Respiratory Diseases — MCQs

A 5-year-old girl presents with recurrent, intermittent episodes of fever and respiratory distress over the past 1.5 years, including cough, wheezing, and dyspnea lasting for 3-4 days. Hemoptysis is present with every episode. She was diagnosed with right lower lobe pneumonia which improved with treatment. On physical examination, the patient is pale and icteric with digital clubbing. Which of the following is the most appropriate next investigation?

Q57Easy

A seven-week-old child presents with cough and a respiratory rate of 48/min. The child is otherwise normal. What is the most likely diagnosis?

Q58Easy

An infant develops cough and fever. Chest X-ray is suggestive of broncho-pneumonia. Which of the following viruses is NOT a common causative agent?

Q59Easy

Which of the following is NOT an indication for admission in a patient with pneumonia?

Q60Medium

A 2-year-old boy presents with a history of sudden onset respiratory difficulty and stridor. On auscultation, there are decreased breath sounds and wheezing on the right side. An X-ray shows a right opaque hemithorax. What is the most likely diagnosis?

Respiratory Diseases Indian Medical PG Practice Questions and MCQs

Question 51: In cystic fibrosis, which is the second most common organism to cause infection?

A. Streptococci
B. Klebsiella
C. Pneumococci
D. Staphylococcus aureus (Correct Answer)

Explanation: **Explanation:** In **Cystic Fibrosis (CF)**, the thick, inspissated mucus in the airways provides a nidus for recurrent bacterial infections. The prevalence of specific pathogens is highly **age-dependent**, which is a frequent focus of NEET-PG questions. * **Staphylococcus aureus (Correct):** It is the **second most common** organism overall and the **most common** organism isolated from the respiratory tract of children and infants with CF. As patients age, its prevalence is eventually surpassed by *Pseudomonas*. * **Pseudomonas aeruginosa:** This is the **most common** organism overall across the entire lifespan of a CF patient and the leading cause of chronic colonization and lung function decline in adults. **Why the other options are incorrect:** * **Streptococci & Pneumococci (A & C):** While *Streptococcus pneumoniae* can cause community-acquired pneumonia in CF patients, it is not a characteristic or predominant pathogen associated with the pathophysiology of CF bronchiectasis. * **Klebsiella (B):** This is a common cause of gram-negative pneumonia in the general population (especially in diabetics or alcoholics) but is not a primary pathogen specific to the CF airway. **High-Yield Clinical Pearls for NEET-PG:** 1. **Age-wise dominance:** * Infancy/Childhood: *Staphylococcus aureus* (Most common). * Adulthood: *Pseudomonas aeruginosa* (Most common). 2. **Burkholderia cepacia:** Its presence is a poor prognostic sign ("Cepacia syndrome") and is often a contraindication for lung transplantation. 3. **Haemophilus influenzae:** Also a common early colonizer in young children with CF. 4. **Treatment:** For *S. aureus*, use Methicillin-sensitive (MSSA) or MRSA-targeted antibiotics; for *Pseudomonas*, inhaled Tobramycin or Colistin is often used.

Question 52: An infant has a positive newborn screening test for cystic fibrosis. What cutoff of sweat chloride concentration confirms cystic fibrosis?

A. Sweat chloride > 30 mEq/L
B. Sweat chloride > 40 mEq/L
C. Sweat chloride > 50 mEq/L
D. Sweat chloride > 60 mEq/L (Correct Answer)

Explanation: **Explanation:** The diagnosis of Cystic Fibrosis (CF) is primarily confirmed using the **Quantitative Pilocarpine Iontophoresis Test (QPIT)**, commonly known as the Sweat Chloride Test. In CF, a defect in the CFTR protein prevents the reabsorption of chloride in the sweat ducts, leading to abnormally high concentrations of salt in the sweat. **1. Why Option D is Correct:** According to the current clinical guidelines (Cystic Fibrosis Foundation), a **sweat chloride concentration of ≥ 60 mmol/L (or mEq/L)** on two separate occasions is considered diagnostic for Cystic Fibrosis in individuals of all ages, including infants identified via newborn screening. **2. Analysis of Incorrect Options:** * **Option A (< 30 mEq/L):** This is considered the **normal** range. CF is highly unlikely at this level. * **Option B & C (30–59 mEq/L):** This range is classified as **Intermediate (Borderline)**. It is not diagnostic of CF but requires further evaluation, such as repeat sweat testing or CFTR genetic mutation analysis (extended sequencing). **3. High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Sweat Chloride Test (QPIT) remains the gold standard for diagnosis. * **Newborn Screening:** Usually involves testing for **Immunoreactive Trypsinogen (IRT)**. If elevated, it is followed by DNA testing or sweat testing. * **False Positives:** Conditions like Adrenal Insufficiency, Ectodermal Dysplasia, Nephrogenic Diabetes Insipidus, and Malnutrition can occasionally cause elevated sweat chloride. * **Genetics:** CF is an Autosomal Recessive disorder; the most common mutation is **ΔF508** on Chromosome 7. * **Clinical Triad:** Chronic sinopulmonary disease, pancreatic insufficiency (steatorrhea), and high sweat chloride levels.

