Infectious Diseases - Listeriosis and Syphilis Flashcards
What dietary advice should you give to avoid listeriosis?
Avoid raw food, soft cheeses, un-pasturised milk, reheated food
In pregnancy how does listeriosis present?
2/3 women will have flu-like symptoms, GI symptoms, fever.
Often mis diagnosed as UTI/flu
Rarely can cause meningitis, endocarditis, respiratory failure
Listeriosis may have what impact on the pregnancy?
May cause:
- Chorioamnionitis
- septic miscarriage
- fetal inutero
How does early onset neonatal disease present
Most common after acute febrile illness
- neonate symptomatic at birth or within in few days of birth
- Associated with disseminated granulomas involving liver, placenta, solid organs, septic shock, respiratory disease
How does late onset neonatal disease present?
Occurs in term neonates after uncomplicated pregnancy, typically meningitis
How to treat listeriosis?
Antibiotics once infection is suspected - ampicillin, pen G, amnioglycosides
What type of pathogen causes syphilis?
Treponema pallidum
What is the incubation period of syphilis?
10-90 days
How does primary symphilis present?
Chancre - genital/peri-anal/rectal
Indurated painless ulcer
Regresses spont after 2-6 weeks
What proportion develop secondary syphilis if untreated?
25%
How does secondary symphilis present?
6-8 weeks after primary syphilius - fever, malaise, macula-papular rash (mm and palms/soles), lymphadenopathy, mouth ulcers, condylomata lata
Resolves within 1-3 months
If untreated what proportion will develop tertiary/late syphilis?
30%
How does tertiary syphilis present?
Gumma, joints, skin/resp tract/ sub-periosteal aspect of long bones, chariots joints
Quatarnary syphilis
Aortic aneurysms/aortis
What stage is transmission of syphilus the greatest?
What is the risk with primary infection?
Early disease
40%
Effect of syphilis in pregnant
Bacteria can cross placenta from 14 weeks, infecting baby.
30-40% fetal loss.
1/3 that survive will have congenital syphilis.
Higher risk of transmission if primary infection or later gestation.
What are the 3 main types of serological tests for syphilus? Name examples
1 . Non-treponmeal test (non-specific) -→ VDRL and rapid plasma reagin (RPR) test
- Treponemal tests (specific) →
- EIA treponema enzyme immunoassay
- CLIA
- TPHA
- TPPA
- fluorescent treponema antibody absorption (FTA-ABS) assay
- microhaemagglutination assay for T palladium antibody (MHA-TP) (detect antibody to treponemal antigen)
- CLIA - T-pallidum specific IgM antibody tests - anti-treponema IgM EIA and immunoblot
For non-treponmeal tests
- When do they become reactive?
4-8weeks after the infection
For non-treponmeal tests
Sensitivity for primary, latent and late syphilis?
60-90%
For non-treponmeal tests
Sensitivity for secondary syphilis?
100%
For non-treponmeal tests, false +ve rate and false -ve?
Both about 1%
For non-treponmeal tests, what factors make false +ve test more likely?
Elderly
Pregnant
Drug addiction
Malignancy
Autoimmune disease (SLE)
Viral disease (Epstein Barr, hepatitis)
Protozoal
Mycoplasma infection
What tests are used as primary screening tests for syphilis?
Treponema EIA/CLIA (preferable testing IgM and IgG) or TPPA
In pregnancy if screening treponema serology test is positive? what should be done
Retest original sample for difference serological test or send second sample for treponema serology
If second treponemal serology +ve?
Performed quantitative non-treponema test RPR or VDRL
Refer to GUM/paeds/neoantes
If a second test does confirm syphilis, what test should be sent?
RPR/VDRL - helps stage the infection and indicated need for treatment
What RPR/VDRL titres indicated active disease that needs treatment?
> 16
Sensitivity of FTA-ABS for syphilis?
85-100% at all stage of the disease
Sensitivity of MHA-TP for syphilis?
60-85%
False +ve rate of MHT-TP and FTA-ABS
1%
What is the prozone phenomenon?
False negative response (most common with RPP test) resulting from overwhelming antibody timers which interfere with the proper formation of the antigen-antibody lattice to form +ve flocculation.
More likely with HIV co-infection
Table summaries how to test for syphilis in prengnacy
What proportion of babies with congenital syphilis will be asymptomatic at birth?
2/3rds
Most will develop symptoms by 5 weeks
What test is used to monitor the response to treatment for syphilis?
RPR/VDRL test
When does treponmeal screening tests become +vce in relation to the chance?
Negative before chancre develops and up to 2 weeks afterwards.
Roughly what proportion of +ve UK screening are due to false +ve?
Adequately treated before pregnancy?
23% false +ve
46% adequately treated pre-pregnancy
If syphilis in pregnancy, when to refer to Fetal Medicine?
What can be seen on USS?
26 weeks
Hydrops, hepatosplenomegaly, intraheptic microcacifications, placentomegaly.
When should retreatement of syphilis be considered?
Uncertainty of adequacy of treatment
The serological cure RPR/VDRL 4 for drop did not occur
Treatment of syphilis
Single dose Benzadine penicillin G 2.4
What reaction may occur when Ben Pen is given in treatment of syphilis?
Jarisch-Herxheimer reaction (40%) - pregnancy women may experience uterine contractions which resolve within 24 hrs
If a woman has been treated before pregnancy, doe the neonate need testing?
Not at risk of re-infection so neonate does not need testing
How are infants to mothers diagnosed and/or treated for syphilis during pregnancy tests for congenital syphilis?
RPR/VDRL ration and IgM at birth, then 3 monthly until negative
If remain stable or increased, evaluate and treat for congenital syphilis
Which babies should be treated for congenital syphilis?
the case of:
- Infants with suspected congenital syphilis
- Infants born to mothers treated less than four weeks prior to delivery
- Infants of mothers treated with non-penicillin regimens
Infants born to untreated mothers
- Infants born to mothers who were inadequately treated or who have no documentation of being treated
