Treponema Pallidum

Question 1

Structural Characteristics of T.Pallidum

Answer 1

Spiral
Darkfield or immunofluorescence
Outer Membrane: NO LPS
3 Axial fibrils aka internal flagellum in periplasm

Question 2

What are the characteristiscs of T.Pallidum in culture?

Answer 2

Long generation time (30hrs)
Sensitive to drying and heat
Microaerophilic (survives 3-5% O2)
Outer membrane protein antigens not well characterized for pathogenicity

Question 3

How is Syphilis transmitted?

Answer 3

Intimate sexual contact with infective primary or secondary lesion

Placental transfer- > congenital infection -> neonatal disease

Question 4

How long after acquiring infection will there be no sexual spread?

Answer 4

> 4 years

Question 5

Where is syphilic most common in?

Answer 5

Drug use
Truck routes
Core groups
Gay men

Question 6

Describe the pathogenesis of Syphilis

Answer 6

Pass through intact mucosa/injured skin -> multiply locally -> dissemination to lymph nodes and organs -> no sx until critical level reached (primary lesion at 10-90 days after inoculation)

Question 7

Which stages of syphilis are self-limiting?

Answer 7

Primary and Secondary

Followed by latency

Question 8

What is the pathologic lesion in syphilis?

Answer 8

Obliterative Endarteritis

Question 9

What is the characteristic of primary syphilis?

Answer 9

Ulcerative lesion at site of inoculation with regional adenopathy

Painless papule - chancre
Darkfield positive
Firm local adenopathy
No systemic manifestations
Self limiting

Question 10

What are the characteristics of secondary syphilis?

Answer 10

Systemic flu-like illness 2-10 weeks after primary lesion heals

Papulosquamous rash: entire body
Moist areas-> papules coalesce-> condylomata lata

Other sites: hepatitis, aseptic meningitis, periostitis, nephritis

Fever and generalized lymphadenopathy

Heals spontaneously

May recur over 4 years

Question 11

What is the result of untreated syphilis?

Answer 11

1/3 will be resolved

2/3 will form latent syphilis or develop into late syphilis

Question 12

What is involved in tertiary/late syphilis?

Answer 12

Neurosyphilis
CV syphilis: proximal aortic aneurysm, ascending aortic aneurysm
Late benign Gummatous Syphilis: in bone and cartilage, etc

Question 13

What are characteristics of latent syphilis?

Answer 13

Positive Treponemal Serology Test

No lcinical sx/manifestations

Question 14

What are the 4 types of Neurosyphilis?

Answer 14

Asymptomatic: CSF infected w/ no signs or sx

Meningovascular: Chronic meningitis -> affects arteries and cranial nerves

Paresis: Cortical degeneration -> mental changes

Tabes Dorsalis: Demyelination of posterior columns and dorsal roots -> ataxia, loss of pain and temp

Question 15

What is the presentation of congenital syphilis?

Answer 15

Infection in utero

Normal at birth -> multisystem disease later

Question 16

How can congenital syphilis be prevented?

Answer 16

Prevent with screening of all pregnant women for syphilis

Treat during preganncyc if positive

Question 17

What are the microscopic diagnosis methods for syphilis?

Answer 17

Darkfield : primary and secondary lesions

Direct Fluorescent Ab test

PCR

Question 18

Can you culture for syphilis?

Answer 18

No- Cannot cultivate IN VITRO

Question 19

How is syphilis diagnosed usually?

Answer 19

Screen with RPR -> if positive, confirm with specific treponemal test -> FTA -> positive => syphilis likely

If FTA is negative , RPR is probably false positive

Question 20

What is RPR?

Answer 20

Rapid Plasma Reagin- Nontreponemal test of patient serum with Ab

Question 21

What is FTA?

Answer 21

Fluorescent Treponemal Ab-Absorption Test

Pt serum overlayed on dead T.pallidum reagent -> wash -> counterstain with fluorescent anti IgG -> psoitive
Qualitative test

Question 22

How is Syphilis treated?

Answer 22

Benzathine Pen G - treatment of choice

Single dose injection for primary and secondary syphilis

IV penicillin for 2 weeks or more for tertiary syphilis

Question 23

What is J-H Reaction?

Answer 23

Reaction after penicillin treatment for syphilis due to toxic products being released from killed spirochetes

Question 24

What is an alternative treatment for syphilis?

Answer 24

Tetracycline

Question 25

What are the nontreponemal serological tests?

Answer 25

RPR, VDRL

Question 26

What are hte treponemal serological tests?

Answer 26

FTA
TPPA
EIA
Chemiluminescence