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5-6 Infection

5-6 Infection. Tuberculosis and Syphilis. Dr. Tarek Atia. Tuberculosis (TB). Communicable disease It is a chronic granulomatous disease Causative organism: Mycobacterium tuberculosis; tubercle bacilli of two types ( human and bovine ),

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5-6 Infection

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  1. 5-6 Infection Tuberculosis and Syphilis Dr. Tarek Atia

  2. Tuberculosis (TB) Communicable disease It is a chronic granulomatous disease Causative organism: Mycobacterium tuberculosis; tubercle bacilli of two types (humanand bovine), Typically results in Caseous(necrosis) granulomas

  3. Route of infection • Respiratory tract: Inhalation of infected droplets from patient with open TB. • Intestinal tract: Ingestion of infected milk • Skin by inoculation: (butchers). • Congenital by trans-placental spread

  4. Epidemiology • ~ 1/3 of the world’s population are infected. • A leading single cause of death globally (~ 6% of deaths worldwide); 3 million deaths / year. • The lung is the most common important clinical site of infection.

  5. Pathogenesis Macrophages are the primary cells infected by M. tuberculosis. • Early in infection  the bacteria replicate & are essentially unchecked • later in infection T-helper response stimulates macrophages to contain the proliferation of the bacteria.

  6. Pathogenesis • Once inside the macrophage, M. tuberculosis replicates within the phagosome by blocking fusion of the phagosome & lysosome

  7. Types of TBinfection Primary TB Secondary TB - Re-infection (2nd time) - Adult - Well developed - Exudative - Anywhere - Not usually affected • Nature: Infection for the first time • Age: Children • Hypersensitivity and immunity : not developed - Tissue reaction: Proliferation - Sites: Tonsil, lung, intestine - Lymph nodes: Always affected

  8. Primary TB In Non Immunized individuals (Children) • Primary Tuberculosis: • Self Limited disease • Ghons focus, Primary lung complex. • Primary Progressive TB • Miliary TB and TB Meningitis. • Common in Immuno-suppressed individuals

  9. Sites of 1ry TB - Tonsils (1ry cervical complex): TB tonsillitis, TB lymphadenitis, TB lymphangitis. - Lung (1ry pulmonary complex): Ghon`s focus, TB lymphadenitis, TB lymphangitis . -Intestine (1ry intestinal complex): TB enteritis, TB lymphadenitis, TB lymphangitis.

  10. Ghon`s Focus • Small rounded about 1cm focus, present anywhere in the lung, commonly peripheral and subpleural. • Central caseation and cold abscess may occur.

  11. Secondary Tuberculosis: • Post Primary in immunized individuals. • Reactivation or Reinfection • Caseation (Caseous Necrosis), cavity - soft granuloma • Pulmonary or extra-pulmonary

  12. Tissue reaction to Tb bacilli Cellular (proliferative) reaction: occurs in 1ry TB, and leads to a tubercle (granuloma) formation , which is microscopically formed of - Epitheloid cells (Macrophages) - Caseous Necrosis - Giant cells - Lymphocytes and plasma cells - Fibroblasts

  13. Pathological picture of granuloma • Collection of chronic inflammatory cells. • Central Caseous necrosis. • Active macrophages. • Outer layer of lymphocytes, plasma cells & fibroblasts. • Langhans giant cells – fused epithelioid cells.

  14. Typical CavitatingGranuloma

  15. TB Brain

  16. TB intestine Spinal TB - Potts Disease

  17. Syphilis • Is a chronic, systemic venereal disease with multiple clinical presentations, caused by the spirochete Treponema Pallidum • Treponema pallidum is a microaerophilic spirochete. • T. pallidum is delicate organism, rapidly killed by drying or changes in the temperature

  18. Modes of transmission • It is transmitted during sexual contact • Mucous membranes are optimal sites of infection. • The organism is transmitted from an active cutaneous or mucosal lesion in a patient to the un-infected partner • Trans-placental congenital syphilis

  19. Clinical Features Syphilis is divided into three stages: • Early (Primary & Secondary) • Late (Tertiary) syphilis, • Congenital syphilis

  20. Primary Syphilis Occurs ~ 3 weeksafter the contact with infected person. • Clinically, the lesion is single, firm, non-tender, raised & red button-like mass called a “Chancre” • It will gradually enlarge to produce a painless, shallow ulcer with a clean, moist base. • It resolves in 3-6 weeks with or without therapy

  21. The chancre contains an intense infiltrate of plasma cells, with scattered macrophages and lymphocytes. • The causative organisms are visible with silver stains at the surface of the ulcer

  22. Site • Genital sites: Located on the penis, uterine cervix, or vaginal wall • Extragenital sites: anus, lip, tongue, nipple • Regional Lymph Nodes are slightly enlarged & firm, but painless.

  23. Secondary Syphilis • Occurs 2-10 weeks after the resolution of primary chancre • Occurs in ~ 75% of untreated individuals • These lesions resolvespontaneously after several weeks

  24. Secondary syphilis is characterized by: • Generalized lymph node enlargement. • Mucocutaneous lesions: Condyloma lata. • Diffuse rash on the palms &soles • Mild fever, malaise, weight loss, headache and arthritis.

  25. Condyloma lata “broad-based elevated lesions” in moist skin “ano-genital regions, inner thighs and axillae”

  26. Condyloma Latum

  27. Skin rash Secondary syphilis

  28. Tertiary (Late) stage of syphilis Occurs many yearsafter the primary lesion • Is rare and occurs in ~ 1/3 of untreated individuals. • Has 3 main manifestations: • Cardiovascular syphilis • Neurosyphilis • Benign 3ry syphilis

  29. A- Cardiovascular syphilis • Occurs in >80% of cases. • Occurs 10-40yrs after the primary syphilis • Active inflammatory lesions of the aorta

  30. B- Neurosyphilis • Occurs in 5-10% of cases. It may be symptomatic or asymptomatic causing. • Abnormal cerebrospinal fluid • General paresis • Tabes dorsalis: • Abnormal sensations • Problems walking such as with the legs far apart • Loss of coordination and reflexes • Joint damage, especially of the knees • Muscle weakness - Vision changes • Bladder control problems - Sexual function problems

  31. C- Benign 3ry syphilis Formation of Gumma:is a localized destructive granuloma that is white-gray and rubbery. • It occurs singly or multiply, and is of variable sizes • Found mostly in the skin, subcutaneous tissues, liver, bones, joints, or oral cavity

  32. Gumma: • It contains a central zone of coagulation necrosis surrounded by a mixed inflammatory cells as lymphocytes, plasma cells, activated macrophages and a dense peripheral zone of fibrosis. • The causative bacteria are rarely seen in gumma.

  33. Tertiary syphilis Gumma of the nose Gumma of nose & palate

  34. Tertiary syphilis Gumma of the nose Gumma of skull

  35. Congenital syphilis Transplacental infection of the fetus occurs in the first and second trimesters of pregnancy if the mother has untreated early “1ry & 2ry” syphilis • The risk of fetal infection if mother has early infection is >75% • Intra-uterine death & perinatal death occur in ~40% of untreated cases

  36. Diagnosis of Congenital Syphilis • Diagnosis of congenital syphilis is based on: • Clinical manifestations • Dark-field microscopy • Serologic tests

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