Respiratory Diseases Practice Questions

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

Left upper lobe. **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).

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

Laryngomalacia. ### 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**.

Q: 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?

Posterior basal segment of left lung. **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.

Q: 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?

CT chest. **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.

Q: 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?

Croup. **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.

Q: 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?

Bronchiolitis. **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.

Question 1

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

Accepted Answer

Left upper lobe

Answer

Right upper lobe

Answer

Right middle lobe

Answer

Left lower lobe

Question 2

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

Accepted Answer

Laryngomalacia

Answer

Laryngotracheobronchitis

Answer

Respiratory obstruction

Answer

Foreign body aspiration

Question 3

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

Accepted Answer

E. Histolytica

Answer

Pneumococcus

Answer

Staphylococcus

Answer

Klebsiella

Question 4

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?

Accepted Answer

Posterior basal segment of left lung

Answer

Right upper lobe

Answer

Right lower lobe

Answer

Lateral basal segment

Question 5

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:

Accepted Answer

Oral steroids are not beneficial in mild croup.

Answer

Nebulized racemic epinephrine is an accepted treatment for moderate or severe croup.

Answer

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.

Answer

Corticosteroids decrease the edema in the laryngeal mucosa through their anti-inflammatory action.

Question 6

Which of the following statements regarding bronchiolitis is NOT true?

Accepted Answer

It commonly occurs in children below 2 years of age.

Answer

Bronchiolitis is a self-limiting viral illness, most commonly caused by respiratory syncytial virus.

Answer

Ribavirin is indicated for severe cases or in immunocompromised patients.

Answer

It can predispose children to the later development of asthma.

Question 7

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?

Accepted Answer

CT chest

Answer

Nasal transmembrane potential difference

Answer

DNA analysis for F508del mutation

Answer

72-hour fecal fat estimation

Question 8

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?

Accepted Answer

Croup

Answer

Bronchiolitis

Answer

Asthma

Answer

Laryngomalacia

Question 9

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?

Accepted Answer

The child has pneumonia

Answer

Treatment for wheeze

Answer

Antibiotics should not be given

Answer

Fever should be treated

Question 10

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?

Accepted Answer

Bronchiolitis

Answer

Asthma

Answer

Chronic Bronchitis

Answer

Pneumonia

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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