Respiratory Diseases — MCQs
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Pneumatoceles on chest radiographs in a child with pneumonia are most commonly associated with which organism?
Kartagener syndrome is not associated with which of the following?
A 9-month-old infant presents with a 2-day history of fever, cough, and breathlessness following an upper respiratory infection. The infant is febrile and has a respiratory rate of 80/min, with intercostal and subcostal retractions and extensive rhonchi on auscultation. A chest X-ray reveals a hyperinflated chest. What is the most likely diagnosis?
A 6-month-old child presents with a cough and a respiratory rate of 50 breaths per minute. What does this finding indicate?
A lateral X-ray of the upper airway in a 2-year-old boy reveals a "thumb sign". What is the most likely diagnosis?
Which of the following is seen in Bronchiolitis?
Which of the following is uncommon in children?
A child presents with respiratory distress and a chest X-ray shows multiple air-filled spaces. What is the most likely diagnosis to be excluded from the differential diagnosis?
What is the most common cause of Bronchiolitis?
All of the following are features of acute severe asthma EXCEPT?
Respiratory Diseases Indian Medical PG Practice Questions and MCQs
Question 61: Pneumatoceles on chest radiographs in a child with pneumonia are most commonly associated with which organism?
- A. Staphylococcus (Correct Answer)
- B. Pneumococcus
- C. Streptococcus
- D. Hemophilus influenza
Explanation: **Explanation:** The presence of **pneumatoceles** (thin-walled, air-filled cysts within the lung parenchyma) is a classic radiologic hallmark of **Staphylococcal pneumonia**. **1. Why Staphylococcus is Correct:** *Staphylococcus aureus* produces specific toxins and enzymes (such as Panton-Valentine Leukocidin) that cause significant tissue necrosis and inflammation. This leads to a "check-valve" mechanism where air enters the interstitial space during inspiration but becomes trapped during expiration. This localized alveolar rupture and air trapping result in the formation of pneumatoceles. While they often appear alarming on X-ray, they are usually transient and resolve spontaneously with appropriate antibiotic therapy. **2. Why Other Options are Incorrect:** * **B. Pneumococcus (*S. pneumoniae*):** The most common cause of community-acquired pneumonia in children. It typically presents as lobar consolidation and is more frequently associated with pleural effusions rather than pneumatoceles. * **C. Streptococcus (*S. pyogenes*):** Often causes rapidly progressive pneumonia with early, large pleural effusions and empyema, but pneumatoceles are rare. * **D. Hemophilus influenzae:** Usually presents as bronchopneumonia or lobar pneumonia. Since the introduction of the HiB vaccine, its incidence has significantly decreased, and it is not typically associated with cavitary or cystic lesions. **3. NEET-PG High-Yield Pearls:** * **Triad of Staphylococcal Pneumonia:** Pneumatocele, Pleural effusion, and Empyema (often associated with pyopneumothorax). * **Management:** Most pneumatoceles are asymptomatic and require **conservative management** (observation); they should not be drained unless they cause tension symptoms or become infected. * **Other causes of pneumatoceles:** Hydrocarbon aspiration, trauma, and *Pneumocystis jirovecii* (in immunocompromised hosts).
Question 62: Kartagener syndrome is not associated with which of the following?
- A. Situs inversus
- B. Subluxation of lens (Correct Answer)
- C. Bronchiectasis
- D. Sinusitis
Explanation: **Explanation:** **Kartagener Syndrome** is a subset of **Primary Ciliary Dyskinesia (PCD)**, an autosomal recessive disorder characterized by the structural and functional impairment of cilia. The classic triad of Kartagener syndrome includes **Situs inversus, Bronchiectasis, and Sinusitis.** 1. **Why Subluxation of Lens is the Correct Answer:** Subluxation of the lens (Ectopia lentis) is not a feature of Kartagener syndrome. It is typically associated with connective tissue disorders like **Marfan syndrome** (upward dislocation) or **Homocystinuria** (downward dislocation). Ciliary dysfunction in Kartagener syndrome affects motile cilia, whereas lens stability depends on zonular fibers (fibrillin), which are unrelated to ciliary motility. 2. **Analysis of Incorrect Options:** * **Situs inversus (Option A):** Occurs in 50% of patients with PCD. During embryogenesis, normal ciliary beat is required for the left-right patterning of internal organs. Absent ciliary function leads to random organ placement. * **Bronchiectasis (Option C):** Impaired mucociliary clearance leads to chronic endobronchial infections, resulting in permanent dilation of the bronchi. * **Sinusitis (Option D):** Ciliary dysfunction in the paranasal sinuses prevents mucus drainage, leading to chronic inflammation and recurrent infections. **High-Yield Clinical Pearls for NEET-PG:** * **The Triad:** Bronchiectasis + Sinusitis + Situs Inversus. * **Infertility:** Common in males due to immotile spermatozoa (flagella are modified cilia) and in females due to impaired ciliary action in the fallopian tubes. * **Diagnosis:** Screening via **Nasal Nitric Oxide (nNO)** levels (low in PCD). Gold standard is **Digital High-Speed Videomicroscopy** or Electron Microscopy (showing absence of dynein arms). * **Genetics:** Most common defect is the absence of **outer dynein arms**.
