Respiratory Diseases — MCQs

Respiratory Diseases Indian Medical PG Practice Questions and MCQs

Question 121: Bag and mask ventilation is contraindicated in all except?

A. Transient tachypnea of newborn (Correct Answer)
B. Tracheo-esophageal fistula
C. Diaphragmatic hernia
D. Meconium aspiration syndrome

Explanation: **Explanation:** The core principle behind contraindications for Bag and Mask Ventilation (BMV) in neonates is the risk of introducing air into the gastrointestinal tract, which can lead to life-threatening complications or worsen the underlying pathology. **Why Option A is Correct:** **Transient Tachypnea of Newborn (TTN)** is caused by delayed resorption of fetal lung fluid. It is a parenchymal lung disease where the primary issue is fluid in the alveoli, not a structural defect. If a neonate with TTN develops respiratory failure or severe apnea, BMV is a safe and standard initial resuscitative measure to provide positive pressure and improve oxygenation. **Why the Other Options are Incorrect:** * **Diaphragmatic Hernia (CDH):** This is an absolute contraindication for BMV. Air entering the stomach and intestines (which are located in the thoracic cavity) will distend the bowel, further compressing the hypoplastic lungs and shifting the mediastinum, leading to rapid clinical deterioration. Immediate endotracheal intubation is required. * **Tracheo-esophageal Fistula (TEF):** In cases with a distal fistula, BMV forces air through the fistula into the stomach. This causes gastric distension, which elevates the diaphragm (splinting respiration) and increases the risk of life-threatening gastric perforation or severe aspiration of gastric acid into the lungs. * **Meconium Aspiration Syndrome (MAS):** While not always an absolute contraindication, BMV is generally avoided in the presence of thick meconium if the infant is non-vigorous. BMV can push meconium deeper into the distal airways, worsening the "ball-valve" obstruction and increasing the risk of air leak syndromes like pneumothorax. **High-Yield Clinical Pearls for NEET-PG:** * **TTN** is most common in term infants delivered via elective C-section (missing the "thoracic squeeze"). * **CDH Management:** "Intubate, don't ventilate (with bag/mask)." Always use a large-bore orogastric tube for decompression. * **Radiology Tip:** TTN shows "sunburst appearance" or "fluid in fissures," while CDH shows "gas-filled bowel loops in the hemithorax."

Question 122: What is the most common cause of stridor in infants and children?

A. Congenital subglottic stenosis
B. Laryngomalacia (Correct Answer)
C. Vocal cord paralysis
D. Foreign body in the airway

Explanation: **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.

Question 123: What is the most common location of a congenital cyst in the lung?

A. Right bronchus (Correct Answer)
B. Left bronchus
C. Pleural surface
D. Perihilar intrapulmonary

Explanation: **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.

Question 124: Respiratory Syncytial Virus causes all of the following in children except?

A. Bronchiolitis
B. Croup
C. Pneumonia
D. Rhinosinusitis (Correct Answer)

Explanation: **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.

Question 125: Which one of the following causes Pectus carinatum?

A. Pulmonary emphysema
B. Childhood asthma (Correct Answer)
C. Atelectasis
D. Lobar pneumonia

Explanation: **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.

Question 126: Which organism most commonly causes bronchitis in children?

A. Haemophilus influenzae (Correct Answer)
B. Respiratory Syncytial Virus (RSV)
C. Mycoplasma pneumoniae
D. Epstein-Barr Virus (EBV)

Explanation: **Explanation:** In the context of pediatric respiratory infections, it is crucial to distinguish between **Acute Bronchitis** and **Acute Bronchiolitis**. **Why Haemophilus influenzae is correct:** While the majority of acute bronchitis cases in adults are viral, in the pediatric population (specifically regarding chronic or bacterial-associated bronchitis), **non-typeable *Haemophilus influenzae*** is the most frequently isolated bacterial pathogen. It is a common commensal of the upper respiratory tract that can migrate to the lower airways, especially following a viral insult or in children with underlying airway hyper-reactivity. *Streptococcus pneumoniae* and *Moraxella catarrhalis* are other common culprits, but *H. influenzae* remains the most prevalent in clinical studies of pediatric bronchitis. **Analysis of Incorrect Options:** * **Respiratory Syncytial Virus (RSV):** This is the most common cause of **Bronchiolitis** (inflammation of the smaller airways) in infants under 2 years of age, not classic bronchitis. * **Mycoplasma pneumoniae:** This is a common cause of "Atypical Pneumonia" and bronchitis in **older children and adolescents** (school-aged), but it is less common than *H. influenzae* across the general pediatric spectrum. * **Epstein-Barr Virus (EBV):** Primarily causes Infectious Mononucleosis. While it can cause pharyngitis and lymphoid hyperplasia, it is a rare cause of isolated bronchitis. **Clinical Pearls for NEET-PG:** * **Bronchiolitis vs. Bronchitis:** Always look for the age and clinical signs. RSV = Bronchiolitis (Wheezing, <2 years). *H. influenzae* = Bronchitis (Productive cough, older children). * **Protracted Bacterial Bronchitis (PBB):** A high-yield diagnosis characterized by a chronic wet cough (>4 weeks) that responds to Amoxicillin-Clavulanate; the most common organism isolated is *H. influenzae*. * **Management:** Most acute bronchitis is self-limiting; however, if bacterial etiology is suspected (PBB), Beta-lactamase inhibitors are the treatment of choice.

