treponema pallidum: syphilis Flashcards Preview

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Flashcards in treponema pallidum: syphilis Deck (45):

Sprirochete genera

Treponema – syphilis, yaws, bejel, pinta, and part of the NF on mucosal surfaces.
Borrelia – Lyme disease and relapsing fever.
Leptospira – causing leptospirosis.


Nonpathogenic Treponema are ?? and are present in ??
(e.g. T. denticola) and on virtually all mucosal surfaces.
Diagnosis of syphilis requires ??

normal flora of humans
oral cavity

These are the same places where the primary chancre of syphilis occurs.

differentiating between the Treponema normal flora versus T. pallidum.


Pathogenic Treponema: Human:

T. pallidum var. pallidum (syphilis).


Characteristics of T. pallidum, etiologic agent of syphilis (hard chancre), a genital ulcer disease (GUD).

unicellular, G-, motile, “delicate” very thin, elongated spirochete
(coiled/helical) with a very small genome relative to the pathogen’s size.


T. pallidum G- cell wall architecture

-Phospholipid outer membrane - a paucity of proteins and no LPS (It is postulated that the lack of outer membrane proteins [OMP] causes the organism to have a “low profile”, immunologically).
-Lipoprotein - induce similar responses as endotoxin, a potent immunomodulator (important in Jarisch-Herxheimer reactions).


T. pallidum: motile or non-motile?
visible or not visible on Gs??

Highly motile by means of an "endoflagella/periplasmic flagella".

Cells are not visible on gram-stained smears (too thin), but cells are visible by darkfield microscopy


T. pallidum: slow or fast growing?

slow growth rate & cannot be cultured in vitro. The only known way to predictably grow or expand a syphilis isolate is to inject lesion material into rabbit testicles on a living rabbit.


T. pallidum sensitivity to ??

various environmental factors is great (e.g. high (>42°C) and low
temperature (4°C), desiccation, soap & water, etc. are lethal to T. pallidum).


T. palladium host/reservoir?
mode of transmission??

Humans are the sole host and reservoir.

-Direct Contact - Sexual transmission is the primary mechanism of spread via
microscopic creaks/breaks in the mucous membranes and skin.
-Transplacentally (in utero): congenital infections--> to congenital syphilis.
-Lab workers have been infected accidentally.
-Blood and blood transfusions is a potential source of infection.


Syphilis is a systemic disease involving the ??, which can result in pathology in various organs during stages of the full course of the disease.

inflammatory response


T. pallidum Vascular pathology:

-Endarteritis/ Endarteritis obliterates: proliferative concentric thickening of small BVsby endothelial & fibroblastic cells--> reduction in the caliber of the vessel lumen or even blocking the vessels. Partially responsible for 1o/2o lesions and manifestations of tertiary (3o) syphilis.

-Periarteritis: proliferation of the adventitial cells and cuffing of the vessel by inflammatory cells consisting of monocytes, plasma cells, lymphocytes.


?? are prone to develop more severe syphilitic disease.

Immunosuppressed patients


immune response to syphilis: T. pallidum-specific Antibodies: IgM titer peak during ?? and then rapidly decline. IgG titer peak when?? but declines very slowly over time.
?? are present when clinical signs appear.

secondary syphilis

at end of secondary syphilis after the IgM peak

Both IgM, IgG antibodies


immune response to syphilis: ?? response appears to dominate in primary syphilis, the agent drives a conversion to ??response in secondary syphilis.



Primary syphilis: incubation period ?? during which the
organisms multiply locally, and at the same time or some time later, enter and disseminate the ??. As the spirochetes multiply locally, an immune response slowly evolves that induces ??

an average of 21 days (range is 3 to 90 days)

draining lymphatics and/or bloodstream

chancre formation


Hard single chancre/genital ulcer develops at the ??
what is it??

-is a button-like induration (i.e., firm-hard), sharply demarcated, clean based, lesion with an eroded center and serous discharge, usually painless and is highly infectious


can there be multiple chancres??
when/how do they heal??

YES. Occasionally, there may be multiple chancres. Chancre heals spontaneously in 26w, except in the immunocompromised patient.


how can chancres go unnoticed??

what can alter its appearance??

Besides being painless, the chancre may be so small or anatomically located so as to go unnoticed and is especially difficult to find in females and tends to be more conspicuous in males. Many (60% of all) patients do not recall lesions of any sort.

-Secondary bacterial or viral infections (e.g., herpes) of the chancre


Syphilis should be included in the ddx of ??

any lesion or ulcer of the genitalia, rectum, anus, lip, or hand of sexually active patients.


There may be accompanying ?? which appears 7-10 days after the chancre develops.

painless, regional and generalized lymphadenopathy

regional: bilateral inguinal – A chain of discrete, firm, freely movable, nonsupprative nodes


Secondary syphilis is a disseminated infection involving ??
which occurs about ?? after exposure
Duration is ?? if untreated.
Several relapses are possible mostly within ??

virtually every organ system

6wks (range is 2wks-6 months)

1 to 2 months

the first year


Syphilis manifestations are protean (assuming different forms) and each time a patient manifests with S&S of secondary syphilis, the patient is ??

infectious to his/her partner(s)


syphilis s/s: rash

A bilaterally symmetrical, non-pruritic, infectious
-usually starts on the palms of the hands and the soles of the feet, the mouth, anus and spreads throughout the body. (centripetal spread?)
-can be macular, maculopapular, pustular, annular, scaling. All forms may be present at one time and may be widely distributed over the whole body.


syphilis s/s: mucous patches AKA condylomata lata

*highly infectious* raised, painless, with a central erosion and covered with a thin membrane and are found on the genital, oral, and/or rectal mucosa (warm moist tissue)


syphilis s/s: Alopecia

patchy hair-loss with a “moth-eaten” appearance of scalp & eyebrows.


syphilis Constitutional s/s

Low-grade fever, malaise, headache, arthralgais,
generalized lymphadenopathy.


syphilis can invade any organ, but commonly ??

liver (hepatitis); kidney (immune-complex glomerulonephritis); eye, CNS (meningitis/encephalitis), arthritis, GI tract.