Question 63: A 9-month-old infant presents with a 2-day history of fever, cough, and breathlessness following an upper respiratory infection. The infant is febrile and has a respiratory rate of 80/min, with intercostal and subcostal retractions and extensive rhonchi on auscultation. A chest X-ray reveals a hyperinflated chest. What is the most likely diagnosis?
- A. Bronchial asthma
- B. Foreign body aspiration
- C. Bacterial pneumonia
- D. Bronchiolitis (Correct Answer)
Explanation: **Explanation:** The clinical presentation is classic for **Acute Bronchiolitis**, the most common lower respiratory tract infection in infants (peak age 2–6 months). It is typically caused by **Respiratory Syncytial Virus (RSV)**. **Why Bronchiolitis is correct:** 1. **Age:** It primarily affects children under 2 years. 2. **Prodrome:** It starts with a viral URI (fever, cough) followed by lower respiratory distress. 3. **Pathophysiology:** Inflammation and edema of small airways lead to obstruction. This causes **air trapping**, which manifests as **hyperinflation** on X-ray and widespread **rhonchi/wheezing** on auscultation. A respiratory rate of 80/min indicates significant distress. **Why other options are incorrect:** * **Bronchial asthma:** Rarely diagnosed in a 9-month-old during the first episode. Asthma is a recurrent condition; bronchiolitis is the "first episode of wheezing" in an infant. * **Foreign body aspiration:** Usually presents with sudden onset choking and asymmetrical breath sounds/localized wheeze, not a febrile viral prodrome. * **Bacterial pneumonia:** Typically presents with high fever, toxic appearance, and localized crepitations or dullness on percussion, rather than diffuse wheezing and hyperinflation. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** RSV (followed by Rhinovirus). * **X-ray findings:** Hyperlucency, depressed diaphragm, and horizontal ribs. * **Treatment:** Primarily supportive (oxygenation and hydration). Routine use of bronchodilators, steroids, or antibiotics is **not** recommended. * **Risk Factor:** Prematurity and congenital heart disease increase severity.
Question 64: A 6-month-old child presents with a cough and a respiratory rate of 50 breaths per minute. What does this finding indicate?
- A. No pneumonia
- B. Pneumonia (Correct Answer)
- C. Severe pneumonia
- D. Very severe pneumonia
Explanation: This question tests your knowledge of the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines for classifying respiratory infections in children aged 2 months to 5 years. ### **Explanation of the Correct Answer** According to IMNCI criteria, the primary indicator for **Pneumonia** is **Fast Breathing** (Tachypnea) in the absence of chest indrawing or danger signs. The thresholds for fast breathing are age-specific: * **< 2 months:** ≥ 60 breaths/min * **2 to 12 months:** ≥ 50 breaths/min * **12 months to 5 years:** ≥ 40 breaths/min In this case, the 6-month-old child has a respiratory rate of 50 bpm, which meets the exact cutoff for fast breathing, thus classifying the condition as **Pneumonia**. ### **Analysis of Incorrect Options** * **A. No pneumonia:** This classification is used when a child has a cough/cold but the respiratory rate is *below* the age-specific threshold (e.g., < 50 bpm for a 6-month-old) and no chest indrawing is present. * **C. Severe pneumonia:** This requires the presence of **Chest Indrawing** (subcostal retraction) in addition to cough or fast breathing. * **D. Very severe pneumonia:** This classification (often grouped with Severe Pneumonia in newer guidelines) is used if any **General Danger Signs** are present, such as inability to drink/breastfeed, lethargy, unconsciousness, or convulsions. ### **NEET-PG High-Yield Pearls** * **Counting Rule:** Always count the respiratory rate for a full **60 seconds** when the child is calm. * **Treatment:** IMNCI recommends oral **Amoxicillin** (40 mg/kg/dose twice daily for 5 days) for "Pneumonia" managed at home. * **Stridor:** If a child has stridor while calm but no danger signs, it is also classified as Severe Pneumonia and requires urgent referral.
