Syphilis, Toxoplasmosis and CMV Flashcards
(36 cards)
Definition of syphilis
A bacterial sexually transmitted infection caused by the spirochete Treponema pallidum, which results in substantial morbidity and mortality.
How is the incidence of syphilis changing in the UK
The number of cases is on the rise in the UK, in part due to increased levels of immigration from countries where infection is prevalent.
What is the prognosis of syphilis in pregnancy
- Mother-to-child transmission may occur if the expectant mother has syphilis and is usually devastating to the foetus if left untreated in pregnancy
- There is a foetal loss rate of 50%. Additionally, infection carries a risk of miscarriage, preterm birth, still birth and congenital syphilis.
- Around 2/3 of babies with congenital syphilis will be asymptomatic at birth but most will develop symptoms by 5 weeks of age
Characteristics of neonatal syphilis
- Neonatal disease may manifest as rhinitis, a diffuse maculopapular, desquamative rash with extensive sloughing of the epithelium, particularly on the palms and soles
- Also presents with splenomegaly, anaemia, thrombocytopenia and jaundice
- 50% of infants will die in the neonatal period
- If left untreated, leads to physical and neurological impairment in the future
What is the clinical course of syphilis
Characterised by STAGES:
* Primary and secondary where the person is symptomatic and highly infectious
* Latent (early/late)- asymptomatic
* Tertiary, where syphilis reactivates and serious complications are common
Presentation of primary syphilis
Presents with a painless genital chancre
* < 2cm ulcer at the site of inoculation- classically solitary, painless, indurated, non-exudative (appears around 3 weeks after inoculation)
Presentation of secondary syphilis
A manifestation of bacterial dissemination and classically presents with a diffuse, symmetric, copper maculopapular rash which is possibly pruritic (occurs 6 weeks to 6 months after infection)
* Commonly appears on the palms or soles. Mucus lesions, patchy alopecia, fever, headaches and generalised painless adenopathy may occur
Presentation of tertiary syphilis
Without treatment, 14-40% of people with syphilis progress to tertiary disease- irreversible damage to any organ (primarily neurological, cardiovascular)
When should syphilis be screened for in pregnancy, how is this done. What other investigations should be conducted for syphilis
At the booking visit
* Screening involves enzyme immunoassay- detects antibodies to Treponema pallidum
* Will be positive for antibodies against treponemal infections including non-syphilis treponemal infection and in those with a *previous *syphilis infection
* If positive repeat and perform TPPA
Genital ulcers can be swabbed and sent for microscopic identification of syphilis bacteria
Blood cultures
Confirmatory test= Treponema Pallidum particle agglutination (TPPA) or haemagglutination
Diagnosis of congenital syphilis
- Ultrasound markers
- Non-immune hydrops fetalis
- FGR
- Lesions of the head and of the GI tract
Management of syphilis in pregnancy
- Refer to the GUM clinic for appropriate contact tracing and determination of the stage of infection and complications
- Treatment for early disease (primary, secondary and early latent syphilis)= Benzylpenicillin G 2.4 million units once daily IM for 10 days
- In the case of penicillin allergy oral erythromycin or IM ceftriaxone can be used with caution (does not cross the placental barrier completely so foetus is left untreated)
- Treatment for late stage syphilis)= Benzylpenicillin G 2.4 million units IM once weekly for three consecutive weeks
- Parenteral penicillin has a 98% success rate at preventing congenital syphilis
What is a Jarish-Herxheimer reaction
- Due to release of proinflammatory cytokines in response to dying organisms
- Presents with worsening of symptoms and fever for 12-24 hours after starting tx
- May be associated with uterine contractions and foetal distress
- So, women may be admitted at the time of treatment for monitoring
Definition of toxoplasmosis
A disease caused by infection with the intracellular protozoan parasite Toxoplasma gondii, found in cat litter, soil and raw or undercooked meat. One third of the world’s population is infected with the parasite although it often remains unrecognised as patients do not exhibit symptoms.
What is the incidence of toxoplasmosis in the Uk
Approximately 2 per 1000 pregnancies
When is toxoplasmosis dangerous in pregnancy
- Placental infection is only a significant risk if the mother acquires the infection during or immediately before pregnancy (up to 3 months before conception)
How long after inoculation does parasitaemia occur
Within 3 weeks (spread via blood and lymphatic system)
What is the risk of congenital toxoplasmosis in first, second and third trimesters
o First trimester ~10 %
o Second trimester ~25%
o Third trimester >85%
When is infection with toxoplasmosis most likely to cause congenital sequalae
Infection is more likely to cause congenital sequalae and complication in early pregnancy (85%) than late pregnancy (10%).
(more likley to cause congenital disease in late pregnancy)
Presentation of toxoplasmosis in pregnancy
- Immunocompetent people are generally asymptomatic, or may exhibit non specific flu-like symptoms including fever, headache, muscle pain and lymphadenopathy.
Manifestations and complications of toxoplasmosis in the neonate
Manifestations of toxoplasmosis in the neonate:
* Hydrocephalus, microcephaly, intracranial calcifications, retinochoroiditis, strabismus, blindness, epilepsy, psychomotor and mental retardation, petechiae due to thrombocytopenia, immunocompromised (most infants are asymptoatic at birth and develop symptoms later on)
* Significant risk of miscarriage and stillbirth
* Long term foetal effects include visual impairment due to persistence of a toxoplasmosis cyst that subsequently ruptures
Evidence of toxoplasmosis spread to newborns through breastfeeding or human-human contact
None
Investigations for toxoplasmosis in pregnancy
- Challenge is to distinguish between acute primary infection and past chronic infection
Serology (difficult to distinguish):
* IgM and IgG antibodies both rise within 1 to 2 weeks of acute infection but can persist for years (IgM) or throughout life (IgG)
* Absence of IgG or IgM antibodies indicates no previous infection (identifies women at risk during pregnancy)
* Four-fold increase in IgG antibody titre indicates a recent infection
* IgG antibody avidity testing can help confirm acute infection: Avidity of Ig binding to T.gonadii. Avidity shifts from low to a high index around 5 months after infection (low avidity index- suggests infection within past 5 months)
* Sabin-Fieldman dye test
Other:
* USS: may see hydrocephalus, microcephaly, intracranial calcification, ventricular dilation, ascites, IUGR
* Parasitic culture and molecular studies of amniotic fluid- PCR of amniotic fluid is highly accurate for identification of T.gonadii. Amniocentesis should only be offered if maternal primary infection is confirmed
* Screening is not routinely offered as it is rare for babies to be affected- women are advised to avoid eating raw meat, handling cats and cat litter and to wear gloves when gardening
Management of Toxoplasmosis PCR +ve in mother, -ve in baby
Spiramycin (3-week course, 2-3g/day)
* Prevents vertical, transplacental infection. Spiramycin is a macrolide which cannot cross the placenta but remains concentrated in it
* Can be given before 20 weeks gestation and continued throughout pregnancy if no evidence of transmission to foetus
Management of toxoplasmosis PCR +ve mother, +ve baby
Pyrimethamine + Sulfadiazine
* Need to discuss the options including TOP, or continuation of pregnancy with more aggressive antibiotic treatment
* Treat baby for up to 1 year after delivery (if no TOP)
* Clinical and ophthalmological examinations should be performed regularly for several years to screen for any sequalae
* Adjunct: Prednisolone
