Respiratory Diseases Practice Questions

Q: What is the most common cause of viral pneumonia in infants?

Respiratory Syncytial Virus (RSV). **Explanation:** **1. Why Respiratory Syncytial Virus (RSV) is Correct:** RSV is the leading cause of lower respiratory tract infections (LRTI) in infants and young children worldwide. It is the most common cause of both **bronchiolitis** and **viral pneumonia** in children under the age of one. The virus causes inflammation of the small airways and necrosis of the respiratory epithelium, leading to airway obstruction and characteristic wheezing. In the context of NEET-PG, RSV is the "default" answer for most viral respiratory emergencies in infancy. **2. Analysis of Incorrect Options:** * **A. Rhinovirus:** While it is the most common cause of the "common cold" (upper respiratory infection) across all age groups, it is a less frequent cause of primary pneumonia compared to RSV in infants. * **C. Reovirus:** These are generally associated with mild upper respiratory symptoms or gastrointestinal issues (e.g., Rotavirus) but are rarely implicated as a primary cause of pneumonia. * **D. Cytomegalovirus (CMV):** CMV pneumonia typically occurs in **immunocompromised** patients (e.g., post-transplant) or as part of a congenital infection. It is not a common cause of community-acquired pneumonia in immunocompetent infants. **3. Clinical Pearls for NEET-PG:** * **Seasonality:** RSV outbreaks typically occur in winter and early spring. * **Diagnosis:** The gold standard is PCR, but Rapid Antigen Detection Tests (RADT) are commonly used in clinical practice. * **Radiology:** Chest X-rays in viral pneumonia typically show **hyperinflation** and bilateral patchy infiltrates (interstitial pattern) rather than lobar consolidation. * **Treatment:** Management is primarily supportive (oxygen, hydration). **Palivizumab** (a monoclonal antibody) is used for prophylaxis in high-risk preterm infants.

Q: Which of the following is the investigation of choice for Congenital Lobar Emphysema?

Helical CT. **Explanation:** **Congenital Lobar Emphysema (CLE)** is a developmental anomaly characterized by over-inflation of one or more pulmonary lobes (most commonly the Left Upper Lobe) due to a "check-valve" mechanism that allows air entry but prevents its exit. **Why Helical CT is the Investigation of Choice:** While a Chest X-ray is the initial screening tool (showing a hyperlucent lobe with mediastinal shift), **Helical CT (Computed Tomography)** is the investigation of choice. It provides superior anatomical detail, confirming the diagnosis by showing the hyperinflated lobe and attenuated vascularity. Crucially, it helps exclude extrinsic causes of airway compression (like vascular rings or bronchogenic cysts) and assesses the status of the remaining lung parenchyma, which is essential for surgical planning. **Analysis of Incorrect Options:** * **A. Bronchography:** This is an obsolete technique involving the injection of contrast into the bronchi. It has been replaced by CT due to its invasive nature and risk of respiratory distress. * **C. MRI:** While useful for vascular anomalies, it is inferior to CT for evaluating lung parenchyma and is not the primary diagnostic modality for CLE. * **D. Bronchoscopy:** This is primarily used to rule out *intrinsic* obstructions like mucus plugs or foreign bodies. It is not the definitive diagnostic tool for the structural hyperinflation seen in CLE. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Left Upper Lobe (40-50%) > Right Middle Lobe (30%) > Right Upper Lobe (20%). * **Clinical Presentation:** Usually presents in the neonatal period or early infancy with progressive respiratory distress. * **Management:** Surgical lobectomy is the definitive treatment for symptomatic cases. * **Key X-ray finding:** Hyperlucent lobe with herniation to the opposite side and depression of the ipsilateral diaphragm.

Q: A 4-year-old asthmatic child presents with inability to speak, rapid shallow breathing, and pulsus paradoxus. Arterial blood gas analysis reveals respiratory acidosis. What is the next best step in managing this patient?

Urgent endotracheal intubation. **Explanation:** The clinical presentation describes **Status Asthmaticus** with "Life-Threatening" features. The presence of **respiratory acidosis** on ABG in an acute asthma attack is an ominous sign. Normally, a patient in respiratory distress should have respiratory alkalosis due to hyperventilation. A normal or high $PaCO_2$ (leading to acidosis) indicates **respiratory muscle fatigue** and impending respiratory failure. **Why Option A is correct:** Urgent endotracheal intubation and mechanical ventilation are indicated when there are signs of exhaustion, altered sensorium, or "silent chest," and specifically when ABG shows a rising $PaCO_2$ (acidosis). The inability to speak and pulsus paradoxus further confirm the severity of the airway obstruction and the need for definitive airway management. **Why other options are incorrect:** * **Option B:** Hyperbaric oxygen is used for carbon monoxide poisoning or decompression sickness, not for asthma. * **Option C:** While MDIs and steroids are standard for mild-to-moderate asthma, they are insufficient and too slow for a patient in respiratory failure. * **Option D:** Subcutaneous terbutaline may be used in severe cases, but aminophylline is no longer a first-line drug due to its narrow therapeutic index. Neither addresses the immediate need for ventilatory support in the presence of acidosis. **NEET-PG High-Yield Pearls:** * **The "Silent Chest":** A dangerous sign in asthma where airflow is so limited that wheezing disappears. * **ABG Progression:** Early asthma = Respiratory Alkalosis (low $CO_2$). Late/Severe asthma = Respiratory Acidosis (high $CO_2$). * **Pulsus Paradoxus:** Defined as a drop in systolic BP >10 mmHg during inspiration; it correlates with the severity of airway obstruction.

