NBME 10. 179. Rh isoimmunization 12-18 (1)

Question 1

exposure of fetal Rh(+) blood can occur in what cases?

Answer 1

commonly during delivery
or earlier in pregnancy: with vaginal bleeding or interventions such amniocentesis.

Question 2

risk of significant complications occurs when?

Answer 2

NOT WHEN INITIAL EXPOSURED (if it occured during pregnancy)!!
risk for complications is for subsequent pregnancies - if fetal will be R(+) => severe hemolytic anemia of newborn (erythroblastosis fetalis)

Question 3

how acts RhoGAM?

Answer 3

acts by binding to Rh(D) positive cells that enter the maternal circulation, preventing immune system from developing antibodies to the Rh(D) antigen.

Question 4

when is administered RhoGAM normally? 2

Answer 4

at 28 weeks and following delivery

Question 5

in what scenarios administration of RhoGAM is also needed? 2

Answer 5

any invasive procedure (eg amniocentesis)
Any confirmed or potential episodes of FETOMATERNAL bleeding.

Question 6

When is RhoGAM is ineffective?

Answer 6

in a patient who has already developer Rh(D) antibodies

Question 7

Duffy sensitization? CP?

Answer 7

Duffy sensitization (Choice A) is a similar phenomenon as Rh isoimmunization.

It occurs as a result of exposure of the immune system to the red blood cell antigen Duffy protein when it is not present on the patient’s cells. The mother can be exposed to Duffy in a similar manner as Rh, and it can also cause hemolytic anemia of the newborn.