4. Congenital perinatal infectons Flashcards
What are the timing of congenital perinatal infections?
· Perinatal (intrauterine)
o Infection acquired/carried by mother and transmitted to the developing getus
· Perinatal
o Infection transmitted around the time of delivery
· Postnatal/Postpartum
o Infection acquired after delivery
o Family, health care workers, community
What are the modes of infection?
- Vertical transmission o From mother to fetus (transplacental) o From mother to baby (breast milk) - Horizontal transmission o From one person/baby to another - Ascending infection o Vaginal organisms producing fetal infection
What are the effects on the fetus?
- Non specific effects of maternal infection o Fetal death o Premature delivery (influenza) - Specific effects of infection o Benign/self-limiting o End organ damage (Rubella, CMV) o Chronic infection e.g. Hepatitis B/C, HIV
What are the common features of herpes virus?
- Primary infection
- Dormant period
- Reactivation when immunocompromised, elderly.
What are the characteristics of Varicella Zoster Virus? (VZV)
- Herpesviridae family
- Large 120nm
- Icosahedral
- dsDNA
- Enveloped
Latent infection – Dorsal root ganglia
What is the infectious period for chicken pox?
10-21 days
What is the mode if infection of chicken pox?
Respiratory/Direct contact with lesions
What are the symptoms of chicken pox?
Fever, lethargy, pruritic vesicular rash
What are the complications of chicken pox?
- Secondary bacterial infection (through skin lesions) o Commonly Strep pyo o Staph aureus (Purpura Fulminans) - Pneumonitis o More common in adults (25x) o Tachypnoea, cough, haemoptysis - Acute cerebellar ataxia 1/4000, complete recovery 2-4 weeks
What are the features of maternal VZV?
- 0.5% occurs in childbearing age
- There is a relative state of immunosuppression during pregnancy
- More severe in pregnant adults
- Smoking is an independent variable
- Respiratory symptoms day 2-5
o Productive cough with hemoptysis
Deaths most commonly occur in 3rd trimester due to increased cardiorespiratory requirement for baby
What is the mode of transmission for congenital VZV syndrome
Cross placental transmission
What will a primary infection of VZV cause in the first trimester for the foetus?
o Cicatricial scarring (dermatomal)
o Limb hypoplasia
o Microcephaly, cataracts
o Mental retardation
GI & Genitourinary abnormalitiesWhat are the features of Perinatal VZV?
- Primary maternal varicella o -7 to +2 days from delivery o Lack specific antibody - 17-30% transmission to neonate - Disseminated infection Mortality 25-30%
Who should be given prophylactic VZIG?
- Given post exposure (
What vaccine is available for VZV?
o Live attenuated virus (OKA strain) o Seroconversion 90% o Given at 18m o 2 doses > 12 y.o. Non-immune adults in high risk occupations
What treatments are available for VZV?
- Acyclovir
o Treatment for acute varicella
§ Oral if
What are the characteristics of CMV?
- Hepesviridae
- Icosahedral capsid
- dsDNA
- Spherical lipid envelope
- Multinucleate giant cells
Latent infection in WBC
How can CMV be transmitted?
- Saliva
- Urine
- Breast milk
- Blood
- Semen
- Cervical secretion
- Transplacental
- Transplant tissue
Where is the most likely place for CMV to be transmitted?
Transmission occur mostly from day care centres (75%) and virus can live on surfaces up to 24 hours
What is the seroepidemiology of CMV?
- Increased rate during childhood, adolescence and child-bearing years
- Developed countries
o 1 year 14%
o 2 years 26%
o 10 years 33%
o Adults 40-60% - Developing countries
o 3 years 80%
o Adults >90%
o Don’t see congenital CMV very often because most people are immune
What is the route of infection for CMV?
- Trans placental – Haematogenous
- Perinatal – Genital secretions, breast milk, saliva
- Later – Toddlers in day-care
- Adults – Sexual/non-sexual close contact
What is the route of post-partum infection for CMV?
- Infants
What are the consequences of post-partum infection of CMV?
Causes sepsis-link syndrome
o Hepatomegaly
o Respiratory distress
Atypical lymphocytosis
What is the rate of congenital CMV?
0.3-2% of all births
What is the consequences of primary infection of congenital CMV?
- 0.3-2% of all births
- Primary infection
o 10% symptomatic
§ 10-15% long term sequalae if asymptomatic
o 10-30% mortality
o Long term sequelae - If symptomatic presents with (80-100% long term sequalae)
o Owl eye viral inclusions
o Rash & Hepatosplenomegaly
What is the source and the rates of CMV fetal infection?
Fetal infection Primary - 1% of women - 20-50% Fetal infection Reactivation - 10-30% of women 1-3% fetal infection
Why is IgM lab test useless for testing primary infection for CMV infection?
IgM remains positive for months and years so can’t be used to time primary infection
What lab test can we use to test for primary or secondary infection of CMV?
Avidity test – early in infection the avidity is low, as immune system matures the antibody bind more strongly
How do we confirm fetal CMV infection?
- PCR amniotic fluid
- Fetal (cord) blood
o IgM sensitivity 70-80%
o VMC PCR sensitivity 10-30%
o Non-specific – anemia, platelets LFT
What are the consequences of fetal CMV infection?
