Case of the Day: Infections Flashcards
A prenatal patient calls, stating she was exposed to a child with Fifth’s disease.
How do you counsel her?
Caused by parvovirus and also called erythema infectiosum, Fifth’s is a common infection that attacks erythroid stem cells and may lead to aplastic crisis.
5% risk of SAB but not teratogenic. Primary fetal risk is aplastic anemia, followed by myocarditis or fetal hepatitis. The highest risk time for infection is less than 20 weeks.
Parvovirus: what are the signs and symptoms in the mother?
“Slapped cheek” rash, peripheral arthritis, Fever, malaise, myalgia
Parvovirus: What labs would you order?
Parvovirus IgG and IgM; IgM can be detected 10 days after exposure and persists for three months or more
If IgG positive and IgM negative: no risk to fetus
If both IgG and IgM negative: repeat in 2-4 weeks
If IgG negative and IgM positive: fetus is at risk and should follow with MCA Doppler weekly for 10 weeks
Parvovirus: how is nonimmune hydrops managed?
Amniocentesis for parvovirus PCR
Cordocentesis for fetal hematocrit
Transfusion
A 24-year-old teacher comes to your office informing you that two of her students were diagnosed with varicella.
How should she be counseled about her risk of infection?
Varicella zoster virus is a highly contagious DNA virus with a 90% acquisition rate for nonimmune people. It is contagious from 1-2 days prior to rash until lesions have crusted.
VZV: What are maternal signs of infection?
Fever, malaise, then truncal vesicular rash
Adults can develop pneumonia or encephalitis
VZV: how can diagnosis be made?
Primarily clinical
ELISA of IgM and IgG
VZV: What is the major complication of infection during pregnancy?
How is this treated?
Pneumonia: 15-25% mortality risk
IV acyclovir 10 mg/kg every 8 hours
VZV: how should infected women be managed during pregnancy?
Determine immunity
If nonimmune, give VZIG within 10 days
Isolate patient from other pregnant women
Oral acyclovir if rash develops.
A 31-year-old G0 with a history of genital herpes presents to the office at 37 weeks with prodromal HSV symptoms.
Describe her counseling and evaluation.
30% of US population are anti-HSV 2 positive. 50% of US population are anti-HSV 1 positive. Cervical viral shedding occurs in 0.5% of deliveries.
PCR testing of a vesicle is the most accurate method for diagnosis. Viral culture is currently the standard for diagnosis and is more accurate with active lesions.
VZV: what are the fetal risks of maternal infection?
Congenital varicella syndrome with cutaneous scars, mental retardation, congenital cataracts, limb hypoplasia, growth restriction. 30% mortality. 1-2% risk 8 to 20 weeks.
Neonatal infection with 50% risk if delivered 7 days prior to rash or 7 days after, 10% mortality
HSV: what is the recommended mode of delivery for active genital lesions or prodromal symptoms?
What is the risk of neonatal transmission with vaginal delivery for recurrent HSV?
Cesarean
3%
HSV: how is a recurrent episode during pregnancy treated?
What dosing can be given for suppression?
Valacyxlovir 500 mg twice daily for 3 days or acyclovir 400 mg 3 times daily for 5 days.
Valacyclovir 500 mg twice daily from 36 weeks or acyclovir 400 mg three times daily. (Same as above!)
HSV: In a patient with a history of HSV, but has no lesions, does that guarantee a healthy fetus at vaginal delivery?
Pretty much. The rate of neonatal HSV with an asymptomatic mother is approximately two per 10,000.
HSV: how should recurrent HSV lesions distant from the genital hiatus be managed?
Cover with occlusive dressing and allow vaginal delivery
