D
  • 28 weeks gestation (26-32 weeks)
    > removes any Rh pos fetal cells that enter maternal circulation prior to delivery
  • <72 hrs post-delivery of Rh pos or wk D pos infant
    > removes fetal cells from circulation at time of delivery
  • additional dose may be given throughout pregnancy (amniocentesis, trauma, incomplete/therapeutic abortion)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

standard dose RhIg

A
  • 300 ug
  • 1-300 ug will clear: 30 mL whole blood; 15 mL packed cells

** additional vials may be needed depending on size of bleed **

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

prior to RhIg, what was the only treatment for jaundice babies?

A

phototherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

RhIg effectiveness

A
  • 15% of white women are Rh neg
  • no RhIg given = anti-D production = 12-13%
  • 1 dose postnatal = 1%
  • 28 wk and postnatal dose = 0.1%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

half-life of RhIg

A

23-26 days
- may be detected up to 8 weeks in patients following injection (passive anti-D) and can interfere with PRETRANSFUSION testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

T or F. RhIg is not effective when active anti-D is present

A

T! it’s a prevention strategy so if it’s made… can’t remove it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T or F. RhIg prevents antibody production to other blood group antigens

A

F! you can still make anti-c, -kell, etc.

21
Q

does passive anti-D harm the fetus?

A

no because given at last few weeks of pregnancy so risk is low and titre goes down eventually

22
Q

other uses of RhIg

A
  • Rh incompatible transfusions
    > may be given to Rh neg females of child-bearing potential <45y who received Rh pos blood (emergency, error, Rh pos platelets)
  • treatment for idiopathic thrombocytopenic purpura (ITP)
    > given to non-splenectomized Rh pos patients as an alternative to IVIg
23
Q

prenatal testing follow up when antibody screen is positive

A
  • Ab ID with panel
  • perform titration
  • antigen type mother and father
  • verbal report to physician: antibody screen, ID, and titre
24
Q

T or F. Level of Ab titre may not correspond to disease severity in infant

A

T

even though mom has a high Ab titre of anti-D, fetus could still be Rh neg

25
Q

This titre is significant for IgG antibodies

A

titre of 16 or greater

26
Q

any ttre of this blood group is significant

A

anti-K

- Kell can cause severe HDFN; on erythrobasts

27
Q

What is considered a significant rise in titre?

A

greater than two tubes

  • 8 to 32 is significant
  • 8 to 16 is not
28
Q

when do they check om’s Ab titre

A

month 7, 8, 9… etc.
physician decides what to do
could do amniocentesis to check bilirubin levels

29
Q

what to do with a positive DAT?

A

elution

30
Q

Elution

A

removes Abs for identification (panel)

31
Q

dissociation

A

removes antibody for antigen typing

32
Q

fetal bleed screen

A
  • Rosette test
  • detects if >30 mL Rh pos fetal cells entered maternal circulation
  • formed on maternal sample taken 1 hr after delivery (when bleed happens)
  • if mother is eligible for RhIg - FBS will be performed
  • positive result means additional RhIg is required (NOT COMMON)
33
Q

Kleihauer Betke test

A
  • determines how much Rh pos blood has entered maternal circulation
  • determines how many extra doses of RhIg is required
34
Q

elution methods

A
  • acid
  • heat
  • organic solvents
35
Q

acid elution method

A

decreased pH will disrupt bonds between antigen and antibody

  • add acid (pH 3) to elute antibodies from cells
  • centrifuge and recover supernatant
  • add buffer (pH 7) to supernatant restore pH
36
Q

heat elution method

A
  • dentatures protein structure of antigen so antibodies are released
  • Landsteiner-Miller Heat 56C
  • Lui-Freeze Thaw
37
Q

organic solvents elution method

A

disrupts bonds betwen antigen and antibody by decreasing surface tension/dissolving lipid membrane

  • Ether
  • Xylene
  • Dichoromethane
38
Q

partial elution

A
  • dissociation or cell-saving elution
  • EDTA Glycine Acid (EGA) = destory Kell antigens
  • Chloroquine diphosphate (CDP)
  • ZZAP/WARM
    > Papain = destroys MNS, Duffy, Chido & Rodgers
    > DTT = destroys Kell
  • modified heat 45C
39
Q

this test is performed on the mother’s postpartum sample to determine if > 30 mL of fetal blood has entered her circulation

A

Rosette test

40
Q

how to perform a Rosette test

A
  • maternal 3% suspension made
  • incubate ^ with monoclonal anti-D at RT (binds to infant Rh cells)
  • wash to remove unbound Abs
  • indicator cells added = R2R2 cells that will bind to antibody-coated infant cells causing agglutination that can be detected MICROSCOPICALLY
  • presence of agglutinates = significant amount of fetal cells in maternal circulation (>30 mL)
  • follow-up testing for quantitation
41
Q

T or F. Fetal cells are usually macrocytic

A

T

42
Q

this test is performed to quantitate the number of fetal cells present in the maternal circulation

A

Kleihauer-Betke test

43
Q

purpose of Kleihauer-Betke test

A

once size of bleed is determined, dose of RhIg can be calculated and administered to clear the fetal cells and prevent Ab formation

44
Q

how to perform Kleihauer-Betke test

A
  • PBS made from maternal postpartum sample and acid-treated
  • fetal cells remain intact bc of high HbF; adult Hb = eluted from maternal cells
  • slides are washed
  • stained
  • examined microscopically
  • # of fetal cells (STAINED) are counted per number of maternal cells (ghost cells)> volume of bleed is calculated to determine how much additional RhIg is required
45
Q

Number of (extra) vials of RhIg needed calculation

A

= [% fetal cells x maternal blood volume (~5000 mL)] / 30 mL (how much one vial can remove)

46
Q

goal of an exchange transfusion

A
  • reduce bilirubin level
  • remove sensitized cells
  • remove unbound maternal Ab
  • correct infant anemia
47
Q

blood product for an exchange transfusion

A

whole blood (red cells mixed with AB plasma) with a hematocrit of 0.55 (0.50 - 0.60)

48
Q

exchange transfusion

A

small amount of baby’s blood (once born) is removed and replaced by donor whole blood

MLSCI 270 (15 decks)

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