Pathophysiology
A 10-year-old boy is referred to a respiratory physician for persistent bouts of shortness of breath. He also has severe hay fever and eczema. He undergoes a peak expiratory flow test, which suggests signs of outflow obstruction of his lungs. He is trialled on beclomethasone and salbutamol. The physician also informs the mother that he should be kept away from dust, as asthma is a condition that commonly arises from hypersensitivity to dust. Which hypersensitivity is asthma associated with?
Type 1 hypersensitivity
Type 2 hypersensitivity
Type 3 hypersensitivity
Type 4 hypersensitivity
Type 5 hypersensitivity
Type 1 hypersensitivity
A 16-year-old patient with suspected asthma undergoes spirometry. Which of the following patterns is most consistent with asthma during an acute episode?
A) Reduced FEV₁ with reduced FEV₁/FVC ratio
B) Reduced FEV₁ with normal FEV₁/FVC ratio
C) Reduced FVC with increased FEV₁/FVC ratio
D) Normal FEV₁ with reduced total lung capacity
E) Reduced FEV₁ with increased diffusion capacity
A) Reduced FEV₁ with reduced FEV₁/FVC ratio
A 19-year-old patient presents with intermittent wheeze and is diagnosed with mild asthma. Which medication is typically used as first-line reliever therapy for acute symptoms?
A) Inhaled corticosteroid
B) Long-acting β2 agonist
C) Short-acting β2 agonist
D) Leukotriene receptor antagonist
E) Oral corticosteroid
C) Short-acting β2 agonist
A patient with emphysema undergoes CT imaging showing predominant destruction of alveoli in the lower lobes of the lungs. Which underlying condition is most likely responsible?
A) Chronic cigarette smoking
B) Alpha-1 antitrypsin deficiency
C) Chronic bronchitis
D) Long-term exposure to asbestos
E) Recurrent pulmonary infections
B) Alpha-1 antitrypsin deficiency
Lower lobe emphysema - a1-antitrypsin deficiency
Upper lobe emphysema - smoking
A patient experiences an immediate asthmatic reaction after allergen exposure. IgE antibodies bound to mast cells trigger degranulation. Which mediator released from mast cells is most responsible for acute bronchoconstriction?
A) Histamine
B) Leukotriene C4
C) Prostaglandin E2
D) IL-5
E) TNG-alpha
A) Histamine
A 22-year-old patient presents with episodic wheeze and shortness of breath. Asthma is suspected. Which investigation is most useful for assessing eosinophilic airway inflammation and predicting response to inhaled corticosteroids?
A) Fractional exhaled nitric oxide (FeNO)
B) Chest X-ray
C) Peak expiratory flow measurement
D) Arterial blood gas
E) Bronchial biopsy
A) Fractional exhaled nitric oxide (FeNO)
A patient with persistent asthma is started on a combination inhaler containing a long-acting β₂-agonist (LABA) and a long-acting muscarinic antagonist (LAMA) to improve bronchodilation.
Which of the following drugs is an example of a LAMA used in airway disease?
A) Salmeterol
B) Tiotropium
C) Salbutamol
D) Montelukast
E) Beclometasone
B) Tiotropium
A patient with advanced COPD develops type II respiratory failure. Which arterial blood gas pattern is most consistent with this condition?
A) Low PaO₂ with normal PaCO₂
B) Normal PaO₂ with low PaCO₂
C) Low PaO₂ with elevated PaCO₂
D) Elevated PaO₂ with elevated PaCO₂
E) Normal PaO₂ with elevated bicarbonate only
C) Low PaO₂ with elevated PaCO₂
Hypoxaemia (↓ O₂)
Hypercapnia (↑ CO₂)
Eosinophilic infiltration is a hallmark of atopic asthma. Which cytokine is primarily responsible for eosinophil maturation and recruitment to the airway, contributing to chronic inflammation?
A) IL-4
B) IL-5
C) IL-13
D) IL-17
E) TNF-alpha
B) IL-5
A patient with suspected asthma has variable expiratory airflow limitation. Daily home measurements of peak expiratory flow (PEF) are recommended. Which of the following PEF patterns is most consistent with asthma?
A) Constantly low PEF readings
B) PEF variation >20% over the day or week
C) PEF variation <5%
D) Progressive daily increase in PEF
E) Normal PEF with mild nocturnal dip
B) PEF variation >20% over the day or week
A patient with asthma experiences frequent symptoms triggered by exercise and is started on montelukast as part of their management plan. What is the primary mechanism of action of this drug?
A) Activation of β₂ receptors leading to bronchodilation
B) Inhibition of phosphodiesterase increasing cAMP levels
C) Blockade of cysteinyl leukotriene (CysLT1) receptors in the airway
D) Suppression of inflammatory cytokine gene transcription
E) Inhibition of IgE binding to mast cells
C) Blockade of cysteinyl leukotriene (CysLT1) receptors in the airway
A 67-year-old patient with a 45-pack-year smoking history presents with progressive dyspnoea and chronic productive cough. COPD is suspected. Which of the following investigation findings is most consistent with COPD?