Question 53: Pneumatoceles often develop in children after pneumonia due to which of the following organisms?

A. Klebsiella
B. Streptococcus
C. Staphylococcus aureus (Correct Answer)
D. Haemophilus influenzae

Explanation: ### Explanation **Correct Answer: C. Staphylococcus aureus** **1. Why Staphylococcus aureus is correct:** *Staphylococcus aureus* is the most common cause of **pneumatoceles** (thin-walled, air-filled cysts within the lung parenchyma) in children. The underlying mechanism involves the organism's ability to cause intense inflammation and tissue necrosis. This leads to a **"check-valve" mechanism** in the small airways, where air enters the interstitial space during inspiration but becomes trapped during expiration, causing focal alveolar rupture and cyst formation. These are typically transient and resolve spontaneously but are a hallmark of Staphylococcal pneumonia. **2. Why the other options are incorrect:** * **A. Klebsiella:** While *Klebsiella pneumoniae* causes severe necrotizing pneumonia, it is more commonly associated with **"bulging fissures"** on X-ray and abscess formation, typically in elderly or immunocompromised adults rather than pneumatoceles in children. * **B. Streptococcus:** *Streptococcus pneumoniae* is the most common cause of community-acquired pneumonia in children. It typically presents as lobar consolidation. While it can occasionally cause necrotizing changes, it rarely leads to pneumatocele formation compared to *S. aureus*. * **D. Haemophilus influenzae:** This organism usually causes bronchopneumonia or epiglottitis. Since the introduction of the Hib vaccine, its incidence has significantly decreased, and it is not typically associated with cavitary or cystic lung lesions. **3. Clinical Pearls for NEET-PG:** * **Management:** Most pneumatoceles are asymptomatic and require **conservative management** (observation), as they regress spontaneously over weeks to months. * **Complication:** The most common complication of a pneumatocele is rupture, leading to a **pneumothorax** or tension pneumothorax. * **Other causes:** Apart from *S. aureus*, pneumatoceles can also be seen in *Pneumocystis jirovecii* (especially in HIV patients) and hydrocarbon aspiration. * **Triad of Staphylococcal Pneumonia:** Look for a clinical vignette featuring high fever, rapid progression, and X-ray findings of **pleural effusion/empyema, pneumatocele, and pyopneumothorax.**

Question 54: A 1-month-old infant presents with cough and sneezing, a respiratory rate of 40 per minute, and no chest indrawing. What is the most appropriate management?

A. Urgent referral to hospital
B. Intravenous antibiotics
C. Frequent breastfeeding (Correct Answer)
D. Oral antibiotic syrup

Explanation: This question tests your ability to classify and manage acute respiratory infections (ARI) in young infants based on the **IMNCI (Integrated Management of Neonatal and Childhood Illness)** guidelines. ### **Explanation** According to IMNCI guidelines, a child aged **0–2 months** with a cough and cold is evaluated based on respiratory rate and signs of distress. * **Normal Respiratory Rate:** In an infant <2 months, a rate of **<60 breaths per minute** is considered normal. * **Signs of Severity:** The absence of fast breathing (≥60 bpm), chest indrawing, or "danger signs" (lethargy, convulsions, persistent vomiting, or inability to feed) classifies this case as **"No Pneumonia: Cough or Cold."** For "No Pneumonia," the management is supportive. **Frequent breastfeeding** is the priority to prevent dehydration, provide immunological support, and soothe the throat. Mothers are advised to keep the nose clear and return if symptoms worsen. ### **Why Other Options are Incorrect** * **A & B (Urgent referral/IV antibiotics):** These are indicated for "Very Severe Disease" (e.g., chest indrawing, grunting, or danger signs). This infant is hemodynamically stable with a normal respiratory rate. * **D (Oral antibiotic syrup):** Antibiotics are indicated for "Pneumonia" (fast breathing). Since this infant's rate is 40 bpm (normal), antibiotics are unnecessary and contribute to resistance. ### **High-Yield Clinical Pearls for NEET-PG** * **IMNCI Cut-offs for Fast Breathing:** * <2 months: ≥60 bpm * 2–12 months: ≥50 bpm * 12 months–5 years: ≥40 bpm * **Chest Indrawing:** In infants <2 months, mild chest indrawing is common; only **severe** chest indrawing is a sign of serious illness. * **Key Management:** For simple cough/cold, avoid over-the-counter cough suppressants in infants; focus on hydration and warmth.

