Respiratory Diseases — MCQs
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A child with a known history of bronchial asthma presents with respiratory distress, a respiratory rate of 48/min, and can speak barely two words. Nebulized salbutamol was administered, after which the child could speak a sentence, but SpO2 fell from 95% to 85%. What is the most likely explanation for this clinical scenario?
In a child with exercise-induced asthma, which of the following is the most appropriate prophylactic treatment?
In a child with exercise-induced asthma, which prophylactic measure is most appropriate?
In an infant with aspiration pneumonitis, which is the most common lung segment to be involved?
A 7-year-old child presents with acute shortness of breath that began while playing sports, characterized by paroxysms of wheezing and coughing. The child is found sitting, leaning forward, using accessory respiratory muscles, and is tachypneic and tachycardic. Auscultation reveals a prolonged expiratory phase with high-pitched wheezes. Which of the following medications will have the fastest onset of action for this acute attack?
A 3-month-old child presents with moderate fever, non-productive cough, and mild dyspnea. After a course of antibiotics, the child showed transient improvement but subsequently developed high fever, productive cough, and increased respiratory distress. Chest X-ray reveals hyperlucency, and Pulmonary Function Tests (PFTs) show an obstructive pattern. What is the most probable diagnosis?
Which of the following drugs are used in the management of acute severe asthma?
A 12-year-old boy presents with intermittent shortness of breath over the past 6 months. He is not on any medications and has no significant family history. Vitals are within normal limits and lungs are clear to auscultation. Lung function tests reveal a FEV1/FVC ratio of 82%. Which of the following would be most helpful in excluding a diagnosis of asthma in this patient?
A 12-year-old girl with leukemia develops a lower respiratory tract infection with hemoptysis that is shown to be due to right-sided bronchiectasis. In addition to treatment for the underlying leukemia, what management should this patient receive?
When can one diagnose acute respiratory distress in a newborn?
Respiratory Diseases Indian Medical PG Practice Questions and MCQs
Question 131: A child with a known history of bronchial asthma presents with respiratory distress, a respiratory rate of 48/min, and can speak barely two words. Nebulized salbutamol was administered, after which the child could speak a sentence, but SpO2 fell from 95% to 85%. What is the most likely explanation for this clinical scenario?
- A. Ventilation-perfusion mismatch due to increased dead space ventilation (Correct Answer)
- B. Intra-thoracic shunting
- C. Adverse effect of salbutamol
- D. Faulty pulse oximeter reading
Explanation: **Explanation:** This clinical scenario describes a classic paradoxical phenomenon seen during the treatment of acute severe asthma. **1. Why Option A is Correct:** The primary mechanism for the drop in SpO2 after salbutamol administration is **Ventilation-Perfusion (V/Q) mismatch**. In acute asthma, there is intense bronchoconstriction. The body compensates by causing **hypoxic pulmonary vasoconstriction**—shunting blood away from poorly ventilated alveoli to better-ventilated ones to maintain oxygenation. Salbutamol is a potent **vasodilator**. When administered, it causes vasodilation in the pulmonary vasculature *before* it can fully achieve bronchodilation in the most obstructed small airways. This overrides the compensatory vasoconstriction, sending blood flow to "dead space" or poorly ventilated areas. Consequently, blood leaves these areas poorly oxygenated, leading to a transient drop in SpO2 despite clinical improvement in work of breathing. **2. Why Other Options are Incorrect:** * **Option B:** Intra-thoracic shunting typically refers to structural defects (like cyanotic heart disease) and is not the physiological mechanism behind asthma-related desaturation. * **Option C:** While this is a physiological response to the drug, "Adverse effect" is a vague clinical term. V/Q mismatch is the specific *pathophysiological* explanation required for the exam. * **Option D:** While possible in practice, in a standardized exam, the clinical improvement (speaking in sentences) versus the drop in SpO2 is a classic "textbook" trigger for the V/Q mismatch concept. **High-Yield Clinical Pearls for NEET-PG:** * **The "Salbutamol Paradox":** Always monitor SpO2 after the first few doses of nebulization; a 2-5% drop is common and usually transient. * **Management:** This desaturation is easily corrected by providing **supplemental oxygen** alongside nebulization. * **Silent Chest:** Remember that a "silent chest" in asthma is a pre-terminal sign indicating insufficient air movement to even produce a wheeze.
