VIRAL INFECTIONS (based on Williams) Flashcards
What is a major cause of maternal and fetal morbidity and mortality worldwide?
Infections.
How does the maternal-fetal vascular interface affect infections?
It can either protect the fetus or serve as a conduit for transmission.
What factors influence disease outcome in maternal infections?
Maternal serological status. acquisition mode.gestational age at infection and immunological status of mother and fetus.
What does the TORCH acronym stand for?
Toxoplasmosis. Others. Rubella.Cytomegalovirus and Herpesvirus infections.
What is the primary function of regulatory T cells (Tregs) during pregnancy?
They induce maternal immune tolerance to the fetus by expressing FOXP3.
How does pregnancy affect maternal defense against bacterial pathogens?
The immune tolerance mechanisms compromise maternal defense against bacterial infections.
What is horizontal transmission?
The spread of an infectious agent from one individual to another.
What is vertical transmission?
Passage of an infectious agent from mother to fetus via placenta. during labor. delivery or breastfeeding.
What is the secondary attack rate?
The probability that infection develops in a susceptible individual after contact with an infectious person.
When does fetal innate and adaptive immunity begin to develop?
Between 9 to 15 weeks’ gestation.
How is passive immunity provided to the fetus?
Through maternal immunoglobulin G (IgG) transfer across the placenta.
What is the most common perinatal infection in the developed world?
Cytomegalovirus (CMV) infection.
How is CMV transmitted?
Via body fluids such as saliva. semen. urine. blood and cervical secretions.
What is the vertical transmission rate of CMV during pregnancy?
30-36% in the first trimester. 34-40% in the second and 40-72% in the third trimester.
What is the gold standard for diagnosing fetal CMV infection?
CMV polymerase chain reaction (PCR) testing of amniotic fluid.
What are common sonographic findings in fetal CMV infection?
Microcephaly. ventriculomegaly. cerebral calcifications. hepatosplenomegaly. ascites and hyperechoic bowel.
What is symptomatic congenital CMV infection?
A syndrome including growth restriction. microcephaly. intracranial calcifications. chorioretinitis. mental/motor delays. hepatosplenomegaly and thrombocytopenic purpura.
How is primary maternal CMV infection diagnosed?
By IgG seroconversion and low IgG avidity.
What is the sensitivity of amniotic fluid PCR testing for CMV?
70-99%. depending on timing of amniocentesis.
What is the management of pregnant women with primary CMV infection?
Symptomatic treatment; detailed fetal ultrasound; possible amniocentesis for diagnosis.
What are the recommended preventive measures for CMV infection in pregnant women?
Hand washing. avoiding sharing food/utensils and limiting contact with saliva/urine of young children.
Which infections can be transmitted transplacentally?
Varicella-zoster. rubella. CMV. HIV.Zika. SARS-CoV-2. syphilis. toxoplasmosis. malaria. and others.
Which infections can be transmitted via ascending infection?
Group B Streptococcus (GBS). coliform bacteria. HIV.
Which infections can be acquired intrapartum?
Gonorrhea. chlamydia. GBS. tuberculosis. HSV. HPV. HIV. hepatitis B/C. Zika.
What is the main mode of transmission of neonatal CMV infection?
Intrapartum exposure or breastfeeding.
How does congenital CMV affect twins differently?
Infections in dichorionic twins are most likely non-concordant.
Why is routine prenatal CMV serological screening not recommended?
Because primary CMV infection is often asymptomatic and screening may not change management.
What is the role of CMV-specific IgG avidity testing?
To distinguish between recent and past CMV infections.
What is the most common neonatal clinical sign of congenital CMV infection?
Sensorineural hearing loss.
What type of virus is Varicella-Zoster Virus (VZV)?
A double-stranded DNA herpesvirus.
What is the primary mode of transmission of primary varicella (chickenpox)?
Respiratory droplets or direct contact with an infected individual.
What is the incubation period of primary varicella?
10 to 21 days.
What is the risk of infection after exposure to VZV in a non-immune woman?
70 to 90 percent.
How long is a person with primary varicella contagious?
From 1 day before rash onset until all lesions become crusted.
What is the most common cause of mortality in adult varicella infections?
Secondary infection or VZV pneumonia.
What are the risk factors for severe VZV pneumonitis?
Immunosuppression and early bacterial co-infection.
What are the symptoms of VZV pneumonia?
Fever. tachypnea. dry cough. dyspnea and pleuritic pain.
What is the characteristic radiographic finding of VZV pneumonia?
