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Immunohematology - 4444 > Hemolytic disease of the fetus and newborn > Flashcards

Hemolytic disease of the fetus and newborn Flashcards

1
Q

HDFN is also known as

A

Erythroblastosis fetalis

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2
Q

HDFN

A

Fetal or newborn red blood cells (RBCs) are
destroyed by maternal immunoglobulin G (IgG)

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3
Q

Hemolytic disease ofthe fetus and newborn

Maternal antibodies

A

– Cross the placenta
– Sensitize fetal RBCs
– Shorten RBC survival

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4
Q

The genetic reason for hemolytic disease of the fetal newborn

A

Rh negative woman and Rh positive man conceive a child

and then effects 2nd pregnancy

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5
Q

HDFN may occur when fetal cellls escape into

A

the maternal circulation as a result of a
fetomaternal hemorrhage

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6
Q

etiology of fetal RBC antigens

A

that
the mother does not have
stimulate the mother to
produce antibodies

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7
Q

Etiology

Antibodies bind

A

Antibodies bind to fetal
antigens and cause RBC
destruction in the fetal
liver and spleen

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8
Q

Etiology

Before birth

Indirect bilirubin is conjugated by

A

Indirect bilirubin is
conjugated by the
maternal liver

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9
Q

Etiology

Before birth

As RBC destruction continues

A

fetal
erythropoiesis increases

  • Erythroblasts are released
    (erythroblastosis fetalis)
  • Edema occurs in the
    peritoneal and pleural
    cavities (hydrops fetalis)
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10
Q

Etiology

what may result

A

Cardiac failure may result

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11
Q

After birth

Newborn cannot _______

Unconjugated bilirubin binds to albumin and then to ____________

Permanent brain damage ( __________) may result if ___________ binds to tissues of the central nervous system

A

AFTER BIRTH
* Newborn cannot
conjugate bilirubin
* Unconjugated bilirubin
binds to albumin and
then to tissues (jaundice)
* Permanent brain damage
(kernicterus) may result if
bilirubin binds to tissues
of the central nervous
system

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12
Q

Overview of HDFN

what is the RBC antibody type
Fetus must possess an __________ that the mother lacks
___________ is inherited from the father

A

IgG

  • RBC antibody must be IgG
  • Only IgG crosses the placenta
  • Fetus must possess an antigen
    that the mother lacks
  • The gene is inherited from the father
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13
Q

HDFN

Antigen must be

A

Well developed at birth

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14
Q

Types of HDFN

A

Rh (D antigen)
ABO
Other antibodies

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15
Q

Rh HDFN

is the most

A

Severe

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16
Q

Rh HDFN

when are women sensitized

A

D-negative women are sensitized during
the first pregnancy with a D-positive baby

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17
Q

Rh HDFN

Subsequent __________ are affected

A

Pregnancies

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18
Q

Rh HDFN

what is positive

A

DAT

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19
Q

Rh HDFN

symptoms that may occur

A

Jaundice and or anemia may occur

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20
Q

Rh HDFN

Rh immune globulin

A

Is given to prevent Rh HDFN

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21
Q

ABO HDFN

Most common type of

A

HDFN

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22
Q

ABO HDFN

mother has group _____

_______ may be effected

Mothers IgG ________ attaches to babys red cell antigens

A
  • Mother has group O blood; baby has group A or B
    blood
  • First pregnancy may be affected
  • Mother’s IgG anti-A,B attaches to baby’s red cell
    antigens
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23
Q

ABO HDFN

Production of mild symptoms is possible due to

A
  • A or B substances in tissue that may neutralize
    antibodies
  • Fetal/infant RBCs may be poorly developed
  • Fetal/infant RBC sites may be reduced
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24
Q

ABO HDFN

__________ may occur

A

Jaundice

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25
Q

Phototherapy can be used to treat

A

Jaundice

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26
Q

Other types of HDFN

A

-Any IgG can cause HDFN
-Anti-c and anti-K antibodies are
common causes
-Other Kell antibodies and
antibodies to Kidd, Duffy, S, and
-U antigens are less common
-Agglutination with paternal
cells and maternal serum is a
clue to a low-frequency antigen

