TORCH infections, STIs and perinatal and postoperative infection

Overview

Infections around pregnancy fall into three groups:

• Congenital (TORCH) infections: reach the fetus across the placenta and may cause malformations, growth restriction or fetal death.
• Infections acquired at birth: sexually transmitted infections and group B streptococcus pass to the baby in the birth canal.
• Infections after birth or surgery: puerperal sepsis, endometritis, wound and urinary infection.

Common features of congenital infection

Many TORCH infections share: FGR, microcephaly, hepatosplenomegaly, jaundice, thrombocytopenia with purpura ("blueberry muffin" rash), anaemia, and eye and hearing problems. Specific clues help separate them (see the comparison table below).

Rubella

• Togavirus (RNA), spread by droplets. The mother has a fever and rash, but 20-50% of infections are silent.
• Risk falls with gestation:

• Congenital rubella syndrome: sensorineural deafness (commonest), cataracts, heart defects (PDA, pulmonary artery stenosis), microcephaly, learning difficulty, encephalitis, endocrine problems later.
• Management: if infection is confirmed before 16 weeks, offer termination; later infection, reassure with information.
• Prevention: rubella (MMR) vaccine is live, so it is contraindicated in pregnancy. Non-immune women are vaccinated after delivery and advised to avoid pregnancy for 1 month. No case of the syndrome from accidental vaccination in pregnancy has been reported.

Cytomegalovirus (CMV)

• DNA herpes virus; spread by droplets, urine, saliva, sex, blood and transplants. It becomes latent and can reactivate.
• The commonest congenital infection; about 1-2 in 200 babies in the UK.
• Primary infection in pregnancy carries the highest risk of symptomatic disease (about 40%) compared with reactivation (about 1%); but because reactivation is so common, it still causes a large share of cases.
• Mother: usually no symptoms or a mild flu-like illness.
• Fetus/newborn: FGR, microcephaly, periventricular intracranial calcification, ventriculomegaly, hydrops, hepatosplenomegaly, jaundice, petechial rash, chorioretinitis, and later sensorineural deafness and developmental delay.
• Diagnosis: maternal IgG seroconversion (compare with the stored booking sample); IgM alone is not enough as it persists for months. PCR of amniotic fluid confirms fetal infection (the virus is passed in fetal urine).
• Management: no routine screening or proven treatment in pregnancy; discuss termination if ultrasound shows abnormalities. Even with a normal scan, about 20% of infected fetuses may have neurological problems.

Toxoplasmosis

• Protozoan (Toxoplasma gondii); caught from cat faeces, soil and undercooked meat.
• Usually silent in the mother, or a glandular fever-like illness.
• Risk changes with gestation:

• Classic triad: chorioretinitis, hydrocephalus (or microcephaly), and diffuse intracranial calcification. Most infected babies look normal at birth and develop eye problems later.
• Diagnosis: maternal serology (Sabin-Feldman dye test, IgM ELISA, rising titres); PCR of amniotic fluid for the fetus.
• Treatment: spiramycin reduces transmission across the placenta; if the fetus is infected, specialists use pyrimethamine-sulfadiazine with folinic acid (standard teaching). Offer termination if the fetus is badly affected.
• Prevention: avoid raw meat, wash vegetables, wear gloves for gardening and cat litter.

Others

Syphilis

• Treponema pallidum; sexual or transplacental spread (can cross at any stage of pregnancy).
• Primary: painless chancre (may be hidden on the cervix); secondary: rash on palms and soles, mucous patches, condylomata lata.
• Untreated early syphilis infects 70-100% of babies, and about a quarter are stillborn. Risks: miscarriage, stillbirth, FGR, hydrops, preterm birth, neonatal death.
• Screen every pregnant woman at booking. Non-treponemal tests (VDRL, RPR) monitor activity; treponemal tests (EIA, TPHA, FTA-abs) confirm. VDRL may be falsely positive in pregnancy and lupus.
• Treatment: benzathine penicillin; parenteral penicillin prevents about 98% of congenital syphilis. Trace and treat partners.
• Jarisch-Herxheimer reaction: fever and worsening symptoms for 12-24 hours after the first dose, from cytokines released by dying organisms; it can trigger contractions and fetal distress, so many units admit for the first dose.
• Congenital syphilis:

Varicella (chickenpox)

• Over 90% of adults are immune; infection in pregnancy is uncommon but more severe: pneumonia in about 10%, hepatitis, encephalitis; maternal death rate higher than in non-pregnant adults.
• Infectious from 48 hours before the rash until the spots crust (about 5 days).
• Significant contact: same room for 15 minutes or face-to-face.
• Exposed woman: check VZV IgG. If not immune, give varicella zoster immunoglobulin (VZIG), effective up to 10 days after contact.
• Chickenpox in pregnancy: oral aciclovir 800 mg five times daily for 7 days if seen within 24 hours of the rash and over 20 weeks (consider before 20 weeks). Admit if smoker, lung disease, steroids or late pregnancy.
• Fetal varicella syndrome: dermatomal skin scarring, limb hypoplasia, eye defects (cataract, chorioretinitis, microphthalmia), microcephaly. Risk about 1% (lower in the first trimester); not reported after 28 weeks. Arrange a detailed scan 5 weeks after infection.
• Near term: delay elective delivery until 5-7 days after the maternal rash so antibodies can cross. If birth falls within 7 days of the rash (or the mother's rash starts within 7 days after birth), give the baby VZIG.

