Treponema Pallidum and Primary Syphilis

00:01 Here we have treponema pallidum.

00:02 I’ll go through this rather quickly.

00:04 You’ve gone over this in micro.

00:06 The salient points that are important for us in pathology include the following: The picture showing you on dark field microscopy a gram-negative spirochete.

00:14 Now the major spirochete that you absolutely must know for your boards include what? What’s the name of that organism that brings about Lyme’s disease? There you go.

00:23 Borrelia burgdorferi.

00:27 The primary lesion, you need to know the time.

00:30 Let’s make sure we reinforce the time.

00:32 A primary lesion three weeks after contact.

00:35 Three weeks after contact, three weeks after contact for primary.

00:40 And primary, remember, you’ve done the equivalent to a male and on the penis, he would find an ulceration.

00:47 This is not going to be painful.

00:49 Not.

00:50 Why am I emphasizing this? Because it’s important that you review later on what’s known as Haemophilus ducreyi.

00:58 And there you’d find a chancroid, and that is painful.

01:02 So when we talk about chancre and chancroid, most of you probably have seen these on the penis, which is most likely what the presentation will be on your boards.

01:10 However, obviously, these things can also occur in a female.

01:14 A chancre is painless.

01:17 Firm, nontender, raised, red lesion.

01:19 You might find this in the cervix or the vaginal wall.

01:23 Diagnostic testing of symptomatic patients with possible syphilis include two antibody blood tests, the RPR and VDRL. These detect both IgM and IgG antibodies, are reported as titers, and will decrease over time even without treatment. Since both false-positive and false-negative results can be seen, a confirmatory direct treponemal test is recommended when the antibody tests are reactive. These are increasingly being used for screening as well.

01:49 The most commonly used test is called “fluorescent treponemal antibody absorption” abbreviated FTA-ABS Other treponemal tests are available, utilizing techniques such as enzyme or chemiluminescence immunoassays.

02:06 These tests remain positive for life even after treatment with penicillin. Darkfield microscopy is no longer used in clinical practice.

02:13 Rapid serologic tests have been developed with some even using a 10-minute fingerstick treponemal-based antibody test, however these are still being studied at this time.