Respiratory Diseases Practice Questions

Q: What is the most common cause of stridor in infants and children?

Laryngomalacia. **Explanation:** **Laryngomalacia** is the most common cause of congenital stridor in infants and the most frequent congenital anomaly of the larynx. It is characterized by an inward collapse of the supraglottic structures (such as the epiglottis and aryepiglottic folds) during inspiration, leading to airway obstruction. * **Why Option B is Correct:** The classic presentation is **inspiratory stridor** that typically appears within the first two weeks of life. The stridor characteristically worsens when the infant is supine, crying, or feeding, and improves when the infant is prone. Most cases are self-limiting and resolve by 18–24 months of age. **Why the other options are incorrect:** * **A. Congenital Subglottic Stenosis:** This is the third most common congenital laryngeal anomaly. It usually presents with biphasic stridor and is often associated with a history of prolonged intubation (acquired form). * **C. Vocal Cord Paralysis:** This is the second most common cause of neonatal stridor. It can be unilateral (often associated with birth trauma or cardiac surgery) or bilateral (associated with CNS issues like Arnold-Chiari malformation). * **D. Foreign Body in the Airway:** This is a common cause of **acquired** stridor in toddlers (peaking at 1–3 years), but it is not the most common cause overall in the infant/childhood period compared to congenital anomalies. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Flexible fiberoptic laryngoscopy is the gold standard (shows "Omega-shaped" epiglottis). * **Management:** Majority are managed conservatively. Surgical intervention (**Supraglottoplasty**) is reserved for severe cases with failure to thrive, cor pulmonale, or severe apnea. * **Associated Condition:** Gastroesophageal reflux (GERD) is frequently seen in infants with laryngomalacia and can exacerbate symptoms.

Q: What is the most common location of a congenital cyst in the lung?

Right bronchus. **Explanation:** Congenital lung cysts, most commonly referring to **Bronchogenic Cysts**, are the result of abnormal budding of the ventral foregut during the first trimester of gestation. **1. Why the Right Bronchus is correct:** Bronchogenic cysts are typically located in the mediastinum (85%) or the lung parenchyma (15%). Among the mediastinal locations, the most common site is the **subcarinal area**, specifically associated with the **Right Bronchus** (right paratracheal or right tracheobronchial angle). This predilection occurs because the right-sided embryological development of the tracheobronchial tree provides a more frequent site for accessory buds to detach and form cysts. **2. Why the other options are incorrect:** * **Left Bronchus:** While cysts can occur here, they are statistically less common than those on the right side. * **Pleural surface:** Cysts are rarely found on the pleura; they are typically deep-seated within the mediastinum or the intrapulmonary tissue. * **Perihilar intrapulmonary:** Although 15-20% of bronchogenic cysts are intrapulmonary (usually in the lower lobes), the majority are mediastinal and paratracheal/peribronchial in location. **Clinical Pearls for NEET-PG:** * **Histology:** Bronchogenic cysts are lined by **ciliated pseudostratified columnar epithelium** and often contain cartilage, smooth muscle, and mucous glands in their walls. * **Clinical Presentation:** Most are asymptomatic in children but can cause airway compression (stridor, wheezing) or become infected in adults. * **Radiology:** On CT, they appear as well-circumscribed, water-density (or high-protein) masses that **do not communicate** with the tracheobronchial tree. * **Treatment:** Surgical excision is the treatment of choice to prevent complications like infection or malignant transformation.

Q: Respiratory Syncytial Virus causes all of the following in children except?

Rhinosinusitis. **Explanation:** **Respiratory Syncytial Virus (RSV)** is the most significant viral pathogen of the lower respiratory tract in infants and young children. The correct answer is **Rhinosinusitis** because, while RSV commonly causes upper respiratory symptoms like rhinorrhea (the common cold), it is not a primary or typical cause of clinical rhinosinusitis in children. Rhinosinusitis is more frequently associated with bacterial pathogens (e.g., *S. pneumoniae*, *H. influenzae*) or other viruses like Rhinovirus. **Analysis of Options:** * **Bronchiolitis (Option A):** RSV is the **most common cause** of bronchiolitis worldwide. It leads to inflammation, edema, and necrosis of epithelial cells in the small airways, characterized by wheezing and air trapping. * **Croup (Option B):** While Parainfluenza type 1 is the leading cause of Laryngotracheobronchitis (Croup), RSV is a well-recognized secondary cause, especially in younger infants. * **Pneumonia (Option C):** RSV is a major cause of viral pneumonia in children under 2 years of age, often following an initial bout of bronchiolitis. **High-Yield Clinical Pearls for NEET-PG:** * **Seasonality:** RSV outbreaks typically occur in winter and early spring. * **Pathophysiology:** It causes the formation of **syncytia** (multinucleated giant cells) via its Fusion (F) protein. * **Prophylaxis:** **Palivizumab** (a monoclonal antibody against the F protein) is indicated for high-risk infants (preterm, congenital heart disease). * **Diagnosis:** Rapid antigen detection tests or PCR from nasopharyngeal swabs are the gold standards. * **Treatment:** Primarily supportive (hydration, oxygen). Ribavirin is reserved for severe cases in immunocompromised patients.

