Chapter 15 Perinatal Infections Flashcards
toxoplasmosis
infection by protozoan Toxoplasma gondii. transmission by eating cysts in undercooked meat of infected animals / oocysts from feces of an infected CAT.
primary infection of toxo is usually asymptomatic , but may cause congenital infection in the fetus.
Risk of fetal infection highest if infected in 3rd trimester (60%) but risk of SEVERE fetal injury is highest if materal infection occurs in 1st trimester.
complications of fetal toxo infection (fetal infection in 1/3 of cases)
- fetal demise
- impaired vision resulting from chorioretinitis
- uveitis
- seizures
- mental retardation
- enlarged spleen and liver
- disseminated purpuric rash
- significant learning disabilities.
the classic triad consists of chorioretinitis, hydrocephalus, intracranial calcifications
US findings of toxoplasmosis infection in infant:
ventriculomegaly, intracranial calcifications, microcephaly, ascites, hepatosplenomegaly, intrauterine growth restriction
treatment of toxo in pregnancy:
SPIRAMYCIN may reduce risk of congenital infection by 50% (only availabe through FDA after serologic confirmation). PYRIMETHAMINE and SULFADIAZINE is indicated if diagnosis is confirmed in the fetus. FOLINIC ACID must be adminstered with PYRIMETHAMINE to rescue human cells.
in untreated neonates with congenital infection:
poor prognosis with high rates of chorioretinitis, seizures, and severe psychomotor retardation
SYPHILIS
infection by spirochete TREPONEMA PALLIDUM. transmission by DIRECT sexual contact with ulcerative lesions on skin / mucous membranes. congenital infection results from TRANSPLACENTAL PASSAGE OF SPIROCHETES, which has highest risk in the 2nd half of pregnancy and in mothers with primary or secondary syphilis.
congenital infection of syphilis results in
stillbirth 25%, fetal hydrops, preterm labor.
diagnosis of syphilis
direct visualization of spirochetes under darkfield microscopy or direct fluorescent antibody tests from the lesion.
screening tests for syphilis (nontreponemal tests)
- veneral disease research laboratory (VDRL)
- rapid plasma reagin (RPR)
once screening tests are positive, specific treponemal tests (MICROHEMAGGLUTINATION and FLUORESCENT TREPONEMAL ANTIBODY ABSORPTION) are used for confirmation.
treponemal tests remain positive for life with or without treatment
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US findings of syphilis
fetal hepatomegaly, ascities, hydrops, thickened placenta
TX of syphilis
parenteral penicillin drug of choice for all stages of syphilis.
Jarisch-Herxheimer
occurs within several hours of treatment of primary or secondary syphilis and resoles by 24-36 hours.
Fever, chills, malaise, headache, hypotension, transient worsening of cutaneous lesions.
Increases risk of preterm labor / fetal distress if treatment given in 2nd half of pregnancy with this reaction.
Rubella (German measles)
transmission via respiratory droplets. fetal transmission depends on time of exposure to virus. 50-80% of infants exposed to virus within 12 weeks after conception will manifest signs of congenital infection. Rate declines with advancing gestational age. (few fetuses are affected if infection occurs after 18 weeks gestation)
clinical rubella:
3-5 days , non puritic, erythematous maculopapular rash. approximately 60% of infected fetuses will have IUGR
diagnosis of rubella:
isolation if VIRUS from nasal secretions, throat swab, blood, urine , or cerebrospinal fluid (CSF).
SEROLOGIC TESTING : 4 fold increase in the antibody titer indicates infection. Rubella specific IgM antibody = acute infection. rising titers of IgG suggestive of congenital infection.
US findings of rubella:
growth restriction, microcephaly, CNS abnormalities, cardiac abnormalities.
treatment of rubella
none
Cytomegalovirus (CMV)
double stranded DNA herpesvirus transmitted by close personal contact. Risk of fetal infection is highest if mother has a primary CMV infection in the 3rd trimester. Risk of severe fetal sequelae is highest if infection occurs in 1st trimester.
most common congenital CMV infection affecting 0.2-2% of all neonates; leading cause of
hearing loss
risk of transmission with primary maternal CMV infection is ___. risk with recurrent maternal infection is ___.
