#151 Cytomegalovirus, Parvovirus B19, Varicella Zoster, and Toxoplasmosis in Pregnancy Flashcards
What type of virus is cytomegalovirus?
Double-stranded DNA herpes virus
How is cytomegalovirus trasmitted?
Sexual contact or direct contact with infected blood, urine, or saliva
What is the incubation period of cytomegalovirus?
28-60 days (mean, 40 days)
When can viremia be detected after CMV infection?
Can be detected for 2-3 weeks after primary infection
What are typical symptoms of adult CMV infection?
Usually asymptomatic. May experience a mononucleosis-like syndrome (fever, chills, myalgias, malaise, leukocytosis, lymphocytosis, abnormal liver function, and lymphadenopathy)
What is the incidence of primary CMV infection among previously seronegative pregnant women in th US?
0.7-4%
What is a secondary CMV infection?
Intermittent viral excretion in the presence of host immunity, can occur after reactivation of the latent endogenous CMV strain or by reinfection with a different viral strain
What is the incidence of secondary CMV infection (reactivation vs new strain) during pregnancy in US?
13.5%
How does vertical transmission of CMV occur?
Transplacental infection after primary or secondary infection, exposure to contaminated genital tract secretions, breastfeeding
What are the clinical findings of congenital CMV?
Most are asymptomatic at birth. Jaundice, petechiae, thrombocytopenia, hepatosplenomegaly,, growth restriction, myocarditis, and nonimmune hydrops
What is the most common congenital infection? How often does it occur in neonates?
CMV. Occuring in 0.2-2.2% of all neonates.
What type of transmission of CMV is associated with greatest risk of developing clinical sequelae?
Transplacental transmission
Is CMV exposure through breast milk associated with severe neonatal sequelae?
No, typically asymptomatic
Is CMV exposure through cervical secretions during delivery associated with severe neonatal sequelae?
No, typically asymptomatic
What is the risk of transmission of CMV to fetus with primary maternal CMV infection?
30-40%
During which trimester is the risk for vertical transmission of CMV the greatest?
3rd
What are the transmission rates for primary CMV infection by trimester?
30% in first
34-38% in second
40-72% in third
During which trimester is transmission of maternal CMV infection associated with more serious fetal sequelae?
First trimester
Of fetuses infected in utero after primary CMV infection, what % will have signs and symptoms of CMV infection at birth and how many will eventually develop sequelae?
12-18% at birth. Up to 25% will develop sequelae.
What % of infants severely affected by congenital CMV will die?
approximately 30%
What % of infants surviving congenital CMV infection will have severe neurologic morbidity?
65-80%
What is the rate of vertical CMV infection after a recurrent infection?
0.15-2%
What are the typical outcomes after infant infected with maternal CMV reactivation?
Most infants asymptomatic at birth. Congenital hearing loss is most severe sequela. Unlikely to produce multiple sequelae
What type of virus is Parvovirus B19?
Single-stranded DNA virus
What does Parvovirus B19 cause in children?
Erythema infectiosum (aka fifth disease). Slapped cheek appearance, fever, body rash, joint pain
What is the most common symptom of parvovirus B19 infection in immunocompentent adults?
reticular rash on the trunk and peripheral arthropathy, about 20% are asymptomatic
What is a possible manifestation of parvovirus B19, particularly in individuals with underlying hemoglobinopathy?
Transient aplastic crisis
How is parvovirus B19 typically transmitted?
Respiratory secretions and hand-to-mouth contact
When is someone typically infectious with parvovirus B19?
5-10 days after exposure before onset of rash or other symptoms (no longer infectious with rash)
What percentage of reproductive-aged women are seropostiive for parvovirus B19?
50-65%
Exposure to a household member with parvovirus B19 conveys what risk of seroconversion?
50%
What is the risk of transmission of parvovirus B19 in a classroom setting?
20-50%
What are the rates of maternal-to-fetal transmission of parvovirus B19 after acute infection?
17-33%
What adverse pregnancy outcome(s) has parvovirus B19 been associated with?
spontaneous abortion, hydrops fetalis, and stillbirth
What is the rate of fetal loss among women with parvovirus B19 infection before and after 20wks GA?
Before 20wks=8-17%
After 20wks = 2-6%
What percent of nonimmune hydrops fetalis are associated with parvovirus B19 infection?
8-10% (potentially up to 18-27%)
How does parvovirus B19 lead to hydrops fetalis?
