Infections (Obs): CMV, Hep B, HSV Flashcards
What is CMV?
Common infection in pregnancy associated with severe congenital syndrome in the fetus.
What is the aetiology of CMV?
Transmission: sexual, blood, saliva, urine, vertical.
Asociations / Risk factors
Higher SES, immunosuppresson (HIV)
What is the epidemiology of CMV?
50% immunity in pregnant women. 1% seronegative pregnant women will contract it.
What is the history/ exam of CMV?
Often asymptomatic, ?fever, malaise, fatigue.
No clinical signs, lymphadenopathy.
What is the pathology of CMV?
DNA herpes virus. Incubation perios 1 month. Following primary infection, lays dormant and reactivates when immunosuppressed.
What investigations do you do for CMV?
Blood: CMV IgM (current)/IgG (past infection)
USS: fetal anomaly scan
Other: amniocentesis for CMV PCR (6-9wk after primary infection)
What is the management of CMV?
No treatment to prevent transmission to fetus. May offer TOP if evidence of neural damage. Naonatal ganacyclovir can attenuate hearing impairment.
What are the complications/ prognosis of CMV?
High risk of miscarriage, stilbirth, congenital CMV, IUGR, microcephaly, intracerebral calcification, blind, sensorineural deafness, hepatosplenomegaly, skin rash, pneumonitis, mental retardation
40% rate of transmission to fetus if infected mother. Of these, 10% develop fetal CMV syndrome. 90% of children with this develop LT neuro delay.
What is Hep B?
Infection caused by the Hep B virus
What is the aetiology of Hep B?
Transmission by sexual contact, blood borne, vertical
Asociations / Risk factors
Multiple partners, unprotected sex, IVDU, SE asian.
What is the epidemiology of Hep B?
1/100k.
What is the history/ exam of Hep B?
Fever, myalgia, N&V, jaundice, abdominal pain. Asymptomaic in 70%.
Jaundice, hepatomegaly, RUQ tenderness
What is the pathology of Hep B?
DSDNA virus, hepadenavirus familt. Replicates in the liver and causes hepatic dysfunction. Incubation 2-6 months.
What investigations do you do for Hep B?
Bloods: HbsAG (infection), core Ab (anti-HBc IgM acutely), Hep B e-markers (HbeAg – high infectivity strain), LFT.
What is the management of Hep B?
Delivery: C seciton NOT INDICATED, AVOID FBS/FSE.
Postnata: mothers can breastfeed.
Neonatal vaccination: IF mother is HbsAg positive at birth, 1 month, 2 months and booster at 1yr.
Neonatal HBIG: within 48h of delivery, if BW <1500g, if acute infection in pregnanct, if mother is HbeAg positive (or HbeAg negative but anti-HbeAg negative).
What are the complications/ prognosis of Hep B?
Maternal: 10% chronic cirrhosis, hepatitis. High risk of HCC. 1% fulminating hepatitis.
Neonates: 90% develop chronic hepatitis
With tx, vertical transmission rate 10%. .
What is HSV?
Infeciton with HSV in pregnancy
What is the aetiology of HSV?
Transmission by physical contact with open sore. Sex, vertical.
Unprotected sex, immunosuppression, other STIs
What is the epidemiology of HSV?
2% pregnant women.
What is the history/ exam of HSV?
Burning, pain, prutitus, dysuria. May be asymptomatic
Clusters of vescicles with surrounding erythema, can progress to ulceration over time, lymphadenopathy.
What is the pathology of HSV?
DNA herpes virus, 1 is oral 2 is genital.
Dormant period: following primary infection lies dormant in nerve ganglia
Spread to neonate: mainly via direct contact with maternal fluids, but transplacental tranmsission possible. Risk of transmission with vaginal delivery 40% with primary lesions, 2% with recurrent lesions.
What investigations do you do for HSV?
Clincial diagnosis but support with microbiology (viral culture/PCR, STI screen)
Bloods: HSV Ab (primary infeciton in third trimester)
What is the management of HSV?
Antenatal: aciclovir in primary infection
Delivery with primary HSV: if within 6wk of infection, advise C section. If opts for vaginal, give IV ACV intrapartum, avoid PROM/FSE/FBS
Delivery with recurrent HSV: No ned for C section. Womn may opt for C section if lesions detected at onset of labour – can offer daily ACV if lseions found from 36/40
What are the complications/ prognosis of HSV?
Maternal: disseminated herpes (encephalitis, hepatitis, disseminated skin lesions) rare but more common in pregnancy
Neonatal: 1/60k live births – can affect skin, eyes, mouth, CNS, multiple organs. Mortality 2% to 50% depending on local or disseminated.
