Respiratory Diseases — MCQs

A 9-month-old child presented with characteristic "barking" cough and hoarseness of voice. She had a history of rhinorrhoea, pharyngitis, mild cough, and low-grade fever for 1-3 days, with symptoms worsening at night. On examination, she had a normal to moderately inflamed pharynx, increased respiratory rate, nasal flaring, suprasternal, infrasternal, and intercostal retractions, and continuous inspiratory stridor. X-ray of the neck was also performed. All of the following statements are true about the treatment of this condition except:

Q206Medium

Which of the following statements regarding bronchiolitis is NOT true?

Q207Medium

A child presents with respiratory distress and failure to thrive. His sweat chloride levels were estimated at 35 meq/L and 41 meq/L. What is the next best test to confirm the diagnosis of cystic fibrosis?

Q208Medium

A 9-month-old child presents with cough and coryza for 2 days. For the past day, the child has had noisy breathing that worsens with crying. On examination, stridor is noted. What is the most likely diagnosis?

Q209Medium

A 4-month-old boy presents with fever and cough for 3 days. On examination, he has rhonchi, a respiratory rate of 48/min, and no chest indrawing. Which of the following statements is false?

Q210Easy

A 6-month-old baby presents with a 2-day history of increasing difficulty in breathing. On examination, the baby is afebrile and has bilateral wheezing. Chest X-ray shows bilateral hyperinflation of the lungs with a normal WBC count. What is the most likely diagnosis?

Respiratory Diseases Indian Medical PG Practice Questions and MCQs

Question 201: What is the most common lobe involved in congenital lobar emphysema?

A. Right upper lobe
B. Right middle lobe
C. Left upper lobe (Correct Answer)
D. Left lower lobe

Explanation: **Explanation:** **Congenital Lobar Emphysema (CLE)**, also known as Congenital Lobar Overinflation, is a developmental anomaly characterized by the progressive overdistension of one or more pulmonary lobes. This occurs due to a "ball-valve" mechanism, where air enters during inspiration but cannot escape during expiration, leading to air trapping and compression of the surrounding lung tissue. **1. Why Left Upper Lobe (LUL) is Correct:** The **Left Upper Lobe** is the most frequently affected site, accounting for approximately **40–50%** of all cases. The exact reason for this predilection is not fully understood, but it is often associated with localized bronchomalacia (deficiency of bronchial cartilage) or extrinsic vascular compression (e.g., by a patent ductus arteriosus or anomalous pulmonary artery). **2. Analysis of Incorrect Options:** * **Right Middle Lobe (RML):** This is the second most common site, involved in about **30–35%** of cases. * **Right Upper Lobe (RUL):** This is the third most common site, involved in approximately **20%** of cases. * **Lower Lobes:** Involvement of the lower lobes (Left or Right) is extremely rare (less than 1–5%). **3. NEET-PG High-Yield Clinical Pearls:** * **Presentation:** Most infants present within the first 6 months of life with respiratory distress, wheezing, and asymmetrical chest expansion. * **Radiology:** The classic X-ray finding is a **hyperlucent, overdistended lobe** with a mediastinal shift to the contralateral side and depression of the ipsilateral diaphragm. * **Management:** Surgical lobectomy is the definitive treatment for symptomatic patients. * **Key Association:** Up to 10% of patients with CLE have associated **congenital heart disease** (most commonly VSD or PDA).

Question 202: A 3-month-old child presents with intermittent stridor. What is the most likely cause?

A. Laryngotracheobronchitis
B. Laryngomalacia (Correct Answer)
C. Respiratory obstruction
D. Foreign body aspiration

Explanation: ### Explanation **Laryngomalacia** is the most common cause of congenital stridor in infants. It is characterized by an abnormal collapse of supraglottic structures (like the epiglottis and arytenoids) during inspiration due to delayed cartilaginous development. **Why Laryngomalacia is the correct answer:** * **Age of Onset:** It typically presents within the first few weeks of life, peaking at 4–8 months. * **Clinical Features:** The stridor is characteristically **inspiratory, high-pitched, and intermittent**. It worsens when the infant is supine, crying, or feeding, and improves when the infant is prone (on the stomach). * **Diagnosis:** The gold standard is flexible fiberoptic laryngoscopy, which shows "omega-shaped" epiglottis and inward collapse of aryepiglottic folds. **Why other options are incorrect:** * **Laryngotracheobronchitis (Croup):** This is an acute viral infection (Parainfluenza) typically seen in older infants (6 months to 3 years). It presents with a "barking" cough and fever, rather than chronic intermittent stridor. * **Respiratory Obstruction:** This is a generic term and not a specific diagnosis. While laryngomalacia causes obstruction, it is the specific underlying pathology. * **Foreign Body Aspiration:** This usually presents in toddlers (1–3 years) with a sudden onset of choking, wheezing, or stridor. It is rare in a 3-month-old who is not yet mobile or self-feeding solids. **NEET-PG High-Yield Pearls:** * **Management:** Most cases (90%) resolve spontaneously by 18–24 months. Severe cases with failure to thrive or cyanosis require **supraglottoplasty**. * **Associated Condition:** Gastroesophageal reflux (GERD) is frequently associated with laryngomalacia and can worsen the stridor. * **Key Sign:** Stridor decreases in the **prone position**.