Virus is cytotoxic to erythroid precursors, most often results from aplastic anemia, although can be related to myocarditis or chronic fetal hepatitis
When are severe effects most frequently seen among fetuses affect by maternal parvovirus B19 infection (what GA)?
Prior to 20 weeks, particularly second trimester
Within how long after maternal infection with parvovirus B19 would you expect to see hydrops fetalis?
Unlikely to develop if not occurred by 8wks after maternal infection
What type of virus is Varicella zoster?
DNA herpes virus
How is varicella zoster transmitted?
Respiratory droplets or close contact
What is the infection rate among seronegative contacts for varicella zoster?
60-90%
What is the incubation period of varicella zoster?
10-20 days, mean of 14 days
When is the period of infectivity with varicella zoster?
48 hours prior to rash until vesicles crust over
What does primary infection of varicella zoster cause?
Chicken pox: fever, malaise, maculopapular pruritic rash that becomes vesicular
What happens with varicella zoster virus reactivation?
Herpes zoster (aka shingles)
What percentage of women with varicella infection during pregnancy will develop pneumonia?
10-20%
What is the maternal mortality risk of varicella pneumonia during pregnancy?
As high as 40%
How does varicella transmit vertically to fetus?
Through the placenta
What is the risk of congenital varicella syndrome?
0.4-2%
What are the characteristics of congenital varicella?
Skin scarring, limb hypoplasia, chorioretinitis, microcephaly
When is neonatal VZV infection associated with highest rake of neonatal death?
When maternal disease develops from 5 days before delivery to 2 days postpartum
What is the causative agent of toxoplasmosis?
Intracellular parasite Toxoplasma gondii
What is the invasive form of toxoplsam gondii?
A trophozoite
How are humans infected with toxoplasmosis?
Human consumption of cysts in undercooked meat and infected animals, consumption of insect-contaminated food, contact with oocysts from the feces of infected cats or contact with infected materials or insects in soil
How does toxoplasmosis present in adults?
Typically asymptomatic. most commonly Cervical lymphadenopathy (10-20%). Other symptoms: fever, malaise, night sweats, myalgias, hepatosplenomegaly
What is the risk of congenital toxoplasmosis from an infected woman? How does rate change per trimester?
20-50% overall.
First trimester 10-15%.
2nd trimester 25%
3rd trimester >60%
When during gestation is infection with toxoplasmosis associated with more severe sequelae?
The earlier the worse the disease
What are infant sequelae of toxoplasmosis infection?
Chorioretinitis (subsequent severe visual impairment), hearing loss, severe neurodevelopmental delay, rash, hepatosplenomegaly, ascites, fever, periventricular calcifications, ventriculomegaly, and seizures
How can you diagnose maternal CMV infection?
- serum samples collected 3-4 wks apart in parallel for IgG
- Seroconversion from neg to pos (or increase in titer)
- IgG avidity assays (measures maturity of IgG antibody) – immature (low-avidity) produced in first 2-4 months
What percentage of women with CMV-specific IgM have a primary infection?
10-30%. Useful, but not reliable indication of primary infection
What ultrasound findings are concerning for congenital CMV?
abdominal and liver calcifications, hepatosplenomegaly, echogenic bowel or kidneys, ascites, cerebral ventriculomegaly, intracranial calcifications, microcephaly, hydrops fetalis, and growth restriction
How can you diagnose congenital CMV prenatally? What is the sensitivity?
Culture or PCR of amniotic fluid.
culture sensitivity = 70-80%
PCR sensitivity = 78 - 98%
Does the detection of CMV in amniotic fluid predict severity of infection?
No, just highly predictive of congenital infection
What treatments are available for maternal or fetal CMV infection?
No therapies available. Only medications available for patients with AIDS or organ transplants (ganciclovir, valganciclovir, foscarnet)
Which pregnant patients are at higher risk of CMV infection?
Day care/child care workers, family with young children, increasing parity
Should women be screened for CMV before or during pregnancy?
Routine screening of pregnant women for CMV is not recommended.
Does CMV immunity eliminate the possibility of fetal infection?
No, up to 75% of congenital CMV infections worldwide may be due to reactivation of latent virus or reinfection with a new viral strain.
Are women with IgM neg IgG pos Parvovirus B19 at risk for vertical transmission?
No, have immunity
How should you treat a pregnant woman who is positive for parvovirus B19 IgM?