Question 65: A lateral X-ray of the upper airway in a 2-year-old boy reveals a "thumb sign". What is the most likely diagnosis?
- A. Laryngeal polyps
- B. Epiglottitis (Correct Answer)
- C. Subglottic hemangioma
- D. Laryngeal edema
Explanation: ### Explanation **Correct Answer: B. Epiglottitis** The **"Thumb Sign"** is the classic radiological hallmark of **Acute Epiglottitis**. On a lateral soft-tissue X-ray of the neck, the epiglottis appears thickened and rounded, resembling the distal phalanx of a thumb. This occurs due to severe inflammation and edema of the epiglottis and aryepiglottic folds, which narrows the airway (vallecula). Historically, the most common causative agent was *Haemophilus influenzae* type b (Hib), though incidence has decreased significantly due to vaccination. Clinically, it presents as a pediatric emergency characterized by the **"4 Ds"**: Drooling, Dysphagia, Distress, and Dysphonia (muffled "hot potato" voice). **Why other options are incorrect:** * **Laryngeal polyps:** These typically present with chronic hoarseness rather than acute respiratory distress and would appear as small, focal masses on endoscopy, not a generalized "thumb" shape. * **Subglottic hemangioma:** This presents as asymmetric subglottic narrowing (often on an AP view) and typically causes biphasic stridor in infants aged 1–6 months. * **Laryngeal edema:** While it causes airway narrowing, it does not specifically produce the localized, rounded swelling of the epiglottis seen in the thumb sign. **High-Yield Clinical Pearls for NEET-PG:** * **Steeple Sign:** Seen on AP view in **Croup** (Laryngotracheobronchitis) due to subglottic narrowing. * **Management Priority:** The first step is **airway stabilization** (intubation or tracheostomy) in a controlled environment (OR). Never examine the throat with a tongue depressor, as it may trigger fatal laryngospasm. * **Positioning:** Children often adopt the **"Tripod position"** (leaning forward with hands on knees) to maximize airway diameter.
Question 66: Which of the following is seen in Bronchiolitis?
- A. Seen in children 5 months to 3 years of age
- B. Caused by Streptococcus pneumoniae
- C. Chest X-ray shows hyperinflation bilaterally (Correct Answer)
- D. All of the above
Explanation: **Explanation:** **Bronchiolitis** is an acute inflammatory injury of the small airways (bronchioles), typically triggered by a viral infection. It is the leading cause of hospitalization in infants. **Why Option C is Correct:** The hallmark pathophysiology of bronchiolitis involves inflammation, edema, and excessive mucus production, leading to partial or complete airway obstruction. This creates a **"ball-valve" mechanism** where air enters during inspiration but becomes trapped during expiration. Consequently, the classic finding on a Chest X-ray is **bilateral hyperinflation** (evidenced by flattened diaphragms and increased radiolucency), often accompanied by peribronchial thickening or patchy areas of atelectasis. **Why Other Options are Incorrect:** * **Option A:** Bronchiolitis primarily affects infants **under 2 years of age**, with a peak incidence between **2 to 6 months**. While it can occur up to age 2, it is rarely the primary diagnosis in older toddlers (3 years), where asthma or viral wheeze is more common. * **Option B:** The most common causative agent is **Respiratory Syncytial Virus (RSV)**, followed by Rhinovirus. *Streptococcus pneumoniae* is a common cause of bacterial pneumonia, not bronchiolitis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** RSV (70-80% of cases). * **Clinical Presentation:** Starts as an upper respiratory infection (coryza) progressing to lower respiratory signs: **tachypnea, chest indrawing, and fine inspiratory crackles/expiratory wheeze.** * **Diagnosis:** Primarily clinical; X-rays are not routinely required unless the diagnosis is uncertain. * **Management:** Mainly supportive (hydration and oxygenation). Bronchodilators and steroids are generally **not** recommended. * **Palivizumab:** A monoclonal antibody used for prophylaxis in high-risk preterm infants.
