Pulmonary airways disease

Question 1

what are the host defences

Answer 1

same infectious agents can produce markedly different effects in different people
cough reflex, cilia, mucus, antibody deficiency, immunosuppression (diseases, drug) macrophages dysfunction, pulmonary oedema

Question 2

describe acute bronchitis

Answer 2

inflammation of bronchi, often viral, can be bacterial (H. influenzae), can involve larynx and trachea (laryngotracheobronchitis), acute exacerbations of chronic bronchitis are common

Question 3

describe bronchiolitis

Answer 3

inflammation of bronchioles, a feature of chronic bronchitis
primary bronchiolitis - usually in children, respiratory syncytial virus (RSV), tachypnoea and dyspnoea
rare types are follicular bronchiolitis and bronchiolitis obliterans

Question 4

describe localised airway obstruction

Answer 4

airway obstruction - lesion outside the wall (large lymph node), lesion in the wall (tumour), lesion in lumen (foreign body)
causes distal collapse or over-inflation
may be distal lipid or infective pneumonia
normal pulmonary function tests

Question 5

describe diffuse obstructive airways disease

Answer 5

chronic bronchitis, emphysema, asthma, bronchiectasis

Question 6

what is COPD

Answer 6

spectrum of co-existence of chronic bronchitis and emphysema
most patients exhibit a mixture of features
airway involvement also leads to a productive cough as a result of increased mucus production

Question 7

describe chronic bronchitis

Answer 7

cough and sputum for 3 months in 2 consecutive years
aetiology - pollution, smoking
clinical - middle-aged heavy smokers, recurrent low-grade bronchial infections (exacerbations), H. influenzae or S. pneumoniae viruses, airway obstruction may be partially reversible

Question 8

progression of chronic bronchitis

Answer 8

hypercapnia (high CO2 in blood)
hypoxia
pulmonary hypertension
right ventricular failure
coined ‘blue bloater’they appear overweight, fluid retained and blue as they are hypoxic

Question 9

pathology of chronic bronchitis

Answer 9

respiratory bronchiolitis, this can lead to centrilobular emphysema
mucus hypersecretion this can lead to mucus gland hypertrophy which is irreversible
chronic bronchial inflammation which can lead to squamous metaplasia (change in growth from respiratory epithelium) causing an increased risk of malignancy

Question 10

describe emphysema

Answer 10

irreversible dilation of acinar spaces with destruction of walls
usually confined to alveoli but often extended to include respiratory bronchioles
associated with loss of SA for gas exchange

Question 11

describe centrilobular emphysema

Answer 11

strongly associated with smoking
seen in some with pneumoconiosis, particularly coal-workers
must commonly in upper lobes
respiratory bronchiolitis is often present

Question 12

describe panlobular emphysema

Answer 12

usually lower lobes
lungs over distended
associated with alpha-1-antitrypsin deficiency
markedly accelerated in smokers with this disorder

Question 13

describe the other forms of emphysema

Answer 13

paraseptal - distension to pleural surfaces, may be associated with scarring
irregular - associated with scarring, overlap with paraseptal emphysema
bollus - distended areas of more than 10mm
interstitial

Question 14

clinical features of emphysema

Answer 14

hyperventilation
normal pO2 and pCO2
weight loss
right ventricular failure
often co-existing chronic bronchitis, clinical features are mixed
‘pink puffer’

Question 15

how is COPD assessed

Answer 15

using pulmonary function tests
FEV1/FVC less than 0.7 for diagnosis
percent predicted FEV1 to assess severity
FEV1 >80 - mild
FEV1 50-79 - moderate
FEV1 30-49 - severe
FEV1 <30 very severe

Question 16

correlation with COPD symptoms

Answer 16

destruction of alveolar walls leads to loss of SA for gas exchange
increased respiratory drive compensated for drop in O2
pCO2 may be low due to high resp rate
in some cases resp drive may fall, with tolerance of low pO2 and elevation of pCO2
pulmonary vasoconstriction (due to hypoxia) and destruction of pulmonary vasculature lead to pulmonary hypertension

Question 17

what is the eventual consequence of pulmonary hypertension

Answer 17

right ventricular failure
ankle swelling
hepatic congestion, leading to pain, abnormal LFTs and ‘nutmeg’ liver

Question 18

describe asthma

Answer 18

reversible wheezy dyspnoea
increased irritability of bronchial tree with attacks (paroxysmal) of airway narrowing
five aetiological categories - atopic, non-atopic, aspirin-induced, occupational and allergic bronchopulmonary aspergillosis (ABPA)

Question 19

describe atopic asthma

Answer 19

associated with allergy
triggered by a variety of factors (dust, pollen, dust mite etc)
often associated with eczema and hay fever
bronchoconstriction mediated by a type 1 hypersensitivity reaction

Question 20

what does a hypersensitivity reaction lead to

Answer 20

bronchial obstruction with distal overinflation or collapse
mucus plugging of bronchi
bronchial inflammation
mucus gland hypertrophy
bronchial wall smooth muscle hypertrophy
thickening of bronchial basement membranes
last 3 are all irreversible

Question 21

describe non-atopic asthma

Answer 21

associated with recurrent infections
not immunologically mediated
skin testing negative

Question 22

aspirin-induced asthma

Answer 22

associated with recurrent rhinitis, nasal polyps and urticaria (rashes)
mechanism is unclear

Question 23

occupational asthma

Answer 23

hypersensitivity to an inhaled antigen may be non-specific in those woth hyper-reactive airways
may be a specific allergen response

Question 24

ABPA

Answer 24

Specific allergic response to the spores of Aspergillus
fumigatus
Mixed type I and type III hypersensitivity reaction
Mucus plugs common
Associated with bronchiectasis
Not to be confused with an aspergilloma, which is a
fungal ball, usually colonising a pre-existing cavity in
the lung (often tuberculous)

Question 25

factors that contribute to airways obstruction in asthma and their relationship to therapy

Answer 25

mucus plugging - physio, bronchodilators are useful in conjunction
bronchoconstriction - bronchodilators (beta-2 agonists
bronchial oedema and inflammatory cell infiltration - anti-inflammatory agents (inhaled/oral steroids, leukotriene receptor antagonists)
smooth muscle hypertrophy and basement membrane thickening - prevention of inflammation using inhaled steroids as it is irreversible

Question 26

describe bronchiectasis

Answer 26

permanent dilation of bronchi and bronchioles
due to a combination of obstruction and inflammation (usually infection)
may be localised or diffuse, depending on the cause
historically seen inpatients with pulmonary TB involving hilar lymph nodes
classically associated with childhood infections, particularly measles and whooping cough
diffuse bronchiectasis seen in CF patients

Question 27

clinical features of bronchiectasis

Answer 27

chronic cough
production of copious amounts of sputum
finger clubbing
amyloidosis (unusual disorder associated with chronic inflammatory disease, causes renal failure)
respiratory failure