Questions from S 6 Flashcards
Actual exam questions - viral rash in pregnancy table
What proportion of adult females are seronegative?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19 50%
Measles <5%
Rubella 7%
Chickenpox 1-10%
What is the incubation period?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19 4-21 days
Measles 7-21 days
Rubella 14-21 days
Chickenpox 7-21 days
What is the infectivity period?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19 10 days before onset of rash, to day of onset of rash
Measles 4 days before onset of rash, to 4 days after
Rubella 7 days before onset of rash, to 10 days after
Chickenpox 2 days before onset of rash, until all lesions crusted
What is the risk of transmission from household contact? Household attack rate
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19 50%
Measles 99%
Rubella 90%
Chickenpox 70-90%
What is the main adverse outcome in a pregnant woman?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19 arthropathy
Measles pneumonitis/ encephalitis
Rubella arhtritis
Chickenpox pneumonitis/ encephalitis
What is risk of intrauterine infection by gestational age?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19
Under 4 weeks: 0%
5 to 16 weeks: 15%
Over 16 weeks: 25 to 70%, increasing with gestation
Measles
Not known
Rubella
Under 11 weeks: 90%
11 to 16 weeks: 55%
Over 16 weeks: 45%
Chickenpox
Under 28 weeks: 5 to 10%
28 to 36 weeks: 25%
Over 36 weeks: 50%
What is risk of adverse foetal outcome?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19
Under 20 weeks: 9% excess fetal loss. 3% hydrops fetalis, of which about 50% die without treatment
Over 20 weeks: <1%
Measles
Increased foetal loss/ premature delivery
Rubella
Under 11 weeks: 90%
11 to 16 weeks: 20%
16 to 20 weeks: minimal risk of deafness only
Over 20 weeks: no increased risk
Chickenpox - Fetal varicella syndrome risk:
Under 13 weeks: 0.4%
13 to 20 weeks: 2%
Neonatal chickenpox risk in 4 days prior to 2 days postdelivery: 20%
What is the risk to the neonate, if they are exposed to infection shortly after birth?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19
none
Measles
Risk of SSPE with a short onset latency and fulminant course
Rubella
none
Chickenpox
Risk of severe disseminated haemorrhagic chickenpox. An estimated 30 neonates at risk of severe neonatal infection per year
What steps can be taken following exposure to these infections?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19
Fetal hydrops: resolution of infection increased from 5% spontaneous resolution to 55% after intrauterine transfusion
Measles
HNIG to susceptible women and neonates attenuates infection
or illness
Rubella
Counselling for parents to make informed decision about whether to continue with the pregnancy
Chickenpox
PEP to exposed mother and neonate attenuates illness.
Intravenous aciclovir or valcyclovir within 24 hrs of rash
onset for mother. Intravenous aciclovir for infected
neonates
What is the number of infections in pregnancy per year?
Parvo B19
Measles
Rubella
Chickenpox
Parvo B19
1 in 512 pregnancies per year
Measles
close to zero
Rubella
2 pregnancies per year
Chickenpox
3 per 1000 pregnancies per year