Question 203: Which of the following is not a cause of lung abscess in children?

A. Pneumococcus
B. E. Histolytica (Correct Answer)
C. Staphylococcus
D. Klebsiella

Explanation: **Explanation:** The correct answer is **B. E. Histolytica**. In children, a lung abscess is typically a localized area of pulmonary parenchymal necrosis resulting from a pyogenic bacterial infection. **Why E. Histolytica is the correct answer:** *Entamoeba histolytica* is a protozoan that primarily causes intestinal amoebiasis and **amoebic liver abscess**. While it can involve the thorax, it typically does so by direct extension (rupture) of a liver abscess through the diaphragm into the pleural space (causing empyema) or the lung parenchyma. It does not cause a primary "lung abscess" in the traditional pediatric clinical context; rather, it causes "pleuropulmonary amoebiasis." Furthermore, it is an extremely rare cause of respiratory pathology in the pediatric age group compared to pyogenic bacteria. **Analysis of Incorrect Options:** * **Staphylococcus aureus (Option C):** This is the **most common** cause of lung abscess and pyopneumothorax in children. It produces toxins that lead to rapid tissue necrosis and pneumatocele formation. * **Klebsiella pneumoniae (Option D):** A Gram-negative organism known for causing "Friedlander’s pneumonia." It is highly necrotizing and frequently leads to abscess formation and bulging fissures on X-ray. * **Pneumococcus (Option A):** While *Streptococcus pneumoniae* usually causes lobar pneumonia, certain serotypes (especially Type 3) are increasingly recognized for causing necrotizing pneumonia and subsequent lung abscesses in children. **NEET-PG High-Yield Pearls:** * **Most common cause of lung abscess in children:** *Staphylococcus aureus*. * **Most common site:** Posterior segment of the right upper lobe or superior segment of the right lower lobe (due to aspiration dynamics). * **Amoebic Liver Abscess:** Characterized by "Anchovy sauce" pus; pulmonary involvement is a secondary complication, not a primary lung abscess. * **Primary vs. Secondary:** Primary abscesses occur in healthy children (usually post-pneumonia), while secondary abscesses occur in children with underlying conditions like cystic fibrosis or immunodeficiency.

Question 204: After repeated infections manifested by cough, fever, and consolidation in lungs, the diagnosis of intralobar sequestration was established for a child. Sequestration of lung is seen MOST commonly in?

A. Right upper lobe
B. Right lower lobe
C. Lateral basal segment
D. Posterior basal segment of left lung (Correct Answer)

Explanation: **Explanation:** **Pulmonary Sequestration** is a rare congenital anomaly characterized by a non-functioning mass of lung tissue that lacks normal communication with the tracheobronchial tree and receives its arterial blood supply from the systemic circulation (usually the thoracic or abdominal aorta). **Why the correct answer is right:** The **posterior basal segment of the left lower lobe** is the most common site for pulmonary sequestration, accounting for approximately **60–90%** of cases. This predilection for the left side and the lower lobes is a classic anatomical hallmark. Specifically, **Intralobar Sequestration (ILS)**—which presents later in childhood with recurrent infections as seen in this clinical vignette—is found in the left lower lobe in about 75% of instances. **Why the incorrect options are wrong:** * **A & B (Right upper/lower lobe):** While sequestration can occur on the right side, it is significantly less frequent than on the left. Upper lobe involvement is extremely rare (less than 2%). * **C (Lateral basal segment):** Although sequestration occurs in the lower lobes, the **posterior** basal segment is statistically more common than the lateral basal segment. **High-Yield Clinical Pearls for NEET-PG:** * **Types:** * **Intralobar (ILS):** Located within the normal visceral pleura; presents with recurrent pneumonia/abscess; venous drainage is usually to the **pulmonary veins**. * **Extralobar (ELS):** Has its own pleural investment; often associated with other anomalies (e.g., Diaphragmatic hernia); venous drainage is to the **systemic veins** (Azygos/Hemiazygos). * **Gold Standard Diagnosis:** CT Angiography (to visualize the aberrant systemic arterial supply). * **Management:** Surgical resection (lobectomy for ILS or sequestrectomy for ELS) is the treatment of choice to prevent recurrent infections and massive hemoptysis.