Nodular infiltrates similar to other viral pneumonias.
What causes herpes zoster (shingles)?
Reactivation of latent VZV years after primary infection.
What is the characteristic feature of herpes zoster?
Unilateral dermatomal vesicular eruption often with severe pain.
Is herpes zoster more frequent or severe in pregnancy?
No. zoster is not more frequent or severe in gravidas.
What are the features of congenital varicella syndrome?
Chorioretinitis. microphthalmia. cerebral cortical atrophy. growth restriction. hydronephrosis. limb hypoplasia. cicatricial skin lesions.
What is the highest risk period for congenital varicella syndrome?
Between 13 and 20 weeks of gestation.
What is the risk of congenital varicella syndrome if maternal varicella occurs before 13 weeks?
0.4 percent.
What is the neonatal attack rate if exposed to maternal varicella just before or during delivery?
25 to 50 percent.
What is the neonatal mortality rate in severe perinatal varicella?
Approaches 30 percent.
What is the recommended treatment for neonates exposed to maternal varicella?
Varicella-zoster immune globulin (VariZIG).
When should VariZIG be given to neonates?
If maternal varicella occurs 5 days before or up to 2 days after delivery.
What is the best diagnostic test for active maternal varicella infection?
PCR-based testing of vesicular fluid or crusted lesions.
What is the role of PCR-based testing of amniotic fluid in congenital varicella?
A positive result does not correlate well with congenital infection development.
What imaging modality may be used to evaluate for congenital varicella syndrome?
Detailed anatomical sonographic evaluation at least 5 weeks after maternal infection.
What is the recommended serological test for varicella exposure in pregnancy?
VZV IgG serology.
What is the recommended prophylaxis for seronegative pregnant women exposed to varicella?
Intramuscular VariZIG. 125 units per 10 kg body weight (max 625 units).
How long after varicella exposure can VariZIG be given?
Up to 10 days.
What is the recommended antiviral treatment for severe maternal varicella?
Intravenous acyclovir 10–15 mg/kg every 8 hours until afebrile.
What is the recommended treatment for uncomplicated primary varicella in pregnancy?
Oral acyclovir. 800 mg five times daily for 7 days.
Is varicella vaccination recommended in pregnancy?
No. it is a live attenuated virus vaccine and contraindicated in pregnancy.
Can breastfeeding women receive varicella vaccination?
Yes. because the vaccine virus is not secreted in breast milk.
What family of viruses does Influenza A and B belong to?
Orthomyxoviridae.
What are the two surface antigens used to classify Influenza A viruses?
Hemagglutinin (H) and neuraminidase (N).
What are the characteristic symptoms of influenza infection?
Fever. dry cough. systemic symptoms.
What are the severe complications of influenza in pregnancy?
Pulmonary involvement. hospitalization. increased mortality.
What is the recommended antiviral treatment for influenza in pregnancy?
Oral oseltamivir 75 mg twice daily for 5 days.
What is the recommended chemoprophylaxis for pregnant women exposed to influenza?
Oral oseltamivir 75 mg once daily for 7 days.
When should influenza vaccination be given during pregnancy?
Anytime during influenza season. ideally before the end of October.
Is live attenuated influenza vaccine recommended in pregnancy?
No. only inactivated or recombinant vaccines are recommended.
What type of virus is SARS-CoV-2?
Single-stranded RNA coronavirus.
What is the primary mode of transmission of SARS-CoV-2?
Respiratory droplets.
What is the incubation period of COVID-19?
Approximately 5 to 14 days.
What are the most common symptoms of COVID-19?
Fever. cough. myalgia. anosmia. ageusia.
What are the risk factors for severe COVID-19 in pregnancy?
Diabetes. obesity. hypertension. advanced maternal age.
How does severe COVID-19 in pregnancy present radiographically?
Multifocal ground-glass opacities and peripheral consolidations on CT scan.
Is vertical transmission of SARS-CoV-2 common?
No, it is rare.
What is the recommended treatment for severe COVID-19 in pregnancy?
Oxygen therapy. dexamethasone. remdesivir. supportive care.
What is the role of dexamethasone in severe COVID-19?
Reduces mortality in patients requiring supplemental oxygen or mechanical ventilation.
What is the role of remdesivir in COVID-19?
Shortens recovery time in hospitalized patients with low-flow oxygen needs.
What is the best way to prevent SARS-CoV-2 transmission?
Masking.physical distancing. hand hygiene.
Are COVID-19 vaccines recommended in pregnancy?
Yes. they are safe and protective against severe disease.
