Respiratory Diseases — MCQs
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An infant presents with fever and persistent cough. Physical examination and a chest X-ray suggest pneumonia. Which of the following is the most likely cause of this infection?
A 3-year-old child with cystic fibrosis presents with weight loss, irritability, and a chronic productive cough. On physical exam, he is febrile and lung exam reveals intercostal retractions, wheezing, rhonchi, and rales. Chest x-ray demonstrates patchy infiltrates and atelectasis. Gram's stain of the sputum reveals slightly curved, motile gram-negative rods that grow aerobically. Which of the following diseases is most commonly caused by the microorganism responsible for this child's pneumonia?
A child experiences nocturnal asthma attacks twice a week and daytime attacks three or more times per week. According to asthma severity classification guidelines, how would this condition be categorized?
A 3-year-old boy presented with recurrent attacks of pneumonia and otitis media since his first birthday. Diagnosis is X-linked agammaglobulinemia. What is the most likely offending organism?
A 13-year-old known asthmatic presents with severe wheezing and a respiratory rate of 40. Her pulse rate is 120. What is the next best step in management of this patient?
What is the most common etiological agent for acute bronchiolitis in infancy?
Which of the following conditions is characterized by hyperinflation of the lungs on a chest X-ray?
What is the most common mode of treatment for a 1-year-old child with asthma?
A previously healthy 2-year-old black child has developed a chronic cough during the previous 6 weeks. He has been seen in different emergency rooms on two occasions during this period and has been placed on antibiotics for pneumonia. Upon auscultation, you hear normal breath sounds on the left. On the right side, you hear decreased air movement during inspiration but no air movement upon expiration. Inspiratory and expiratory radiographs of the chest are shown. Which of the following is the most appropriate next step in making the diagnosis in this patient?
A 7.5-month-old child presents with cough and mild stridor, initially treated with oral antibiotics showing improvement. Subsequently, the child developed wheeze, productive cough, and mild fever. Radiography reveals hyperlucency, and pulmonary function tests demonstrate an obstructive pattern. What is the most probable diagnosis?
Respiratory Diseases Indian Medical PG Practice Questions and MCQs
Question 11: An infant presents with fever and persistent cough. Physical examination and a chest X-ray suggest pneumonia. Which of the following is the most likely cause of this infection?
- A. Rotavirus
- B. Adenovirus
- C. Coxsackievirus
- D. Respiratory syncytial virus (Correct Answer)
Explanation: **Explanation:** **Why Respiratory Syncytial Virus (RSV) is the correct answer:** Respiratory Syncytial Virus (RSV) is the most common cause of lower respiratory tract infections (LRTIs), including both **bronchiolitis and pneumonia**, in infants and young children worldwide. In the pediatric age group, viruses are responsible for the majority of community-acquired pneumonia cases, and RSV consistently tops the list. It typically presents with fever, cough, tachypnea, and wheezing. On a chest X-ray, viral pneumonia often manifests as bilateral interstitial infiltrates or hyperinflation. **Analysis of Incorrect Options:** * **Rotavirus (A):** This is the leading cause of severe **gastroenteritis** (diarrhea and vomiting) in infants; it does not cause primary respiratory infections. * **Adenovirus (B):** While Adenovirus can cause severe necrotizing pneumonia and conjunctivitis, it is less frequent than RSV. It is more commonly associated with pharyngoconjunctival fever. * **Coxsackievirus (C):** This virus is primarily associated with **Herpangina** and **Hand-Foot-and-Mouth Disease** (Group A) or myocarditis and pleurodynia (Group B), rather than typical pneumonia. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Pneumonia in infants:** RSV (Viral), followed by *Streptococcus pneumoniae* (Bacterial). * **Most common cause of Bronchiolitis:** RSV. * **Diagnosis:** Rapid antigen detection tests or PCR from nasopharyngeal Swabs. * **Treatment:** Primarily supportive (oxygen, hydration). **Ribavirin** is the only antiviral approved but is rarely used. **Palivizumab** (monoclonal antibody) is used for prophylaxis in high-risk preterm infants. * **X-ray finding:** Viral pneumonia usually shows diffuse, patchy, interstitial patterns, whereas bacterial pneumonia often shows lobar consolidation.
