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.

01:31 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.

01:46 These are increasingly being used for screening as well. The most commonly used test is called “fluorescent treponemal antibody absorption” abbreviated FTA-ABS, and there are several others as well.

01:57 These tests remain positive for life even after treatment with penicillin.

02:01 Darkfield microscopy is no longer used in clinical practice.

02:05 Rapid serologic testings can now be done with some evening using a 10-minute fingerstick treponemal-based antibody test, however these are still being studied at this time.