The manifestations are protean and why syphilis is called “the great imitator”.


T. pallidum has a propensity for invading the ??

Pts with 1o and especially 2o syphilis have a more than 40% chance of CNS invasion. -typ. asymptomatic.”


Secondary syphilis resolves ??.
If untreated or inadequate therapy is used, ?? is initiated.

with or without treatment

a latent stage of infection


Latent syphilis is an asymptomatic phase-post-primary syphilis with no ?? but with ?? which can persist for variable periods of time ??
Latent syphilis terminates after ?? or ??

clinical S/S
positive serology
(2 months or for life of patient; average is 4 years).

therapeutic cure occurs or tertiary manifestations develop.


Latent syphilis is arbitrarily divided into ??

early- and late-latent syphilis based on the ability to relapse into secondary disease.


Early latent syphilis occurs when ??
the patient is in latent syphilis anytime ??

Patient is infectious to sex partners due to relapses into ??

the first year of infection -- 365 days from day of
exposure to agent to the end of year

post 1o syphilis, that the patient is asymptomatic in that first year

2o syphilis: Nearly all 2o syphilis relapses occur during early latent syphilis (90%), the remainder in late latent syphilis.


Late latent syphilis occurs when ??.
Patient is NOT considered infectious to sex partners because ??

from the end of 1st yr-->4y

there is a very low rate of relapse to secondary syphilis (less than 10%)


A person is considered infectious during all relapses into secondary syphilis regardless of ??

when they occur.


T. pallidum may be transmitted ?? any time during latent syphilis.

via blood transfusion and a pregnant woman can infect her fetus in utero


Tertiary (Late) syphilis: 1/3 of untreated 2o syphilis pts will undergo a ?? and 1/3 remain ?? Another 1/3 advances to ??

spontaneous cure
persistently infected but asymptomatic
tertiary syphilis


tertiary syphilis is ??
Usually occurs ?? after initial exposure

is a slow, degenerative progressive inflammatory disease affecting any organ system that is refractory to antibiotic treatment and is fatal
10y (range 2 to 30y)


3 tertiary syphilis manifestations

Cardiovascular syphilis/Syphilitic aortitis
Gumma (late, benign syphilis)

* “These divisions of late syphilis are not mutually exclusive. A patient may have more than one type of late involvement.”


Cardiovascular syphilis/Syphilitic aortitis:

Vasculitis/Endarteritis obliterans of vasa vasorum blocks the vessels especially those associated with the aortic arch-->aortic stenosis, aortic regurgitation, coronary artery ostial stenosis, aortic aneurysm


Early Neurosyphilis:
how to dx if asymptomatic??
complications if symptomatic??

-Asymptomatic: dx by a + CSF serology (reactive VDRL), increases in WBC cells present and total protein.
-Symptomatic syphilitic meningitis--acute
-Meningovascular: obliterative endarteritis of meninges, brain, spinal chord, there is CNS damage from cerebral vascular occlusion and infarction-->focal neurologic signs corresponding to the size and location of the lesion.


Late neurosyphilis - Parenchymatous Neurosyphilis: General paresis (also known as general paralysis of the insane, paretic
neurosyphilis, or dementia paralytica)

a progressive dementing illness. In the early stage of disease, general paresis is associated with symptoms of forgetfulness and personality change with progression to severe dementia (Paresis mnemonic: Personality, Affect, Reflexes, Eyes, Sensorium, Intellect, Speech)


Late neurosyphilis - Parenchymatous Neurosyphilis: Tabes dorsalis (also called locomotor ataxia)

a disease of the posterior columns of the SC and of the DRs and DRG-->Ataxia (gait changes, foot slap, etc), areflexia, paraesthesias (lancinating pain)


Tabes dorsalis: Posterior column impairment results in ??
Disruption of the dorsal roots leads to ??

impaired vibration and
proprioceptive sensation, leading to a wide-based gait.

loss of pain and temperature sensation and areflexia.


Tabes dorsalis: Pillary irregularities are among the most common signs and the ?? accounts for approximately one-half of these pillary irregularities.

Argyll-Robertson pupil:
-is smaller than normal.
-does not respond to light but contracts normally to
accommodation and convergence.
-Dilates imperfectly to mydriatics
-Does not dilate in response to painful stimuli).


Gumma (late, benign syphilis) may be result of ??
what is it ??

DTH response to antigens, not viable T. pallidum cells.
A non-specific granulomatous-like lesion in the skin, liver, testes, and bones, etc.
-may be benign but when occurring in the brain or heart-->serious complications
Gummas produce a wide variety of symptoms that are similar to many chronic diseases and this has also led to syphilis being termed "the great imitator"

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