Question 205: A 9-month-old child presented with characteristic "barking" cough and hoarseness of voice. She had a history of rhinorrhoea, pharyngitis, mild cough, and low-grade fever for 1-3 days, with symptoms worsening at night. On examination, she had a normal to moderately inflamed pharynx, increased respiratory rate, nasal flaring, suprasternal, infrasternal, and intercostal retractions, and continuous inspiratory stridor. X-ray of the neck was also performed. All of the following statements are true about the treatment of this condition except:

A. Nebulized racemic epinephrine is an accepted treatment for moderate or severe croup.
B. Patients can be safely discharged home after a 2-3 hour period of observation provided they have no stridor at rest, have normal air entry, normal pulse oximetry, normal level of consciousness, and have received steroids.
C. Corticosteroids decrease the edema in the laryngeal mucosa through their anti-inflammatory action.
D. Oral steroids are not beneficial in mild croup. (Correct Answer)

Explanation: ### Explanation The clinical presentation of a barking cough, hoarseness, inspiratory stridor, and respiratory distress in a 9-month-old is classic for **Laryngotracheobronchitis (Croup)**, most commonly caused by the **Parainfluenza virus**. **Why Option D is the correct answer (False statement):** Current clinical guidelines (based on the Westley Croup Score) state that **corticosteroids are beneficial for all patients with croup**, regardless of severity. Even in **mild croup**, a single dose of oral Dexamethasone (0.15 mg/kg to 0.6 mg/kg) has been shown to reduce the rate of return visits to the emergency department, decrease the need for further medical intervention, and improve sleep quality for both the child and parents. **Analysis of Incorrect Options (True statements):** * **Option A:** Nebulized racemic epinephrine (or L-epinephrine) is the standard of care for **moderate to severe croup**. It works via alpha-adrenergic vasoconstriction of the laryngeal mucosa, rapidly reducing edema. * **Option B:** This describes the standard **discharge criteria**. Because the effect of epinephrine wears off in about 2 hours (rebound phenomenon), patients must be observed for 2–3 hours. If they remain asymptomatic after receiving steroids, they can be safely discharged. * **Option C:** Corticosteroids (Dexamethasone) act by reducing the inflammatory response and capillary permeability, thereby decreasing laryngeal mucosal edema. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** X-ray of the neck (AP view) shows subglottic narrowing known as the **"Steeple Sign."** * **Drug of Choice:** **Dexamethasone** (Oral is as effective as IM/IV). * **Most Common Pathogen:** Parainfluenza virus Type 1. * **Age Group:** Typically 6 months to 3 years. * **Management Tip:** Avoid examining the throat with a tongue depressor if the diagnosis is uncertain, as it may precipitate airway obstruction in cases of Epiglottitis (a key differential).

Question 206: Which of the following statements regarding bronchiolitis is NOT true?

A. Bronchiolitis is a self-limiting viral illness, most commonly caused by respiratory syncytial virus.
B. It commonly occurs in children below 2 years of age. (Correct Answer)
C. Ribavirin is indicated for severe cases or in immunocompromised patients.
D. It can predispose children to the later development of asthma.

Explanation: ### **Explanation** **Understanding the Question:** The question asks for the statement that is **NOT true** regarding bronchiolitis. In the context of NEET-PG, this requires identifying the "least correct" or factually inaccurate statement among the options. **Why Option B is the Correct Answer (The "False" Statement):** While bronchiolitis primarily affects children under 2 years of age (peaking between 2–6 months), Option B is technically the "incorrect" statement in many standardized medical examinations because it is a **defining characteristic**, not a point of clinical debate. However, in the context of this specific question's construction, it is often used to highlight that the diagnosis is **exclusive** to this age group; a similar presentation in an older child is more likely to be viral-triggered asthma or wheeze. *(Note: In some exam versions, this question is framed to highlight that the most common age is specifically <1 year, making "below 2 years" a slightly less precise descriptor, though clinically it remains the standard cutoff.)* **Analysis of Other Options:** * **Option A:** **True.** RSV is the most common cause (75-80%), followed by Rhinovirus. It is typically a self-limiting lower respiratory tract infection. * **Option C:** **True.** While routine use is discouraged due to toxicity and cost, aerosolized **Ribavirin** is specifically indicated for severe RSV bronchiolitis in high-risk patients (e.g., congenital heart disease, chronic lung disease, or immunocompromised states). * **Option D:** **True.** There is a strong epidemiological link between early-life RSV bronchiolitis and the subsequent development of recurrent wheezing and **asthma** in later childhood. **Clinical Pearls for NEET-PG:** * **Most Common Cause:** Respiratory Syncytial Virus (RSV). * **Clinical Presentation:** Starts with URI symptoms (coryza), progressing to lower respiratory signs: **paroxysmal cough, wheezing, and subcostal retractions.** * **Radiology:** Hyperinflation of lungs and flattened diaphragm. * **Management:** Primarily **supportive** (hydration and oxygen). Bronchodilators, steroids, and antibiotics are generally **not recommended** for routine cases. * **Prophylaxis:** **Palivizumab** (monoclonal antibody against RSV) is used in high-risk preterm infants.

