Asthma

Question 1

What is Asthma?

Answer 1

Astmah is a a chronic inflammatory airway disease leading to

• airway obstruction due to
  
  • Muscle spasm (acute)
  • Increased mucus production
  • Inflammation/oedema (chronic)
  • might lead to: fibrosis (chronic)

Question 2

What is the site affected by Asthma?

Answer 2

Generally large airway and small airway <2 micrometers

Question 3

Explain the broad pathophysiology of Asthma

Answer 3

Generally an inflamatory process

• trigger releases inflamatory mediators
• Activation and migration of inflamatory cells
• (Expecially Th2 cells)
• Other WBC also involved
  
  • –> Inflamation
• Also bronchial hyperresponsiveness associated with it

Question 4

What is the aetiology of asthma?

Answer 4

• Genetic predisposition (strong)
• Environmental exposure (hygene hypothesis)
• Air pollutans, pets, mould make it more likely, might be possible triggers

Question 5

What are risk factors for developing asthma?

Answer 5

• Allergens (pets, dust mites, mould, tobocco smoke, pollen)
• Family history
• History of atopy (eczema, allergic rhinits, atopic dermatitis)
• • more

Question 6

What is the epidemiology of asthma?

Answer 6

Variable in different countries

• 5.4 million people in the UK
• more common in men <18
• more common on female >18

Question 7

What is the role of eosiniphiles in asthma?

Answer 7

Are activated by overexpressed Th2 cells,

cause B-cell activation and IgG production,

leading to bronchial submucosal edema and smooth muscle contraction → bronchioles collapse

Leading to Bronchial Inflammation

Question 8

What is the pathophysiology of allergic astmah?

Answer 8

IgE-mediated type 1 hypersensitivity to a specific allergen; characterized by mast cell degranulation and release of histamine after a prior phase of sensitization

Question 9

What is the Pathophysiology of non-allergic Asthma?

Answer 9

1. Irritant asthma: irritant enters lung → ↑ release of neutrophils → submucosal edema → airway obstruction
2. Aspirin-induced asthma: NSAID inhibition of COX-1 → ↓ PGE2 → ↑ leukotrienes and inflammation → submucosal edema → airway obs

Question 10

What are the presenting signs and symptoms of an persistant asthma patient?

Answer 10

• Persistent, dry cough that worsens at night, with exercise, or on exposure to triggers/irritants (e.g., cold air, allergens, smoke)
• End-expiratory wheezes
• Dyspnea
• Chest tightness
• Chronic allergic rhinitis with nasal congestion

Question 11

What are severe asthma symptoms?

Answer 11

• Severe dyspnea
• Pulsus paradoxus
  
  • reduced BP during inspiration (more than 10mmHg systolic) –> weak pulse during inspiration
• Hypoxemia
• Accessory muscle use
• Increased risk of pulmonary infection (in chronic asthma)

Question 12

What is an acute asthma attack?

Answer 12

acute, reversible episode of lower airway obstruction that may be life-threatening

Question 13

What are symptoms of an acute asthma attack?

Answer 13

• Dyspnoe
• Fear
• Agitation

Question 14

What are signs of an asthma attack on examination?

Answer 14

• Use of accessory muscles
• agitation
• tachypnoe
• tachycardia
• reduced SPO2
• Hypercapnia
• Wheezing
• Cyanosis
• Inability to complete short symproma

On Auscultation

• Expiratory wheezing with dry crackles and prolonged expiration
• Decreased breath sounds
  
  • indicating consollidation or “tired” of breathing, might progress into resp arrest

Percussion

• Hyerresonant chest

Question 15

Which investigations would you order if you suspect someone to have asthma?

Answer 15

Diagnostic tests

• Spirometry
  
  • normally reduced FEV1 with reduced FEV1/ FEV ratio
• Methacholine provocation test
  
  • to test for hyperresponsiveness of airways
• Chext X-R
  
  • done to exclude differentials in acute attack
  • in severe attack hyperinflation

Question 16

What are possible complications that can develop in an asthmatic patient?

Answer 16

1. Acute asthma attack (moderate or severe exacerbation)
2. airway remodeling
   
   1. due to chronic inflammation, similar to COPD
3. Infections and more frequent pneumonia

Question 17

What are possible complications that can develop from use of inhaled corticosteroids in asthma?

Answer 17

• Oral candidiasis
• dysphonia
• oesophageal condidiasis

Question 18

What is the management of Asthma?

Answer 18

• Short acting ß2 agonist as reliever
• Offer inhaled corticosteroids
  
  • if symptoms >3/7 as maintanance
  • if uncontrolled with SABA alone
• Leukotriene receptor agonist (review in 4-8 Weeks) e..g montelukast

Question 19

What is the prognosis of patients with asthma?

Answer 19

Depends on severity of asthma

• Might cause remodeling
• generally leading to reduced FEV1
• generally no change in life expectancy
  *

Question 20

How would you manage an acute asthma attack?

Answer 20

1. ICU admission
2. • SABA
3. • Muscareinc antagonist /inhaled anticholinergic
4. O2
5. IV/oral steroids

Question 21

When are asthma symptoms normally worse?

Answer 21

1. At night/early morning
2. When eposed to triggers
   
   1. e.g. pollen/pets
   2. Cold/hot air

Question 22

What drugs normally cause an exacerbation of astmah?

Answer 22

• NSAIDS
• ß-blocker (including glaucoma eye-drops)

Question 23

Why do NSAIDs cause and exacerbation of Asthma?

Answer 23

NSAIDs are COx inhibiors, meaning more Arachidonic acid is available to be turned into Leukotrienes

Leukotrience cause exacerbation of Asthmah in asthmatic patients

Question 24

What is a normal pCo2 for a sick asthmathic?

What happens if that changes?

Answer 24

Normally would expect to see a low pCO2 –> hyperventilation

If it rises –> concerned that if it’s normal or rising this suggests they are failing to keep up and will soon go into worse respiratory failure.

Question 25

What is the MOA of a leukotriene receptor antagonist?

Answer 25

Kompetitive blocks leukotrienes --\> Reducec leukotriene induced inflammation in airways

Question 26

Which other conditions should be considered in someone labeled as "asthma" that does not respond to conventional treatment?

Answer 26

1. Hyperventilation 2. COPD 3. Heart Failure 4. PE