Rhesus

Question 1

How does rhesus sensitization occur?

Answer 1

Leak of Rh +ve foetal RBCs into the maternal (Rh -ve) circulation causes the mother to make IgG antibodies against the Rh D antigen

Question 2

What consequence does sensitization have?

Answer 2

In future pregnancy Anti-D antibodies cross the placenta and cause haemolysis in the foetus; cause haemolytic disease of the newborn

Question 3

How is rhesus sensitization prevented routinely?

Answer 3

Give 500UI anti-D immunoglobulin to all Rh-ve mothers at 28 and 34 weeks (or single dose 1500 UI at 28 weeks)

Question 4

In which circumstances should anti-d be given immediately? (6)

Answer 4

After the birth (either live or stillborn) with Rh-ve mother
Termination
Miscarriage
Invasive procedures e.g. CVS, amnio, fetal blood sampling
Ectopic pregnancy
Antepartum haemorrhage

Question 5

What dose is given following sensitizing events?

Answer 5

500 UI

Question 6

How are anti-D antibodies detected in rhesus negative women?

Answer 6

Indirect Coomb’s test

Question 7

Clinical presentation of HDN (4)

Answer 7

Jaundice
Hepatosplenomegaly
Kernicterus
Hydrops fetalis

Question 8

What is kernicterus? What features are seen?

Answer 8

Bilirubin encephalopathy. Extrapyramidal, auditory, visual abnormalities and cognitive deficit

Question 9

Presentation of hydrops fetalis

a) antenatal (1)
b) postnatal (4)

Answer 9

a) Polyhydramnios

b) oedema, pleural/pericardial effusion, ascites

Question 10

Management of HDN

a) in utero
b) post-natal

Answer 10

a) intrauterine transfusions

b) transfusion; phototherapy