Infectious Diseases - Listeriosis and Syphilis

Question 1

What dietary advice should you give to avoid listeriosis?

Answer 1

Avoid raw food, soft cheeses, un-pasturised milk, reheated food

Question 2

In pregnancy how does listeriosis present?

Answer 2

2/3 women will have flu-like symptoms, GI symptoms, fever.

Often mis diagnosed as UTI/flu

Rarely can cause meningitis, endocarditis, respiratory failure

Question 3

Listeriosis may have what impact on the pregnancy?

Answer 3

May cause:
- Chorioamnionitis
- septic miscarriage
- fetal inutero

Question 4

How does early onset neonatal disease present

Answer 4

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

Question 5

How does late onset neonatal disease present?

Answer 5

Occurs in term neonates after uncomplicated pregnancy, typically meningitis

Question 6

How to treat listeriosis?

Answer 6

Antibiotics once infection is suspected - ampicillin, pen G, amnioglycosides

Question 7

What type of pathogen causes syphilis?

Answer 7

Treponema pallidum

Question 8

What is the incubation period of syphilis?

Answer 8

10-90 days

Question 9

How does primary symphilis present?

Answer 9

Chancre - genital/peri-anal/rectal
Indurated painless ulcer

Regresses spont after 2-6 weeks

Question 10

What proportion develop secondary syphilis if untreated?

Answer 10

25%

Question 11

How does secondary symphilis present?

Answer 11

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

Question 12

If untreated what proportion will develop tertiary/late syphilis?

Answer 12

30%

Question 13

How does tertiary syphilis present?

Answer 13

Gumma, joints, skin/resp tract/ sub-periosteal aspect of long bones, chariots joints

Question 14

Quatarnary syphilis

Answer 14

Aortic aneurysms/aortis

Question 15

What stage is transmission of syphilus the greatest?

What is the risk with primary infection?

Answer 15

Early disease

40%

Question 16

Effect of syphilis in pregnant

Answer 16

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.

Question 17

What are the 3 main types of serological tests for syphilus? Name examples

Answer 17

1 . Non-treponmeal test (non-specific) -→ VDRL and rapid plasma reagin (RPR) test

2. 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
3. T-pallidum specific IgM antibody tests - anti-treponema IgM EIA and immunoblot

Question 18

For non-treponmeal tests
- When do they become reactive?

Answer 18

4-8weeks after the infection

Question 19

For non-treponmeal tests
Sensitivity for primary, latent and late syphilis?

Answer 19

60-90%

Question 20

For non-treponmeal tests
Sensitivity for secondary syphilis?

Answer 20

100%

Question 21

For non-treponmeal tests, false +ve rate and false -ve?

Answer 21

Both about 1%

Question 22

For non-treponmeal tests, what factors make false +ve test more likely?

Answer 22

Elderly
Pregnant
Drug addiction
Malignancy
Autoimmune disease (SLE)
Viral disease (Epstein Barr, hepatitis)
Protozoal
Mycoplasma infection

Question 23

What tests are used as primary screening tests for syphilis?

Answer 23

Treponema EIA/CLIA (preferable testing IgM and IgG) or TPPA

Question 24

In pregnancy if screening treponema serology test is positive? what should be done

Answer 24

Retest original sample for difference serological test or send second sample for treponema serology

Question 25

If second treponemal serology +ve?

Answer 25

Performed quantitative non-treponema test RPR or VDRL Refer to GUM/paeds/neoantes

Question 26

If a second test does confirm syphilis, what test should be sent?

Answer 26

RPR/VDRL - helps stage the infection and indicated need for treatment

Question 27

What RPR/VDRL titres indicated active disease that needs treatment?

Answer 27

>16

Question 28

Sensitivity of FTA-ABS for syphilis?

Answer 28

85-100% at all stage of the disease

Question 29

Sensitivity of MHA-TP for syphilis?

Answer 29

60-85%

Question 30

False +ve rate of MHT-TP and FTA-ABS

Answer 30

1%

Question 31

What is the prozone phenomenon?

Answer 31

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

Question 32

Table summaries how to test for syphilis in prengnacy

Answer 32

Question 33

What proportion of babies with congenital syphilis will be asymptomatic at birth?

Answer 33

2/3rds Most will develop symptoms by 5 weeks

Question 34

What test is used to monitor the response to treatment for syphilis?

Answer 34

RPR/VDRL test

Question 35

When does treponmeal screening tests become +vce in relation to the chance?

Answer 35

Negative before chancre develops and up to 2 weeks afterwards.

Question 36

Roughly what proportion of +ve UK screening are due to false +ve? Adequately treated before pregnancy?

Answer 36

23% false +ve 46% adequately treated pre-pregnancy

Question 37

If syphilis in pregnancy, when to refer to Fetal Medicine? What can be seen on USS?

Answer 37

26 weeks Hydrops, hepatosplenomegaly, intraheptic microcacifications, placentomegaly.

Question 38

When should retreatement of syphilis be considered?

Answer 38

Uncertainty of adequacy of treatment The serological cure RPR/VDRL 4 for drop did not occur

Question 39

Treatment of syphilis

Answer 39

Single dose Benzadine penicillin G 2.4

Question 40

What reaction may occur when Ben Pen is given in treatment of syphilis?

Answer 40

Jarisch-Herxheimer reaction (40%) - pregnancy women may experience uterine contractions which resolve within 24 hrs

Question 41

If a woman has been treated before pregnancy, doe the neonate need testing?

Answer 41

Not at risk of re-infection so neonate does not need testing

Question 42

How are infants to mothers diagnosed and/or treated for syphilis during pregnancy tests for congenital syphilis?

Answer 42

RPR/VDRL ration and IgM at birth, then 3 monthly until negative If remain stable or increased, evaluate and treat for congenital syphilis

Question 43

Which babies should be treated for congenital syphilis?

Answer 43

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