Question 12: A 3-year-old child with cystic fibrosis presents with weight loss, irritability, and a chronic productive cough. On physical exam, he is febrile and lung exam reveals intercostal retractions, wheezing, rhonchi, and rales. Chest x-ray demonstrates patchy infiltrates and atelectasis. Gram's stain of the sputum reveals slightly curved, motile gram-negative rods that grow aerobically. Which of the following diseases is most commonly caused by the microorganism responsible for this child's pneumonia?
- A. Croup
- B. Epiglottitis
- C. Meningitis
- D. Otitis externa (Correct Answer)
Explanation: **Explanation:** The clinical presentation of a child with **Cystic Fibrosis (CF)** presenting with pneumonia, combined with the microbiological description of **slightly curved, motile, aerobic Gram-negative rods**, points directly to ***Pseudomonas aeruginosa***. While *S. aureus* is the most common cause of pneumonia in younger CF patients, *Pseudomonas* becomes the predominant pathogen as they age and is a major cause of morbidity. **1. Why Otitis Externa is Correct:** *Pseudomonas aeruginosa* is the most common causative agent of **Otitis externa** (Swimmer’s ear). In diabetic or immunocompromised patients, it can progress to Malignant Otitis Externa. Identifying the organism's characteristics (Gram-negative, oxidase-positive, aerobic, motile) is key to linking it to its associated clinical conditions. **2. Why Other Options are Incorrect:** * **A. Croup (Laryngotracheobronchitis):** Most commonly caused by **Parainfluenza virus type 1**. * **B. Epiglottitis:** Classically caused by ***Haemophilus influenzae* type b (Hib)**, though incidence has decreased due to vaccination. * **C. Meningitis:** In children, common causes include *S. pneumoniae*, *N. meningitidis*, and *H. influenzae*. *Pseudomonas* is an uncommon cause of meningitis, usually seen only after neurosurgical procedures. **Clinical Pearls for NEET-PG:** * **CF Microbiology:** Early childhood = *S. aureus*; Adolescence/Adulthood = *P. aeruginosa*. * **Pseudomonas Features:** Produces **Pyocyanin** (blue-green pigment) and **Phoverdin**; has a fruity, grape-like odor. * **Ecthyma Gangrenosum:** A characteristic skin lesion (black necrotic eschar) caused by *Pseudomonas* septicemia in neutropenic patients. * **Drug of Choice:** Antipseudomonal penicillins (Piperacillin-Tazobactam), Ceftazidime, Cefepime, or Carbapenems.
Question 13: A child experiences nocturnal asthma attacks twice a week and daytime attacks three or more times per week. According to asthma severity classification guidelines, how would this condition be categorized?
- A. Severe persistent asthma
- B. Moderate persistent asthma (Correct Answer)
- C. Mild intermittent asthma
- D. Mild persistent asthma
Explanation: To classify asthma severity in pediatric patients, we evaluate two main domains: **Daytime symptoms** and **Nocturnal (nighttime) awakenings**. ### Why "Moderate Persistent" is Correct According to the GINA and NHLBI guidelines, **Moderate Persistent Asthma** is characterized by: * **Daytime symptoms:** Daily (or >2 times per week, but not throughout the entire day). * **Nighttime awakenings:** More than once a week (e.g., 2 times/week), but not nightly. In this case, the child has daytime attacks ≥3 times/week and nocturnal attacks 2 times/week, which fits the criteria for Moderate Persistent. ### Why Other Options are Incorrect * **Mild Intermittent:** Symptoms occur ≤2 days/week and nocturnal awakenings ≤2 times/month. This patient exceeds both. * **Mild Persistent:** Symptoms occur >2 days/week (but not daily) and nocturnal awakenings occur 3–4 times/month. This patient’s nocturnal frequency (8 times/month) is too high for this category. * **Severe Persistent:** Symptoms occur throughout the day and nocturnal awakenings occur often (7 times/week). This patient’s symptoms are not yet continuous. ### NEET-PG High-Yield Pearls * **Step-up Therapy:** Moderate persistent asthma typically requires **Step 3 treatment**: Low-dose ICS + LABA or Medium-dose ICS. * **Rule of Two:** If a patient uses a rescue inhaler (SABA) >2 days/week, has >2 nocturnal awakenings/month, or >2 refills/year, their asthma is not well-controlled and requires maintenance therapy. * **PFT Findings:** In Moderate Persistent asthma, the FEV1 is typically between 60% and 80% of predicted.
