Lecture 10: Syphilis

Treponema pallidum is characterized structurally as a gram-negative obligate parasite and [...] that utilizes [...] for motility (List both 2 structural features)

spirochete, endoflagella

The classic primary lesion of syphilis is a [...], which is clinically characterized as a [...] (Identify the lesion name and its key physical feature)

chancre, painless ulcer

Contrast the typical physical characteristics of ulcers in HSV and Chancroid (List both 2 clinical descriptions)

HSV is painful, Chancroid is painful and exudative

Classic skin and mucosal signs of secondary syphilis include a widespread maculopapular rash characteristically involving the [...] and [...] (List both 2 anatomical sites)

palms, soles

Secondary syphilis features highly infectious, moist, wart-like papules in intertriginous zones called [...] and patchy "moth-eaten" hair loss called [...] (Identify both 2 clinical terms)

condylomata lata, alopecia syphilitica

The clinical threshold distinguishing early latent from late latent syphilis is [...] months, where early latent carries a risk of [...] (Identify the time cut-off and the clinical risk)

24, infectious relapse

List the 3 classical clinical forms of tertiary syphilis

neurosyphilis, cardiovascular syphilis, gummatous syphilis

Cardiovascular syphilis is caused by obliterative endarteritis of the [...], which classically leads to the formation of [...] (Identify both 2 vascular structures)

vasa vasorum, aortic aneurysms

The tertiary syphilis manifestation characterized by progressive degeneration of the posterior columns of the spinal cord is called [...]

tabes dorsalis

Early congenital syphilis occurs at $

snuffles

List 4 structural stigmata of late congenital syphilis ($>2$ years of life) affecting the face, teeth, and skeletal limbs

saddle nose, Hutchinson's teeth, frontal bossing, saber shins

Under the case definition for early congenital syphilis, a newborn is classified as an active case regardless of symptoms if the mother did not receive at least 1 dose of Benzathine Penicillin G at least [...] before delivery (Identify the 1 key timeline)

1 month

An infant $

CSF VDRL

Non-treponemal tests like RPR detect antibodies to [...], while treponemal tests like TPHA detect antibodies specific to [...] (Identify both 2 antigen targets)

cardiolipin-cholesterol-lecithin antigens, Treponema pallidum

[...] tests are used to monitor treatment response because their titres drop after therapy, whereas [...] tests typically remain positive for life (Identify both 2 test categories)

non-treponemal, treponemal

The prozone effect in syphilis serology causes a false-negative RPR due to [...] antibody levels, and is resolved by [...] the serum sample (Identify both 2 clinical metrics)

extremely high, diluting

A persistent, stable, low-titre positive non-treponemal antibody level despite definitive, adequate syphilis treatment is called a [...]

serofast state

The traditional syphilis algorithm starts with a qualitative RPR; if reactive, a quantitative RPR is performed where a titre of [...] confirms active syphilis, while a titre of [...] requires confirmatory TPHA (List both 2 titre cut-offs)

>=16,

The reverse testing algorithm begins with an automated [...]; if reactive, it is followed by a qualitative [...] (Identify both 2 diagnostic test categories)

treponemal assay, non-treponemal assay

What is the recommended first-line therapy for early syphilis (primary, secondary, or early latent), and what is the preferred oral alternative for non-pregnant patients with penicillin allergy? (List both 2 regimens)

Benzathine Penicillin G 2.4 million units IM single stat dose, Doxycycline 100 mg BD orally for 14 days

The recommended first-line treatment for latent syphilis of unknown duration or late latent syphilis is [...]

Benzathine Penicillin G 2.4 million units IM weekly for 3 consecutive weeks

The recommended first-line treatment for neurosyphilis is [...]

Crystalline Penicillin G 4 million units IV every 4 hours for 10-14 days

What is the only acceptable treatment for syphilis during pregnancy, and what must be performed if the mother has a documented penicillin allergy? (List both 2 clinical actions)

Benzathine Penicillin G, penicillin desensitization

Symptomatic congenital syphilis in a newborn must be treated with Crystalline Penicillin G at a dose of [...] administered IV for a total of 10 days

50,000 U/kg/dose

For an asymptomatic newborn with a positive RPR, what is the management if the mother was inadequately treated during pregnancy?

Benzathine Penicillin G 50,000 U/kg IM single dose

Serological cure (seroconversion) is defined as a minimum of a [...]-fold decrease in quantitative non-treponemal antibody titre

4

List the 3 equal clinical pathways of the natural history of untreated latent syphilis over a patient's lifetime

biological cure, remain latent for life, develop tertiary syphilis

Untreated maternal syphilis in pregnancy leads to adverse outcomes in up to [...]% of cases, classically presenting as stillbirth, neonatal death, or [...] (List both 2 metrics)

80, congenital syphilis