Question 67: Which of the following is uncommon in children?
- A. Ewing's sarcoma
- B. Neuroblastoma
- C. Osteosarcoma
- D. None of the above (Correct Answer)
Explanation: ### Explanation The correct answer is **D. None of the above**, because all three conditions listed—Ewing’s sarcoma, Neuroblastoma, and Osteosarcoma—are classic pediatric malignancies. In the context of pediatric oncology, these are considered common or characteristic tumors of childhood and adolescence. **Analysis of Options:** * **Neuroblastoma (Option B):** This is the most common extracranial solid tumor of childhood and the most common tumor in infants. It arises from the neural crest cells of the sympathetic nervous system (most commonly the adrenal medulla). It typically presents in children under 5 years of age. * **Osteosarcoma (Option C):** This is the most common primary malignant bone tumor in children and adolescents. It has a bimodal distribution but peaks during the adolescent growth spurt (10–19 years), usually occurring at the metaphyseal ends of long bones (e.g., distal femur). * **Ewing’s Sarcoma (Option A):** This is the second most common bone tumor in children. It typically affects the diaphysis (shaft) of long bones or flat bones (pelvis) and is characterized by the $t(11;22)$ translocation. **Clinical Pearls for NEET-PG:** * **Neuroblastoma:** Look for "dancing eyes, dancing feet" (opsoclonus-myoclonus syndrome) and elevated urinary catecholamines (VMA/HVA). * **Osteosarcoma:** Radiologically characterized by the **"Sunburst appearance"** and **Codman’s triangle** due to periosteal reaction. * **Ewing’s Sarcoma:** Radiologically characterized by an **"Onion-skin appearance"** (lamellated periosteal reaction) and Small Round Blue Cells on histology. * **Age Factor:** While Neuroblastoma is a disease of early childhood, bone tumors (Osteo and Ewing’s) are more frequent in the second decade of life.
Question 68: A child presents with respiratory distress and a chest X-ray shows multiple air-filled spaces. What is the most likely diagnosis to be excluded from the differential diagnosis?
- A. Congenital lung cyst
- B. Congenital diaphragmatic hernia
- C. Congenital lobar aplasia of the lung (Correct Answer)
- D. Congenital adenomatoid malformation
Explanation: **Explanation:** The core of this question lies in distinguishing between pathologies that create **cystic/air-filled spaces** on a chest X-ray versus those that result in a **lack of lung tissue**. **1. Why "Congenital Lobar Aplasia" is the correct answer:** In **Congenital Lobar Aplasia**, there is a complete absence of the lung parenchyma and its associated bronchus and vessels. On a chest X-ray, this typically presents as an **opaque hemithorax** (due to the absence of air-filled tissue) with a mediastinal shift toward the affected side. It does *not* produce multiple air-filled spaces; therefore, it is the outlier that should be excluded from this differential. **2. Analysis of Incorrect Options (Differential for Cystic Lucencies):** * **Congenital Lung Cyst:** These are fluid or air-filled structures that appear as thin-walled, radiolucent circles on X-ray. * **Congenital Diaphragmatic Hernia (CDH):** Abdominal contents (bowel loops) herniate into the thoracic cavity. On X-ray, these air-filled bowel loops mimic multiple cystic spaces. This is a classic "masquerader" of lung cysts. * **Congenital Pulmonary Adenomatoid Malformation (CPAM/CCAM):** This is a multicystic mass of non-functioning lung tissue. Type I and II CPAM characteristically show multiple air-filled cysts of varying sizes on imaging. **NEET-PG High-Yield Pearls:** * **CDH:** Most common site is **Bochdalek** (posterolateral, usually left side). Scaphoid abdomen + respiratory distress is the classic triad. * **Congenital Lobar Emphysema (CLE):** Often confused with cysts, but it shows **hyperlucency** of a single lobe (usually Left Upper Lobe) with mass effect, rather than multiple distinct cysts. * **Pneumatocele:** Often seen post-Staphylococcal pneumonia; these are acquired thin-walled air cysts that can mimic congenital malformations.
