Respiratory Diseases Practice Questions

Q: A 2-month-old infant is brought to the pediatric clinic with a history of high-pitched inspiratory stridor that began shortly after birth. The mother notes that the sound is most noticeable when the baby is crying or feeding. Which of the following is true regarding the diagnosis?

Omega sign improves in the prone position. ***Omega sign improves in the prone position*** - The clinical presentation of chronic, high-pitched inspiratory stridor starting shortly after birth, which worsens with agitation or feeding, is classic for **laryngomalacia**. The hallmark finding on laryngoscopy is an omega-shaped (Ω) **epiglottis** that collapses inward during inspiration; placing the infant in a **prone position** often relieves airway obstruction by allowing the supraglottic tissues to fall forward. *Thumb sign improves in the supine position* - The **thumb sign** is a classic radiographic finding on a lateral neck X-ray indicative of **epiglottitis**, a medical emergency involving inflammation of the epiglottis. Laryngomalacia is a chronic, benign condition, whereas epiglottitis presents with acute onset drooling, tripod positioning, and fever, which are not described in this infant. *Steeple sign is characteristic* - The **steeple sign** seen on AP neck X-rays is diagnostic for **croup** (laryngotracheobronchitis), which typically presents with a barking cough and is caused by parainfluenza virus. This condition usually occurs in older infants and typically presents with acute symptoms rather than a chronic stridor persisting since birth. *Cherry-red epiglottis sign is characteristic* - A **cherry-red epiglottis** observed during examination is a specific sign of acute, bacterial **epiglottitis**, usually caused by *Haemophilus influenzae* type b. This condition presents with rapidly progressive respiratory distress and dysphagia, and looking in the throat is strictly contraindicated due to the risk of precipitating total airway obstruction.

Q: A patient is shown using a metered -dose inhaler as shown in the image. Which of the following statements about spacer use is correct?

Decreases drug wastage & reduces oropharyngeal deposition. ***Decreases drug wastage & reduces oropharyngeal deposition*** - Spacers act as a reservoir, allowing the medication particles to slow down and suspend in the device, which ensures that more **medication reaches the lower airways** rather than impacting the back of the throat. - By minimizing **oropharyngeal deposition**, spacers significantly reduce the risk of common side effects like **oral candidiasis** and dysphonia, particularly with inhaled corticosteroids. *Increases systemic absorption of the drug* - The primary goal of a spacer is to improve **local delivery** to the lungs, not to increase systemic uptake. - In fact, by reducing deposition in the oropharynx, the amount of drug swallowed and subsequently absorbed into the **systemic circulation** from the GI tract is typically **decreased**. *Makes inhaler technique more complicated and less effective* - Spacers actually simplify the **coordination** required between actuating the inhaler and inhaling, making the process much easier for patients, especially children and the elderly. - They are proven to **improve overall drug delivery efficacy** in patients who struggle with the

Q: Which among the following channels is affected in CFTR gene mutation?

Chloride. ***Chloride*** - The **CFTR gene** (Cystic Fibrosis Transmembrane Conductance Regulator) encodes a protein that functions as an **ATP-gated chloride channel** expressed in the epithelial cells of the lungs, pancreas, and sweat glands. - Mutations in this gene lead to defective **chloride transport**, resulting in thick, viscous secretions that cause the clinical manifestations of **cystic fibrosis**. *Potassium* - **Potassium channels** are vital for maintaining resting membrane potential and repolarization in cardiac and neural tissues, not for the pathogenesis of cystic fibrosis. - CFTR is specifically a transmembrane regulator for anions, not cations like potassium. *Sodium* - While sodium transport is dysregulated in cystic fibrosis (due to the **ENaC** channel becoming hyperactive because of the lack of inhibitory regulation by the CFTR protein), it is not the primary ion channel encoded by the CFTR gene. - The primary defect is the inability to transport **chloride** ions across the cell membrane, which secondarily impacts sodium and water movement. *Magnesium* - **Magnesium channels** (such as TRPM6 or TRPM7) regulate systemic magnesium homeostasis and intracellular signaling. - There is no involvement of magnesium transport in the pathophysiology associated with **CFTR gene mutations**.

Q: A patient develops acute respiratory distress, stridor, unilateral hyperinflation of the chest with decreased breath sounds on that side. What is the most likely cause?

