5- infection (tb)
DESCRIPTION
InfectionTRANSCRIPT
![Page 1: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/1.jpg)
Infection
Chronic Inflammation
Dr. Tarek Atia
![Page 2: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/2.jpg)
Chronic Granulomatous Inflammation (CGI)
Definition: a type of chronic inflammation defined
by the presence of granulomas which are small,
(0.5 to 2mm) collections of modified "epithelioid"
histiocytes/macrophages and (Langhan's) giant
cells (fused histiocytes), with a background of new
capillaries, fibroblasts, and new collagen, usually
surrounded by a rim of lymphocytes.
![Page 3: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/3.jpg)
Granulomas occur in response to various diseases
Foreign body
Tuberculosis (Tb)
Syphilis
Fungal (mycotic) infections
![Page 4: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/4.jpg)
Two factors necessary for granuloma formation
Presence of indigestible organisms or
particles (Tb, mineral oil, etc)
Cell mediated immunity (T cells)
![Page 5: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/5.jpg)
Typical tuberculous granuloma showing an area of
central necrosis, epithelioid cells, multiple Langhan`s-
type giant cells, and lymphocytes
Giant cell (Langhan`s cells)
![Page 6: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/6.jpg)
Factors necessary for resolution
• Removal of the offending agent
• Regenerative ability if cells have been destroyed
• Intact stromal framework
![Page 7: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/7.jpg)
- Infection means tissue invasion by pathogenic organism.
- The result of infection depends on:-
- Dose and virulence of the organism
- Body resistance (immunity)
- If the defense mechanisms failed to localize the infection,
organisms or their toxins reach the circulation and
produces their specific manifestations.
![Page 8: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/8.jpg)
InfectionInfection
Pathogenesis
ImmunityImmunity
![Page 9: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/9.jpg)
1- Toxaemias
- Toxaemia means circulation of bacterial toxins in the
blood with production of clinical manifestations.
- It could be acute if a large doses of toxins reaches the
blood within a short time; e.g. pneumonia & cholera.
- Or could be chronic if a small doses of toxins reaches
the blood within a long time; e.g. TB
![Page 10: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/10.jpg)
Clinical manifestations of toxaemia
- Affect the brain: fever, headache, body aches, rigors,
tachycardia.
- Affect the kidney: tubular necrosis, acute renal failure.
- Affect the heart: toxic myocarditis.
- Affect the liver: fatty liver
- Toxic shock
- Peripheral neuritis
![Page 11: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/11.jpg)
2- Bacteraemia
- It means circulation of bacteria, from a septic focus
(sinusitis, otitis media, tonsillitis, ..), in the blood with
production of clinical manifestations.
- Its effect depends on:-
- Body resistance
- Dose and virulence of the organisms
![Page 12: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/12.jpg)
3- Septicemia
• It means multiplication of bacteria and their
toxins in the blood with production of sever clinical
manifestations:
- The causes include:-
- Lowering of the body resistance
- Virulent pyogenic organisms e.g.
- Gonococci in meningitis
- Staph aureus in osteomyelitis
![Page 13: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/13.jpg)
4- Pyaemia
- It means production of multiple small abscesses in
different organs due to circulation and impaction
of septic emboli started from a septic focus.
- According to the site of the original septic focus;
pyaemia can be classified into: Systemic or Portal
![Page 14: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/14.jpg)
Tuberculosis
![Page 15: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/15.jpg)
Tuberculosis (TB)
Communicable disease
It is a chronic granulomatous disease
Causative organism: Mycobacterium tuberculosis;
tubercle bacilli of two types (human and bovine),
Typically results in caseating (necrosis) granulomas
![Page 16: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/16.jpg)
Respiratory tract: Inhalation of infected
droplets from patient with open TB.
Intestinal tract: Ingestion of infected milk
Skin by inoculation: (butchers).