Listeria

• Listeria monocytogenes, a gram-positive bacillus; pregnant women are about 18 times more susceptible (reduced cell-mediated immunity).
• From unpasteurised milk, soft cheese, pâté and chilled foods (it grows in the fridge).
• Flu-like illness; miscarriage, stillbirth, preterm labour; meconium-stained liquor in a preterm fetus is a clue; severe neonatal sepsis.
• Treatment: IV ampicillin.

Sexually transmitted and genital infections

Group B streptococcus (GBS)

• Gram-positive coccus that colonises the vagina in about one in five women; the commonest cause of severe early-onset neonatal sepsis (first 7 days).
• Transmitted during labour after membranes rupture.
• Antenatal treatment of carriage is not recommended; it does not stop recolonisation by labour.
• Offer intrapartum antibiotic prophylaxis when there is:
  • previous baby with GBS disease;
  • GBS found in this pregnancy (swab or bacteriuria);
  • preterm labour (under 37 weeks);
  • prolonged rupture of membranes (over 18 hours);
  • intrapartum fever over 38°C.
• Regimen: IV benzylpenicillin from the onset of labour until delivery (Ten Teachers gives 3 g, then 1.5 g every 4 hours); clindamycin 900 mg IV 8-hourly if allergic.
• Planned caesarean before labour with intact membranes needs no GBS prophylaxis.
• Suspected chorioamnionitis: use broad-spectrum antibiotics that include GBS cover.

Perinatal and postoperative infection

Puerperal pyrexia

Definition: a temperature of at least 38°C recorded on two of the first ten days after birth, ignoring the first 24 hours.

Sources to check ("6 Ws"):

Puerperal sepsis (genital tract sepsis)

• Infection of the genital tract after birth or miscarriage; historically the leading cause of maternal death, and still a major cause worldwide.
• Organisms: usually mixed (bowel and vaginal flora). The most dangerous are group A beta-haemolytic streptococcus (S. pyogenes) and E. coli; others include staphylococci, anaerobes (Bacteroides, peptostreptococci), Klebsiella, Proteus and Chlamydia.
• Why the postpartum uterus is vulnerable: the placental bed is a large raw wound; clots and retained tissue feed bacteria; lacerations and episiotomy offer extra entry points.
• Risk factors: prolonged rupture of membranes, caesarean section, retained products, repeated vaginal examinations, obesity, diabetes, anaemia, immunosuppression, invasive procedures (amniocentesis, cerclage), and group A streptococcal infection in close contacts (for example a child with a sore throat).
• Warning signs: fever or hypothermia, tachycardia, fast breathing, hypotension, oliguria, rigors, offensive lochia, uterine tenderness, rash, confusion, rising early warning (MEOWS) score.
• Management ("sepsis six" principles):

1. Blood cultures before antibiotics; swabs, urine, sputum as indicated. 2. Broad-spectrum IV antibiotics within 1 hour (each hour of delay raises mortality). 3. Measure lactate and haemoglobin. 4. IV fluids (20 ml/kg crystalloid if hypotensive or lactate is 4 mmol/l or more). 5. Oxygen. 6. Monitor hourly urine output. - Remove the source (evacuate retained products, drain abscess); involve a microbiologist and senior staff early.

• Example antibiotic choices from Ten Teachers: piperacillin-tazobactam or a carbapenem plus clindamycin for severe sepsis; clindamycin also switches off streptococcal toxin production. Follow local antibiotic policy.

Endometritis and secondary PPH

• Fever, constant lower abdominal pain, tender uterus, offensive lochia, sometimes with secondary PPH (bleeding from 24 hours to 6 weeks after delivery, commonest at days 7-14).
• Retained products give a bulky uterus with an open os; endometritis alone usually has a closed os.
• Treat with antibiotics; evacuate if retained tissue is present.

Infection after caesarean section

• 5-20 times the infection risk of vaginal birth: fever, wound infection, endometritis, urinary infection, bacteraemia.
• Main risk factors: labour, its length, ruptured membranes, and obesity (wound infection).
• Organisms come mostly from the genital tract: E. coli, other gram-negative rods, GBS, anaerobes.
• Prevention: prophylactic antibiotics at caesarean, skin antisepsis, careful surgical technique, wound care.
• Other causes of postoperative fever: haematoma, atelectasis, DVT.

Urinary tract infection

• Asymptomatic bacteriuria (about 8%) is screened for at booking and treated, because it may progress to pyelonephritis with preterm birth and low birthweight.
• Commonest organism: E. coli. Pyelonephritis needs admission, IV antibiotics and fluids.

TORCH comparison table

Quick revision

• Rubella: worst before 12 weeks; cataract, deafness, PDA; vaccinate after delivery, avoid pregnancy for 1 month.
• CMV: commonest congenital infection; periventricular calcification; deafness.
• Toxoplasma: early = rare but severe, late = common but mild; spiramycin.
• Syphilis: screen all; benzathine penicillin; watch for the Jarisch-Herxheimer reaction.
• Varicella: VZIG within 10 days of contact; aciclovir if rash within 24 hours; FVS not after 28 weeks.
• GBS: IV penicillin in labour if risk factors; clindamycin if allergic.
• Puerperal pyrexia: 38°C on 2 of first 10 days, excluding day 1.
• Puerperal sepsis: GAS and E. coli; cultures, antibiotics within 1 hour, lactate, fluids.

Written by The House Job from standard references (Obstetrics by Ten Teachers; Gynaecology by Ten Teachers).

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