Pocket ObGyn – TORCH Infections / Other Infections in Pregnancy

Dec 9, 2019 admin NHIỄM KHUẨN, PHỤ KHOA, SẢN KHOA 0

Pocket ObGyn – TORCH Infections / Other Infections in Pregnancy
See Abbreviations

  • T-oxoplasmosis, O-ther (Syphilis,Varicella, Parvo), R-ubella, C-ytomegalovirus, H-erpes simplex virus
  • Infections classically transmitted uteroplacetentally or during deliv
  • General rule: ­ gestational age @ time of infxn = ­ transmission rate
  • Rubella & syphilis routinely screened in Preg, others if indicated by Hx/risk factors
  • Most carry risk of IUFD, prematurity, growth restriction in addition to congen defects

Toxoplasmosis (Clin Infect Dis 1994:18:853; Clin Infect Dis 2008;47:554)

  • Epidemiology: ~38% of women have Incident infxn during Preg is 0.2–1%. Congen infxn due to re-infection rare. Congen toxoplasmosis incid 1–2 cases out of 100000.
  • Microbiology: Toxoplasmosis gondii: A ubiquitous protozoan Life cycle: Cat (definitive host of parasite) intestines produce oocysts which produce sporozoites

® passed in feces ® animals eat sporozoites ® cysts form in bone & muscle ®

humans eat raw, undercooked meat, consume the tissue ® infxn. OR, humans ingest oocysts while handling cat litter or soil.

  • Maternal–fetal transmission occurs during active phase of new Transmission rate btw around 30%. Likelihood of transmission ­ w/ gestational age – 15% at 13 w, 44% at 26 w, 71% at 36 w. Severity of congen infections peaks during transmission around 24–30 w.
  • Clinical manifestations: Mat usually subclinical or nonspecific (fever, malaise, LAD, myalgia). Fetal classic triad of chorioretinitis, hydrocephalus, intracranial Also seizures, jaundice, HSM, anemia. Late manifestations, ocular, & neurologic (developmental delay). Subclinical dz more common – only 10% show signs of congen infxn.
  • Dx/screening: No univ Dx by mat serology. A single bld test does not distinguish btw acute & chronic infxn. Nor does IgM vs. IgG distinguish, as both persist in chronic infxn. Rising titers demonstrate new infxn ® 4´ ­ or greater done at least 2 w apart (stable titers = chronic infxn which poses no risk to fetus). Once new infxn documented: PCR of amniotic fluid. US surveillance of fetal dev & manifestations of infxn.
  • Rx (Lancet 2004;363:1965): Spiramycin (1 g TID) or pyrimethamine & sulfadiazine w/ leucovorin (teratogenic risk in 1st trimester w/ latter combo). Rx reduces serious neurologic Unclear if rx prevents transmission & ocular sequelae.
  • Prevention: Hand hygiene, avoiding uncooked meats, cats, unfiltered water, & travel to less developed countries
Syphilis (see below)

Varicella virus (VZV) (BJOG 2011;118:1155)

  • Epidemiology: 90% of women are infected (chickenpox) before adulthood.VZV incid in Preg ~5/10000.
  • Microbiology: Herpes virus responsible for 1° infxn known as VZV (chickenpox) w/ subseq reactivations known as Mat zoster (shingles) rarely a/w congen VZV syn.
  • Clinical manifestations (Obstet Gynecol 1987;69:214): Mat VZV infxn can be VZV PNA = common complication (10–20%) w/ 20–40% mortality w/o antiviral therapy. Congen syn rare <2%.Transplacental transmission <20 w gestation characterized by limb hypoplasia, cutaneous scars, neurologic abnormalities, ocular abnormalities, high mortality.After 20 w transmission, neonat dz 1° infxn near term (w/i 5 d of deliv) neonat mortality as high as 30%. Infxn >5 d from deliv, mat Ab xfer ® more benign neonat infxn.