Monitored for potential infection, regardless of IgG status
What is the next step in management for pregnant woman with known parvovirus b19 exposure and negative IgG and IgM results?
Repeat testing in 4 weeks, if either positive, monitor for potential fetal infection
How can you diagnose fetal parvovirus B19 infection?
PCR of amniotic fluid.
When should testing for fetal parvovirus B19 be considered?
Ultrasound reveals hydrops fetalis
What should be assessed on ultrasound in patient with parvovirus b19 infections?
Ascites, placentomegaly, cardiomegaly, hydrops fetalis, and impaired fetal growth, MCA dopplers peak systolic velocity
How often and for how long after Parvovirus B19 infection should you ultrasound the fetus?
Every 1-2 weeks for 8-12wks after exposure
What is the next step in management for fetus affected by parvovirus B19 and hydrops fetalis or severe fetal anemia?
Fetal blood sampling to test hematocrit in preparation for fetal transfusion
Should all women be screened for parvovirus B19 before or during pregnancy?
Not recommended given low incidence of seroconversion during pregnancy
How do you diagnose maternal varicella zoster virus infection?
Diagnosed on clinical findings (pruritic, vesicular rash). Can unroof lesion and test w/ PCR
What is the risk of congenital varicella syndrome after maternal infection?
1-2%, but these rates may be overestimated
What ultrasound findings are suggestive of congenital varicella?
Hydrops, hyperechogenic foci in the liver and bowel, cardiac malformations, limb deformities, microcephaly, and fetal growth restriction
What should you give and when to pregnant women who contract varicella zoster virus?
Oral acyclovir started within 24 hours of developing the rash. IV acyclovir for varicella pneumonia.
Does maternal treatment of varicella decrease risk of fetal congenital varicella syndrome?
No
What should infants receive if mom develops varicella around birth? How much around birth?
Varicella-zoster immune globulin if mom develops varicella between 5 days before or 2 days after delivery
What should infants who develop varicella within first 2 months of life receive?
Treatment with IV acyclovir
How long after varicella vaccine should a woman wait to conceive?
Delay for 3 months since there is a small chance of mild varicella infection after life, attenuated vaccine
How often does congenital varicella develop after accidental administration of varicella vaccine during pregnancy?
No reports of it happening
How quickly after exposure to person with varicella should a pregnant woman receive treatment and what kind of treatment?
varicella immunoglobulin as soon as possible, ideally within 96 hours of exposure, but up to 10 days after exposure
How do you test for maternal toxoplasmosis infection?
Serologic testing for detection of the specific antibody is primary method
What is the next step to try and identify acute parvovirus b19 infection in a woman with positive IgM and IgG?
Repeat serologic testing in 2-3 weeks, increase in IgG antibodies is consistent with recent infection
Do avidity assays have a role in detecting Parvovirus B19 infection?
Yes, low avidity indicative of primary infection within the past 5 months
What ultrasound findings are found with congenital toxoplasmosis?
Ventriculomegaly, intracranial calcifications, microcephaly, ascites, hepatosplenomegaly, and IUGR
What should be offered to pregnant women when feteal toxoplasmosis is suspected?
Amniocentesis should be offered with PCR
When should amniocentesis be performed for suspected toxoplasmosis infection? Why?
After 18wks gestation to lessen chance of false-negative test result
What is the goal of maternal treatment of suspected Parvovirus B19 infection?
Reduce congenital disease severity. Does not prevent fetal infection.
What should be used to treat maternal toxoplasmosis infection?
Spiramycin, reduces transplacental parasitic transfer
What type of antibiotic is spiramycin?
Macrolide antibiotic
Why is spiramycin the choice for treatment of pregnant women with toxoplasmosis infection (without suspected fetal infection)?
It concentrates in, but does not readily cross, the placenta
How is fetal toxoplasmosis infection treated?
Combination of pyrimethamine, sulfadiazine, and folinic acid. can lessen the severity of disease in the affected fetus
How are infants with symptomatic congenital toxoplasmosis treated?
Pyrimethamine, sulfadiazine, and folinic acid for 1 year
How should women be counseled on prevention of toxoplasmosis?
Proper hand washing techniques, pet care measures, and dietary recommendations. [cat feces, contaminated meat, dairy, produce, water; working in soil without gloves]
Should women be screened for toxoplasmosis before or during pregnancy?
Not recommended, except for women who are immunosuppressed or HIV positive
