A S T H M A (P ATHOGENESI S & CLI NIC AL M ANI FEST ATI ON)

BR O NCH I A C T A S I S ( D E F I N I T I O N , E T I O L OGY & P A TH O GE N ES I S)

L E A R N I N G O B J E CT I VES

At the end of the lecture student should be able to– Define chronic obstructive lung diseases (COPD)– Enlighten the types of COPD– Discuss their common features– Identify the causes, underlying patho-physiology, morphology,

and clinical features of chronic bronchitis

DI F F U SE P U L M O N A RY

DI S EASES • Diffuse pulmonary diseases are divided into

O b st r u ct i v e d i se a s e :characterized by limitation of airflow owing to partial or complete obstruction at any level from trachea to respiratory bronchioles. Pulmonary function test:limitation of maximalairflow rate during forced expiration (FEVI).

R est ri c t i v e d i s e a s e :characterized by reduced expansion of lung parenchyma with decreased total lung capacity while the expiratory flow rate is near normal.Occur in:

1. Chest wall disorder.2. Acute or chronic, interstitial and infiltrative diseases,

e.g. ARDS and pneumoconiosis.

CHR O N I C O B S TRUCT I VE P U L M O N A R Y D I S E A SE • Chronic obstructive pulmonary disease (COPD) is a preventable and

treatable disease state characterized by air flow limitation that is not fully reversible.

• Air flow limitation is usually progressive and is associated with an

abnormal inflammatory response of lungs to noxious particles or gases, primarily caused by cigarette smoking.

CHR O N I C O B S TRUCT I VE P U L M O N A R Y D I S E A SE

• Chronic obstruction to airflow due to chronic bronchitis and/or emphysema.

• Degree of obstruction may be less when the patient is free from respiratory infection and may improve with bronchodilator drugs

• Significant obstruction is always present

WH Y C OPD I S IM PO R T A N T ? • COPD is the only chronic disease that is showing progressive upward

trend in both mortality and morbidity• It is expected to be the third leading cause of death by 2020• Approximately 14 million Indians are currently suffering form COPD*• Currently there are 94 million smokers in India• 10 lacs Indians die in a year due to smoking related diseases

*The Indian J Chest Dis & Allied Sciences 2001; 43:139-47

CHR O N I C O B S TRUCT I VE P U L M O NA R Y D I S E A SE

C H R O N I C O B S T R U C T IVE PULM O N A R Y D I S E A S E

ChChrrononiiccBrBroonncchhiittiiss

MiMixedxedDiDiseasesease

CCOPDOPD

AsthAsthmmaa

EEmmphysphyseemama

P A T H OP H YS I O L O GY OF C OPD • Increased mucus production and reduced mucociliary clearance -

cough and sputum production• Loss of elastic recoil - airway collapse• Increase smooth muscle tone• Pulmonary hyperinflation• Gas exchange abnormalities - hypoxemia and/or hypercapnia

KEY INDICA T ORS F O R CO P D DI A G NO S IS

Ch r on i c c oug h

P r ese n t i n t e r m i tt e n t l y o r e v e r y d a y o ften p r es e n t

t h r oughou t t h e d a y ; se l do m only nocturnal

Ch r on i c s pu t u m

p r odu ct i o n

P r ese n t f o r ma n y y e a r s, w o r st i n w i n t e r s . I n i t i a ll y m u c o i d –

b ec o mes pu r u l e n t w i th exacerba t i o n

D y s p no ea P r og r es s i v e ( w o r s e n s o v er t i me)

Pe r s i ste n t ( p r ese n t e v e r y d a y ) Wo r se o n ex e r c i s e

Wo r se dur i n g r e s p ir at o r y infections

A c u te b r on c h i t i s

R e p eated e p i s od es

H i st o r y o f ex po s u r e to ri sk fa c t o r s

Tob acco sm o ke, o cc up at i on al du sts a n d c h em i c al s m o ke

f r o m ho me c oo k i n g a n d heating fuel

CHR O N I C BR O N C H I T I S • Chronic nonspecific inflammation• Symptoms of cough and sputum production with or without gasping• Recurrent attacks• Chronic proceedingClinical and epidemiological term• Defined clinically as the presence of productive cough not attributable to

other causes on most days for at least 3 months over 2 consecutive years.

Different formsCHR O N I C BR O N C H I T I S

• Simple chronic bronchitis• No airway obstruction

• Chronic mucopurulent bronchitis• Associated with infection

• Chronic asthmaticus bronchitis• Chronic obstructive bronchitis

CHR O N I C BR O N C H I T I S Airflow obstruction is due to:• Inflammation, fibrosis, narrowing of bronchioles (chronic bronchiolitis)• Co-existent emphysema

Stages of Chronic Bronchitis

Stages Time Courses

Exacerbation In a week

Chronic lag phase

One month or longer

stable Lasts for two months

CHR O N I C BR O N C H I T I S • Chronic irritation defensive increase in mucus production with

increase in numbers of epithelial cells (esp goblet cells)• Poor relation to functional obstruction• Role in sputum production and increased tendency to infection

CHR O N I C BR O N C H I T I S • Non-reversible obstruction• In some patients there may be a reversible (“asthmatic”) component

CHR O N I C BR O N C H I T I S

• Pathogenesis:• Smoking – increase mucus secretion – inflammation – epithelial

injury – metaplasia and hypertrophy of mucus glands

M or phol og y:CHR O N I C BR O N C H I T I S

• Enlarged mucus gland, edema• Squamous metaplasia, dysplasia• Inflammation• Chronic bronchiolitis

– Goblet cells in small bronchioles, inflammation, fibrosis, smoothmuscle hypertrophy

N O R M A L VS. CHR O N I C BR O NCH I TI S

CLI NIC AL :CHR O N I C BR O N C H I T I S

– Cough and sputum– Cyanosis, “blue bloater”– Hyperinflated chest– Reduced expansion– Increased resonance on percussion– Reduced breath sounds with end expiratory wheeze– Right ventricular failure

• Ch r on i c B r on c h i t i s – Chronic cough– Shortness of breath– Increased mucus

P RI M A R Y S Y M P T O M S

– Frequent clearing of throat

• Em p h y sema – Chronic cough– Shortness of breath– Limited activity level

D i a gno s i s o f c h r o n i c b r on c h i t i s • Cough & Sputum expectoration & Gasping• Three months /per year or longer• Continuously longer than two years• Exclude other lung and heart disease

If shorter than three months /per year then definite objectiveevidences are demanded (such as X-Ray and lung function et al.)to diagnose.

AUXILLARY EXAMINATION• Chest Radiograph(X-Ray)Non apparent abnormality

Or thickened and increased lung markings are noted.

R E F E RNC ES • B ASI C P ATHOLO GY

8th EDITION PAGE # 488 -489

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