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mash
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05/06/04 - 05:12 PM

A 30-year-old male patient was seen by the emergency service and reported a 2-week history of a penile ulcer. He noted that this ulcer did not hurt.
The laboratory reports that the Venereal Disease Research Laboratory (VDRL) test performed on the patient is reactive at a dilution of 1:4 (4 dils). The patient also reports to you that he has recently been diagnosed with hepatitis A.
In the above patient, which one of the following test combinations for syphilis is most appropriate?

A. FTA-Abs (IgG)/FTA-Abs (IgM)
B. RPR/FTA-Abs
C. RPR/culture of the lesion
D. VDRL/RPR
E. Treponema pallidum hemagglutination (TPHA)/microhemagglutination-Treponema pallidum (MHTP) tests

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piter
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05/06/04 - 05:24 PM

B. RPR/FTA-Abs

mjl1717
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05/06/04 - 05:34 PM

definitely-RPR/FTA-ABS

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usmleasr
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05/07/04 - 04:04 AM

can u explain why? there is a lesion pinless...then why should not we go for TPHA?? :roll:

peekay
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05/07/04 - 05:52 AM

pt already has hepatitis which will probably interfere with the vdrl assay. i will pick
ANS=E
SO CHECK FOR HEMEAGLUTINATION

mash
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05/07/04 - 07:02 AM

my ans is E though ans given is B.........
There are two kinds of tests for the detection of syphilis antibodies: nonspecific tests such as the RPR and VDRL,
and specific tests such as the FTA, TPHA (Treponema pallidum hemagglutination test), and the MHTP (microhemagglutination-T. pallidum).
The difference is that the nonspecific tests use a cross-reactive antigen known as cardiolipin, while the specific tests use a T. pallidum antigen. Although the nonspecific tests are sensitive, they lack specificity and often cross-react in patients who have diabetes, hepatitis, infectious mononucleosis, or who are pregnant. Some patients, especially those with autoimmune diseases, will have both nonspecific (RPR) and specific tests (FTA) positive.

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piter
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05/07/04 - 07:19 AM

also - Treponema pallidum hemagglutination (TPHA)/microhemagglutination-Treponema pallidum (MHTP) tests - best choise in late 2* & 3* syphilis

mjl1717
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05/07/04 - 08:56 AM

This particualar thread could probably go on forever. "I once heard someone say if you know syphilis you know all of medicine"

Just 2 key (not random) points.

1)Secondary syphilis has just about the same incubation period as Hepati
tis B (6 weeks to 6 months) and is the most contagious stage.
2)Jarisch -Herxheimer rxn occurs within a few hours of Rx owing to
increase # of treponemes (fever, HA, INTENSE rash)

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peekay
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05/07/04 - 11:09 AM

i some time wonder if kaplan has reviewed the answers of q-bank. on this forum i have seen people contadicting to their answers and explanations. not so many people can have same answer and are still wrong.

mash
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05/07/04 - 11:12 AM

#10

this is not frm kaplan q bank.......

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peekay
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05/07/04 - 11:28 AM

#11

mash-i did not realize about yur qs
i am just making a general statement. sinc most of the people put qs from q-bank for clarification

Sakaki-
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05/07/04 - 02:15 PM

#12

I'm not too sure myself, but there wouldn't be much point of ordering two tests that are so similar (namely in reference to E). An MHA-TP and a TPPA are virtually the same, except that the TPPA uses latex particles instead of sheep erythrocytes, so conducting the two of them would offer little extra information.

If a pair of tests were to be ordered, a nontreponemal one and a treponemal one would be ordered (the pair of a screen and a diagnostic test).

I'm wondering why an RPR would be ordered if the VDRL test was already positive. Both methods are subject to yielding false positives from hepatitis.

bluestar
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06/19/04 - 08:33 PM

#13

"Sakaki-" wrote:
I'm not too sure myself, but there wouldn't be much point of ordering two tests that are so similar (namely in reference to E). An MHA-TP and a TPPA are virtually the same, except that the TPPA uses latex particles instead of sheep erythrocytes, so conducting the two of them would offer little extra information.

If a pair of tests were to be ordered, a nontreponemal one and a treponemal one would be ordered (the pair of a screen and a diagnostic test).

I'm wondering why an RPR would be ordered if the VDRL test was already positive. Both methods are subject to yielding false positives from hepatitis.

I absolutely agree with Sakaki's point. This is a very good question but I haven't seen the conclusion of the discussion yet. Does each of the two pairs: VDRL/RPR and FTA/TPHA/MHA-TP has similar sensitivity and specificity? Guys, please keep on writing please.

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Sakaki-
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06/21/04 - 11:52 AM

#14

I'm pretty sure that the RPR is more commonly done than the VDRL, with the former usually giving higher titres as well.

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