Question 14: A 3-year-old boy presented with recurrent attacks of pneumonia and otitis media since his first birthday. Diagnosis is X-linked agammaglobulinemia. What is the most likely offending organism?
- A. CMV
- B. Mycoplasma
- C. Pneumocystis jiroveci
- D. Streptococcus pneumoniae (Correct Answer)
Explanation: **Explanation:** **X-linked Agammaglobulinemia (Bruton’s Disease)** is a primary immunodeficiency caused by a mutation in the **BTK gene**, leading to a failure of B-cell maturation. This results in a profound deficiency of all immunoglobulin classes (IgG, IgA, IgM). **1. Why Streptococcus pneumoniae is correct:** Antibodies (immunoglobulins) are essential for the **opsonization** and clearance of **encapsulated bacteria**. Patients with B-cell defects are highly susceptible to recurrent infections with pyogenic encapsulated organisms. *Streptococcus pneumoniae* is the most common cause of pneumonia and otitis media in these patients. Other common pathogens include *Haemophilus influenzae* type b and *Staphylococcus aureus*. **2. Why incorrect options are wrong:** * **CMV (Cytomegalovirus):** This is a viral pathogen. Defense against viruses primarily relies on **T-cell (cell-mediated) immunity**. CMV is more common in SCID or HIV, not isolated B-cell defects. * **Mycoplasma:** While *Mycoplasma* can cause chronic lung disease in XLA, it is less common than pyogenic bacteria for acute recurrent pneumonia. * **Pneumocystis jiroveci:** This is an opportunistic fungus characteristic of **T-cell deficiencies** (e.g., SCID, HIV). In XLA, T-cell function remains intact, providing protection against *P. jiroveci*. **Clinical Pearls for NEET-PG:** * **Timing:** Symptoms typically start after **6 months of age**, once maternal IgG wanes. * **Physical Exam:** Characteristically shows **absent or hypoplastic tonsils** and lymph nodes (due to lack of germinal centers). * **Diagnosis:** Flow cytometry shows **absent B-cells (CD19+/CD20+)** with normal T-cell counts. * **Associated Risk:** These patients are also susceptible to **Enteroviruses** (e.g., Echovirus, Poliovirus), which can cause chronic meningoencephalitis. Live viral vaccines (like OPV) are contraindicated.
Question 15: A 13-year-old known asthmatic presents with severe wheezing and a respiratory rate of 40. Her pulse rate is 120. What is the next best step in management of this patient?