  • Dx/screening: Mother: Characteristic vesicular papules in different stages of Culture or immunofluorescence studies. Serology early in infxn can confirm mat nonimmunity. PCR testing of amniotic fluid + US to detect fetal infxn.
  • Rx: 1° chickenpox or exposed & VZV IgG negative: Antiviral therapy w/i 24 h of rash appearance. Acyclovir 800 mg 5´ daily or Valacyclovir 1 g TID for 7 VZV zoster secondary infxn: Ig w/i 72 h of exposure. May be effective up to 10 d after exposure. Pregnant women w/ varicella PNA should be admitted & treated w/ IV acyclovir.

Parvovirus (N Engl J Med 1987;316:183; Prenat Diagn 2011;31:419)

  • Epidemiology: Incid of acute parvovirus in Preg = 3%. By adulthood 30–60% of women have had
  • Microbiology (Rev Med Virol 2003;13:347): Risk of vertical transmission to fetus ~33%. Virus affects fetal erythroid progenitor
  • Clinical manifestations: Children & adults ® erythema infectiosum: Lace-like rash often on face “slapped check,” arthropy, aplastic Fetal infxn: Hydrops & stillbirth <24 w; >24 w, persistent risk of hydrops, but ¯ likelihood of sev infxn & death. Hydrops from anemia ® reduced survival of fetal red cells ® high-output CHF.
  • Dx/screening: Exposed women should be tested w/ serology: + IgM w/o IgG =

acute infxn. PCR amniotic fluid + US to confirm dx

  • Rx: W/ confirmed infxn ® surveillance for up to 12 Weekly US & MCA dopplers to look for fetal anemia. Intrauterine xfusion can be done to correct fetal anemia & ¯ fetal mortality.

Rubella (Lancet 1982;2:781; Glob Libr Women’s Med 2012)

  • Epidemiology: Rare in the US given immunization ~90% of pop immune
  • Congen rubella extremely rare – <1 case/y in US recently
  • Microbiology: Self-limited viral infxn transmitted in droplets or nasopharyngeal secretions from infected persons, commonly from contact w/ infected Congen infxn occurs via hematogenous spread across placenta. Earlier transmission = higher likelihood of sev defects.
  • Clinical manifestations: Mat often subclinical: Fever, desc maculopapular rash, LAD (post auricular), URI-like, nonspecific Infxn in 1st trimester usually results in miscarriage. Infxn after 20 w unlikely to result in neonat manifestations. Classic fetal syn: Growth restriction, cataracts, cardiac defects, hearing defects, hepatosplenomegaly. Late manifestations: DM, thyroid disorders, panencephalitis.
  • Dx/screening: Univ screening at initial prenatal visit ® nonimmune pts vaccinated Dx by serology titer immediately following exposure. If Ab + ® woman likely immune, no risk to fetus. Conversion of (–)Ab or 4´ ­ titer indicates acute infxn (rpt titers 2–4 w apart). Confirm by IgM or direct PCR of fetal bld.
  • Rx/prevention: Mat supportive No rx exists for preventing transmission or for fetal infxn. Nonimmune mothers should be vaccinated postpartum. MMR vaccine should not be administered to pregnant women b/c of theoretical risk of transmission from live virus. Advised to avoid conception for

1 mo following vaccine

Cytomegalovirus (CMV) (Infect Dis Obstet Gynecol 2011;2011:1)

  • Epidemiology: Most common congen infxn. Birth prevalence ~5%. Seropositivity in childbearing women ~58% in US. Risk factors: Low socioeconomic status (near 100%), non-White, multiparous. Most common infectious cause of sensorineural hearing loss.
  • Microbiology: Herpes virus family, latent in numerous organs following infxn. Transmitted by close interpersonal contact including sexual contact & Congen CMV: Transplacental transmission. Peripartum transmission does not harm dev of neonate.
  • Transmission (Obstet Gynecol Surv 2010;65:736): 1° mat infxn, ~35% More likely to cause fetal infxn & sequelae. Reactivation of latent virus: 1–2% transmission rate. Reinfection w/ different strain poss.
  • Clinical manifestations: 1° CMV – asx or a/w a mononucleosis-like Fetal infxn & sequelae more common at <20 w gestation. 90% are asx; 5–10% overtly symptomatic w/ 5% mortality; 50–60% w/ sev neurologic morbidity: Microcephaly, ventriculomegaly, chorioretinitis, HSM, sensorineural hearing loss. Late infxns a/w hepatitis, PNA, purpura, & thrombocytopenia.
  • Dx/screening: Routine screening not currently recommended in US. Dx by seroconversion during IgM helpful for reactivated infxn. Low IgG avidity

indicative of primary infxn (can perform avidity testing).Viral culture can be performed, but does not distinguish btw new & recurrent. US screening for anomalies should be performed in suspected case. If CMV infxn present ® amniocentesis to detect fetal infxn.