Q: Which one of the following causes Pectus carinatum?

Childhood asthma. **Explanation:** **Pectus carinatum** (pigeon chest) is a chest wall deformity characterized by the outward protrusion of the sternum and ribs. **Why Childhood Asthma is correct:** Chronic, severe childhood asthma leads to recurrent airway obstruction and hyperinflation of the lungs. During growth, the persistent increased work of breathing and the use of accessory muscles exert chronic outward pressure on the developing, pliable thoracic cage. This mechanical stress results in the permanent outward bowing of the sternum. In contrast, **Pectus excavatum** (funnel chest) is often associated with conditions like Marfan syndrome or rickets. **Analysis of Incorrect Options:** * **Pulmonary Emphysema:** While emphysema causes a **"Barrel Chest"** (increased anteroposterior diameter due to air trapping), it is typically a disease of adults. Pectus carinatum specifically refers to a structural deformity occurring during the developmental years of the skeletal system. * **Atelectasis:** This involves lung collapse, which leads to a *decrease* in thoracic volume. If chronic and unilateral, it may cause a flattening or indrawing of the chest wall on the affected side, not a protrusion. * **Lobar Pneumonia:** This is an acute infectious process. Structural bony deformities like pectus carinatum require chronic, long-term mechanical stress and do not result from short-term inflammatory conditions. **High-Yield Clinical Pearls for NEET-PG:** * **Harrison’s Sulcus:** A horizontal groove along the lower border of the thorax (at the insertion of the diaphragm), often seen in children with chronic asthma or rickets. * **Barrel Chest:** Characteristic of COPD/Emphysema (Ratio of AP to Transverse diameter becomes 1:1). * **Rachitic Rosary:** Knobby deformities at the costochondral junctions, pathognomonic for Rickets.

Q: An 18-month-old child presents with low-grade fever, stridor, and barking cough. A chest X-ray was taken. What is the line of treatment?

Single dose of dexamethasone. **Explanation:** The clinical presentation of low-grade fever, barking cough, and inspiratory stridor in an 18-month-old is classic for **Croup (Laryngotracheobronchitis)**, most commonly caused by the Parainfluenza virus. The characteristic X-ray finding (implied) is the **"Steeple Sign,"** representing subglottic narrowing. **Why Dexamethasone is correct:** Corticosteroids are the mainstay of treatment for Croup. A **single dose of Dexamethasone** (0.15 mg/kg to 0.6 mg/kg, orally or parenterally) reduces laryngeal mucosal edema. It has been shown to decrease the severity of symptoms, reduce the need for hospitalization, and shorten the duration of stay. In moderate to severe cases, nebulized L-epinephrine is added for rapid symptomatic relief. **Why other options are incorrect:** * **A. Third-generation cephalosporins:** These are used for **Acute Epiglottitis** (caused by *H. influenzae*), which presents with high fever, drooling, and a "Thumb sign" on X-ray. Croup is viral and does not require antibiotics. * **B. Heimlich's maneuver:** This is the emergency management for **Foreign Body Aspiration**, which typically presents with sudden-onset choking and unilateral wheezing, not a prodromal fever. * **C. Reassurance:** While mild croup can be managed at home, "reassurance" alone is insufficient as Dexamethasone is now recommended for even mild cases to prevent progression. **NEET-PG High-Yield Pearls:** * **Most common cause:** Parainfluenza virus Type 1. * **X-ray Sign:** Steeple sign (Subglottic narrowing) on AP view. * **Age group:** 6 months to 3 years. * **Scoring system:** Westley Croup Score is used to assess severity. * **Key differentiator:** Epiglottitis has a "cherry-red epiglottis" and no barking cough; Croup has a barking cough and subglottic edema.