Q: A 5-year-old boy presents with a 3-day history of cough and fever. On physical examination, his temperature is 39.6°C, respiratory rate is 48 breaths per minute, and there are decreased breath sounds on the right side. His chest x-ray reveals findings consistent with pneumonia. What is the most common causative organism associated with this condition?

Staphylococcus aureus. **Explanation:** The clinical presentation of high-grade fever (39.6°C), tachypnea (RR 48/min), and localized decreased breath sounds in a 5-year-old is highly suggestive of **Community-Acquired Pneumonia (CAP)**. **Why Staphylococcus aureus is the correct answer:** While *Streptococcus pneumoniae* is the most common cause of bacterial pneumonia across all pediatric age groups, among the options provided, **Staphylococcus aureus** is a significant and virulent pathogen. In the context of NEET-PG questions, if *S. pneumoniae* is absent from the options, *S. aureus* is the preferred choice, especially when the presentation implies a more severe or rapidly progressive course. *S. aureus* is notorious for causing necrotizing pneumonia, lung abscesses, and empyema (which explains the decreased breath sounds). **Analysis of Incorrect Options:** * **A. Haemophilus influenzae:** Since the introduction of the Hib vaccine, the incidence of *H. influenzae* type b pneumonia has drastically declined. It is now a less common cause than *S. aureus*. * **C. Escherichia coli:** This is a common cause of pneumonia in **neonates** (0-2 months) due to vertical transmission during birth, but it is rare in a 5-year-old child. * **D. Neisseria meningitidis:** While it can cause respiratory symptoms during systemic meningococcemia, it is an extremely rare cause of primary focal pneumonia. **NEET-PG High-Yield Pearls:** * **Most common cause overall (all ages):** *Streptococcus pneumoniae*. * **Most common cause in Neonates:** Group B Streptococcus (GBS) and *E. coli*. * **Atypical Pneumonia (School-age):** *Mycoplasma pneumoniae* (look for "walking pneumonia" or bullous myringitis). * **Staphylococcal Pneumonia Hallmark:** Look for **pneumatoceles** (thin-walled air cysts), empyema, or pyopneumothorax on X-ray. * **Post-Viral Pneumonia:** *S. aureus* is the classic secondary invader following an Influenza infection.

Q: Kartagener's syndrome includes all of the following, except:

Cystic fibrosis. **Explanation:** Kartagener’s syndrome is a subset of **Primary Ciliary Dyskinesia (PCD)**, an autosomal recessive disorder characterized by structural or functional defects in the cilia. The classic triad of Kartagener’s syndrome includes **Situs inversus, Bronchiectasis, and Sinusitis.** **Why Cystic Fibrosis (Option D) is the correct answer:** Cystic Fibrosis is a distinct genetic disorder caused by mutations in the **CFTR gene**, leading to thick, viscous secretions. While both Kartagener’s and Cystic Fibrosis present with recurrent respiratory infections and bronchiectasis, they have different underlying etiologies. Cystic Fibrosis is not a component of Kartagener’s syndrome; rather, it is a major differential diagnosis. **Analysis of Incorrect Options:** * **Situs inversus (Option A):** Present in approximately 50% of patients with PCD. It occurs due to the failure of embryonic nodal cilia to coordinate the left-right orientation of internal organs. * **Bronchiectasis (Option B):** Chronic ciliary immotility leads to impaired mucociliary clearance, resulting in recurrent pulmonary infections and permanent dilation of the bronchi. * **Sinusitis (Option C):** Defective cilia in the paranasal sinuses prevent the drainage of mucus, leading to chronic inflammation and infection. **High-Yield Clinical Pearls for NEET-PG:** * **The Defect:** Most commonly due to the absence of **Dynein arms** (inner or outer) in the microtubular structure of cilia (9+2 arrangement). * **Infertility:** Males are often infertile due to immotile spermatozoa (flagellar defect), while females may have reduced fertility due to affected cilia in the fallopian tubes. * **Screening:** The **Saccharin test** (measures mucociliary clearance time) or exhaled **Nasal Nitric Oxide (nNO)** levels (characteristically low in PCD). * **Confining the Diagnosis:** Electron microscopy of ciliary biopsy or genetic testing is the gold standard.

Q: Which of the following respiratory rates is considered abnormal in the specified age groups?

