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congenital syphilis ?

Guest danielirra

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Guest danielirra

hi all

It´s basic, but this always generates discussion in our service. the patient is 35 weeks pregnant, one single control, VDRL 1/16 FTA abs positive, our discussion is ,if we should consider it a previous serologic title or indicate benzathine penicillin. If the birth occurs before the month, the infant shoud be treated ? and to end , do you have experience in the use of benzathine penicillin en the neonate ?

I hope your answers as soon as possible

thanks in advance

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Guest Omer

Syphilis is caused by Trepenoma Pallidum which is a form of spindle shape bacteria known as Spirochetes. By the way , Spirochetes can cause diseases ranging from Lyme disease( Borrelia Burgdorferi) to relapsing fever(Borrelia Recurrentis).

There are other types of treponema that can cause diseases like, Yaws and Penta.

Treponema Pallidum can not be grown in any culture in vitro .This is why they depend on either serology testing or direct visualization with dark field microscopy for diagnosis.

The method of screening which is used is either the VDRL( Venereal Disease Research Laboratory) or RPR(Rapid Plasma Reagin). These screening test are simple , sensitive and less expensive. If the screening test is positive then a more specific tests are needed. These are the Treponema antibody tests. These tests are ; FTA-abs, TPHA and MHA-TP. They have (confusing names), may be because we rarely request them, but they detect treponemal antibodies using different methods.

If the Treponemal antibody testing is positive ,then it confirm the disease. If the terponemal antibody tests are negative, then the positive screen test(VDRL or RPR) might be a false positive test.

But keep in mind , the issue is not that simple. The VDRL and RPR become negative by 1 year in primary infection and by 2 years in secondary syphilitic infection.This should happen with institution of adequate treatment. The other issue is that Treponemal antibodies remain positive for decades ,even if the patient receives full treatment.Furthermore, reinfection can happen after full course of treatment (treating the other partner is important). To further complicate the issue, seroconversion for the Treponemal antibodies might take upto 6 weeks.

In the clinical scenario above there is a positive screening test with positive Treponemal antibody test which might indicates the following possibilities;

1.primary or secondary syphilis, maternal history and full assessment by adult ID .


3.persistent Treponemal antibodies with still positive VDRL or RPR. Assess the history of previous test.

In all three possibilities, I would urgently consult with paediatric ID and adult ID and would err on treating the mother with Penicillin. The placenta or the cord should be examined with dark field microscopy for visualization of the motile Treponema . I would collect the baby blood( not the cord) for serology and I would send CSF for VDRL,cell count, chemistry ,etc. I would definitely start treating this baby with Penicillin, of course with the collaboration of Paeds ID.

Omer Hamud


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Guest danielirra

thank you very much for information and reviews ,to complicate things even more, we received the first FTA negative (first pregnancy itwo years ago, VDRL + ) but now the result is "indeterminated " (?) . We request a new FTA. false positive VDRL ? thanks

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Guest danielirra

sorry, perhaps "undeterminated" could be a borderline FTA-ABS test but as shown in the article this would happen in early syphilis. thanks

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