ORAL REVALIDA 2

Question 1

What is the causative agent of syphilis?

Answer 1

Treponema pallidum subsp. pallidum, a spirochete.

Question 2

How is syphilis transmitted?

Answer 2

Through direct contact (e.g., sexual contact) or placental transmission (congenital syphilis).

Question 3

What happens during the incubation period of syphilis?

Answer 3

The bacteria spread through the bloodstream to organs. This stage lasts 10 days to 10 weeks and has no symptoms.

Question 4

What is the hallmark symptom of primary syphilis?

Answer 4

A painless, non-bleeding ulcer called a chancre, appearing 2-3 weeks post-infection.

Question 5

When do antibodies appear in primary syphilis?

Answer 5

1-4 weeks after the chancre appears.

Question 6

How is T. pallidum detected in primary syphilis?

Answer 6

Darkfield microscopy of the lesion.

Question 7

What are the symptoms of secondary syphilis?

Answer 7

Skin rash, fever, malaise, pharyngitis, weight loss, joint pain, and lymphadenopathy.

Question 8

What is condyloma lata?

Answer 8

Large, plate, flat topped papules that occur in warm, moist areas (e.g., perianal region) and are highly infectious.

Question 9

Are serologic tests positive in secondary syphilis?

Answer 9

Yes, both nontreponemal and treponemal tests are positive.

Question 10

What characterizes latent syphilis?

Answer 10

a stage of syphilis with no signs or symptoms but with positive serologic tests (treponemal & nontreponemal)

Question 11

What is the difference between early and late latency?

Answer 11

Early latency: 1 out of 4 individuals relapse into secondary syphilis.
Late latency: No relapse; patient is resistant to reinfection.

Question 12

When does tertiary syphilis occur?

Answer 12

2 to 40 years after initial infection.

Question 13

What are gummas in tertiary syphilis?

Answer 13

• Destructive, granulomatous lesions that can be single or multiple caused by hypersensitivity to treponemal antigens.
• They heal slowly, leaving an atrophic scar with hyperpigmented borders. They are treatment-responsive.

Question 14

What cardiovascular complications can occur in tertiary syphilis?

Answer 14

Syphilitic aortitis, aortic valve insufficiency, and thoracic aneurysm.

Question 15

What are the neurological effects of neurosyphilis?

Answer 15

Blindness, senility, and other neurological impairments.

Question 16

Can Treponema pallidum cross the placenta?

Answer 16

Yes, it can infect the fetus at any stage of maternal syphilis.

Question 17

What are the possible fetal outcomes?

Answer 17

Late abortion, stillbirth, neonatal death, neonatal disease, or latent infection.

Question 18

Which maternal syphilis stages have the worst fetal outcomes?

Answer 18

Primary and secondary syphilis.

Question 19

How can congenital syphilis be prevented?

Answer 19

Maternal treatment within the first 4 months of pregnancy.

Question 20

What are the clinical signs of congenital syphilis?

Answer 20

• Maculopapular rash with desquamation (mouth, palms, soles)
• Hemolytic anemia, jaundice, hepatosplenomegaly
• Abnormal cartilage and bone development
• Mental retardation

Question 21

How is syphilis diagnosed?

Answer 21

Signs and symptoms, detection of spirochetes in
lesion, and positive syphilis serology

Question 22

What samples are used for direct detection of T. pallidum?

Answer 22

CSF, umbilical cord, skin, or mucous membrane lesions.

Question 23

What microscopy techniques are used to detect T. pallidum?

Answer 23

• Darkfield microscopy
• Silver stain
• Direct Fluorescent Antibody (DFA-TP) test (fluorescent-labeled antibody detection).

Question 24

What antibodies are produced in Treponema pallidum infection?

Answer 24

Nonspecific antibody, reagin, and specific treponemal antibodies.

Question 25

Why are nontreponemal tests only used for screening?

Answer 25

They detect reagin, which can cross-react with antigens from SLE, autoimmune diseases, pregnancy, and chronic infections (e.g., hepatitis), leading to false positives.

Question 26

What are examples of nontreponemal antigen tests?

Answer 26

VDRL, USR, and RPR.

Question 27

Why must nontreponemal test results be confirmed?

Answer 27

They have a high false positive rate (30%), so treponemal tests confirm the diagnosis.

Question 28

What are examples of treponemal antigen tests?

Answer 28

FTA-ABS, TP-PA, and microhemagglutination tests

Question 29

What does the VDRL test detect?

Answer 29

Reagin antibodies against cardiolipin, cholesterol, and lecithin

Question 30

How are VDRL test results interpreted?

Answer 30

Microscopic flocculation, reported as NR (nonreactive), WR (weak reactive), or R (reactive).

Question 31

When does VDRL become positive?

Answer 31

1-3 weeks after the chancre appears.

Question 32

What is the primary use of the VDRL test today?

Answer 32

CSF testing for neurosyphilis (the only serologic test approved for CSF).

Question 33

How does the USR test differ from VDRL?

Answer 33

a modified VDRL test wherein Choline-chloride EDTA is added, allowing testing of unheated serum.

Question 34

What is the principle of the RPR test?

Answer 34

- Macroscopic flocculation using VDRL antigen with charcoal particles for visualization. - The antigen is not attached to the charcoal as in latex agglutination assays. The charcoal is trapped in the flocculation reaction, which allows the reaction to be seen macroscopically.

Question 35

How is the RPR test reported?

Answer 35

As qualitative (reactive/nonreactive) or semiquantitative (antibody titers)

Question 36

What is the principle of the TP-PA test?

Answer 36

Treponemal antigen is combined with liposomes. If antibodies are present, a mat of agglutination forms in wells of a microtiter plate.

Question 37

What type of test is FTA-ABS?

Answer 37

An indirect antibody test.

Question 38

What antigen does the FTA-ABS test use?

Answer 38

The Nichol’s strain of T. pallidum.

Question 39

How are nonpathogenic treponemal antibodies removed in FTA-ABS?

Answer 39

By absorbing the serum with the Reiter’s strain of nonpathogenic treponeme

Question 40

How are FTA-ABS results determined?

Answer 40

Fluorescence intensity, graded 1+ to 4+.

Question 41

FTA-ABS test process

Answer 41

1. Nichol's strain of T. pallidum subsp. pallidum is affixed into wells of microscope slides. 2.Patient serum is heat inactivated. Nontreponemal antibody is absorbed from patient serum with a sorbent of Reiter's strain of nonpathogenic treponeme. 3. Sera are placed in the wells of the microscope slide. 4. FITC-labeled antihuman antibody is added. 5. Fluorescent reactions are graded 1 to 4+

Question 42

what is abbott’s syphilis test used for

Answer 42

lateral flow immunochromatographic assay for qualitative detection of T. pallidum antibodies (IgG, IgM, IgA)

Question 43

principle of rapid/abbott syphilis test

Answer 43

The recombinant Treponema pallidum antigens (17, 15 kDa) conjugated with colloidal gold patient specimen and specimen diluent moves along the membrane chromatographically to the test region T and forms a visible line

Question 44

how many drops of serum, and how much time till you read the results in syphilis rapid test

Answer 44

4 drops of serum, 5-20 mins

Question 45

reagents and materials used for abbott syphilis test

Answer 45

- test device ( coated w/ t. pallidum antigens) - assay diluent - capillary pipette - sample