Respiratory rate > 50/min in a child between 2-12 months age. This question tests the fundamental knowledge of the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** criteria for identifying fast breathing, which is a key clinical sign for diagnosing pneumonia in resource-limited settings. ### **Explanation of the Correct Option** According to IMNCI guidelines, **fast breathing** (tachypnea) is defined based on age-specific thresholds. For a child aged **2 months to 12 months**, the cutoff for fast breathing is a respiratory rate **≥ 50 breaths per minute**. Therefore, a rate > 50/min is considered abnormal and indicative of potential pneumonia. ### **Analysis of Incorrect Options** * **Option A:** In the 2–12 month age group, a rate of 40/min is considered normal. The threshold for abnormality only begins at 50/min. * **Option C:** For children aged **1 year to 5 years**, fast breathing is defined as a respiratory rate **≥ 40 breaths per minute**. A rate of 30/min is well within the normal physiological range for this age group. * **Option D:** For young infants **less than 2 months** of age, the threshold for fast breathing is **≥ 60 breaths per minute**. A rate of 50/min is considered normal in a newborn or young infant. ### **High-Yield Clinical Pearls for NEET-PG** * **IMNCI Cut-offs for Fast Breathing:** * < 2 months: **≥ 60/min** * 2 months to 12 months: **≥ 50/min** * 12 months to 5 years: **≥ 40/min** * **Measurement Protocol:** The respiratory rate must be counted for a **full 60 seconds** when the child is calm and not crying. * **Pneumonia Classification:** Under WHO/IMNCI, "Pneumonia" is classified by fast breathing alone, while "Severe Pneumonia" is characterized by the presence of **chest indrawing** or any general danger signs (inability to feed, lethargy, convulsions).

Question 1

A 2-year-old boy presented to the ER with stridor, hoarseness of breath, and difficulty in swallowing. The patient also has a history of recurrent chest infections for which he was frequently hospitalized. Upper GI endoscopy was normal. Chest x-ray findings are pending. What is the most likely diagnosis?

Accepted Answer

Dysphagia lusoria

Answer

Achalasia cardia

Answer

Nutcracker esophagus

Answer

Diffuse esophageal spasm

Question 2

What is the most common cause of viral pneumonia in infants?

Accepted Answer

Respiratory Syncytial Virus (RSV)

Answer

Rhinovirus

Answer

Reovirus

Answer

Cytomegalovirus (CMV)

Question 3

A 14-year-old boy presents with headache, fever, and cough for 2 days. Sputum is scant and non-purulent, and Gram stain reveals many white cells but no organisms. With which medication should treatment be initiated?

Accepted Answer

Erythromycin

Answer

Cefazolin

Answer

Amikacin

Answer

Trovafloxacin

Question 4

Which of the following is the investigation of choice for Congenital Lobar Emphysema?

Accepted Answer

Helical CT

Answer

Bronchography

Answer

MRI

Answer

Bronchoscopy

Question 5

A 4-year-old asthmatic child presents with inability to speak, rapid shallow breathing, and pulsus paradoxus. Arterial blood gas analysis reveals respiratory acidosis. What is the next best step in managing this patient?

Accepted Answer

Urgent endotracheal intubation

Answer

Hyperbaric oxygen therapy

Answer

Metered dose inhaler with salbutamol and corticosteroids

Answer

Subcutaneous terbutaline with aminophylline drip

Question 6

A 13-year-old patient with sickle-cell anemia presents with respiratory distress and an infiltrate on chest radiograph. Laboratory findings include: hemoglobin 5 g/dL; hematocrit 16%; white blood cell count 30,000/mL; and arterial blood gases (room air) pH 7.1, PO2 35 mm Hg, and PaCO2 28 mm Hg. These values indicate which of the following?

Accepted Answer

Acidemia, metabolic acidosis, respiratory alkalosis, and hypoxia

Answer

Alkalemia, respiratory acidosis, metabolic alkalosis, and hypoxia

Answer

Acidosis with compensatory hypoventilation

Answer

Long-term metabolic compensation for respiratory alkalosis

Question 7

A 5-year-old boy presents with a 3-day history of cough and fever. On physical examination, his temperature is 39.6°C, respiratory rate is 48 breaths per minute, and there are decreased breath sounds on the right side. His chest x-ray reveals findings consistent with pneumonia. What is the most common causative organism associated with this condition?

Accepted Answer

Staphylococcus aureus

Answer

Haemophilus influenzae

Answer

Escherichia coli

Answer

Neisseria meningitidis

Question 8

Kartagener's syndrome includes all of the following, except:

Accepted Answer

Cystic fibrosis

Answer

Situs inversus

Answer

Bronchiectasis

Answer

Sinusitis

Question 9

Which of the following respiratory rates is considered abnormal in the specified age groups?

Accepted Answer

Respiratory rate > 50/min in a child between 2-12 months age

Answer

Respiratory rate > 40/min in a child between 2-12 months age

Answer

Respiratory rate > 30/min in a child between 1-5 years age

Answer

Respiratory rate > 50/min in a child between < 2 months age

Question 10

Which of the following are features of bronchiolitis?

Accepted Answer

Caused by RSV

Answer

Wheeze is present

Answer

Pulmonary edema is common

Answer

Seen in immunocompromised hosts

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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