Foreign body aspiration. ### Explanation The clinical presentation of **acute respiratory distress, stridor, and unilateral hyperinflation** is a classic triad for **Foreign Body Aspiration (FBA)**. **Why Foreign Body Aspiration is Correct:** When an object is aspirated, it often creates a **"check-valve" effect**. During inspiration, the airways dilate, allowing air to pass the object. During expiration, the airways narrow, trapping air distal to the foreign body. This leads to **obstructive emphysema (unilateral hyperinflation)** and decreased breath sounds on the affected side. Stridor indicates the object may be lodged in the upper airway or trachea, while localized wheezing or decreased air entry suggests a bronchial location (most commonly the right main bronchus). **Why Other Options are Incorrect:** * **Asthma:** Typically presents with bilateral diffuse wheezing and a history of atopy. It does not cause focal unilateral hyperinflation unless complicated by a secondary pneumothorax. * **Aspiration Pneumonia:** Usually presents with fever, cough, and crackles rather than acute stridor. Radiologically, it shows opacification/consolidation rather than hyperinflation. * **Pleural Effusion:** This would result in **stony dullness** on percussion and **collapsed/shifted lung** (mediastinal shift away from the lesion), but the affected side would show decreased expansion and opacification on X-ray, not hyperinflation. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis & Management:** Rigid Bronchoscopy (both diagnostic and therapeutic). * **Most Common Site:** Right main bronchus (due to it being wider, shorter, and more vertical). * **Radiological Sign:** Mediastinal shift away from the affected side during expiration (due to air trapping). * **Age Group:** Most common in children aged 1–3 years (the "peanut" age).

Q: Pneumatocele is commonest in which of the following conditions?

Staphylococcal pneumonia. **Explanation:** **Staphylococcal pneumonia** is the correct answer because it is a necrotizing infection characterized by the production of toxins (such as Panton-Valentine Leukocidin) and enzymes that cause tissue destruction. This leads to the formation of **pneumatoceles**—thin-walled, air-filled tension cysts within the lung parenchyma. These occur due to a "check-valve" mechanism where air enters the necrotic area during inspiration but becomes trapped during expiration. While pneumatoceles are transient and usually resolve spontaneously, they are a classic radiological hallmark of *Staphylococcus aureus* infection in children. **Analysis of Incorrect Options:** * **Pneumococcal pneumonia (A):** Caused by *Streptococcus pneumoniae*, this typically presents as lobar consolidation. While it is the most common cause of bacterial pneumonia, it rarely causes cavitation or pneumatoceles. * **H. influenzae pneumonia (C):** Usually presents as bronchopneumonia or lobar involvement. While it can cause pleural effusions, pneumatocele formation is not a characteristic feature. * **Viral pneumonia (D):** Typically presents with interstitial infiltrates and hyperinflation. It does not cause the focal parenchymal necrosis required to form pneumatoceles. **NEET-PG High-Yield Pearls:** * **Most common complication** of Staphylococcal pneumonia: Empyema or Pyopneumothorax. * **Radiological triad for Staph pneumonia:** Bronchopneumonia, Pneumatoceles, and Pleural effusion/Empyema. * **Management of Pneumatocele:** Most are asymptomatic and require **conservative management** (observation), as they regress over weeks to months. Surgery is only indicated if they cause tension pneumothorax or become infected.

Question 1

A 2-month-old infant is brought to the pediatric clinic with a history of high-pitched inspiratory stridor that began shortly after birth. The mother notes that the sound is most noticeable when the baby is crying or feeding. Which of the following is true regarding the diagnosis?

Accepted Answer

Omega sign improves in the prone position

Answer

Thumb sign improves in the supine position

Answer

Steeple sign is characteristic

Answer

Cherry-red epiglottis sign is characteristic

Question 2

A patient is shown using a metered -dose inhaler as shown in the image. Which of the following statements about spacer use is correct?

Accepted Answer

Decreases drug wastage & reduces oropharyngeal deposition

Answer

Increases systemic absorption of the drug

Answer

Makes inhaler technique more complicated and less effective

Answer

Has no effect on drug delivery

Question 3

Which among the following channels is affected in CFTR gene mutation?

Accepted Answer

Chloride

Answer

Potassium

Answer

Sodium

Answer

Magnesium

Question 4

A patient develops acute respiratory distress, stridor, unilateral hyperinflation of the chest with decreased breath sounds on that side. What is the most likely cause?

Accepted Answer

Foreign body aspiration

Answer

Asthma

Answer

Aspiration pneumonia

Answer

Pleural effusion

Question 5

Pneumatocele is commonest in which of the following conditions?

Accepted Answer

Staphylococcal pneumonia

Answer

Pneumococcal pneumonia

Answer

H. influenzae pneumonia

Answer

Viral pneumonia

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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