Chapter 15 Infectious DiseasesChapter 15 Infectious Diseases

Yang-Qiaohong

Guangzhou Universticy OF TCM

CONTENTSCONTENTS

• TUBERCULOSIS(TB)• TYPHOID FEVER• BACILIARY DYSENTERY• LEPROSY• LEPTOSPROSIS• EPIDEMIC HEMORRHAGIC FEVER• SEXUALLY TRANSMITTED DISEASE

Introduction

Although the features of pathologic

change of infectious diseases is different,

its basic pathological changes is the same,

belong to the inflammation.

肾盂肾炎志贺氏菌痢疾

疟疾斑疹伤寒

登革热病

流行性腮腺炎狂犬病

风疹麻疹水痘

雅司病

淋巴管

流感白喉

小儿麻痹症 黄热病

TUBERCULOSIS(TB)TUBERCULOSIS(TB)

• Tuberculosis(TB) is an infectious disease caused by several different species of mycobacteria.

• The lung is his prime targetThe lung is his prime target, but any , but any

organ may be infected.organ may be infected.

A. EtiologyA. Etiology

• Tuberculosis is caused by mycobacterium tuberculosis, which is a slender slightly curved rod-shaped aerobic bacterium. 1~4μm

B. TransmissionB. Transmission

• The main routes of tuberculosis infection are (1) pulmonary, (2) intestinal, (3) tonsillar, (4) cutaneous, and (5) placental ( congenital ).

• The disease usually is spread by droplets from a patient with a cavitary lesion that opens into a bronchus.

PathogenesisPathogenesis

• Five strains of mycobacterium tuberculosis are recognized ( human, bovine, murine, avian and reptilian ) and infection can occur by inhalation, ingestion (rare following testing of cattle and pasteurization) and inoculation.

• The tissue damage associated with tuberculosis is due to the specific reactivity of the immnue system occurring as a result of the presence of the bacterium.This expresses itself in two ways:

• (1) Enhanced resistance to infection and more effectivt clearing of the bacterium.

• (2) Appearance of hypersensitivity causing most of the damage.

2. Pathogenic substance of 2. Pathogenic substance of mycobacterium tuberculosis mycobacterium tuberculosis

① Lipid: ⅰ Related to pathogenicity, especially glycolipidRelated to pathogenicity, especially glycolipid

cord factor:

wax D: cause severe allergy→ tissue damage

destroy the membrane of mitochondria inhibit the emigration of leukocyte related to the formation of granuloma

ⅱ ⅱ Protect bacillary bodies from Protect bacillary bodies from digestion of macrophagedigestion of macrophage

inhibit bacteria combine with lysosome, the bacteria can survive

ⅲ ⅲ PhosphatidePhosphatide change the macrophage into epithelioid cells in the inflammatory focus

② Polysaccharide lipoarabinomannan

inhibit activity of macrophage

secreting TNF-α: necrosis

IL-10: inhibit cell

immune

③ Protein:Heat-shock protein

Ag autoinmmune reaction

Pathogenesis Cell immunity

Type hypersensitivityⅣ

Three consideration are involved in the pathogenesis of TB(1) Quantity of bacteria(2) Virulence of pathogen(3) Responsiveness of the body sensitivity and immune response

Basic pathological changesBasic pathological changes

reactivity quantityvirulencefeatures of tissue

difference difference lesionslesions

Basic pathological changesBasic pathological changes • 2. Proliferative changes• (1) Conditions• early stage immunity↓quantity↑ virulence↑ • severe hypersensitivity• (2) Pathologic changes• serous or serofibrinous • early :neutrophils• late :macrophages• (3) Site • lung, serosa, synovialis, meninges• (4) Result absorbed completely development proliferation necrosis

Basic pathological changesBasic pathological changes • 1. Exudative changes

characteristic lesion→tubercleFormation of tubercle possesses certain diagnostic feature

• (1) Conditions• early stage • immunity↓quantity↑virulence↑ • severe hypersensitivity• (2) Pathologic changes• quantity↓ virulence↓ strong immune reaction

Basic pathological changesBasic pathological changes ① Gross

the size of a millet clear edge grayish , semitransparent yellow with necrosis, somewhat rise on the surface of organ

② LM: typical lesion→tubercle ( formation based on cell immune ) Center: caseous necrosis Surrounding epithelioid cell Langhans giant cell Outside lymphocyte fibroblast

Basic pathological changesBasic pathological changes ① Gross

the size of a millet clear edge grayish , semitransparent yellow with necrosis, somewhat rise on the surface of organ

② LM: typical lesion→tubercle ( formation based on cell immune ) Center: caseous necrosis Surrounding epithelioid cell Langhans giant cell Outside lymphocyte fibroblast

Basic pathological changesBasic pathological changes ⅰ Epithelioid cell Source: macrophage phagocytize→M.tuberculosis Shape: large, abundant cytoplasm, pseudopod Function: phagocytize, kill mycobacterium

ⅱ Langhans giant cell Source fusion of epithelioid cells division of nuclei without cytoplastic division Shape: multinuclei, floral hoop or horseshoe-like Function: phagocytizing and killing mycobacterium

Langhans giant cell

Epithelioid cell

Basic pathological changesBasic pathological changes 3. Alterative changes (1) Conditions: quantity↑ virulence↑resistence↓ severe allergy (2) Lesion: feature→caseous necrosis ① ① GrossGross: slight yellow, homogenous, exquisite creamy ② ② LM:LM: red staining, no structure, granular substance (3) Result uneasily absorbed not autolysis, excluded sometimes: softed, liquefy→spread

Basic pathological changesBasic pathological changes

Three lesions can exist simultaneously transform one another

BACILLARY DYSENSES

• Bacillary dysentery is an acute infectious inflammatory disease of the colon,occasionally involving the ileum as well,caused by microorganisms of the genus shigella