30-40%
0.15%-2%
CMV clinical symptoms:
asymptomatic in adults; occasionally mild flulike illness. 85-90% of infants with congenital CMV are asymptomatic; of these, 10%-15% develop hearing loss, chorioretinitis, dental defects by age 2 years.
diagnosis of CMV: routine screening not recommended.
maternal dx: seroconversion from NEG to POS or greater than 4 fold increase in anti-CMV IgG titers is evidence of infection.
US findings for CMV:
intracerebral calcifications, ventriculomegaly, microcephaly, oligohydramnios, growth restrction, and hydrops (less common: heart block, echogenic bowel, meconium peritonitis, renal dysplasia, ascities, pleural effusions)
treatment for CMV:
Intravenous CMV specific hyperimmune globulin every month throughout pregnancy.
Herpes Simplex Virus (HSV)
oropharyngeal or genital infection by double stranded DNA herpesvirus. transmission via sexual contact.
diagnosis of HSV:
viral culture of vesicle fluid; results usually available in 48-72 hours.
treatment: for HSV
supportive measures: 1. oral analgesics, topical anesthetics, frequent bathing followed by drying affected area with hair dryer; oral acyclovir therapy (valacyclovir and famciclovir)
2. neonatal infection prevented by cs in PRESENCE of herpes lesions.
3 women with nongenital herpes should utilize barriers and avoid contact of newborn with infected maternal skin until lesions have encrusted.
prevention: HSV
suppressive viral therapy encouraged at or beyond 36 weeks. (in women with active recurrent genital herpes)
Gonorrhea
gram NEGATIVE Neisseria gonorrhoeae. 2nd most commonly reported communicable disease in US.
- risk of transmission from infected male to female partner is 50-90%
clinical Gonoorrhea:
most women asymptomatic; but may report vaginal discharge / dysuria. Women in 2nd and 3rd trimesters are at increased risk of disseminated disease: 1st stage: chills, fevers, vesicles -> pustules with hemorrhagic base; rarely, perihepatitis, endocarditis meningitis.
2nd stage: septic arthritis.
gonorrhea increases risk for
premature rupture of membraes (PROM), chorioamnionitis, preterm delivery, IUGR, neonatal sepsis, postpartum endometritis.
neonatal sequelae:
ophthalmia neonatorum ilateral conjunctivitis, which can lead to corneal ulceration and blindness if untreated, and disseminated gonococcal infection.
group b streptococcal infection (GBS)
gram positive bacteria. caused by streptococcus agalactiae. overall case fatality rate of 4% to 6%.
2-3% in term.
16-30% in preterm
early onset neonatal infection within 1st week of life, usually in first 48 hrs. rapid clinical deterioration and high mortality rate; which may lead to death within hours from SEPTIC SHOCK and RESPIRATORY DISTRESS. MENINGITIS in 10-30%
negative predictive value of GBS cultures performed gestation before delivery is
95-98%. clinical utility decreases at >5 weeks before delivery.
GBS in urine
give intrapartum antibiotic prophylaxis . prenatal screening at 35-37 weeks is not indicated.
- treat bacteriuria as usual at time of culture positivity. this will not eradicate recolonization from genitourinary and gastrointestinal tracts; therefore IAP still indicated.
women with previous birth of infant with GBS DISEASE should receive IAP
true.
they do not require prenatal screening.
Varicella Zoster irus (VZV)
causes varicella (chickenpox) and herpes zoster infections (Shingles)
transmission of VZV
respiratory droplets and direct contact with vesicular lesions.
clinical sx of VZV:
rash, disseminated, puritic, vesicular rash in multiple stages of evolution.
20% adults develop pneumonia; 1% encephalitis.
FEtal complications: spontaneous abortion, fetal death, congenital anomalies (ris <1% at less than 1 2 weeks gestation, and 2% weeks 13-20).
40% will have IUGR. neonatal varicella occurs when mother develops acute varicella between 5 days prior to delivery to 2 days after delivery. manifestations of neonatal varicella: mucocutaneous lesions, visceral infection, pneumonia, encephalitis; 30% will die without immediate treatment.
diagnosis of varicella zoster virus
identification of anti VZV IgM antibody.
US findings for VZV in neonate:
IUGR, microcephaly, ventriculomegaly, echogenic foci in liver and bowel, limb anomalies, hydrops.
if susceptibe pregnant pt exposed to varicella, she should receive
IM varicella zoster immune globulin (VZIG) or oral acyclovir within 72-96 hrs.
prevention: varicella vaccine is a live virus vaccine. it is contraindicated in pregnancy.
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