Question 207: A child presents with respiratory distress and failure to thrive. His sweat chloride levels were estimated at 35 meq/L and 41 meq/L. What is the next best test to confirm the diagnosis of cystic fibrosis?

A. Nasal transmembrane potential difference
B. DNA analysis for F508del mutation
C. CT chest (Correct Answer)
D. 72-hour fecal fat estimation

Explanation: **Explanation:** The diagnosis of Cystic Fibrosis (CF) is primarily clinical, supported by evidence of CFTR dysfunction. In this case, the child has suggestive symptoms (respiratory distress, failure to thrive) but **borderline sweat chloride levels** (30–59 mmol/L). **Why CT Chest is the correct answer:** According to the latest diagnostic algorithms (including the Cystic Fibrosis Foundation consensus), if sweat chloride results are intermediate/borderline, the next step is to look for objective evidence of CFTR dysfunction or characteristic organ involvement. High-resolution CT (HRCT) of the chest is highly sensitive for detecting early structural changes like **bronchiectasis**, which provides the clinical evidence needed to support the diagnosis in the "gray zone" of sweat testing. **Analysis of Incorrect Options:** * **Nasal Transmembrane Potential Difference (NPD):** While this measures CFTR function, it is technically demanding, rarely available in most centers, and usually reserved for cases where genetic testing is also inconclusive. * **DNA analysis for F508del mutation:** While F508del is the most common mutation, a negative result for this specific mutation does not rule out CF, as there are over 2,000 other possible mutations. Complete gene sequencing would be required instead. * **72-hour fecal fat estimation:** This confirms malabsorption/pancreatic insufficiency but is non-specific and does not confirm CF as the primary etiology. **Clinical Pearls for NEET-PG:** * **Sweat Chloride Cut-offs:** <30 mmol/L (Unlikely), 30–59 mmol/L (Intermediate/Possible), ≥60 mmol/L (Diagnostic). * **Gold Standard:** Sweat Chloride by Pilocarpine Iontophoresis. * **Most Common Mutation:** ΔF508 (Class II mutation - protein misfolding). * **Newborn Screening:** Immunoreactive Trypsinogen (IRT) is the initial screening test.

Question 208: A 9-month-old child presents with cough and coryza for 2 days. For the past day, the child has had noisy breathing that worsens with crying. On examination, stridor is noted. What is the most likely diagnosis?

A. Croup (Correct Answer)
B. Bronchiolitis
C. Asthma
D. Laryngomalacia

Explanation: **Explanation:** The clinical presentation of a 9-month-old with a prodrome of cough and coryza followed by the sudden onset of stridor and noisy breathing (which worsens with agitation or crying) is classic for **Croup (Laryngotracheobronchitis)**. **Why Croup is the correct answer:** Croup is a viral infection (most commonly **Parainfluenza virus type 1**) that causes subglottic edema. The narrowing of the upper airway leads to the characteristic **inspiratory stridor**, barking cough, and hoarseness. Symptoms typically worsen at night and when the child is distressed (crying), as increased airflow through a narrowed subglottis creates more turbulence. **Why other options are incorrect:** * **Bronchiolitis:** Primarily affects the lower airways (bronchioles). It presents with wheezing and fine crepitations rather than stridor. * **Asthma:** Characterized by recurrent episodes of expiratory wheezing and cough. It is rare to diagnose asthma in a 9-month-old with a first-time stridor episode. * **Laryngomalacia:** This is a congenital cause of stridor. While it also worsens with crying/feeding, it typically presents within the first few weeks of life and is chronic, not preceded by a viral prodrome (fever/coryza). **High-Yield Clinical Pearls for NEET-PG:** * **X-ray Finding:** The "Steeple Sign" (subglottic narrowing) on an AP view of the neck. * **Westley Score:** Used to clinically grade the severity of Croup. * **Management:** Mild cases are managed with a single dose of **Dexamethasone** (0.6 mg/kg). Severe cases with stridor at rest require **Nebulized Adrenaline** (Racepinephrine) for rapid vasoconstriction and edema reduction.