Q: What respiratory rate is considered tachypnea in a 2-month-old infant?

60 breaths per minute. **Explanation:** The definition of tachypnea in children is based on age-specific thresholds established by the **World Health Organization (WHO)** and the **Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines. These thresholds are critical for the clinical diagnosis of pneumonia in resource-limited settings. **Why Option C is Correct:** For an infant aged **2 months to 12 months**, tachypnea is defined as a respiratory rate of **≥ 50 breaths per minute**. However, the question asks for the threshold at exactly **2 months**. According to IMNCI criteria: * **< 2 months:** ≥ 60 breaths/min * **2 months to 12 months:** ≥ 50 breaths/min * **12 months to 5 years:** ≥ 40 breaths/min In clinical practice and exams, the "2-month-old" is often the transition point. If the infant is strictly categorized in the "up to 2 months" bracket (0–59 days), **60 breaths per minute** is the diagnostic cutoff for tachypnea. **Analysis of Incorrect Options:** * **Option A (40 bpm):** This is the threshold for tachypnea in children aged **1 to 5 years**. * **Option B (50 bpm):** This is the threshold for infants aged **2 months to 12 months**. * **Option D (70 bpm):** While this is definitely tachypnea, it is not the *minimum* threshold used for diagnosis; it usually indicates severe respiratory distress. **High-Yield Clinical Pearls for NEET-PG:** * **Counting Rule:** The respiratory rate must be counted for a **full 60 seconds** when the child is calm and not crying. * **Pneumonia Diagnosis:** In the IMNCI algorithm, tachypnea is the most sensitive clinical sign for identifying pneumonia. * **Danger Signs:** If tachypnea is accompanied by chest indrawing, it is classified as "Severe Pneumonia" or "Very Severe Disease."

Question 1

Bag and mask ventilation is contraindicated in all except?

Accepted Answer

Transient tachypnea of newborn

Answer

Tracheo-esophageal fistula

Answer

Diaphragmatic hernia

Answer

Meconium aspiration syndrome

Question 2

What is the most common cause of stridor in infants and children?

Accepted Answer

Laryngomalacia

Answer

Congenital subglottic stenosis

Answer

Vocal cord paralysis

Answer

Foreign body in the airway

Question 3

What is the most common location of a congenital cyst in the lung?

Accepted Answer

Right bronchus

Answer

Left bronchus

Answer

Pleural surface

Answer

Perihilar intrapulmonary

Question 4

Respiratory Syncytial Virus causes all of the following in children except?

Accepted Answer

Rhinosinusitis

Answer

Bronchiolitis

Answer

Croup

Answer

Pneumonia

Question 5

Which one of the following causes Pectus carinatum?

Accepted Answer

Childhood asthma

Answer

Pulmonary emphysema

Answer

Atelectasis

Answer

Lobar pneumonia

Question 6

Which organism most commonly causes bronchitis in children?

Accepted Answer

Haemophilus influenzae

Answer

Respiratory Syncytial Virus (RSV)

Answer

Mycoplasma pneumoniae

Answer

Epstein-Barr Virus (EBV)

Question 7

What is the most common cause of pulmonary abscesses in Cystic Fibrosis?

Accepted Answer

Pseudomonas aeruginosa

Answer

Staphylococcus aureus

Answer

Burkholderia cenocepacia

Answer

Nontuberculous mycobacteria

Question 8

An 18-month-old child presents with low-grade fever, stridor, and barking cough. A chest X-ray was taken. What is the line of treatment?

Accepted Answer

Single dose of dexamethasone

Answer

Third-generation cephalosporins

Answer

Heimlich's maneuver

Answer

Reassurance

Question 9

What respiratory rate is considered tachypnea in a 2-month-old infant?

Accepted Answer

60 breaths per minute

Answer

40 breaths per minute

Answer

50 breaths per minute

Answer

70 breaths per minute

Question 10

What is the preferred inhalation method for a 3-year-old child with bronchial asthma?

Accepted Answer

Metered Dose Inhaler (MDI) with a spacer and a face mask

Answer

Metered Dose Inhaler (MDI) with a spacer

Answer

Metered Dose Inhaler (MDI) directly

Answer

Rotary capsule (Rotacap)

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

On this page

Practice by Chapter

Want unlimited practice?