A) Spirometry showing FEV₁/FVC > 0.80 with reduced total lung capacity
B) Chest X-ray showing hyperinflated lungs with flattened diaphragms
C) CT scan showing diffuse interstitial fibrosis and honeycombing
D) Arterial blood gas showing respiratory alkalosis with low CO₂
E) Spirometry showing normal FEV₁ with reduced diffusion capacity only
B) Chest X-ray showing hyperinflated lungs with flattened diaphragms
A 25-year-old patient with atopic asthma has airway inflammation dominated by T-helper 2 (Th2) lymphocytes. Which of the following correctly matches a Th2 cytokine with its primary effect in asthma pathophysiology?
A) IL-4 → recruits eosinophils to the airway
B) IL-5 → promotes IgE class switching
C) IL-13 → contributes to goblet cell hyperplasia and mucus production
D) IL-17 → enhances mast cell degranulation
E) TNF-alpha → drives airway eosinophilia
C) IL-13 → contributes to goblet cell hyperplasia and mucus production
IL-4: drives B-cell class switching to IgE
IL-5: recruits and activates eosinophils
IL-13: stimulates goblet cell hyperplasia, mucus overproduction, and contributes to airway hyperreactivity
Fractional exhaled nitric oxide (FeNO) is increasingly used in asthma diagnosis. Which statement best describes its clinical utility?
A) FeNO levels correlate with neutrophilic airway inflammation
B) FeNO can confirm reversibility of airflow obstruction
C) FeNO reflects eosinophilic airway inflammation and steroid responsiveness
D) FeNO is used to detect structural airway changes
E) FeNO is primarily used to exclude COPD
C) FeNO reflects eosinophilic airway inflammation and steroid responsiveness
A patient with severe allergic asthma continues to have exacerbations despite high-dose inhaled corticosteroids and long-acting bronchodilators. They are started on omalizumab.
What is the primary mechanism of action of this drug?
A) Blocks IL-5 to reduce eosinophil production
B) Prevents IgE from binding to Fc receptors on mast cells and basophils
C) Inhibits leukotriene synthesis in airway macrophages
D) Activates β₂ receptors causing bronchodilation
E) Inhibits phosphodiesterase to increase cAMP
B) Prevents IgE from binding to Fc receptors on mast cells and basophils
A patient with COPD presents with worsening dyspnoea, increased sputum production, and purulent sputum. Which of the following microorganisms is most commonly responsible for bacterial COPD exacerbations?
A) Staphylococcus aureus
B) Haemophilus influenzae
C) Mycoplasma pneumoniae
D) Legionella pneumophila
E) Klebsiella pneumoniae
B) Haemophilus influenzae
Haemophilus influenzae
Streptococcus pneumoniae
Moraxella catarrhalis
A 40-year-old patient with poorly controlled asthma continues to have persistent wheeze and airflow limitation despite maximal therapy. Which of the following is a hallmark feature of chronic airway remodelling in asthma?
A) Smooth muscle contraction
B) Smooth muscle hypertrophy
C) Mucus secretion
D) Acute inflammation
B) Smooth muscle hypertrophy
A 24-year-old patient with intermittent wheeze undergoes spirometry for suspected asthma. Baseline spirometry shows reduced FEV₁ with a low FEV₁/FVC ratio. After administration of an inhaled bronchodilator, which of the following spirometry changes would be most consistent with a diagnosis of asthma?
A) Increase in FEV₁ ≥12% and ≥200 mL from baseline
B) No change in FEV₁ after bronchodilator therapy
C) Progressive reduction in FEV₁ after bronchodilator therapy
D) Reduction in total lung capacity
E) Decrease in diffusion capacity (DLCO)
A) Increase in FEV₁ ≥12% and ≥200 mL from baseline
A 34-year-old patient with severe asthma continues to have frequent exacerbations despite high-dose inhaled corticosteroids and long-acting β₂-agonists. The patient is started on a monoclonal antibody that targets interleukin-5 (IL-5).
What is the primary therapeutic effect of this treatment in asthma?
A) Inhibition of IgE binding to mast cells
B) Reduction of eosinophil maturation and survival
C) Direct relaxation of bronchial smooth muscle
D) Blockade of leukotriene receptors in airway tissue
E) Suppression of prostaglandin synthesis in inflammatory cells
B) Reduction of eosinophil maturation and survival
A patient with long-standing COPD develops progressive lower limb oedema, hepatomegaly, and raised jugular venous pressure. Which complication of COPD best explains these findings?
A) Pulmonary fibrosis
B) Cor pulmonale
C) Pulmonary embolism
D) Bronchiectasis
E) Pleural effusion
B) Cor pulmonale