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1、Childhood Tuberculosis,檀卫平 中山二院,Definition,Tuberculosis is caused by Mycobacterium tuberculosis , isolated by Robert Koch in 1882 , M.bovis(seldom) mainly involves the lungs, but may spread to other organs consumption （肺痨）,Epidemiology,19th century, 25% deaths by TB 1940s, effective medicines Annual
2、ly, 8 million become ill with tuberculosis, 2 million people die The morbidity / mortality are high in developing countries China has the worlds second largest tuberculosis epidemic (after India) incidences rates 113 per 100,000 in China,Epidemiology,Age:60% Infant -5yr Male:female-1:1 (adults male
3、predominate) TB adults exposure 2yr,HIV coinfection, immunocompromise, malnutrition HIV/AIDS, drug-resistant,Etiology,Tubercle bacillus: aerobic,non-Motile,non-spore-forming, high lipid content acid-fast, weak Gram(+) grows slowly Sensitive to heat/sunlight tolerate in humid or dry or cold. withstan
4、d weak disinfectants and survive in a dry state for weeks.,Dr. Robert Koch discovered the tuberculosis bacilli in 1882 He received the Nobel Prize in physiology or medicine in 1905 for this discovery,Tuberculosis is transmitted by airborne droplet nuclei(containing tubercle bacilli ) prolonged, freq
5、uent, or intense contact cough, sneeze, speak, or spit,Many droplet nuclei are capable of floating in environment for several hours Large particles may be inhaled by person breathing the same air and impact on the trachea or wall of the upper airway,The transmission is determined,The probability of
6、contact with active not latent TB intimacy and duration of contact effectiveness of ventilation numbers and virulence of the M. tuberculosis strain in infectious droplets,Pathogenesis,tubercle bacillus,Human immunity,Pathogenesis,90% infected with Mycobacterium tuberculosis asymptomatic, latent TB i
7、nfection 10% progress to TB disease if untreated, the death rate for these active TB cases is more than 50%,Pathogenesis,mycobacteriapulmonary alveolireplicate within macrophages picked up by dendritic cells transport to local LN spread through bloodstream to other tissues/organs secondary TB lesion
8、s primary site of infection :upper part of the lower lobe, or lower part of the upper lobe of lung secondary TB lesions: apex of the upper lobes , peripheral lymph nodes, kidneys, brain, and bone,Human Immunity /hypersensitivity after TB infection,Specific immunity after infected or given BCG vaccin
9、e Cell-mediate immunity develops within 4-8 weeks after infected with bacillus Many immunologic cells: Macrophages, T/B lymphocytes, fibroblasts involved,Two types of cells are essential in the formation of TB,Macrophages: directly phagocytize TB and processing and presenting antigens to T lymphocyt
10、e T lymphocytes(CD4+): induce protection through the production of lymphokines,T lymphocytes(CD4+),Genetic factors (HLA-BW35)play a key role in innate non-immune resistance to infection with M. Tuberculosis These genes may have a role in determining susceptibility to tuberculosis,Basic pathologic ch
11、anges,infiltrationhyperplasia(granuloma), ulceration or calcification in different stage host defensebacteria, granuloma calcification,A characteristic tubercle at low magnification (A) and in detail (B) central caseation surrounded by epithelioid and multinucleated giant cells(C) mycobacteria with
12、acid-fast stains (D).,Progression of tuberculosis,Absorption Fibrosis Calcification Deterioration: enlargement of infected aeras and appear newer infiltrated regions or spreading.,Five common clinical patterns,1. Primary pulmonary tuberculosis (Primary Complex and Bronchial Lymphnode-Tuberculosis) 2
13、. Milliary Tuberculosis (acute, subacute and chronic hematogenous pulmonary tuberculosis) 3. secondary pulmonary tuberculosis Infiltrative pulmonary tuberculosis Chronic fibrocavenous pulmonary tuberculosis 4.Tuberculous pleuritis 5.Extrapulmonary tuberculosis,Diagnosis,History and Clinical Manifest
14、ations Tuberculin testing Lab examination X-ray bronchoscopy Puncture of adenopathy,History /Clinical Manifestations,systemic signs: fever, weight loss, fatigue, night sweats, wasting TB Contaction ：adults in family History of BCG Vaccination Acute infectious disease recently : measles,whooping coug
15、h Allergy to TB：erythema nodosum 、herpetic conjunctivitis,Tuberculin skin test,a skin test to determine past or present infection with the tuberculosis bacterium; based on hypersensitivity of the skin to tuberculin Method of test protein purified derivative PPD 0.1ml intradermal injection Site: inte
16、rnal side of medium-distal 1/3 left forearm 6 - 10mm Result: 48-72hrs, transverse diameter,Result is read by measuring the diameter of induration 48-72hrs,Induration 5mm negative Induration 5-9mm(+) Induration 10-19mm(+) Induration 20mm (+) A positive tuberculin skin test indicates tuberculous infection, with or without disease,Tuberculin testing A positive tuberculin test is of great use in children, with limited diagnostic significance in adults,
