Asthma

Question 1

Describe the pathophysiology of asthma focusing on bronchi

Answer 1

Inflammation of the bronchi makes them narrow this causes wheezing due to the constriction and the lumen reduces. The inflammation causes the mucus glands to produce an excessive sputum which blocks the air pathways.

The muscles around the bronchi become irritated and contract, this can cause sudden worsening of symptoms which can cause an Asthma attack.

Question 2

Symptoms of asthma

Answer 2

Cough- worse at night
SOB
Chest tightness
Wheezing- high- pitched due to narrowing
Increase mucus production
Dyspnoea
Low peak flow

Question 3

Differential diagnosis of asthma

Answer 3

Bronchitis
COPD
Congestive heart failure
Pulmonary emblosim

Question 4

Risk factors of asthma

Answer 4

• Common presents in children
• influenced by genetics and environment
• Family history
• environment
• exposure to allergens or smoke

Question 5

Air flow obstruction in asthma is caused by what three main pathological process’

Answer 5

1. Inflammatory cell infiltration- acute and chronic inflammatory cells intermingled with atypical lymphocytes
2. Mucus hypersecretion
3. Smooth muscle contraction

Question 6

Is airway obstruction reversible?

Answer 6

This is reversible but may become irreversible due to:
1. basement membrane thickening,
2. collagen deposition
3. fibrosis,
4. airway remodelling,
5. smooth muscle hypertrophy.

Question 7

What is acute asthma

Answer 7

wide range of triggers can exacerbate asthma at any point.

Avoidable triggers: cigarette smoking, allergens e.g. animals, airborne, environmental irritants e.g. perfumes, medications

Unavoidable triggers: exercise, infections

Question 8

What is asthma

Answer 8

Is a chronic inflammatory disease of the airways characterised by reversible airway obstruction, bronchial hyperresposiveness and airway remodelling

Question 9

Describe the inflammation stage

Answer 9

Triggering agents: allergens, pollutants, exercise and cold air can initiate an inflammatory response.

Dendritic cells capture these allergens and present them to the TH cells

The TH cells release cytokines

Mast cells that regulate cytikines are activated that release histamines.

Histamines trigger symptoms such as nasal congestion, runny nose and rash

Question 10

Describe airway hyperresponsiveness

Answer 10

• Chronic inflammation makes the airways highly sensitive to triggers
• Smooth muscle cells in the bronchi contract excessivley in response to a stimuli causing narrowing of the airways.

Question 11

Describe airway obstruction

Answer 11

1. Bronchoconstriction: smooth muscle contraction narrows the aiway lumen
2. Mucosal oedema: inflammatory swealling reduces the airway diameter.
3. Mucus hypersecretion: goblet cells hyperplasia (increase production) and submucosal gland hypertropy ( increase in size) causing increase mucus production and contributing to airway plugging

Question 12

Describe airway remodelling

Answer 12

• Chronic inflammation leads to structural changes in the airway including:

1. Thickening of the basement membrane
2. Fibrosis in the subepithelial layers
3. Smooth muscle hypertropy and hyperplasia
4. Angiogensis ( new blood vessel formation)

Question 13

What symptoms are during an asthma attack

Answer 13

Severe breathlessness
Tachypnoea
USe of accessory muscles
Cyanosis