Question 132: In a child with exercise-induced asthma, which of the following is the most appropriate prophylactic treatment?
- A. Prophylaxis with inhaled corticosteroids
- B. Prophylaxis with a short-acting beta-agonist taken just before exercise
- C. Prophylaxis with montelukast (Correct Answer)
- D. Breathing exercises
Explanation: **Explanation:** **Why Montelukast is the Correct Answer:** Exercise-induced bronchoconstriction (EIB) is primarily mediated by the release of **leukotrienes** and mast cell degranulation triggered by the inhalation of cool, dry air. **Montelukast**, a Leukotriene Receptor Antagonist (LTRA), is highly effective for long-term prophylaxis in children with exercise-induced asthma. It provides a sustained protective effect (up to 24 hours) and, unlike beta-agonists, does not lead to the development of tachyphylaxis (tolerance) with daily use. In the context of pediatric management, it is often preferred for its oral administration and systemic efficacy in preventing exercise-related symptoms. **Analysis of Incorrect Options:** * **Option A (Inhaled Corticosteroids):** While ICS are the gold standard for *chronic persistent asthma*, they are not the specific first-line choice for isolated exercise-induced symptoms unless the patient has underlying daily asthma. * **Option B (Short-acting Beta-agonists - SABA):** SABAs (like Salbutamol) are excellent for *immediate* pre-exercise prevention (taken 15–30 minutes before). However, frequent use leads to **tachyphylaxis**, reducing their duration of action and effectiveness over time. * **Option D (Breathing exercises):** While helpful as an adjunct therapy to improve lung capacity, they cannot prevent the biochemical inflammatory cascade that causes EIB. **NEET-PG High-Yield Pearls:** * **Diagnosis:** EIB is diagnosed by a **≥10-15% drop in FEV1** after a standardized exercise challenge. * **Drug of Choice for Acute Prevention:** SABA is the most effective for *immediate* protection, but **Montelukast** is the preferred *prophylactic* agent for long-term control in children to avoid tolerance. * **Cromolyn Sodium:** Another option for EIB (stabilizes mast cells), but less commonly used now due to the superior efficacy of LTRAs and SABAs.
Question 133: In a child with exercise-induced asthma, which prophylactic measure is most appropriate?
- A. Prophylaxis with steroids
- B. Prophylaxis with mast cell stabilizers (Correct Answer)
- C. Prophylaxis with theophylline
- D. Breathing exercises
Explanation: **Explanation:** **Exercise-Induced Bronchoconstriction (EIB)** occurs due to the loss of heat and moisture from the airways during rapid breathing, leading to mast cell degranulation and the release of inflammatory mediators like histamine and leukotrienes. **Why Option B is Correct:** **Mast cell stabilizers** (e.g., Sodium Cromoglycate or Nedocromil) are the classic prophylactic agents for EIB. They work by stabilizing the mast cell membrane, preventing the release of bronchoconstrictive mediators triggered by exercise. When administered 10–20 minutes before physical activity, they effectively prevent symptoms without the systemic side effects of other drugs. **Why Other Options are Incorrect:** * **Option A (Steroids):** While Inhaled Corticosteroids (ICS) are the mainstay for *chronic* persistent asthma, they are not used as immediate "prophylaxis" right before exercise because they do not provide acute protection against EIB. * **Option C (Theophylline):** This is a weak bronchodilator with a narrow therapeutic index and significant side effects. It is not a first-line or preferred agent for exercise prophylaxis. * **Option D (Breathing exercises):** While helpful for general lung health, they cannot prevent the biochemical and physiological trigger of mast cell degranulation caused by exercise. **NEET-PG High-Yield Pearls:** * **Drug of Choice (DOC):** Short-Acting Beta-Agonists (**SABA**, e.g., Salbutamol) are currently considered the most effective first-line prophylaxis for EIB when used 5–15 minutes before exercise. * **Alternative/Classic Answer:** If SABA is not an option, **Mast Cell Stabilizers** are the preferred answer in traditional exam patterns. * **Non-Pharmacological Tip:** A thorough warm-up period and wearing a mask in cold weather can reduce the severity of EIB. * **Montelukast (LTRA):** Can also be used for EIB prophylaxis, especially in patients who do not want to use inhalers.
