Pregnancy: Blood borne diseases Flashcards
Rubella CMV Parvovirus Chickenpox Influenza Syphilis Zika HIV Covid-19 Group B strep
What is rubella?
- also known as German measles
- a viral infection caused by the togavirus.
- rare since the MMR vacciine
If a pregnant woman gets rubella what are the risks?
- spontaenous abortion
- fetal death
- congenital rubella syndrome
When during the pregancy is the risk of catching rubella highest in terms of damage to the fetus?
- 8-10 weeks - risk of damage = 90%
- after 16 weeks - rare
What are features of congenital rubella syndrome?
- sensorineural deafness
- congenital cataracts
- congenital heart disease (e.g. patent ductus arteriosus)
- growth retardation
- hepatosplenomegaly
- purpuric skin lesions
- ‘salt and pepper’ chorioretinitis
- microphthalmia
- cerebral palsy
What are RF for contracting rubella?
incomplete immunisation, exposure to infectious contacts, and international travel
How might a woman with rubella present?
- maculopapular rash (begins on face and spreads to head and feet lasts 3-4 days)
- fever
- arthralgias ( 70% adult women fingers wrists knees)
- lymphadenopathy
- pt with unsure immunisation
Investigations for rubella?
1
- Serology - rubella specific IgM serum antibody.
* Result : IgM raised in acute serum (recently exposed). this is confirmed by later IgG with 4 fold rise in 2-3 weeks) - FBC - can cause thrombocytopenia
NOTE:
* v similiar clinically to parovirus B19 so check parovirus B12 serology as 30% risk of transplacental infection, with a 5-10% risk of fetal loss
You suspect a pregnant woman has rubella. Who do you need to inform?
suspected cases should be discussed immediately with the local Health Protection Unit (HPU)
How do you manage rubella in pregnancy?
- discuss with local Health Protection Unit
- rubella no longer checked at booking visit so if tested and not immune tell to avoid anyone who might have it
- offer MMR vaccination in post natal period (should not be given to pregnant / trying to get pregnant)
BMJ BP
* refer to high risk perinatal specialist and paediatric infectious disease specialst to evaluate risk of fetal infection
* termination an option if high risk of congenital ruubella syndrome
* high dose intramuscular immunoglobulin is not proven to prevent congenital rubella syndrome so not routinely recommended (might use if woman would not consider termination)
What is the incubation period for rubella in pregnancy?
- Incubation period i= 14-21 days
- People are infectious from 7 days before they get symptoms and up to 4 days after the onset of the rash.
What is cytomegalovirus (CMV?)
- Herpes virus
- Very common over 50% have been exposed to it
- primary infection for people with normal immune system is usually asymptomatic.
- after primary infection CMV establishes life long latency in host cells
- periodic re-activations controllled by immune system
- Problem for immunocompromised
What are the features of congenital CMV infection in the newborn?
- growth retardation
- pinpoint petechial ‘blueberry muffin’ skin lesions
- microcephaly
- sensorineural deafness
- encephalitiis (seizures)
- hepatosplenomegaly
Is CMV screened for antenatally?
NO - not routinely
done if mother has:
* mononucleosis-like symptoms such as lymphadenopathy, rash and sore throat, fatigue, fever
- can be offered to mothers who request testing
What investigations would you do for a pregnant woman with CMV?
*Serolgoy - CMV-IgM acute infection, CMV IgG suggests past infection
* Amniocentesis or fetal blood sampling allow for testing of CMV starting from 21 weeks of gestation
* Fetal US every 2-4 weeks after diagnosed CMV to check for abnormalities e.g. growth restriction, microcephaly, enlarged liver
treatment for CMV in pregnancy?
No treatment
prevention
What is Parvovirus B19?
How is it spread?
A DNA virus- causes erythema infectiosum (fifth disease / slapped cheek syndrome)
Spread by respiratory droplets
When is contracting Parvovirus B19 most dangerous for a pregnant mother?
Can effect unborn baby in first 20 weeks of pregnancy
What are the symptoms of Parvovirus B19 in pregnant woman?
often no symptoms in pregancy
can get:
* ‘slapped cheeck’ rash
* maculopapular rash
* fever
* arthralgia
What is the incubation period for parvovirus B12?
4-20 day incubation period
(50% women in UK are immmune)
people are infectious 3-5 days before appearance of rash
If suspect a woman has parvovirus B12, how do you diagnose?
- Maternal IgM and IgG checked. A paired sample in acute and convalecent phase> 10 days apart.
- IgM antibodies appear and IgG titres increase
What are the maternal effects of parvovirus B19 ?
minimal unless immunocompromised
* if so, can lead to sudden haemolysis needing blood transfusion to treat
What are the fetal consequences of parvovirus B12?
30% fetus’s infected causing
* fetal suppression of erythropoesis
* cardiotoxicity
This leads to:
* cardiac failure
* fetal hydrops
10% of fetus’s infected <20 weeks will die
Explain how parvovirus B12 can lead to fetal hydrops
- parvovirus B19 crosses the placenta
- this causes severe anaemia due to viral suppression of fetal erythropoiesis → heart failure secondary to severe anaemia → the accumulation of fluid in fetal serous cavities (e.g. ascites, pleural and pericardial effusions)
- treated with intrauterine blood transfusions
How do you manage Parvovirus B12 ?
- No specific treatment
- Serial US looking for signs of fetal anaemia (fetal hydrops and abnormal middle cerebral artery Dopplers)
- if fetus develops anaemia manage in tertiary fetal medicine unit and consider in utero red cell transfusion