If baby is normal at birth - Serial audiometry o Deafness 5-15% o Delayed up to 5 years - Serial visual assessment o Chorioretinitis o Optic atrophy - Psychomotor assessment o Microcephaly, developmental delay, behavioral
If symptomatic
- Confirm diagnosis with CMB in the first 2 weeks via urine
- Cranial ultrasound
- Need multidisciplinary approach to management
What is the treatment for CMV infection?
- Ganciclovir
- Given to symptomatic
6m of treatment will half the sensory and neurological deficit.
What are the characteristics of Rubella virus?
- Togavirus
- ssRNA, enveloped
- Human only reservoir
- 25-50% infections asymptomatic
How is Rubella transmitted?
- Nasopharyngeal secretions
o Highly infectious = 50-90% of susceptible in an outbreak
Infectious form -7 to 14 days
What is the infectious period of Rubella?
14-21 days
What is the clinical presentation of Rubella?
- Fever – low grade
- Lymphadenopathy (95%) persists for 2 weeks
o Occipital, postauricular, posterior cervical - Exanthem
o Maculopapular; face à trunk à limbs - Polyarthralgia/arthritis
What is the outcome of congenital rubella syndrome?
- Infection in the 1st trimester is the most damaging
- Gestational age influences deficit
o >12/40 Retinopathy and deafness only - Outcome
o 1/3 lead normal life
o 1/3 live with parents
o 1/3 institutionalized - Classical triad
o Ophthalmological – cataracts, glaucoma, retinopathy
o Cardiac – Patent Ductus arteriosis, Pulmonary artery stenosis
o Auditory – Sensorineural deafness - Other symptoms
o Neurological – Meningoencephalitis, behavioral
o Others – IGUR
What investigations can be done to test for Rubella?
- Serological confirmation o IgG o IgM - Fetal diagnostic testing o Amniotic fluid, cord blood o Fetal IgM
What can be done to prevent Rubella?
- Vaccine (live attenuated)
- Seronagtive women vaccinated postpartum
o Avoid vaccination during pregnancy
What are the features of Parovirus?
ssDNA virus
What is the infectious period of Parovirus
4-21 days
How does Parovirus cause disease?
- Shorten RBC progenitor o Acute aplastic crisis o Chronic hemolytic anemia - Erythema infectiosum; Fifth disease - Arthalgia + rash in adults
What happens in congenital parovirus infection?
- 60-70% pregnant women immune
- Hydrops foetalis (anemia)
- Higher chance of fetal loss in first trimester
o May require intrauterine transfusion
How do you diagnose a parovirus infection?
Serology - IgG past infection; Immunity - IgM present at time of rash; positive for 2-4 months PCR Ultrasound at 1-2 weekly intervals Fetal blood sampling Intrauterine transfusion. Serology - IgG past infection; Immunity - IgM present at time of rash; positive for 2-4 months PCR Ultrasound at 1-2 weekly intervals Fetal blood sampling Intrauterine transfusion.
How is Herpes Simplex virus transmitted to baby?
- Usually infection via secretion from mother during labor o Skin-eye-mouth o Encephalitis o Disseminated
When is the risk of transmission of HSVhighest ?
- Risk of transmission highest when mom gets infected (primary infection)
Leads to abortion, IUGR, preterm labor
What is the management of HSV?
- Primary infection during pregnancy
o Acyclovir treatment and suppression until delivery
o Caesarean section - Recurrent disease during pregnancy
o Acyvlovir suppression
o Avoid instrumentation
o Careful clinical examination for lesions
o Investigation of baby for colonization
What is the most likely cause of Syphilis transmission to fetus?
- Transmission to fetus o Primary 90% o Secondary 60-90% o Early latent 40% Late latent
What are the outcomes of congenital syphilis infectioN?
o Stillbirth 40%
o Premature delivery
How is Congenital Syphilis prevented?
Antenatal screening important to prevent congenital infection, prevent further sexual transmission and progression to tertiary syphilis
- Non-Treponemal test (VLRL, RPR) to test for non-specific antibodies. Reduced if treatment is effective
- Treponemal test (EI, TPHA, TPPA, FTA-Abs)
positive slighly earlier, positive for life
Taxoplasma Gondii
- Primary infection 1/1000
- 75% women susceptible
- 70-90% asymptomatic at birth
o Rash, LN, Chorioretinitis, hydrocephalus - IgM unreliable
- Screening not recommended
- Education regarding routes of infection important
How is Group B strep transmitted to baby?
- Carriage in bowel/vagina 20-30%
- Baby infected via ascending infection or colonized at delivery
- 40-70% colonized
- 1% invasive disease
What are the maternal risk factor for postpartum group B strep infection?
- Preterm delivery
- Prolonged ruptured membranes
- Intrapartum fever
- Chorioamnionitis
- Previous baby with GBS
What is the early onset infection of Group B Strep?
- First 48h
- Peripartum infection
- Pneumonia & Septicaemia common
What is the late onset infection of Group B strep?
- Colonisation at birth
- Possibly breast milk transmission
- Meningitis common
What is the treatment of Group B strep
Penicillin + Gentamicin
How can Group B Strep be prevented?
- Intrapartum chemoprophylaxis
o Screening for carriage
o Risk factors for neonatal disease
What are the standard pre-pregnancy screening?
- Routing screening test including varicella
- Vaccinate with MMR + Varicella
- Check rubella immunity after 1-2 months and revaccinate if necessary
- Avoid pregnancy for 1 month
Women in contact should have CMV serology check and be counseled appropriately