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27
Q

ANY _______ can cause HDFN

A

IgG

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28
Q

__________ and _________ antibodies are common causes

A

Anti-c and anti-K

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29
Q

what are less common causes of HDFN

A

Kell, Kidd, Duffy, S, and U

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30
Q

what is a clue to a low frequency antigen

A

Agglutination with paternal cells and. maternal serum

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31
Q

Prenatal testing serves two purposes

A

– Identifies D-negative women who are candidates for RhIG
– Identifies women with antibodies capable of causing HDFN

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32
Q

Antibody titration helps determine

A

helps determine whether certain
procedures should be performed

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33
Q

Antibody titration

Baseline titer is determined in the first _________ and repeated at ___________

A

Baseline titer is determined in the first
trimester and repeated at 4- to 6-week
intervals (sample is frozen for future testing)

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34
Q

Antibody titration

A titer that rises by

A

2
dilutions (compared to
baseline) is significant

35
Q

A titer of ___ or ____ s
usually critical for anti-D
and other Rh antibodies

A

16-32

is
usually critical for anti-D
and other Rh antibodies

36
Q

The highest concentration of dilution compared with these two numbers

1:2 or 1:128

A

1:128

37
Q

Ultrasound

Color doppler ultrasonography can detect

A

Fetal anemia

38
Q

Ultrasound

Color Doppler ultrasonography can
detect fetal anemia

leads to

A

Increased cardiac output and low
blood viscosity

39
Q

Ultrasound

Severity of anemia is determined by evaluating the peak ___________

A

systolic velocity
in the middle cerebral artery

40
Q

Amniocentesis is scanned by

A

spectrophotometrically for
350 to 700 nm

41
Q

Amniocentesis

A change in optical density above

A

baseline (450
nm) is a measure of bilirubin

42
Q

Aminocentesis

The OD is plotted on a

A

Liley
graph (using gestational age)
– Upper zone (zone 3): severe
HDFN
– Middle zone (zone 2):
moderate disease
– Lower zone (zone 1): mild
disease

43
Q

Aminocentesis

Three alternatives exist based on results

A

– Pregnancy continues to term
– Intrauterine transfusion is performed
– Early labor is induced
* Fetal lung maturity must be determined (lecithin-sphingomyelin
[L:S] ratio should be greater than 2:1)

44
Q

Cordocentesis

Fetal blood sample is taken for

A
  • Hemoglobin and hematocrit testing
  • Bilirubin testing
  • RBC genotyping
45
Q

Cordocentesis

_________ is low

A

1% to 2%

46
Q

Cordocentesis

Cordocentesis can be used for

A

intravascular transfusions in cases
of severe HDFN

47
Q

Fetal genotyping

A
  • Fetal DNA can be typed using maternal
    plasma during the second trimester
  • Predicting the fetal genotype could avoid
    amniocentesis or cordocentesis if the fetus
    lacks the antigen
48
Q

Postpartum testing

D testing

A

– All infants born to D-negative mothers are tested,
including for weak D antigen

49
Q

Postpartum testing

False negative results

Preform what

A
  • D-antigen sites are blocked by antibody (blocking
    phenomenon)
  • Perform elution (will demonstrate anti-D antibody)
50
Q

False positive results

A
  • Weak D test is performed on RBCs coated with antibodies
  • Rh control will be positive at antihuman globulin (AHG)
    phase
51
Q

Cord blood or neonate testing

ABO testing

A
  • Only the forward grouping is
    performed
  • ABO antibodies are not yet produced
  • Cord blood is washed to remove
    Wharton’s jelly
52
Q

DAT

A
  • Elution may be necessary if the test is
    positive and if the mother’s antibody
    has not been identified or the
    maternal serum sample is unavailable
  • If the eluate is negative, an antibody
    to low-frequency antigen is
    suspected
  • If the eluate is positive with A or B
    cells and negative with screening
    cells, ABO HDFN is indicated
53
Q

Prevention

RhIG prevents

A

alloimmunization in D-negative
mothers

54
Q

RhIG only prevents

A

formation of anti-D antibody

55
Q

Antepartum administration

Intitial dose (300ug) is given at

A

28 weeks’ gestation

56
Q

Postpartum administration

A
  • Nonimmunized women receive one full dose of RhIG within 72
    hours of delivery
  • More than one dose may be necessary if the mother has
    fetomaternal hemorrhage of more than 30 mL
57
Q

