Infectious diseases during pregnancy Flashcards Preview

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Flashcards in Infectious diseases during pregnancy Deck (16):
1

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)

2

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

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

Parvovirus B19 (slapped cheek or fifth disease)

airborne infection: incubation 4-20 days
potentially infectious during period before rash
- 40% of women child bearing age susceptible to infection
- 1/3 adults asymptomatic
- no vaccine or treatment
- 50% risk of transmission from infected mother to her fetus
- diagnosis by suspecting infection after exposure and rise in antibodies to Parvovirus B19
- 10% excess loss in first 20 weeks
- 9-20 weeks 3% risk of fetal anaemia -> fetal transfusion increases survival if anaemia diagnosed on ultrasound