Congenital by transplacental spread
Route of infection
![Page 17: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/17.jpg)
Pathogenesis
Macrophages are the primary cells infected by M. tuberculosis.
◦ Early in infection bacilli replicate & are essentially unchecked
◦ later in infection T-helper response stimulates
macrophages to contain the proliferation of the
bacteria.
![Page 18: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/18.jpg)
• Once inside the macrophage, M. tuberculosis
replicates within the phagosome by blocking fusion
of the phagosome & lysosome
![Page 19: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/19.jpg)
Pathogenesis
![Page 20: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/20.jpg)
Types of Tb infection
Primary TB
- Nature: Infection for the 1st time
- Age: Children
- Hypersensitivity and immunity :
not developed
- Tissue reaction: Proliferation
- Sites: Tonsil, lung, intestine
- Lymph nodes: Always affected
Secondary TB
- Re-infection (2nd time)
- Adult
- Well developed
- Exudative
- Anywhere
- Not usually affected
![Page 21: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/21.jpg)
Primary TB
In Non Immunized individuals (Children)
• Primary Tuberculosis:
– Self Limited disease
– Ghon`s focus, Primary complex.
• Primary Progressive TB
–Miliary TB and TB Meningitis.
– Common in Immuno-suppressed individuals
![Page 22: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/22.jpg)
Sites of 1ry TB
- 1ry cervical complex: TB tonsillitis, TB lymphadenitis,
TB lymphangitis.
- 1ry pulmonary complex: Ghon`s focus, TB hilar
lymphadenitis, TB lymphangitis .
- 1ry intestinal complex: TB enteritis, TB lymphadenitis,
TB lymphangitis.
![Page 23: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/23.jpg)
Ghon`s Focus
• Small rounded about 1cm
focus, present anywhere in
the lung, commonly
peripheral and subpleural.
• Central caseation and cold
abscess may occur.
![Page 24: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/24.jpg)
Primary or Ghon’s Complex
Primary tuberculosis is
the pattern seen with
initial infection with
tuberculosis in children.
Reactivation, or secondary
tuberculosis, is more
typically seen in adults.
![Page 25: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/25.jpg)
Secondary Tuberculosis:
• Post Primary in immunized individuals.
• Reactivation or Reinfection
• Caseation, cavity - soft granuloma
• Pulmonary or extra-pulmonary
• Local or systemic spread / Miliary
– Vein – via left ventricle to whole body
– Artery – miliary spread within the lung
![Page 26: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/26.jpg)
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
- Caseation necrosis
- Giant cells
- Lymphocytes
- Fibroblasts
![Page 27: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/27.jpg)
Cavitary Tuberculosis
When necrotic tissue is
coughed up cavity.
Cavitation is typical for large
granulomas.
Cavitation is more common
in the secondary reactivation
tuberculosis - upper lobes.
![Page 28: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/28.jpg)
Fate of Tuberculosis
1- When the body resistant is good: healing occurs by fibrosis,
followed by calcification and ossification.
2- When the body resistant is low: spreading of the infection :-
Blood
- Direct along the tissue space
- Along the natural passages
- Along the serous cavities as pleura
- Lymphatic to the regional lymph nodes
![Page 29: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/29.jpg)
Morphology of granuloma
1. Collection of chronic inflammatory cells.
2. Central Caseous necrosis.
3. Active macrophages - epithelioid cells.
4. Outer layer of lymphocytes, plasma cells & fibroblasts.
5. Langhans giant cells – fused epithelioid cells.
![Page 30: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/30.jpg)
Epitheloid cells in granuloma
Caseation necrosis
![Page 31: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/31.jpg)
Typical Cavitating Granuloma
![Page 32: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/32.jpg)
TB Brain
![Page 33: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/33.jpg)
TB intestine
![Page 34: 5- Infection (TB)](https://reader034.vdocuments.mx/reader034/viewer/2022042618/577cc37d1a28aba7119622d3/html5/thumbnails/34.jpg)
Spinal TB - Potts Disease