- A. Oxygen and nebulized salbutamol (Correct Answer)
- B. Oxygen and metered dose inhaler of salmeterol
- C. Oxygen and intravenous aminophylline
- D. Oxygen and intravenous magnesium sulfate
Explanation: ### Explanation **Correct Option: A (Oxygen and nebulized salbutamol)** The patient is presenting with an **Acute Exacerbation of Asthma**, characterized by tachypnea (RR 40) and tachycardia (PR 120). According to GINA (Global Initiative for Asthma) and IAP guidelines, the first-line management for acute asthma is ensuring adequate oxygenation (target SpO2 94-98%) and rapid bronchodilation. **Short-Acting Beta-2 Agonists (SABA)** like **Salbutamol**, delivered via nebulization or MDI with a spacer, are the gold standard for immediate relief of airway obstruction. **Why other options are incorrect:** * **Option B:** Salmeterol is a **Long-Acting Beta-2 Agonist (LABA)**. LABAs have a slow onset of action and are used for maintenance therapy, not for emergency rescue. * **Option C:** IV Aminophylline is no longer recommended as a first-line agent due to its narrow therapeutic index and significant side effects (arrhythmias, seizures) compared to safer inhaled therapies. * **Option D:** IV Magnesium Sulfate is considered an **add-on therapy** for severe or life-threatening exacerbations that do not respond to initial treatment with SABA and systemic corticosteroids. It is not the "next best step" before trying SABA. **High-Yield Clinical Pearls for NEET-PG:** * **First-line treatment:** SABA (Salbutamol) + Ipratropium bromide (in severe cases) + Systemic Corticosteroids. * **Silent Chest:** A grave clinical sign indicating minimal air movement; it is a medical emergency requiring immediate escalation. * **Pulsus Paradoxus:** A drop in systolic BP >10 mmHg during inspiration, often seen in severe asthma. * **Objective assessment:** Peak Expiratory Flow (PEF) <50% of predicted indicates a severe exacerbation.
Question 16: What is the most common etiological agent for acute bronchiolitis in infancy?
- A. Influenza virus
- B. Parainfluenza virus
- C. Rhinovirus
- D. Respiratory syncytial virus (Correct Answer)
Explanation: **Explanation:** **1. Why Respiratory Syncytial Virus (RSV) is Correct:** Acute bronchiolitis is a clinical syndrome characterized by inflammation, edema, and necrosis of the epithelial cells lining the small airways (bronchioles), leading to increased mucus production and bronchospasm. **Respiratory Syncytial Virus (RSV)** is the most common cause, accounting for approximately **50–80%** of all cases. It typically affects infants under 2 years of age, with a peak incidence between 2 and 6 months, often occurring in seasonal outbreaks (winter and early spring). **2. Analysis of Incorrect Options:** * **A. Influenza virus:** While it can cause severe lower respiratory tract infections and pneumonia, it is a less frequent cause of the specific clinical syndrome of bronchiolitis compared to RSV. * **B. Parainfluenza virus:** This is the most common cause of **Croup (Laryngotracheobronchitis)**, characterized by a barking cough and inspiratory stridor, rather than the wheezing seen in bronchiolitis. * **C. Rhinovirus:** This is the leading cause of the common cold (upper respiratory infection). While it is the second most common cause of bronchiolitis, it lags significantly behind RSV in prevalence. **3. High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Characterized by a prodrome of URI symptoms followed by lower respiratory signs: **wheezing**, fine crackles, tachypnea, and chest retractions. * **Diagnosis:** Primarily clinical. Chest X-ray typically shows **hyperinflation** and flattened diaphragm. * **Management:** Mainly supportive (hydration and oxygenation). **Nebulized hypertonic saline** may be used in hospitalized patients. Routine use of bronchodilators, steroids, or antibiotics is **not** recommended. * **Prophylaxis:** **Palivizumab** (a monoclonal antibody against RSV F protein) is indicated for high-risk infants (e.g., extreme prematurity, congenital heart disease).
Question 17: Which of the following conditions is characterized by hyperinflation of the lungs on a chest X-ray?