Question 134: In an infant with aspiration pneumonitis, which is the most common lung segment to be involved?
- A. Left apical segment
- B. Right apical segment (Correct Answer)
- C. Right middle segment
- D. Right basal segment
Explanation: **Explanation:** The localization of aspiration pneumonitis is primarily determined by the **anatomical orientation of the bronchi** and the **position of the patient** during the aspiration event. **Why the Right Apical Segment is correct:** In infants, aspiration most commonly occurs while they are in a **supine (lying flat)** position. Due to the effects of gravity, aspirated contents follow the most dependent bronchi. In the supine position, the **posterior segment of the right upper lobe** (often referred to generally as the apical region in simplified exam contexts) and the **superior segments of the lower lobes** are the most dependent areas. Furthermore, the right main bronchus is shorter, wider, and more vertical than the left, making the right lung the most frequent site for aspiration. **Analysis of Incorrect Options:** * **Left apical segment:** The left main bronchus is more horizontal and narrower due to the position of the heart, making it less likely for aspirated material to enter the left side compared to the right. * **Right middle segment:** This area is more commonly involved in "Middle Lobe Syndrome" (chronic compression by lymph nodes) rather than acute aspiration in a supine infant. * **Right basal segment:** These segments are the most common site for aspiration in individuals who are **upright or standing** at the time of the event. **High-Yield Clinical Pearls for NEET-PG:** * **Supine Position:** Most common site is the **Posterior segment of the Right Upper Lobe** (followed by the superior segment of the right lower lobe). * **Upright Position:** Most common site is the **Posterior basal segment of the Right Lower Lobe**. * **Lateral Position (Right side):** Most common site is the **Posterior segment of the Right Upper Lobe**. * **Mendelson Syndrome:** A specific type of chemical pneumonitis caused by the aspiration of acidic gastric contents (pH <2.5), often during anesthesia.
Question 135: A 7-year-old child presents with acute shortness of breath that began while playing sports, characterized by paroxysms of wheezing and coughing. The child is found sitting, leaning forward, using accessory respiratory muscles, and is tachypneic and tachycardic. Auscultation reveals a prolonged expiratory phase with high-pitched wheezes. Which of the following medications will have the fastest onset of action for this acute attack?
- A. Albuterol inhalation (Correct Answer)
- B. Beclomethasone inhalation
- C. Ephedrine oral
- D. Salmeterol inhalation
Explanation: **Explanation:** The clinical presentation of acute shortness of breath, wheezing, and use of accessory muscles in a 7-year-old child is classic for an **acute asthma exacerbation**. **1. Why Albuterol is correct:** Albuterol (Salbutamol) is a **Short-Acting Beta-2 Agonist (SABA)**. It is the "gold standard" for acute bronchospasm because it acts directly on the beta-2 receptors of the bronchial smooth muscle, leading to rapid relaxation and bronchodilation. When administered via inhalation (MDI with spacer or nebulization), it has an onset of action within **5 to 15 minutes**, making it the fastest-acting rescue medication among the choices. **2. Why the other options are incorrect:** * **Beclomethasone (B):** This is an Inhaled Corticosteroid (ICS). While essential for long-term control of airway inflammation, its effects take hours to days to manifest. It has no role in the immediate reversal of acute bronchoconstriction. * **Ephedrine oral (C):** Oral medications have a slower onset due to first-pass metabolism and systemic absorption. Furthermore, ephedrine is a non-selective sympathomimetic with significant cardiovascular side effects and is not used in modern asthma management. * **Salmeterol (D):** This is a Long-Acting Beta-2 Agonist (LABA). While it is a potent bronchodilator, it has a slow onset of action (15–30 minutes) and is strictly used for maintenance therapy, never as a monotherapy for acute attacks. **Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC)** for acute asthma: Inhaled SABA (Albuterol/Salbutamol). * **Silent Chest:** A dangerous clinical sign in severe asthma where airflow is so restricted that wheezing disappears; it indicates impending respiratory failure. * **Pulsus Paradoxus:** A drop in systolic BP >10 mmHg during inspiration, indicating severe airway obstruction. * **Ipratropium Bromide:** Often added to Albuterol in the ER for synergistic effects in moderate-to-severe exacerbations.
