Dr. Rubin -- Congenital/Perinatal Infections Flashcards
3 protective immunity mechanisms for fetus and neonate
- Placenta (filter microorganisms)
- Maternal Ab (mostly 3rd term)
- Breast milk (secretory IgA)
Time of fetal infection that produces the most devastating effects
1st trimester
3 types of effects of fetal infection
- Interference with normal development
- Inflammatory reaction to the infection
- Placental insufficiency leading to poor growth
How to recognize exposure of a pregnant woman
- Usually asymptomatic
- Detection of specific IgM Ab to an offending agent or rising titer of IgG helpful to assess risk
- Baseline immunity will help to excluse dx (i.e. immunity against Rubella, CMV, parvo, etc)
Ig findings that indicate fetal infection
Presence of specific IgM or rising IgG titre
4 ways to isolate offending agents to diagnose infant
- Viral cultures of urine and other body secretions for CMV, Rubella, HSV
- PCR amplification if possible (i.e. Toxo)
- Pathology of placenta
- Darkfield microscopy from lesions for *T. pallidum *(syphillis)
4 fetal infections that you absolutely cannot miss (important to treat)
- Toxoplasmosis
- Syphilis
- HSV
- HIV
Fetal infection with no effective treatment
Rubella
Fetal infection with which there is only a possibility of treatment benefit
CMV (partial and transient improvement)
9 examples of organisms that are included in the O (other) of TORCH screen
- Syphilis
- TB
- Listeria
- Leptospirosis
- Hepatitis B
- Enteroviruses
- Varicella
- Parvovirus
- HIV
etc
Common misconception about TORCH
- There is no one test that will screen for congenital infections
- Nothing replaces a good clinical accumen and directed specific testing
11 common features associated with TORCH agents
- Prematurity
- IUGR
- Congenital defects
- Abnormal head size
- Intracranial Ca++
- Periventricular
- Diffuse
- Eye abormalities
- Earing loss
- Hepatosplenomegaly
- Hematologic AbN
- Bone lesions
- Inflammtion of CSF
2 conditions of adnormal head size associated with TORCH agents
- Microcephaly
- Hydrocephaly
3 eye abnormalities associated with TORCH agents
- Chorioretinitis
- Cataracts
- Micophthalmia
Define TORCH
- Toxoplasma
- Other (covered in another card)
- Rubella
- Cytomegalovirus
- Herpes
Classic triad of congenital toxoplasmosis
- Hydrocephaly
- Diffuse intracranial calcifications
- Chorioretinitis
Approach to congenital toxoplasmosis
- Refer to maternal serology
- If not done, start with Toxo IgG and then Toxo IgM
- NEG
- POS
- Ophthalmology assessment for chorioretinitis
- Head imaging (CT vs. US vs Xray)
Use of NEG in congenital toxoplasmosis diagnosis
- Toxo IgG = excludes Congenital Toxoplasmosis
- Toxo IgM = does not totally exclude
Describe the use of POS in congenital toxoplasmosis
- Look at titre and avidity –> strong avidity = more remote infection
- Toxo IgM = increases the likelihood, but + for >6 months
Approach to toxoplasmosis during pregnancy
- Seruconversion documents
- Positive IgM
- PCR on amniotic fluid
- Serial ultrasounds, looking for ventricular dilatation
- Placental histology
Treatment for positive aminiotic fluid PCR in event of suspected toxoplasmosis during pregnancy
Pyramethamine and sulfadiazine and folinic acid supplements
Treatment for negative amniotic fluid PCR in event of suspected toxoplasmosis
Spiramycin
Approach to suspected congenital rubella (7)
- Check mom’s rubella status prior to the current pregnancy
- If positive = excludes rubella
- If negative or unknown, check Rubella IgG on Mom or baby
- If negative = excludes Rubella –> immunize Mom
- If positive –> rubella IgM
- If positive = Congenital Rubella
- If Negative –> Rubella Viral Cultures
Approach to suspected congenital CMV
- Urine viral culture for CMV
- POSITIVE = if done within first 2 - 3 weeks of birth –> CMV
- NEGATIVE = exclude CMV
- No need for serology
3 potential manifestations of congenital herpes
- Skin, eye, mucous membrane (“SEM”)
- Encephalitis
- Disseminated
Approach to suspected congenital herpes
- Lesion –> viral cultures
- POSITIVE = herpes
- No lesions
- Culture mouth, NP, eyes, urine ,rectum
- POSITIVE > 48 hours after birth = viral replication vs. colonization after intrapartum exposure
- CSF and blood HSV PCR
- Tissue diagnosis
- Culture mouth, NP, eyes, urine ,rectum
NOTE: HSV IgG and IgM not very helpful
Approach to suspected congenital syphillis
Check naternal serology and recheck at time of delivery, or thereafter
- NEGATIVE = exclude
- POSITIVE = review history, prior treatment
3 of the only congenital infections that are treatable
- Syphillis
- Toxoplasmosis
- HSV
2 sequelae of maternal primary CMV in pregnancy
- Severe psychomotor delay (50 - 60%)
- Hearing loss (30 - 60%)
Primary etilogy of Fifth Disease (erythema infectiousum)
Parvovirus B19
Effect of parvovirus in hemoglobinopathy patietns
Aplastic crisis
Effects of parvovirus B19 in pregnancy
- ?Spontaneous abortion in 1st trimester
- Fetal anemia nad hydrops in 2nd and 3rd trimester
- ?Stillbirth
3 general effects of parvovirus B19
Bone marrow aplasia (hemolysis) –> severe anemia and CHF
4 other infectious causes of nonimmune hydrops
- Toxoplasmosis
- Rubella
- CMV
- Syphillis
Diagnosis of parvovirus B19
Serology on mom at time of exposure
- If IgG positive = immune
- If IgG negative = check and follow IgM and IgG
Why is elevated alpha-fetoprotein a potential marker for adverse outcome
Produced in fetal liver, which is the major site for fetal erythropoiesis and major site of infection for B19
Approach to a mother who is sAg and eAg positive for hepatitis B
High transmission and risk for infant to become chronic carrier = give HBIG and first dose of vaccine at birth (then at 1, 6 months)
Describe perinatal HCV transmission
- Low (<5%)
- Increased if co-infected iwth HIV (18-20%)
HCV diagnosis in infant
Follow serology at 6, 12, 18 months
PCR potentially
When to give prophylactic antiviral to infants exposed to HSV at birth (4)
- Eyes, NPA and urine cultures are positive
- Primary infection in mother
- Premature with limited transfer of maternal Ab
- Instrumentation
5 situations that cause higher risk of HSV to infant
- First episode of maternal infection in pregnancy (i.e. versus recurrent)
- Multiple cervial lesions
- Rupture of membranes > 6 hours
- Instrumentation, scalp electrodes
- Prematurity, no maternal antibody
4 manifestations of VZV embryopathy
- Limb scarring and atrophy
- Bony defects
- CNS abnormalitis
- Eye, chorioretinitis
3 potential manifestations of Varicella Zoster infection in newborn
- VZV embryopathy
- Development of Zoster early in life
- Congenital vericella syndrome
Approach to suspected congenital varicella zoster infection
- Unlikely that VZIG is protective in fetus
- Give VZIG to newborn in maternal varicella 5 days before to 2 days after delivery