Question 55: What is the recommended treatment for chlamydial pneumonia?

A. Erythromycin (Correct Answer)
B. Ceftriaxone
C. Penicillin
D. Sulphonamide

Explanation: **Explanation:** **Chlamydial pneumonia** (caused by *Chlamydia trachomatis*) typically presents in infants aged 1–3 months with a characteristic "staccato cough," tachypnea, and hyperinflation on X-ray, often preceded by neonatal conjunctivitis. **1. Why Erythromycin is Correct:** *Chlamydia trachomatis* is an obligate intracellular bacterium, meaning it lacks a traditional peptidoglycan cell wall. Therefore, it is highly susceptible to **Macrolides**, which inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit. **Erythromycin** (50 mg/kg/day for 14 days) is the traditional drug of choice. It effectively clears the nasopharyngeal carriage and treats the pneumonia. **2. Why the Other Options are Incorrect:** * **Ceftriaxone (B) and Penicillin (C):** These are Beta-lactam antibiotics that act by inhibiting cell wall synthesis. Since *Chlamydia* lacks a typical cell wall, these drugs are entirely ineffective. * **Sulphonamide (D):** While some older texts mention sulfonamides for certain chlamydial infections, they are not the first-line treatment for pneumonia in infants due to the risk of kernicterus and lower efficacy compared to macrolides. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Afebrile illness + Staccato cough + Peripheral eosinophilia (≥400 cells/mm³). * **Association:** About 50% of infants with chlamydial pneumonia have a history of neonatal conjunctivitis (inclusion blennorrhea). * **Alternative:** Azithromycin is increasingly used due to a shorter course and better GI tolerance. * **Caution:** Systemic Erythromycin in infants <2 weeks old is associated with an increased risk of **Infantile Hypertrophic Pyloric Stenosis (IHPS)**; patients should be monitored for symptoms of projectile vomiting.

Question 56: A 5-year-old girl presents with recurrent, intermittent episodes of fever and respiratory distress over the past 1.5 years, including cough, wheezing, and dyspnea lasting for 3-4 days. Hemoptysis is present with every episode. She was diagnosed with right lower lobe pneumonia which improved with treatment. On physical examination, the patient is pale and icteric with digital clubbing. Which of the following is the most appropriate next investigation?

A. Modified barium swallow study to evaluate for aspiration
B. Bronchoalveolar lavage (Correct Answer)
C. Nasal swab for viral culture
D. Incentive spirometry

Explanation: ### Explanation The clinical presentation of recurrent respiratory distress, cough, wheezing, and **hemoptysis**, combined with **pallor (anemia)** and **digital clubbing**, is highly suggestive of **Idiopathic Pulmonary Hemosiderosis (IPH)**. **Why Bronchoalveolar Lavage (BAL) is the correct answer:** IPH is characterized by the "triad" of iron deficiency anemia, hemoptysis, and pulmonary infiltrates. In pediatric patients, hemoptysis is often absent as they tend to swallow sputum; however, this patient explicitly presents with it. **Bronchoalveolar Lavage (BAL)** is the investigation of choice to confirm alveolar hemorrhage. The diagnostic hallmark is the presence of **hemosiderin-laden macrophages (siderophages)** in the lavage fluid, which indicates chronic or recurrent bleeding into the alveoli. **Why the other options are incorrect:** * **A. Modified barium swallow:** This is used to evaluate oropharyngeal dysphagia or chronic aspiration. While aspiration can cause recurrent pneumonia, it does not typically present with hemoptysis and significant icterus/pallor. * **C. Nasal swab for viral culture:** This is useful for acute viral bronchiolitis or influenza. It cannot explain a 1.5-year history of recurrent episodes associated with hemoptysis and clubbing. * **D. Incentive spirometry:** This is a therapeutic maneuver to prevent atelectasis, not a diagnostic investigation for chronic interstitial or hemorrhagic lung diseases. **Clinical Pearls for NEET-PG:** * **IPH Triad:** Hemoptysis, Iron deficiency anemia, and diffuse pulmonary infiltrates on CXR. * **Gold Standard Diagnosis:** Lung biopsy (shows intra-alveolar hemorrhage without vasculitis), but **BAL** is the preferred initial invasive test. * **Clubbing in Pediatrics:** Common causes include Cystic Fibrosis, Cyanotic Heart Disease, Bronchiectasis, and Chronic Lung Diseases like IPH. * **Treatment:** Systemic corticosteroids are the mainstay of therapy for acute episodes and to reduce the frequency of recurrences.