Question 136: A 3-month-old child presents with moderate fever, non-productive cough, and mild dyspnea. After a course of antibiotics, the child showed transient improvement but subsequently developed high fever, productive cough, and increased respiratory distress. Chest X-ray reveals hyperlucency, and Pulmonary Function Tests (PFTs) show an obstructive pattern. What is the most probable diagnosis?
- A. Alveolar microlithiasis
- B. Post-viral syndrome
- C. Follicular bronchitis
- D. Bronchiolitis obliterans (Correct Answer)
Explanation: **Explanation:** The clinical presentation describes a classic biphasic course of **Bronchiolitis Obliterans (BO)**. BO is a chronic obstructive lung disease resulting from an insult to the lower respiratory tract (most commonly post-infectious following Adenovirus or Mycoplasma). 1. **Why it is correct:** The initial phase involves an acute respiratory infection (fever, cough). After a period of relative improvement, the child develops progressive respiratory distress due to fibrotic narrowing and occlusion of the small airways (bronchioles). The characteristic **hyperlucency** on X-ray represents air trapping, and PFTs confirm a **fixed obstructive pattern** that does not respond to bronchodilators. 2. **Why incorrect options are wrong:** * **Alveolar microlithiasis:** A rare genetic condition characterized by calcium phosphate deposits in alveoli. X-ray shows a "sandstorm" appearance (diffuse fine opacities), not hyperlucency. * **Post-viral syndrome:** This is a broad term for lingering symptoms (like a cough) after a virus. It does not typically present with high fever, severe distress, or fixed obstructive PFTs. * **Follicular bronchitis:** Usually associated with immunodeficiency or connective tissue disorders; it presents with peribronchial nodules on CT rather than diffuse hyperlucency. **NEET-PG High-Yield Pearls:** * **Most common cause:** Adenovirus (Serotypes 3, 7, 21). * **Radiology:** Look for the **"Mosaic Perfusion"** pattern on HRCT (areas of air trapping/hypoperfusion mixed with normal lung). * **Key differentiator:** Unlike asthma, the obstruction in BO is **non-reversible** with bronchodilators. * **Management:** Primarily supportive; steroids may be used in the early inflammatory phase, but the damage is often permanent.
Question 137: Which of the following drugs are used in the management of acute severe asthma?
- A. Epinephrine
- B. Ipratropium
- C. Terbutaline
- D. All of the above (Correct Answer)
Explanation: **Explanation:** The management of acute severe asthma (status asthmaticus) in children focuses on rapid reversal of airflow obstruction and correction of hypoxemia. **1. Why "All of the above" is correct:** * **Ipratropium Bromide:** This is an anticholinergic agent. When added to inhaled SABA (Short-Acting Beta-Agonists) like Salbutamol, it provides a synergistic effect, significantly reducing hospitalization rates in children with severe exacerbations. * **Epinephrine (Adrenaline):** While inhaled SABAs are first-line, subcutaneous or intramuscular Epinephrine is indicated in patients with severe respiratory distress who are unable to move enough air to inhale aerosols effectively, or when inhaled therapy is unavailable. * **Terbutaline:** This is a parenteral SABA. It can be administered subcutaneously or as an intravenous infusion in refractory cases of acute severe asthma that do not respond to initial aggressive nebulization. **2. Clinical Pearls for NEET-PG:** * **First-line treatment:** Inhaled SABA (Salbutamol) via MDI with spacer or nebulizer, plus systemic corticosteroids (Prednisolone/Dexamethasone). * **Magnesium Sulfate:** IV Magnesium sulfate is a high-yield "next step" for patients not responding to initial therapy; it acts as a potent bronchodilator by inhibiting calcium influx into smooth muscles. * **Aminophylline:** Its use has declined due to a narrow therapeutic index and side effects (arrhythmias, seizures), but it remains a rescue option in ICU settings. * **Oxygen Target:** Maintain SpO2 between 94-98% in children. **Summary:** All three drugs (Epinephrine, Ipratropium, and Terbutaline) are recognized components of the emergency pharmacotherapy toolkit for pediatric acute severe asthma depending on the severity and route of administration required.
