TUBERCULOSIS

http://images.google.com/imgres?imgurl=http://www.healthybaccha.com/tuberculosis1.jpg&imgrefurl=http://www.healthybaccha.com/tuberculosis.htm&h=350&w=261&sz=61&hl=en&start=139&um=1&tbnid=T_7mfVUKmKxnJM:&tbnh=120&tbnw=89&prev=/images%3Fq%3Dtuberculosis%26start%3D120%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DIBMA,IBMA:2006-30,IBMA:en%26sa%3DN

WHAT IS IT ? Bacterial infectionBacterial infection

Caused by Caused by Mycobacterium tuberculosis Mycobacterium tuberculosis (also(also called called tubercle bacillustubercle bacillus))

Damages a person’s lungs or other parts ofDamages a person’s lungs or other parts of the bodythe body

Fatal if not treated properlyFatal if not treated properly

• Mycobacterium – Slender, aerobic rods

Gram +ve, Acid fast

M.tuberculosis – Reservoir- Humans

M.bovis –Reservoir – contaminated milk

M.Avium intracellulare-opportunistic (AIDS)

TB flourishes in

Poverty, Over crowding, Malnutrition

DM, CRF

Alcoholism

Immunosuppression

TRANSMISSION• Spreads through the air when aSpreads through the air when a person with active TB (Inhalation)person with active TB (Inhalation)

– CoughsCoughs

– SpeaksSpeaks

– LaughsLaughs

– SneezesSneezes

• IngestionIngestion

SPREAD OF TB Local Spread

Lymphatic spread

Haematogenous Spread

Natural passages – Pleurisy,

Peritonitis (salpingitis), Laryngitis ,

Ileocaecal

PATHOGENESIS

• Breath in infected air and bacilli go to lungs through bronchioles

• Bacilli infect alveoli

• Macrophages attack bacteria, but some survive

• Infected macrophages separate and form tubercles

Hypersensitivity to tubercular antigens

Cell Mediated immunity

Caseating granulomas, Cavitation

Host response to lipids such as Mycosides

(cord factor) & glycolipids ( Wax-D) on the

bacterial cell wall

Type IV Hypersensitivity

Primary cells infected

are

MACROPHAGES

ACTIVE INFECTIONACTIVE INFECTION

Unhealthy personUnhealthy person

Bacilli overwhelm immune systemBacilli overwhelm immune system

Bacilli break out of tubercles in alveoli Bacilli break out of tubercles in alveoli

and spread through and spread through

bloodstreambloodstream

LATENT INFECTIONLATENT INFECTION

Initial infection controlled Initial infection controlled

by immune systemby immune system

Bacilli remain confined in Bacilli remain confined in

tubercles for yearstubercles for years

DIAGNOSIS

• Mantoux testMantoux test

• Medical history, Medical history,

x-rays, and smears forx-rays, and smears for

AFB, AFB, Sputum cultureSputum culture, ,

PCRPCR

http://en.wikipedia.org/wiki/Image:TB_in_sputum.png

SYMPTOMS• Perpetual CoughPerpetual Cough

• FeverFever

• Weight lossWeight loss

• Night sweatsNight sweats

• Loss of appetiteLoss of appetite

• FatigueFatigue

• Swollen glandsSwollen glands

• Pain while breathingPain while breathing

http://images.google.co.in/imgres?imgurl=http://umanitoba.ca/faculties/medicine/history/notes/glossary/2fig10.jpg&imgrefurl=http://umanitoba.ca/faculties/medicine/history/notes/glossary/glossary8.html&h=199&w=301&sz=28&hl=en&start=85&tbnid=RGgD3taU5B92PM:&tbnh=77&tbnw=116&prev=/images%3Fq%3Dtuberculosis%26start%3D80%26ndsp%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN

EVOLUTION OF TUBERCLE ( Granuloma)PMN Macrophages

Poorly degradable bacilli

CD4+ T cells ( IFN, TNF) Epithelioid cells

Hard Tubercle Soft Tubercle

GRANULOMA

Central caseous necrosis surrounded by

epithelioid cells, Langhan’s giant cells,

Rim of lymphocytes and fibroblasts.

http://en.wikipedia.org/wiki/Image:CD_Granuloma.jpg

http://images.google.co.in/imgres?imgurl=http://www.microscopyu.com/galleries/pathology/images/tuberculosis/tuberculosis40x03large.jpg&imgrefurl=http://www.microscopyu.com/galleries/pathology/tuberculosislarge.html&h=368&w=508&sz=87&hl=en&start=11&tbnid=SYxWGUttqLr_QM:&tbnh=95&tbnw=131&prev=/images%3Fq%3Dtuberculosis%26svnum%3D10%26hl%3Den%26lr%3D

FATE OF GRANULOMA

Cold Abscess

Sinus Formation

Fibrosis

Dystrophic calcification

CLINICAL SPECTRUM

Primary – previously unexposed, unsensitized person

Secondary – Previously sensitized person

- Follows primary,

- Reactivation of dormant lesion,

- Exogenous reinfection ( Large

inoculum of virulent bacilli)

Primary tuberculosis

GHON’S COMPLEX( Primary complex)

Ghon’s Focus- Subpleural focus in the

upper part of lower lobe/

lower part of upper lobe Lymphatic component Lymph node component – Hilar &

Tracheo-bronchial

Fate of Primary TB

Fibrosis, calcification

Progressive Pulmonary TB

Primary Miliary TB

Secondary TB

Secondary Tuberculosis

Initially -- small focus (2 cm) of

consolidation in the apical pleura

Develop a small area of caseation, fibrosis

Fate of secondary TB

Heal with fibrosis

Fibrocavitary TB

Pneumonia

Miliary TB

Progressive Pulmonary TB

Child, Elderly, Immunocompromised

Erosion of blood vessels hemoptysis

Erosion into bronchus

Empyema, effusion, pleuritis

MILIARY TUBERCULOSIS

Miliary = ‘millet seeds’

Spread thro’ lymphatics

Lesions- small / microscopic

Liver, Spleen, Kidney, Brain, Bonemarrow adrenals, fallopian tubes, epididymis, etc.

Isolated organ TB:

• Meningitis

• Renal

• Osteomyelitis

• Adrenals

• Salpingitis

• Pott’s spine

• Lymphadenitis- Scrofula

• Intestinal

IMMUNIZATION

Bacilli Calmette Guerin ( BCG)

[ Attenuated Strains of Bovine type of Bacilli]