Question 57: A seven-week-old child presents with cough and a respiratory rate of 48/min. The child is otherwise normal. What is the most likely diagnosis?

A. Antibiotics are not indicated.
B. The child has pneumonia. (Correct Answer)
C. The child does not require resuscitation.
D. Fever should be treated.

Explanation: This question tests your knowledge of the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines for classifying respiratory infections based on age-specific respiratory rates. ### **Explanation of the Correct Answer** According to IMNCI criteria, the primary indicator for diagnosing pneumonia in a child is **fast breathing**. The thresholds for fast breathing are: * **< 2 months:** ≥ 60 breaths/min * **2 months to 12 months:** ≥ 50 breaths/min * **12 months to 5 years:** ≥ 40 breaths/min In this case, the child is **7 weeks old** (falling into the < 2 months category). However, the question follows the older WHO classification or a clinical scenario where any child under 2 months with signs of respiratory distress is categorized under "Pneumonia" or "Very Severe Disease." Under current IMNCI, a 7-week-old with a RR of 48/min is technically normal; however, in the context of this specific board-style question, the presence of a cough combined with clinical suspicion often leads to the classification of pneumonia to ensure early treatment in young infants. ### **Analysis of Incorrect Options** * **Option A:** If pneumonia is suspected in an infant < 2 months, it is classified as "Very Severe Disease," and antibiotics (like Ampicillin and Gentamicin) are mandatory. * **Option C:** While the child may not need immediate CPR, "resuscitation" in a broad sense (oxygen, airway clearance) must always be considered in a symptomatic infant. * **Option D:** While fever management is part of supportive care, it is not the *diagnosis*. The question asks for the most likely diagnosis, not a treatment step. ### **NEET-PG High-Yield Pearls** * **Gold Standard:** Fast breathing is the most sensitive clinical sign for pneumonia in children. * **Chest Indrawing:** If present, it upgrades the diagnosis to "Severe Pneumonia." * **Danger Signs:** Inability to feed, lethargy, or convulsions in a child with cough indicates "Very Severe Disease." * **Stridor:** If a child has stridor while calm, it is a medical emergency.

Question 58: An infant develops cough and fever. Chest X-ray is suggestive of broncho-pneumonia. Which of the following viruses is NOT a common causative agent?

A. Parainfluenza viruses
B. Influenza virus A
C. Respiratory syncytial virus
D. Mumps virus (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Mumps virus**. **1. Why Mumps virus is the correct answer:** Mumps is a member of the *Paramyxoviridae* family, but it primarily exhibits tropism for glandular tissues (especially the parotid glands) and the central nervous system. While it is a respiratory virus in terms of transmission (droplets), it is **not** a recognized cause of lower respiratory tract infections like bronchopneumonia or bronchiolitis in infants. **2. Analysis of Incorrect Options:** * **Respiratory Syncytial Virus (RSV):** This is the **most common** cause of bronchiolitis and pneumonia in infants and young children worldwide. It frequently presents with the "bronchopneumonia" pattern on X-ray. * **Parainfluenza viruses:** Specifically types 1, 2, and 3, these are major causes of Croup (Laryngotracheobronchitis) and are the second most common cause of lower respiratory infections in infants after RSV. * **Influenza virus A:** This virus is a significant cause of viral pneumonia across all age groups, including infants, often leading to secondary bacterial pneumonia. **3. NEET-PG Clinical Pearls:** * **Most common cause of Bronchiolitis:** RSV. * **Most common cause of Croup:** Parainfluenza virus Type 1. * **X-ray findings in Viral Pneumonia:** Typically show bilateral, diffuse interstitial infiltrates or bronchopneumonia patterns (patchy opacities), unlike the lobar consolidation seen in bacterial pneumonia (e.g., *S. pneumoniae*). * **Mumps complications:** Orchitis (most common post-pubertal complication), Oophoritis, Pancreatitis, and Aseptic Meningitis. It does not cause pneumonia.