Question 138: A 12-year-old boy presents with intermittent shortness of breath over the past 6 months. He is not on any medications and has no significant family history. Vitals are within normal limits and lungs are clear to auscultation. Lung function tests reveal a FEV1/FVC ratio of 82%. Which of the following would be most helpful in excluding a diagnosis of asthma in this patient?
- A. Absence of peripheral blood eosinophilia
- B. Negative allergy skin tests
- C. Negative methacholine challenge (Correct Answer)
- D. Normal total serum IgE level
Explanation: ### Explanation **Correct Answer: C. Negative methacholine challenge** The diagnosis of asthma is based on the demonstration of **reversible airway obstruction**. In this patient, the FEV1/FVC ratio is 82% (normal is typically >75-80% in children), indicating no active obstruction at the time of testing. When a patient has suggestive symptoms but normal spirometry, a **Bronchial Provocation Test** (e.g., Methacholine Challenge) is indicated. Methacholine is a cholinergic agonist that induces bronchoconstriction. A **negative result** (failure to cause a 20% drop in FEV1 at standard doses) has a very high **Negative Predictive Value (NPV)**. Therefore, it is the most helpful tool to **exclude** asthma. If the test is negative, the diagnosis of asthma is highly unlikely. **Why other options are incorrect:** * **A & D (Eosinophilia and IgE):** While asthma is often associated with atopy (Type I Hypersensitivity), many patients have "intrinsic" asthma or non-atopic phenotypes. Normal eosinophil counts and IgE levels do not rule out the disease. * **B (Allergy Skin Tests):** These identify specific triggers (sensitization) but are not diagnostic of asthma itself. Many asymptomatic individuals have positive skin tests, and many asthmatics have negative ones. --- ### High-Yield Clinical Pearls for NEET-PG: * **Gold Standard for Diagnosis:** Spirometry showing reversibility (increase in FEV1 ≥12% and ≥200 mL after bronchodilator inhalation). * **Methacholine Challenge:** Used when spirometry is normal. It is highly sensitive but lacks specificity (can be positive in allergic rhinitis or COPD). * **FEV1/FVC Ratio:** In obstructive diseases like asthma, both FEV1 and FVC decrease, but FEV1 decreases more, leading to a **decreased ratio (<0.75-0.80)**. * **Step-up Therapy:** If a patient is symptomatic on SABA alone, the next step is adding a Low-dose Inhaled Corticosteroid (ICS).
Question 139: A 12-year-old girl with leukemia develops a lower respiratory tract infection with hemoptysis that is shown to be due to right-sided bronchiectasis. In addition to treatment for the underlying leukemia, what management should this patient receive?