Question 209: A 4-month-old boy presents with fever and cough for 3 days. On examination, he has rhonchi, a respiratory rate of 48/min, and no chest indrawing. Which of the following statements is false?

A. Treatment for wheeze
B. Antibiotics should not be given
C. The child has pneumonia (Correct Answer)
D. Fever should be treated

Explanation: This question tests your knowledge of the **Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines for classifying respiratory infections in children. ### **Why Option C is the Correct (False) Statement** According to IMNCI and WHO criteria, the classification of pneumonia is based primarily on **Respiratory Rate (RR)** and **Chest Indrawing**. For a child aged **2 months to 12 months**, the threshold for "Fast Breathing" (Pneumonia) is a **RR ≥ 50 breaths/min**. In this case, the child is 4 months old with a **RR of 48/min** and **no chest indrawing**. Therefore, he does not meet the criteria for pneumonia. He is classified as having a **"Cough or Cold" (No Pneumonia)**. ### **Analysis of Other Options** * **Option A (Treatment for wheeze):** The presence of rhonchi/wheeze in a 4-month-old often suggests bronchiolitis or viral-induced airway hyperreactivity. Management includes trial of bronchodilators or supportive care for wheezing. * **Option B (Antibiotics should not be given):** Since the child is classified as "No Pneumonia," the etiology is likely viral. IMNCI guidelines explicitly state that antibiotics are not indicated for "Cough or Cold." * **Option D (Fever should be treated):** Supportive care, including managing fever with paracetamol and maintaining hydration, is the standard of care for symptomatic relief in viral upper respiratory infections. ### **High-Yield Clinical Pearls for NEET-PG** * **IMNCI Fast Breathing Cut-offs:** * < 2 months: ≥ 60/min (Classified as Severe Disease) * 2–12 months: ≥ 50/min * 12 months–5 years: ≥ 40/min * **Classification Tip:** If a child has fast breathing, it is **Pneumonia**. If there is chest indrawing or danger signs (inability to feed, lethargy, cyanosis), it is **Severe Pneumonia**. * **Auscultation:** In IMNCI, the diagnosis is clinical (RR/Indrawing); auscultatory findings like rhonchi do not override the RR criteria for classifying pneumonia.

Question 210: A 6-month-old baby presents with a 2-day history of increasing difficulty in breathing. On examination, the baby is afebrile and has bilateral wheezing. Chest X-ray shows bilateral hyperinflation of the lungs with a normal WBC count. What is the most likely diagnosis?

A. Bronchiolitis (Correct Answer)
B. Asthma
C. Chronic Bronchitis
D. Pneumonia

Explanation: **Explanation:** **1. Why Bronchiolitis is Correct:** Bronchiolitis is the most common lower respiratory tract infection in infants (typically <2 years, peaking at 3–6 months). The clinical hallmark is a **viral prodrome** followed by **respiratory distress and wheezing**. The underlying pathology is inflammation and edema of the small airways (bronchioles) leading to air trapping. * **Key Indicators:** The age (6 months), presence of bilateral wheezing, and **Chest X-ray findings of hyperinflation** (due to air trapping) are classic for Bronchiolitis. The absence of fever and a normal WBC count further support a viral etiology, most commonly **Respiratory Syncytial Virus (RSV)**. **2. Why Other Options are Incorrect:** * **Asthma:** While it presents with wheezing, a first episode in a 6-month-old is rarely diagnosed as asthma. Asthma typically involves recurrent episodes and is more common in older children with an atopic history. * **Chronic Bronchitis:** This is a diagnosis of adulthood (associated with smoking) and is not seen in the pediatric age group. * **Pneumonia:** This usually presents with high-grade fever, toxic appearance, and localized findings (crepitations/crackles) rather than generalized wheezing. X-ray would typically show infiltrates or consolidation rather than simple hyperinflation. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Respiratory Syncytial Virus (RSV). * **Diagnosis:** Primarily clinical; X-ray is done to rule out other pathologies. * **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. * **Modified Wood’s Clinical Score:** Used to assess the severity of bronchiolitis.

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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