- A. Congestive Cardiac Failure (CCF)
- B. Congenital lobar emphysema (Correct Answer)
- C. Diaphragmatic hernia
- D. Foreign body aspiration
Explanation: ### Explanation **Correct Answer: B. Congenital lobar emphysema (CLE)** **Why it is correct:** Congenital lobar emphysema is a developmental anomaly characterized by the over-distension and **hyperinflation** of one or more pulmonary lobes (most commonly the left upper lobe). This occurs due to a "check-valve" mechanism, often caused by deficient bronchial cartilage, which allows air to enter during inspiration but prevents it from escaping during expiration. On a chest X-ray, this manifests as a **hyperlucent, hyperinflated lobe** with a mediastinal shift to the opposite side and depression of the ipsilateral diaphragm. **Why the other options are incorrect:** * **A. Congestive Cardiac Failure (CCF):** Typically presents with cardiomegaly, pulmonary venous congestion, Cephalization (upper lobe diversion), and Kerley B lines, rather than focal or generalized hyperinflation. * **C. Diaphragmatic Hernia:** Characterized by the presence of **air-filled bowel loops** in the thoracic cavity and a scaphoid abdomen. The lung on the affected side is usually hypoplastic (shrunken), not hyperinflated. * **D. Foreign Body Aspiration:** While a foreign body *can* cause obstructive emphysema (hyperinflation) if it creates a partial block, it is an **acquired** condition. In the context of neonatal or congenital respiratory distress questions, CLE is the classic "textbook" answer for congenital hyperinflation. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for CLE:** Left Upper Lobe (40-50%) > Right Middle Lobe (30%). * **Management:** Surgical lobectomy is the definitive treatment for symptomatic cases. * **Differential Diagnosis:** CLE can be confused with a tension pneumothorax; however, the presence of **faint bronchovascular markings** within the hyperlucent area in CLE helps distinguish it from the completely devoid-of-markings space in a pneumothorax.
Question 18: What is the most common mode of treatment for a 1-year-old child with asthma?
- A. Inhaled short-acting beta-2 agonist (Correct Answer)
- B. Oral short-acting theophylline
- C. Oral ketotifen
- D. Leukotriene agonist
Explanation: **Explanation:** The management of asthma in children focuses on relieving acute symptoms and controlling chronic inflammation. For a 1-year-old child, the **Inhaled Short-Acting Beta-2 Agonist (SABA)**, such as Salbutamol, is the first-line treatment for acute symptomatic relief (rescue medication). **Why Option A is correct:** Inhaled SABAs are the gold standard for treating acute bronchospasm. In infants and toddlers, these are ideally delivered via a **Metered-Dose Inhaler (MDI) with a spacer and a face mask**. This route ensures rapid onset of action directly at the airways with minimal systemic side effects compared to oral routes. **Why other options are incorrect:** * **B. Oral Theophylline:** This is rarely used in modern pediatrics due to its narrow therapeutic index, the need for blood level monitoring, and significant side effects (tachycardia, seizures). * **C. Oral Ketotifen:** This is an H1-antihistamine and mast cell stabilizer. It has no role in the treatment of acute asthma exacerbations and is generally considered ineffective as a primary controller. * **D. Leukotriene Receptor Antagonists (e.g., Montelukast):** While used as an add-on controller therapy for chronic asthma, they are not the "most common" or first-line treatment for acute relief in a 1-year-old. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Asthma in children <5 years is often termed "Wheeze" or "Reactive Airway Disease" as spirometry is difficult to perform. * **Delivery Device:** For children <4 years, the preferred interface is **MDI + Spacer + Face Mask**. For children >4 years, a mouthpiece is preferred. * **Step-wise approach:** If SABA use is required more than twice a week, the next step is adding an **Inhaled Corticosteroid (ICS)**, which is the most effective long-term controller.
Question 19: A previously healthy 2-year-old black child has developed a chronic cough during the previous 6 weeks. He has been seen in different emergency rooms on two occasions during this period and has been placed on antibiotics for pneumonia. Upon auscultation, you hear normal breath sounds on the left. On the right side, you hear decreased air movement during inspiration but no air movement upon expiration. Inspiratory and expiratory radiographs of the chest are shown. Which of the following is the most appropriate next step in making the diagnosis in this patient?
- A. Measure the patient's sweat chloride.
- B. Consult pediatric surgery for bronchoscopy. (Correct Answer)
- C. Prescribe broad-spectrum oral antibiotics.
- D. Initiate a trial of inhaled b-agonists.
