Parvovirus B19 Forest

Question 1

Parvovirus is AKA?

Answer 1

Slapped cheek, Fifth disease

Question 2

When is parvovirus infectious?

Answer 2

10 days before rash

Question 3

When is the risk to fetus greatest?

Answer 3

<20w 9% fetal loss

Question 4

What should you do is parvovirus infection confirmed?

Answer 4

Refer to fetal medicine for urgent USS
Amnio 6w after infx
MCA for peak systolic velocity every 2 weeks - when PSV is 1.5MOM should do cordocentesis +/-blood transfusion

Question 5

Maternal signs of parvo?

Answer 5

Lace-like rash on torso/feet, children with cheek rash, anaemia (breathless, confused), fever

Question 6

Fetal signs of parvo?

Answer 6

FETAL ANAEMIA leading to hydrops and heart failure.
50% fatality if hydrops occurs

Question 7

Treatment for parvo
<24 weeks?
>24 weeks?
if hydropic?

Answer 7

<24 weeks? USS monitoring
>24 weeks? Assess MCA Vmax - if PSV 1.5 for cordocentesis for haematocrit. If Hct <30% for IU blood transfusion
if hydropic? FBS +/- blood transfusion

Question 8

If clinical suspicion of parvovirus, how do you test?

Answer 8

Test maternal serum antibodies IgG and IgM
Difficult to distinguish from rubella clinically

Question 9

How does transfusion treat parvovirus?

Answer 9

Mature erythrocytes are not susceptible to parvo infection and RBCs last 120 days which should allow enough time for maternal antibodies to cross placenta