  • Prevention: Hygienic precautions:Washing hands, avoidance of close contact
  • Rx: High-titer CMV Ig may ¯ transmission & fetal/neonat morbidity

Herpes Simplex Virus (HSV) (N Engl J Med 1997;337:509)

  • Epidemiology: HSV-1 or HSV-2 seroprevalence in pregnant females up to 72%. Congen HSV very rare, 1 in 5000–20000. Seroconversion during Preg = 7% in women seronegative to both types.
  • Microbiology: 50–70% of genital HSV caused by HSV-2. Genital HSV-1 ­ due to oral–genital Transmission can occur transplacentally (rare) or through contact w/ mother’s genital tract during labor/deliv. Mat 1∞ infxn (0.1% incid) a/w higher transmission rates at deliv than recurrent infxn (mat antibodies are protective).
  • Clinical manifestations: 1° infxn: Fever, malaise, dysuria, tender inguinal, LAD, painful genital Many pts have mild or subclinical presentation.Vesicles

® crusting ulcers. Recurrent episodes vary in frequency, usually milder & shorter than 1° episode. Latency: Dorsal nerve roots btw episodes. Neonat HSV: Mucocutaneous involvement (~45%), CNS dz (~33%), dissem dz w/ multiorgan involvement (~25%). Congen infxn extremely rare, can cause systemic dz w/ mortality >50%. Late trimester mat infections correlated w/ increased rates of preterm labor, preterm birth, & IUGR.

  • Dx/screening: Univ screening not Dx by culture or PCR if lesion present. Serology can distinguish HSV type; IgM indicative of acute infxn.
  • Rx (MMWR Recomm Rep 2010;59:1): 1° infxn: Acyclovir 400 mg TID ´ 7–10 d or Valacyclovir 1 g BID ´ 7–10 Recurrent infxn: Acyclovir 400 mg TID ´ 5 d or Valacyclovir 500 mg BID ´ 3 d. Suppressive therapy recommended for women w/ recurrent genital HSV from 36 w until deliv: Acyclovir 400 mg TID or Valacyclovir 500 mg BID. At time of deliv, careful exam of woman’s genital tract should be performed.Women w/ active lesions of vulva, vagina, or cervix should be offered CD. Lesions on buttocks, mons, thighs, or anus can be covered during deliv.
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Other Infections in Pregnancy

Influenza (Obstet Gynecol 2010;115:717) See also Chap 13.

  • Epidemiology: During flu pandemics (including 2009 H1N1), pregnant women ­

mortality rate, ­ hospitalization, ­ ICU admission, & ­ deaths

  • Clinical manifestations: Influenza ® critical illness in Preg & carries much higher mortality Physiologic changes of Preg ® less cardiopulmonary reserve & altered immune system. Transplacental transmission rare & insig. Mat illness may lead to premature deliv.
  • Dx/screening: Rapid flu testing available in 15 min or less, but sens is fairly poor

~63%. In pregnant & recently (<2 w) postpartum women, rx should be administered clinically. Do not await diagnostic results.

  • Rx: Neuraminidase Ppx for exposed: Oseltamivir 75 mg daily ´ 10 d or Zanamivir 10 mg daily ´ 10 d. Rx: Oseltamivir 75 mg BID ´ 5 d or Zanamivir 10 mg BID ´ 5 d.
  • Prevention: All pregnant women should receive inactivated influenza vaccination regardless of gestational age, & preferably by the beginning of flu
Hepatitis B Virus (HBV) And see Chap 15.
  • Epidemiology: Prevalence ~1% US & 15–20% endemic areas (SE Asia, China, subSaharan Africa). Major source of morbidity from hepatitis, cirrhosis, & 5–10% of acutely infected will become chronic carriers. In endemic areas, perinatal is primary form of transmission.
  • Microbiology (JAMA 1985;253:1740): Maternal–fetal transmission primarily during deliv. Transmission 40–90% w/o ppx, much higher if HBeAg +. CD does not prevent Breastfeeding does NOT ­ rate of transmission (Obstet Gynecol 2002;99:1049).
  • Clinical manifestations: Mat 1° infxn: Abdominal pain, fever, N/V, Almost all infected infants become chronic carriers, although infxn generally asx. Infected newborns have risk for liver dz later in life.

