Pathogenesis of T.pallidum

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Questions and Answers

What is a common characteristic of primary syphilis lesions?

They typically appear as painful ulcers.

They are only found in patients with HIV.

They are usually accompanied by severe systemic symptoms.

They are single and occur at the site of inoculation. (correct)

Which factor may facilitate perivascular infiltration in T.pallidum infections?

Capsule polysaccharide.

Fibronectin.

Hyaluronidase. (correct)

Outer membrane protein.

The incubation period for syphilis can vary between which of the following days?

9-90 days. (correct)

5-20 days.

30-60 days.

7-14 days.

What is the primary mode of transmission for venereal syphilis?

Sexual contact. Signup and view all the answers

What happens to a chancre during the primary stage of syphilis?

It undergoes necrosis in the center. Signup and view all the answers

Which of the following statements about secondary syphilis is accurate?

It is caused by the spread of spirochetes through the blood. Signup and view all the answers

What is a potential condition resulting from untreated syphilis?

Tertiary syphilis. Signup and view all the answers

How does T.pallidum enter the human body?

Via shared needles, transfusions, or sexual contact. Signup and view all the answers

What characteristic symptoms are typically observed in the initial stage of syphilis?

Flu-like symptoms, lymphadenopathy, and a generalized mucocutaneous rash Signup and view all the answers

What is a common outcome for most secondary lesions in syphilis?

They heal spontaneously in 4-5 years Signup and view all the answers

What defines 'latent syphilis'?

Absence of clinical manifestations but positive serological tests Signup and view all the answers

Which of the following is a fate that can occur in latent syphilis?

Development of late syphilis Signup and view all the answers

Which condition is a common manifestation of tertiary syphilis?

Cardiovascular complications including cardiac failure Signup and view all the answers

Which of the following describes congenital syphilis?

Transmission from mother to fetus transplacentally Signup and view all the answers

What is a known manifestation of late congenital syphilis?

Interstitial keratitis and bilateral knee effusions Signup and view all the answers

Occupational syphilis is primarily associated with which group?

Medical and paramedical workers handling patients Signup and view all the answers

Which laboratory method is used for diagnosing syphilis?

Demonstration of spirochetes under the microscope Signup and view all the answers

What type of lesions can be a characteristic of gummatous syphilis?

Granulomatous lesions of the skin and bones Signup and view all the answers

Study Notes

Pathogenesis of Treponema pallidum

T. pallidum is a strict human pathogen responsible for syphilis.
Possible virulence factors include:
- Outer membrane protein: Functions as an adherence factor.
- Enzyme hyaluronidase: Facilitates perivascular infiltration.
- Fibronectin: Exhibits antiphagocytic properties.

Clinical Syndromes Caused by T. pallidum

Venereal syphilis: Transmitted through sexual contact.
Nonvenereal syphilis: Includes congenital syphilis and occupational syphilis.

Modes of Infection

Transmission occurs through:
- Sexual contact.
- Direct introduction into the vascular system via shared needles or transfusions.
- Direct cutaneous contact with infectious lesions.
- Transplacental transfer from mother to fetus.
Main source of infection: Patients.
Variable incubation period: Ranges from 9 to 90 days.

Stages of Untreated Venereal Syphilis

Primary syphilis:
- Characterized by the formation of a chancre—indurated painless ulcer.
- Chancre commonly appears on the genitalia, cervix, perianal region, mouth, or anal canal.
- Initial presentation: Small red papule enlarges and becomes necrotic.
- May occur as multiple lesions in immunocompromised individuals (e.g., HIV).
- Associated regional lymphadenopathy is painless.
- Chancres typically heal within 1 to 5 weeks, while lymphadenopathy can persist.
Secondary syphilis:
- Develops 1 to 3 months after healing of the primary lesion.
- Symptoms include "flu-like" syndrome, lymphadenopathy, and generalized mucocutaneous rash.
- Characteristic features: Roseolar/papular skin rashes, mucous patches in the oropharynx, condylomata at mucocutaneous junctions.
- Involvement of eyes and meninges may occur.
- Patients are highly infectious; most secondary lesions resolve within 4 to 5 years, leading to a latent stage.
Latent syphilis:
- Absence of clinical manifestations with positive serological tests.
- Normal cerebrospinal fluid (CSF) findings are observed.
- Classified as early latent (within the first year) or late latent (after the first year).
- Infectious potential remains during latent phase, with risks of persistent infection, late syphilis development, or spontaneous cure.
Tertiary syphilis:
- Develops decades after primary infection with destructive inflammatory effects on various organs.
- Common forms:
  - Cardiovascular syphilis: Complications include endarteritis, cardiac failure, aortic aneurysm.
  - Neuro syphilis: Manifestations include tabes dorsalis, general paresis, dementia.
  - Gummatous syphilis: Rare granulomatous lesions affecting skeleton, skin, or mucocutaneous tissues.

Nonvenereal Syphilis

Congenital syphilis: Transmitted transplacentally from mother to fetus.
- Can occur at any stage of pregnancy; early manifestations appear within 2 years of age, including rhinitis, mucocutaneous lesions, bone changes, hepatosplenomegaly, and lymphadenopathy.
- Late congenital syphilis (after 2 years) is noninfectious, with symptoms like interstitial keratitis, eighth-nerve deafness, Clutton's joints.
- Residual effects: Hutchinson's teeth, mulberry molars, saddle nose, saber shins.
Occupational syphilis: Occurs in healthcare workers handling cases of secondary syphilis.
- Lesions typically develop on the palms and other exposed skin areas.

Laboratory Diagnosis

Diagnosis involves demonstrating spirochetes via microscopy and detecting antibodies in serum or CSF.
Specimens for testing include serous transudates from moist lesions such as primary chancres.

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Description

Explore the virulence factors and clinical syndromes caused by T.pallidum, a strict human pathogen responsible for syphilis. This quiz covers key aspects such as adherence factors, the role of hyaluronidase, and methods of transmission. Test your understanding of this important topic in microbiology.