Infectious diseases during pregnancy Flashcards
Rubella
Risk of congenital abnormality decreases with gestational age
- visual, hearing loss
- cardiac defects
- intellectual disability
- behavioural problems
- often multiple abnormalities
Can also lead to pregnancy loss and cogenital rubella syndrome (CRS)
Hep B
DNA virus
transmission: blood, STI, mother-to-child
Assay of immune markers
- HB surface antibody: seen in immunised individuals
- HB core antibody: seen in natural infections
- HB surface antigen: persistence for more than 6/12 = carrier
- HBe antigen presence = highly infectious carrier
Symptoms: adults = appear several months after infection, from severe to almost asymptomatic -> 5% after cure will become carriers and at risk of cirrhosis and liver failure
infants = mild acute illness but high rate of chronic carriage (90%), high rate of Hep Be antigen status
Vaccination 2, 4 6 months, at risk globulin within 12 hrs of birth
Breastfeeding ok for Hep B + mum if infant vaccinated
UTI
E. Coli most common, common in pregnancy due to decreased bladder tone & capacity -> can have frequency, dysuria, urgency to asymptomatic
- associated with low birth weight & pre-term labour
- pyelonephritis high risk
Diagnosis
- Dipstick (first indicator) -> MSU -> UTI if increased WCC & >10^5 bacterial colonies/mL
Treatment
- increased fluid intake/urinary alkaliniser
- antibiotics: cephalexin, nitrofurantoin, amoxycillin, potassium clavulanate
- 10 days treatment
- if severely febrile -> hospitalisation & IV antibiotics
Varicella Zoster (Chickenpox & Shingles)
Herpes virus: incubation 10-14 days, infectious from 2 days before rash until all lesions crusted over
- severe in adults & life threatening in pregnant women (10% viral pneumonia)
- fetus: fairly benign, 3-5% risk of skin & eye lesions, shortened limbs & microcephaly - esp in 1st trimester
- Screen & immunise prior to pregnancy -> varicella negative woman known to be exposed to varicella given zoster immune globulin (ZIG)
- aciclovir
Herpes (HSV)
HSV 2 = 12% in Aus, almost all is genital
HSV 1 = 60-80%, oral some genital
20% who are seropositive have recognisable genital symptoms -> still transmissible
Neonatal HSV infection = 30-50% mortality
- 1st episode of genital HSV within 6-8 weeks of vaginal delivery has 50% risk of neonatal infection - C-section recommended
Pregnancy: prevent neonatal herpes, woman unaware she carries infection
- aciclovir or valaciclovir -> used in third trimester to reduce recurrences close to delivery
- ask if partner has known herpes -> consider type specific serology
- suppressive therapy for male partner, no vaginal sex in 3rd trimester, treating with antivirals no help in preventing infection, monitor carefully for symptoms
HIV
To prevent early HIV detection required, all Australian women should be offered HIV testing after appropriate risk assessment at the first antenatal visit
- HIV women = ARV therapy (not efavirenz, teratogenic)
- should be co-managed by infectious disease specialist
- use combination ARV & elective CS
- in developing countries, short course of AZT (zidovudine) late in pregnancy can reduce maternal-infant transmission
Zika
mosquito-born flavivirus -> found in Qld
sporadic outbreaks in humans: rash, fever, malaise
virus persist for up to 6 months in semen -> male partner
- links with Guillain-Barre syndrome and microcephaly
Listeria
common in environment -> transmitted as foodborne infection, causes mild flu-like illness
incubation 1-90 days
baby infected 3 days after mother develop symptoms
- 30-55% risk of miscarriage or stillbirth if infected 2nd-3rd trimester
treat 10-14 days penicillin
- killed by cooking, thrives in cold
- good food hygiene, avoid high risk foods
HPV
warts common during pregnancy: 5-15%
can enlarge rapidly due to altered immunity in pregnancy
- wart paints containing Podophyllin or Imiquimod cannot be used
- laser, cryotherapy and diathermy safe
- can obstruct delivery, usually regress after delivery
Syphilis
Antenatal screening important for latent infections
- if not treated
- 40% prematurity and perinatal death
- 60% asymptomatic at birth and develop by 2 months - hepatomegaly & rash
- 12% die in infancy with treatment
- transmission: early as 9 weeks
Chlamydia
Infection during pregnancy associated with
- post-abortion PID
- premature rupture of the membranes and low birth weight
- conjunctivitis - 20-50%
- pneumonitis: risk 10-20%
Azithromycin or erythromycin drugs of choice in pregnancy
- infected infant treated with erythyromycin syrup, 50mg/kg per day orally, in 4 divided doses for 14 days
Group B Streptococcus
10-30% women carry, 20% babies colonised at birth
1/200 babies develop sepsis and mortality rate may be as high as 50% from shock, respiratory infection and meningitis
- treatment by intrapartum penicillin (at least 4 hrs before delivery)
- clindamycin or erythromycin if allergy
- routine low vaginal and anal swab at 35-37 weeks & treatment of those at risk: preterm labour, premature RM, fever in labour
Chorioamnionitis
Infection of placenta and membranes
- E. Coli, Group B strep, bacterial vaginosis
- symptoms: maternal fever, uterine tenderness, preterm labour and malodorous discharge
- diagnosis: cervical swab-white cells ++, culture of pathogenic organisms
- may cause preterm labour and foetal loss, pneumonia and septicaemia in the infant, suggested link the cerebral palsy
- mother risk of endometriosis, esp CS
- treatment is with IV antibiotics and urgen delivery if foetus viable
Toxoplasmosis
Cat or possum faeces or in uncooked meat
intrauterine infection during primary exposure as high as 40%
syndrome: chorioretinitis, intracranial calcification and hydrocephalus
- most infants unaffected
- risk infection lower in early pregnancy but more severe
- screening not routine in Aus
- treatment via spiramycin (not available in Aus)
- Public health advice:
- food & general hygiene, don’t drink unpasteurised milk, was fruits, minimize contact with young cats, cover children’s sandpits
Cytomegalovirus (CMV)
Urine, saliva, blood, tears, semen and breast milk
- mild infection with sub-clinical illness
- CMV most prevalent congenital viral infection
- main risk of maternal CMV acquisition: child care worker or kids in child care
- assume children under 3 have CMV in urine & saliva -> basically hand hygiene and don’t interact with them
symptoms: seizures, cerebral palsy, developmental delay, hearing and vision loss - rise in maternal IgM unreliable unless known recent contact
- IgG avidity more accurate
- treatment difficult