Explanation: ***Consult pediatric surgery for bronchoscopy*** - The **asymmetric breath sounds** with decreased air movement on inspiration and **no air movement on expiration** suggests a **check-valve mechanism** consistent with **foreign body aspiration**. - **Air trapping** visible on expiratory chest radiographs in a **2-year-old toddler** with recurrent unilateral pneumonia strongly indicates **bronchoscopy** is needed for both diagnosis and removal. *Measure the patient's sweat chloride* - **Sweat chloride testing** is used to diagnose **cystic fibrosis**, which typically presents with **bilateral lung involvement** and **failure to thrive**. - The **unilateral findings** and **check-valve mechanism** are not characteristic of cystic fibrosis. *Prescribe broad-spectrum oral antibiotics* - **Antibiotics** have already been tried twice without resolution, indicating this is not a **bacterial pneumonia**. - The **mechanical obstruction** from a foreign body requires **physical removal**, not antimicrobial therapy. *Initiate a trial of inhaled β-agonists* - **β-agonists** are used for **bronchospasm** in conditions like asthma, which typically causes **bilateral wheezing**. - The **unilateral air trapping** and **check-valve pattern** indicate **mechanical obstruction**, not bronchospasm.
Question 20: A 7.5-month-old child presents with cough and mild stridor, initially treated with oral antibiotics showing improvement. Subsequently, the child developed wheeze, productive cough, and mild fever. Radiography reveals hyperlucency, and pulmonary function tests demonstrate an obstructive pattern. What is the most probable diagnosis?
- A. Bronchiolitis obliterans (Correct Answer)
- B. Post-viral syndrome
- C. Pulmonary alveolar microlithiasis
- D. Follicular bronchitis
Explanation: **Explanation:** **Bronchiolitis Obliterans (BO)** is a chronic obstructive lung disease following a severe lower respiratory tract insult (usually viral, like Adenovirus). The clinical hallmark is a **"biphasic" course**: an initial acute episode (fever, cough, stridor) that shows partial improvement, followed by persistent or progressive symptoms of airway obstruction (wheeze, productive cough, and exercise intolerance). * **Why it is correct:** The presence of persistent wheezing and productive cough after an initial infection, combined with **hyperlucency** on X-ray (due to air trapping) and an **obstructive pattern** on PFTs, is classic for BO. The initial "improvement" followed by chronic obstruction is the key diagnostic clue. **Why other options are incorrect:** * **Post-viral syndrome:** This typically presents as a transient hyper-reactive airway (cough/wheeze) that resolves over a few weeks without the permanent obstructive changes or hyperlucency seen in BO. * **Pulmonary alveolar microlithiasis:** A rare genetic disorder characterized by calcium deposits in alveoli. Radiography would show a "sandstorm" appearance (diffuse fine opacities), not hyperlucency. * **Follicular bronchitis:** Usually associated with immunodeficiency or connective tissue disorders; it presents with nodules on CT rather than the classic post-infectious obstructive picture. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Adenovirus (Types 3, 7, and 21) is the most frequent trigger for post-infectious BO. * **Radiology:** Look for the **"Mosaic Perfusion"** pattern on HRCT (areas of air trapping interspersed with normal lung). * **Diagnosis:** Primarily clinical and radiological; lung biopsy is the gold standard but rarely required. * **Management:** Supportive care, bronchodilators, and sometimes pulses of corticosteroids.
Practice by Chapter
Upper Respiratory Tract Infections
Practice Questions
Lower Respiratory Tract Infections
Practice Questions
Asthma Management
Practice Questions
Cystic Fibrosis
Practice Questions
Bronchiolitis
Practice Questions
Foreign Body Aspiration
Practice Questions
Sleep-Disordered Breathing
Practice Questions
Congenital Lung Malformations
Practice Questions
Pleural Diseases
Practice Questions
Tuberculosis in Children
Practice Questions
Chronic Lung Disease in Premature Infants
Practice Questions
Pulmonary Function Testing
Practice Questions
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