Question 127: What is the most common cause of pulmonary abscesses in Cystic Fibrosis?

A. Pseudomonas aeruginosa (Correct Answer)
B. Staphylococcus aureus
C. Burkholderia cenocepacia
D. Nontuberculous mycobacteria

Explanation: **Explanation:** In patients with **Cystic Fibrosis (CF)**, the defective CFTR protein leads to thick, dehydrated mucus, providing an ideal environment for chronic endobronchial infections. While the microbiology of CF evolves with age, **Pseudomonas aeruginosa** is the most significant pathogen. It is the most common cause of chronic lung infection, progressive bronchiectasis, and **pulmonary abscesses** in older children and adults with CF. Its ability to form biofilms and produce virulence factors (like elastase) leads to significant tissue destruction and cavitation. **Analysis of Options:** * **Staphylococcus aureus (Option B):** This is typically the **earliest** pathogen to colonize the CF airway in infants and young children. While it causes pneumonia and abscesses in the general pediatric population, in the specific context of CF-related chronic lung disease and abscess formation, *Pseudomonas* eventually becomes the dominant isolate. * **Burkholderia cenocepacia (Option C):** Part of the *B. cepacia* complex, this is a highly virulent organism associated with "Cepacia syndrome" (rapid clinical decline). While dangerous and often multi-drug resistant, it is much less common than *Pseudomonas*. * **Nontuberculous mycobacteria (Option D):** These (e.g., *M. abscessus*) are increasingly recognized in CF patients and can cause cavitary lesions, but they are not the "most common" cause of pulmonary abscesses compared to Gram-negative bacteria. **High-Yield Clinical Pearls for NEET-PG:** * **Most common organism overall in CF (all ages):** *Staphylococcus aureus* (early) and *Pseudomonas aeruginosa* (late/chronic). * **Most common cause of death in CF:** Respiratory failure due to chronic infection (most often *Pseudomonas*). * **Drug of Choice for Pseudomonas in CF:** Often requires combination therapy (e.g., Ceftazidime/Piperacillin + Aminoglycoside or inhaled Tobramycin). * **Key Diagnostic:** Sweat Chloride test (>60 mEq/L).

Question 128: 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?

A. Third-generation cephalosporins
B. Heimlich's maneuver
C. Reassurance
D. Single dose of dexamethasone (Correct Answer)

Explanation: **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.

Question 129: What respiratory rate is considered tachypnea in a 2-month-old infant?

A. 40 breaths per minute
B. 50 breaths per minute
C. 60 breaths per minute (Correct Answer)
D. 70 breaths per minute

Explanation: **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 130: What is the preferred inhalation method for a 3-year-old child with bronchial asthma?

A. Metered Dose Inhaler (MDI) with a spacer and a face mask (Correct Answer)
B. Metered Dose Inhaler (MDI) with a spacer
C. Metered Dose Inhaler (MDI) directly
D. Rotary capsule (Rotacap)

Explanation: **Explanation:** The primary goal of aerosol therapy in pediatric asthma is to ensure effective drug delivery to the lower airways while minimizing oropharyngeal deposition. The choice of device is strictly determined by the child’s age and developmental ability to coordinate the inhalation technique. **1. Why Option A is Correct:** Children under the age of 4–5 years lack the coordination required for a "press and breathe" technique and cannot generate the high inspiratory flow rates needed for dry powder inhalers. For a **3-year-old**, a **Metered Dose Inhaler (MDI) with a Valved Holding Chamber (Spacer) and a Face Mask** is the gold standard. The spacer eliminates the need for hand-breath coordination, and the face mask ensures a tight seal for children who cannot yet use a mouthpiece reliably. **2. Analysis of Incorrect Options:** * **Option B (MDI with Spacer):** This is the preferred method for children **aged 4–6 years** who can transition from a mask to a mouthpiece but still require a spacer to compensate for poor coordination. * **Option C (MDI directly):** This requires perfect hand-breath coordination. It is generally not recommended for children and is often difficult even for adults. * **Option D (Rotacap/DPI):** Dry Powder Inhalers (DPIs) are breath-actuated and require a forceful, deep inspiration. They are typically reserved for children **>6 years old**. **3. NEET-PG High-Yield Pearls:** * **Age-wise preference:** * <4 years: MDI + Spacer + Face Mask. * 4–6 years: MDI + Spacer + Mouthpiece. * >6 years: MDI + Spacer OR Dry Powder Inhaler (DPI). * **Clinical Fact:** MDIs with spacers are proven to be as effective as (and often superior to) nebulizers for treating acute asthma exacerbations in the emergency department, with fewer side effects like tachycardia. * **Technique:** Ensure the child takes 5–6 breaths (tidal breathing) per puff of the MDI into the spacer.

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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