7. Infections in pregnancy Flashcards
Why are infections more prevalent and more dangerous during pregnancy?
The mother is relatively immunosuppressed
There are physiological changes occurring in the mother leaving her more vulnerable
When are infections more likely to cause harm to the foetus/mother?
All of the foetal development is occurring in the first trimester so infections during this time will impact on the foetus
Infections in the third trimester are more harmful to the mother
What are the main infections that occur during pregnancy and how can these be easily remembered?
TORCHES Toxoplasmosis Other Rubella Cytomegalovirus (CMV) Herpes simplex virus (HSV) e.g. HIV, hepatitis
How are infections diagnosed in pregnancy?
Bacterial infection - swab or sample and culture this
Viral infection - serology or Pcr (this is very sensitive and very quick)
What are the different antibodies present in the bloodstream in response to an infection?
IgM is the first antibody produced in response to an infection
IgG is the second
If the patient is IgM positive then they have had a recent, acute infection
If the patient is IgG positive then they have contracted an infection in the past 24-48 hours
How common is cytomegalovirus and what type of virus is this?
When might this occur during pregnancy?
This is a herpes virus and is extremely common
50% of UK adults have had past exposure to this (50% of adults at IgG positive)
This can occur during any time in the pregnancy
Having it in the first trimester is most problematic to the foetus
When is CMV virus most dangerous to the foetus?
If the mother contracts CMV for the first time in the pregnancy then the foetus is more likely to develop congenital CMV
If the mother has had CMV in the past then the risk to the baby is much less
How common is congenital CMV and how is it diagnosed?
0.7% of live births have congenital CMV
Diagnosed via the maternal serology CMV IgG and IgM and also the neonatal urine/saliva
What are the symptoms of congenital CMV?
IUGR, seizures, hepatosplenomegaly, microcephaly
Sensorineural deafness is the most common symptom - CMV is the most common cause of this
What is the treatment for congenital CMV?
Ganciclovir
What is the varicella zoster virus responsible for and how is this transmitted?
This is also a Herpes virus - this is the virus responsible for chickenpox (varicella) in children and shingles in adults
Spread via droplet infection so is very infectious - respiratory spread
The later the mother develops this, the more damaging it is
What is the effect of VZV on the foetus?
Congenital varicella syndrome
The risk of this is greater in the second trimester than in the first
During the second trimester, development of the limbs occurs and so this will be impacted
Neonatal varicella
This occurs if the mother has VZV around the time of delivery (most severe if 5 days prior or 2 days post delivery)
This is transmission of the virus in utero and the foetus develops chicken pox following birth
What are the clinical presentations of VZV in the adult?
Dermatomal rash - this occurs because the VZV virus is reactivated from one dorsal root ganglia e.g. the opthalmic dorsal root ganglion would affect the eye
How is VZV diagnosed?
Look at the clinical presentations
Serology to see any antibodies to VZV
Swab of vesicle fluid for PCR usage
What is the treatment for VZV?
Prevention: vaccination - VZV immunoglobulin (this is a live vaccine so cannot be given during pregnancy
Treatment: (val)aciclovir - safe during pregnancy
How common is the Herpes simplex virus (HSV) and how does it present?
Extremely common - HSV1 more oral and HSV2 is more genital (now realising they are both responsible both)
80% of primary HSV infection is asymptomatic
Presents with a cold sore, genital or oral ulceration, CNS infection ( very problematic), HSV encephalitis
What is the effect of HSV on the neonate?
Can cause a very severe infection in the neonate - can be infected whilst passing through the birth canal
What is the treatment for HSV?
Aciclovir
How common is rubella and how is it diagnosed?
Aka. German measles
Not a very common infection - 95% of people are vaccinated against this
Diagnosed via serology/oral fluid PCR for IgG
What is the treatment for rubella?
There is currently no available treatment - currently not a massive issue as the vaccination rate is so high via MMR
What is the risk and effect of congenital rubella?
What are the symptoms in the neonate?
There is a 90% risk of passing the infection to the child in the first trimester and this decreases as time goes on
One of the most devastating diseases for the foetus - eye abnormalities causing them to become blind, sensorineural hearing loss congenital heart disease, death
Can the MMR vaccine be administered during pregnancy?
No
What is parovirus and when is it common?
This is a viral rash - also known as slap cheek virus
This virus targets the red blood cells
Most people have this as children
How is parovirus diagnosed?
Maternal serology and PCR
Foetal ultrasound
What are the symptoms of parovirus on the neonate?
Hydrops fetalis i.e. cardiac failure in the foetus - this is because the virus targets hte production of red blood cells and foetal anaemia can result in cardiac failure
What is the treatment for parovirus in the foetus?
Intrauterine blood transfusion
What is the natural host of the virus toxoplasmosis and how is this transmitted to humans?
Cat - humans are the intermediate host via ingestion of oocytes
This occurs via the consumption of cat faeces or via eating infected meat
Lifelong infection - can be reactivated
What are the clinical features of congenital toxoplasmosis?
IUGR Hydrocephalus Cerebral calcification Microcephaly Hepatosplenomegaly
Greatest risk to the foetus in the first trimester
What is the treatment of congenital toxoplasmosis?
Treatment is dependent on the trimester Spyramicin Pyrumethamine Sulfadiazine Folinic acid
What is the pathogen responsible for syphilis?
Treponema Pallidum
When is the highest risk of transmission of syphilis in pregnancy?
What risks does syphilis carry for the pregnancy?
Highest risk of transmission during the first trimester
Increased risk of miscarriage, still birth, prematurity
What is the treatment for syphilis?
Penicillin
What are the symptoms of early congenital syphilis and when does this occur?
Early - in the first 0-2 years of life: Rash Rhinorrhoea Osteochondritis Lymphadenopathy
What are the symptoms of late congenital syphilis and when does this occur?
Late - after 2 years of age: Hutchinson's teeth Clutton's joints High arched pallet Deafness Saddle nose deformity
What are the ethical issues associated with congenital viral infections?
Antenatal screening can allow detection of high risk pregnancies and allows treatment if required but serology can sometimes appear falsely positive - repetition of blood tests can be an anxious period for mum
Some of the things tested for cannot be treated anyway - is it worth testing for in this case?
What infections are tested for antenatally?
Hepatitis B infection
Human Immunodeficiency Virus
Syphilis
Plus regular ultrasound to detect and monitor foetal development
