Obstructive lung disease

Question 1

What is asthma

Answer 1

hypersensitivity (type 1) response to allergens (dust mite, fungi, pollen)., leading to reversible obstruction.

mast cell, histamine, cytokines

Atopic (genetic) and environmental.

Question 2

pathophysiology of asthma

Answer 2

Primarily mast cell degranulation and histamine
release as a result of allergen exposure in the
acute phase, causing mucus plugging and airway
bronchoconstriction

Question 3

Examples of obstructive lung disease

Answer 3

asthma, chronic bronchitis, emphysema, bronchiectasis

Question 4

Asthma treatment BTS

Answer 4

1. Inhaled SABA, salbutamol
2. Inhaled corticosteroid (ICS) 200-800mcg/day. beclometasone, ciclesonide, budesonide
3. Inhaled LABA, salmeterol
   >if good response, continue LAA
   >if benefit from LABA but not controlled, continue LABA and increase ICS to 800 mcg/day
   >if no response to LABA, stop LABA. increase ICS to 800 mcg/day, and consider using leukotriene receptor antagonist. montelukast, zafirlukast, and pranlukast
   4.increase ICS to 2000 mcg/day, or add leukotriene receptor antagonist
4. offer daily steroid tablet and ICS 2000 mcg /day, prednisone (mainly gluco)
   >refer to speailist
   >omalizumab (Subcut), monoclonal antibody against IgE, stops mast cell degranulation
   >bronchial thermoplasty

Question 5

COPD definition

Answer 5

Airway limitation secondary to inflammation caused by stimuli, not reversible. Emphysema and chronic bronchitis.

Question 6

COPD in the young should make you suspect which genetic cause of COPD?

Answer 6

alpha 1 antitrypsin deficiency.

Question 7

what in alpha 1 antitrypsin deficiency?

Answer 7

a lack of A1AT, so there is not stopping the breakdown of elastin by neutrophil elastine.

This leads to alveolar destruction.
a. Congestion of the liver with the enzyme alpha-1 antitrypsin (which is produced there in an attempt to compensate)
eventually causes destruction of hepatocytes,
leading to liver disease.

Question 8

what is centrilobular emphysema?

Answer 8

Smokers tend to develop centrilobular emphysema
which typically affects proximal acini
and the upper lung

Question 9

what is panlobular emphysema?

Answer 9

patients
with alpha-1 antitrypsin deficiency tend
to develop panlobular emphysema,
broadly affecting the lower lung

Question 10

Which organism is the most common cause of COPD exacerbation?

Answer 10

Haemophilus

influenzae

Question 11

Clinical features of COPD?

Answer 11

exertional breathlessness
wheeze
sputum production
haemoptysis
bronchitis in the winter
weight loss

Question 12

MRC dyspnoea scale

Answer 12

1. not troubled by SOB unless on exertion
2. SOB when hurrying up a hill
3. walks slower than contemporaries, or has to stop for breath at own pace
4. stops after 100 yards for breath, or a few minutes
5. too breathless to leave the house or upon dressing

Question 13

what is the difference between emphysema and chronic bronchitis

Answer 13

e: alveolar wall destruction due to inflammatory changes

CB: goblet cell hyperplasia and increased mucus secretion leading to chronic cough.

Question 14

Investigation of COPD

Answer 14

1. Spirometry
2. MRC dyspnoea
3. CXR (hyperinflation)
4. sputum culture

Question 15

management of COPD

Answer 15

1. inhaled SABA (salbutamol) or SAMA (muscarinic antagonists, ipratropium)
   2.Use FEV1 ad a guide
   FEV1> 50%: LABA (salmeterol) or LAMA (tiotropoum) and discontinue SAMA
   FEV1<50%, LABA +ICS. Or LAMA
2. Theophylline oral modified release(a xanthines, a muscle relaxer) and mucolytics (Carbocisteine and acetylcysteine, oral)
3. Long term oxygen therapy, when PaO2< 7.3 or PaO2 <7.3–8kPa with secondary polycythaemia,
   nocturnal hypoxaemia, or pulmonary
   hypertension
4. Surgical, bullectomy, or lung transplant
   Bullectomy is considered in patients who have a single large bulla on CT scan and an FEV1 <50% predicted