- A. Right pneumonectomy
- B. Selective antibiotics, physiotherapy, and bronchodilator therapy (Correct Answer)
- C. Tracheostomy
- D. Cough-suppressant medication
Explanation: ### Explanation **Concept Overview:** Bronchiectasis is a chronic condition characterized by permanent, abnormal dilation of the bronchi due to a cycle of inflammation and infection. In a child with leukemia, immunosuppression often leads to recurrent or severe lower respiratory tract infections, which can damage the airway wall. The primary goal of management is to break the cycle of infection and improve airway clearance. **Why Option B is Correct:** The standard of care for bronchiectasis is **conservative medical management**. 1. **Selective Antibiotics:** Targeted to treat acute exacerbations and reduce the microbial load (often *Pseudomonas* or *H. influenzae*). 2. **Physiotherapy (Chest PT):** Postural drainage and percussion are vital to clear the stagnant, thick mucus that predisposes the patient to further infection. 3. **Bronchodilators:** These help reverse any associated airway hyperreactivity and improve the efficacy of chest physiotherapy. **Why Other Options are Incorrect:** * **Option A (Pneumonectomy):** Surgery is a last resort. It is only considered in localized disease that is refractory to medical management or in cases of life-threatening hemoptysis. In a leukemic patient, the surgical risk is high due to cytopenias. * **Option C (Tracheostomy):** This is indicated for upper airway obstruction or long-term mechanical ventilation, neither of which is the primary issue in localized bronchiectasis. * **Option D (Cough Suppressants):** These are **contraindicated**. Coughing is a protective mechanism required to clear infected secretions. Suppressing it leads to mucus plugging and worsening infection. **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** High-Resolution CT (HRCT) scan of the chest (shows "Signet ring sign"). * **Most Common Cause (Global):** Post-infectious (e.g., following Measles, Pertussis, or Tuberculosis). * **Kartagener Syndrome:** A classic triad of Bronchiectasis, Situs Inversus, and Sinusitis (Primary Ciliary Dyskinesia). * **Management Goal:** "Toilet of the Bronchi" (aggressive airway clearance).
Question 140: When can one diagnose acute respiratory distress in a newborn?
- A. Within 7 days of known clinical insult
- B. Respiratory failure not fully explained by cardiac failure or fluid overload
- C. Left ventricular dysfunction
- D. All of the above (Correct Answer)
Explanation: This question refers to the diagnostic criteria for **Neonatal Acute Respiratory Distress Syndrome (NARDS)**, which were standardized by the **Montreux Definition (2017)** to distinguish it from other neonatal lung pathologies like RDS (Surfactant Deficiency) or TTN. ### **Explanation of Options** * **Option A (Timing):** Acute onset is defined as occurring within **7 days** of a known or suspected clinical insult (e.g., sepsis, meconium aspiration, pneumonia). This timeline is consistent with the Berlin criteria used in adults and pediatrics. * **Option B (Exclusion of Hydrostatic Edema):** A core requirement for diagnosing ARDS is that the respiratory failure and pulmonary edema must **not be fully explained** by cardiac failure or fluid overload. This ensures the pathology is due to increased alveolar-capillary permeability (inflammatory) rather than high pressure (hydrostatic). * **Option C (Cardiac Assessment):** To satisfy Option B, clinicians must rule out significant **Left Ventricular (LV) dysfunction**. In neonates, this is typically done via echocardiography to ensure the pulmonary edema is "non-cardiogenic." Since all three criteria—acute timing, exclusion of fluid overload, and absence of primary LV dysfunction—are mandatory components of the Montreux Definition, **Option D (All of the above)** is the correct answer. ### **NEET-PG High-Yield Pearls** * **Montreux Definition:** The first international consensus for NARDS. * **Oxygenation Index (OI):** Unlike adults (who use P/F ratio), neonatal ARDS severity is often graded using the **Oxygenation Index (OI)**. * *Formula:* $OI = \frac{FiO_2 \times \text{Mean Airway Pressure (MAP)} \times 100}{PaO_2}$ * **Radiology:** Diagnosis requires bilateral opacities on chest X-ray that are not fully explained by effusions, collapse, or nodules. * **Key Trigger:** Sepsis is the most common extra-pulmonary cause of NARDS.
Practice by Chapter
Upper Respiratory Tract Infections
Practice Questions
Lower Respiratory Tract Infections
Practice Questions
Asthma Management
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Cystic Fibrosis
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Bronchiolitis
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Foreign Body Aspiration
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Sleep-Disordered Breathing
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Congenital Lung Malformations
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Pleural Diseases
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Tuberculosis in Children
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Chronic Lung Disease in Premature Infants
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Pulmonary Function Testing
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