Question 69: What is the most common cause of Bronchiolitis?
- A. RSV (Respiratory Syncytial Virus) (Correct Answer)
- B. Adenovirus
- C. Parainfluenza virus
- D. Mycoplasma pneumoniae
Explanation: **Explanation:** **Bronchiolitis** is a clinical syndrome of the lower respiratory tract occurring in children less than 2 years of age, characterized by inflammation, edema, and necrosis of epithelial cells lining the small airways. **1. Why RSV is the Correct Answer:** **Respiratory Syncytial Virus (RSV)** is the most common cause of bronchiolitis, responsible for approximately **50–80%** of all cases. It typically occurs in seasonal outbreaks (winter and early spring). The virus leads to the proliferation of goblet cells and excessive mucus production, causing the characteristic "air trapping" and wheezing seen in infants. **2. Analysis of Incorrect Options:** * **B. Adenovirus:** While it can cause bronchiolitis, it is less common. However, it is notorious for causing **Bronchiolitis Obliterans**, a severe, chronic obstructive lung disease following the acute infection. * **C. Parainfluenza virus:** This is the most common cause of **Croup (Laryngotracheobronchitis)**, characterized by a barking cough and inspiratory stridor, rather than bronchiolitis. * **D. Mycoplasma pneumoniae:** This is a common cause of **Atypical Pneumonia** in older children (school-age) and adolescents, but it is an infrequent cause of bronchiolitis in infants. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Primarily clinical. Chest X-ray typically shows hyperinflation and flattened diaphragm. * **Risk Factors:** Prematurity, low birth weight, and congenital heart disease. * **Treatment:** Supportive care (hydration and oxygenation) is the mainstay. Routine use of bronchodilators, steroids, or antibiotics is **not** recommended. * **Prophylaxis:** **Palivizumab** (a monoclonal antibody against RSV) is indicated for high-risk preterm infants. * **Key Sign:** The first sign of bronchiolitis in very young infants may be **Apnea**.
Question 70: All of the following are features of acute severe asthma EXCEPT?
- A. Respiratory rate > 25 breaths/min
- B. Heart rate > 110 beats/min
- C. PEF < 50% of predicted value
- D. Temperature > 102°F (Correct Answer)
Explanation: **Explanation:** Acute severe asthma (formerly known as "Status Asthmaticus") is a clinical diagnosis based on the severity of airway obstruction and the physiological stress it places on the respiratory and cardiovascular systems. **Why Option D is the Correct Answer:** **Temperature > 102°F** is not a diagnostic feature of acute severe asthma. While a viral or bacterial infection can trigger an asthma exacerbation, fever itself is not used to grade the severity of the asthma attack. The classification of "Severe" is based on markers of respiratory failure and hemodynamic strain. **Analysis of Incorrect Options (Features of Severe Asthma):** * **Respiratory Rate > 25 breaths/min (Option A):** Tachypnea is a compensatory mechanism for hypoxia and increased work of breathing. In children/adults, a rate >25-30 bpm is a hallmark of severity. * **Heart Rate > 110 beats/min (Option B):** Tachycardia occurs due to sympathetic overactivity, stress, and the potential side effects of beta-agonist therapy. A heart rate >110 bpm (in adults/older children) signifies significant physiological distress. * **PEF < 50% of predicted (Option C):** Peak Expiratory Flow (PEF) is an objective measure of airway obstruction. A value <50% of the patient's best or predicted value indicates a severe exacerbation. **High-Yield Clinical Pearls for NEET-PG:** * **Life-Threatening Asthma (The "Silent Chest"):** Look for "Red Flags" like cyanosis, exhaustion, silent chest on auscultation, bradycardia, hypotension, or a PEF < 33%. * **Blood Gas Paradox:** In early asthma, patients have respiratory alkalosis (low $PaCO_2$) due to hyperventilation. A **"normal" $PaCO_2$** (35-45 mmHg) in a severe attack is an ominous sign of impending respiratory failure and muscle fatigue. * **Pulsus Paradoxus:** A drop in systolic BP >10 mmHg during inspiration is often present in severe cases.
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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