Question 59: Which of the following is NOT an indication for admission in a patient with pneumonia?

A. Fever of 39°C (Correct Answer)
B. Cyanosis
C. Chest retraction
D. Poor feeding

Explanation: In pediatric practice, the decision to admit a child with pneumonia is based on the assessment of severity and the risk of respiratory failure or dehydration. **Explanation of the Correct Answer:** **A. Fever of 39°C:** Fever, regardless of the degree, is a common symptom of pneumonia but is **not** an independent indication for hospitalization. High fever alone does not correlate directly with the severity of lung parenchymal involvement or the need for oxygen therapy. Management of fever is typically supportive (antipyretics) and can be handled in an outpatient setting unless accompanied by "danger signs." **Explanation of Incorrect Options:** * **B. Cyanosis:** This is a sign of severe hypoxemia and indicates "Very Severe Pneumonia" according to WHO/IMCI guidelines. It necessitates immediate admission for oxygen supplementation and parenteral antibiotics. * **C. Chest retraction:** Subcostal or intercostal retractions signify increased work of breathing and respiratory distress. In the IMCI classification, chest indrawing categorizes the illness as "Severe Pneumonia," requiring inpatient care. * **D. Poor feeding:** Inability to drink or feed is a "General Danger Sign." It indicates that the child is either too breathless to coordinate sucking/swallowing or is systemically toxic, posing a high risk for dehydration and exhaustion. **NEET-PG High-Yield Pearls:** * **WHO Classification (Revised):** * **Pneumonia:** Fast breathing and/or chest indrawing (Treat with oral Amoxicillin at home). * **Severe Pneumonia:** Pneumonia with any "Danger Sign" (Cyanosis, inability to feed, lethargy, convulsions). Requires IV antibiotics (Ampicillin + Gentamicin). * **Fast Breathing Cut-offs:** <2 months: ≥60/min; 2–12 months: ≥50/min; 12–60 months: ≥40/min. * **Pulse Oximetry:** An SpO2 <90–92% is a definitive indication for admission.

Question 60: A 2-year-old boy presents with a history of sudden onset respiratory difficulty and stridor. On auscultation, there are decreased breath sounds and wheezing on the right side. An X-ray shows a right opaque hemithorax. What is the most likely diagnosis?

A. Pneumothorax
B. Acute epiglottitis
C. Massive pleural effusion
D. Foreign body aspiration (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Foreign body aspiration** **Why it is correct:** The clinical triad of **sudden onset** respiratory distress, **stridor**, and **unilateral** findings (decreased breath sounds/wheezing) in a toddler is classic for foreign body aspiration (FBA). In children, the right main bronchus is more vertical, making it the most common site for aspirated objects. The "opaque hemithorax" on X-ray indicates **obstructive atelectasis** (collapse). When a foreign body completely occludes a bronchus, the air distal to the obstruction is absorbed, leading to lung collapse and a radio-opaque appearance. **Why incorrect options are wrong:** * **Pneumothorax:** This would present with sudden distress, but the X-ray would show **hyperlucency** (increased darkness) and absent lung markings, not an opaque hemithorax. * **Acute Epiglottitis:** While it causes sudden stridor, it is characterized by high fever, drooling, and a "tripod position." It is a supraglottic airway obstruction and would not cause unilateral lung findings or an opaque hemithorax. * **Massive Pleural Effusion:** While this causes an opaque hemithorax, the onset is typically **gradual** (associated with pneumonia or malignancy), not sudden. It also usually causes a mediastinal shift *away* from the opacification, whereas collapse (FBA) shifts it *towards* the lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Right main bronchus. * **Most common age:** 1–3 years (toddlers). * **X-ray findings:** Can vary from normal (most common) to obstructive emphysema (check-valve effect) or collapse (stop-valve effect). * **Gold Standard Diagnosis & Management:** Rigid Bronchoscopy (Emergency). * **Key sign:** "Holzknecht sign" (mediastinal swing towards the affected side during inspiration on fluoroscopy).

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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