 

  • Dx/screening: Dx by + surface Ag (HBsAg). Immunity is indicative of loss of HBsAg & appearance of HBsAb (Ab). IgM anti-HBc is indicative of primary infxn; sometimes only sign of infxn btw loss of HbsAg & rise of HBeAg a marker of high infectivity, carries high vertical transmission rates. Chronic infxn is determined by persistence of HBsAg >6 mo. ACOG recommends univ screening by checking HBsAg in prenatal panel.
  • Rx: Vaccination universally recommended if serologically Lamivudine during 3rd trimester may ¯ rate of transmission (Obstet Gynecol 2010;116:147). HepBIg & HBV vaccine recommended as ppx for neonates of HbsAg+ women. ¯ rate of transmission by almost 90% (JAMA 1985;253:1740).

Hepatitis C Virus (HCV) (Hepatology 2001;34:223; Am Fam Physician 2010;82:1225) See Chap 15.

  • Epidemiology: 8% of noninstitutionalized persons carry HCV antibodies
  • Microbiology: Vertical transmission ~2% – primarily during Risk factors for increased transmission include increased viral load, HIV coinfection, mat drug use, prolonged ROM, procedures during labor (fetal scalp electrode, operative vaginal deliv). CD does not appear to lower rates (Arch Gynecol Obstet 2011;283:255). Breastfeeding does not to appear to ­ transmission. Infected infants are generally asx, sometimes w/ temporary transaminitis.
  • Dx/screening: Hepatitis C screening is not univ; based on risk HCV Ab + ®

obtain viral load, genotype. HCV by RIBA if concern for false-positive.

  • Rx: Std – combined pegylated interferon alfa-2a & Not safe rx during Preg, ribavirin = teratogenic.Vaccinate for HBV if not infected or immune.

Tuberculosis (TB) (Chest 1992;101:1114)

  • Epidemiology: Same in Preg as general Btw 5–10% of reproductive women have reactive tuberculin skin test. Worldwide TB = leading infectious dz cause of mat mortality. Risk factors in US: Low socioeconomic status, urban area, IV drug use, homelessness, immigrant from underdeveloped country, & incarceration.
  • Clinical manifestations: 3–4% develop active TB during 1st 5–15% will later develop an active infxn. Active TB: Cough, fever, hemoptysis, weight loss, fatigue, night sweats. Untreated active infxn has a 50% mortality rate at 5 y. Active TB ® congen infxn through transplacental transmission. Extremely rare & a/w miliary TB.
  • Dx/screening: Screening should occur in women w/ risk of progression from latent to TST or interferon gamma release assay. Those w/ positive testing should undergo CXR.

 

Classification of TST reaction
TST size (mm) Group in which this is considered positive
³5 HIV +, close contact w/ cases, abn CXR, immunosuppressed pts (chemo, glucocorticoids)
³10 Persons at risk of reactivation, chronic renal failure, DM, malignancies, children <4 yo, foreign born from TB prevalent countries, residents & employees of high-risk settings
³15 Healthy individuals w/ low likelihood of true TB infxn
From Jensen PA, Lambert LA, Iademarco MF, et al. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care settings, 2005. MMWR Recomm Rep. 2005;54(RR-17):1–141.
  • Rx (MMWR 2000;49:1):

Latent TB: 9 mo INH 5 mg/kg/d. Can delay rx of latent TB until 2–3 mo PP unless high risk of progression to active dz (HIV+, recent contacts)

Active TB: INH, rifampin, ethambutol ± pyrazinamide ´ 9 mo minimum. Streptomycin should be avoided in Preg (congen deafness). Breastfeeding not contraindicated during rx. Infant should be given pyridoxine (B6) if mother is on INH.

See Abbreviations

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