Rosette Test

A
58
Q
A
59
Q

Screening for fetomaternal hemorrhage

RhIG candidates are screened for

A

Fetomaternal hemorrhage

60
Q

Screening for
Fetomaternal Hemorrhage

Most common screening method is the rosette test

A
  • Uses postpartum maternal specimen
  • Maternal RBCs are incubated with anti-D antibody
  • D-positive indicator cells are added
  • Rosettes are observed under the microscope
  • Less than 1 rosette per 3 low-power fields: one dose of RhIG
  • More than 1 rosette per 3 low-power fields: bleed must be
    quantitated
61
Q

Quantifying Fetomaternal
Hemorrhage

To calculate the additional doses of RhIG, what is used

A

flow
cytometry or the Kleihauer-Betke test is performed

62
Q

Quantifying Fetomaternal
Hemorrhage

Kleihauer-Betke test is based on the following facts

A

– Fetal hemoglobin is resistant to acid (retains dye)
– Adult hemoglobin is not resistant to acid (ghost-like)

63
Q

Kleihauer-Betke
Acid Elution

Hemoglobin ____ is resistant to acid elution

Expose thin smear of blood to acid buffer,

A

F

Expose thin smear of blood to acid buffer adult
hemoglobin eluted out.

64
Q

Kleihauer-Betke
Acid Elution

A
  • Smears are stained with hematoxylin and erythrosin
    B.
  • Adult rbcs appear as ghost cells, stroma only, while
    fetal cells appear bright pink and refractile.
  • Count number of fetal cells in 2000 adult cells.
  • Precision of test poor even in experienced hands.
  •  Flow Cytometry!
65
Q

RhIG dosing calculation

A
66
Q

Treatment

Intrauterine transfusions

ABO/Rh and DAT results should be interpreted with

A

caution in newborns who
have had intrauterine transfusions

67
Q

Treatment

Intrauterine transfusions

_________ may phenotype as group O, D negative blood because group O, D-negative unit is given

A

Cord blood

68
Q

Intrauterine Transfusions

DAT may be

A

Falsely negative or weakly positive

69
Q

Intrauterine Transfusion

Corrects

A

anemia and prevents heart failure

70
Q

Intrauterine transfusion

Blood for intrauterine transfusion

Lacks what

RBCs collected within

A

Group O Rh neg RBCs

Lack
antigens
which
antibo-
dy(ies) are
directed

within 7 days

71
Q

Blood for intrauterine transfusions

__________ to prevent graft- versus host disease

A

Irradiated

72
Q

blood to Intrauterine transfusions

Negative for

A

Cytomegalo-
virus and/or
leukocyte
reduced

73
Q

Blood for intrauterine transfusion

Negative for Hgb ____

A

Negative for Hgb S

74
Q

Exchange transfusion

Replacement of

A

1-2 whole blood volume

75
Q

Exchange transfusion

Corrects anemia without expanding the _________

Removes newborns RBC and replaces with _________

Reduces what

A
  • Corrects anemia without expanding the blood volume
  • Removes newborn’s RBCs and replaces them with
    antigen-negative cells
  • Reduces bilirubin (prevents kernicterus)
  • Reduces maternal antibody
76
Q

Exchange
Transfusion

_________ is determined in a infant

A

ABO and D

77
Q

Exchange Transfusion

Maternal or Infant serum or plasma is.used for

Antigen negative units are given if

what is determined in the infant

A
  • ABO and D
    typing is
    determined in
    the infant
  • Maternal or
    infant serum or
    plasma is used
    for antibody
    screening
  • Antigen-negative
    units are given if
    antibody is
    present
78
Q

Exchange
Transfusion

Procedure

A
  • Cannulate umbilical vein.
  • “Pull” baby blood.
  • Wait
  • “Push” donor blood.
  • Wait
  • Repeat
79
Q

Phototherapy

Initial treatment for

A

hyperbilirubinemia

80
Q

Phototherapy

Mild cases of

A

HDFN, such as ABO HDFN

81
Q

Phototherapy

Uses fluorescent

A

blue light (420 to
475 nm)

82
Q

Phototherapy

light converts bilirubin to

A

Light converts bilirubin to isomers
that are excreted in the bile

83
Q

Phototherapy

If patient is unresponsive

A

exchange
transfusion may be necessary

84
Q
A

Immunohematology - 4444 (17 decks)

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