Rhesus Disease

Question 1

Where are rhesus antigens found on the RBC surface?

Answer 1

Non-glycosylated transmembrane proteins

Question 2

in a sentence what is Rhesus disease?

Answer 2

When R negative blood is exposed to R positive blood and so rhesus antibodies develop

Question 3

What antibodies form from the Duffy blood group reaction

Answer 3

Fya antibodes

Question 4

What antibodies develop from Kidd blood group reaction?

Answer 4

JKa antibodies

Question 5

Inheritance pattern of rhesus

Answer 5

Dominant

Question 6

Why does Rhesus disease not become evident in the first pregnancy

Answer 6

In the first pregnancy the woman becomes sensitised and the actual reaction will occur in subsequent

Question 7

What 3 factors are the extent of sensitisation dependant upon?

Answer 7

Extend of transplacental haemorrhage, maternal immune response and concurrent ABO incompatibility

Question 8

Describe the effects of Rhesus disease on the body

Answer 8

Haemolysis, extramedullary haemopoiesis, anaemia, hepatomegally, splenomegally, high output cardiac failure

Question 9

Effects on the fetus caused by rhesus disease

Answer 9

Anaemia, hydrops, death

Question 10

Effects on newborn caused by rhesus disease

Answer 10

Anaemia, hyperbilirubinaemia (due to haemolysis), kernicterus, deafness, neonatal jaundice, extramedullary erythropoiesis in liver, cardiac dysfunction, cardiomegaly, cardiac failure, fetal oedema, ascites, hydrothorax

Question 11

When is RAADP given?

Answer 11

When a rhesus negative mother has a rhesus positive partner

Question 12

How long after sensitising event should/can anti-D antibodies be given?

Answer 12

should be 72 hours but can be up to 10 days

Question 13

How many units are given to sensitising events in pregnancies below 20 weeks vs above 20 weeks?

Answer 13

250 IU and 500 IU

Question 14

Test for fetomaternal haemorrhage

Answer 14

Keilhauer test (additional Anti-D if haemorrhage over 4ml)

Question 15

How many units are given as RAAPD and what 2 regimens can these take?

Answer 15

1500IU at 28 weeks, or 1 dose at 28 weeks and one at 34 weeks

Question 16

Important history questions in rhesus disease?

Answer 16

Any miscarriages? blood transfusions? obstetric history? previously effected pregnancies (gestation, outcome of pregnancy, treatment, any phototherapy or transfusions required)

Question 17

In a parental heterozygous rhesus grouping how do you determine if the fetus in rhesus positive or negative?

Answer 17

NIPT of maternal serum

Question 18

At what IU/ml maternal serum level does fetus need monitoring at fetal medicine unit and what level is there risk of fetal anaemia?

Answer 18

5-10 IU then need fetal medicine unit, 10+ then risk of fetal anaemia

Question 19

USS investigations for fetal anaemia

Answer 19

Fluid collection, fetal movements, MCA doppler with high peak systolic velocity

Question 20

Treatment of fetal anaemia when less than 34 weeks

Answer 20

IU transfusion into umbilical vein repeated at 2 weeks

Question 21

Treatment of fetal anaemia when over 34 weeks

Answer 21

Steroids, consider delivery,

Question 22

In a sensitised woman if the titres are above 10IU then what monitoring needs to be performed?

Answer 22

Fetal anaemia, movements, hydrops, MCA doppler

Question 23

Different in management of fetal anaemia in a fetus under 34 weeks vs over 34 weeks

Answer 23

under 34 weeks = IU transfusion, over 34 weeks = consider delivery and steroids

Question 24

What is the type of antibodies that form as a result of sensitization reaction?

Answer 24

IgM anti-D antibodies

Question 25

What is the type of antibodies that form as a result of the secondary exposure to Rhesus?

Answer 25

IgG anti-D antibodies

Question 26

Why are IgG antibodies worse than IgM in terms of Rhesus?

Answer 26

IgG can cross the placenta and coat fetal Rh positive cells

Question 27

During haemolytic anaemia of the fetus, what is released from the liver during extramedullary erythropoeisis?

Answer 27

Erythroblasts in erythroblastosis fetalis

Question 28

What should you always check when taking a rhesus history?

Answer 28

Have you had any blood transfusions?

Question 29

If a woman has positive anti-D antibodies, how often do you check the antibody titre and quantitation?

Answer 29

Every 2 weeks

Question 30

How do you check for fetal anaemia?

Answer 30

Doppler of MCA

Question 31

If doppler of MCA shows peak systolic velocity increase then what should be done?

Answer 31

Cordocentesis

Question 32

How will fetal hydrops appear on USS?

Answer 32

Polyhydramnios, ascites, pericardial effusion, skin oedema

Question 33

Potential side effects of cordocentesis?

Answer 33

Puncture, IU infection, bleeding from site, early rupture of membranes, fetal bradycardia, organ needle injury

Question 34

What stage are the babies usually delivered at?

Answer 34

35 weeks

Question 35

What needs to be administered alongside fetal transfusion of packed red blood cells in a fetus suffering Rhesus Disease?

Answer 35

steroids, availability of theatre for emergency CS, inform neonatal unit

Question 36

What do you test cord blood for on delivery of baby suffering Rhesus Disease?

Answer 36

Hb, haematocrit, bilirubin

Question 37

Kleuhauer test?

Answer 37

Allows you to estimate number of fetal cells in maternal circulation and administer anti-D accordingly

Question 38

What test is performed on neonatal blood to check for extent of rhesus reaction?

Answer 38

Coombs test

Question 39

When do you perform antibody screen on mother?

Answer 39

At booking 28-35 weeks gestation

Question 40

How does prophylactic dosage of anti-D change during time of pregnancy and extent of blood mixing?

Answer 40

before 20 weeks give 250IU after 20 weeks give 500IU and if the mixing is more than 4ml then give an extra dose

Question 41

Routinely what weeks gestation are the 2 doses of Anti-D usually given?

Answer 41

28 weeks and 34 weeks