Respiratory Diseases Practice Questions

Q: A 7.5-month-old child presents with cough and mild stridor, initially treated with oral antibiotics showing improvement. Subsequently, the child developed wheeze, productive cough, and mild fever. Radiography reveals hyperlucency, and pulmonary function tests demonstrate an obstructive pattern. What is the most probable diagnosis?

Bronchiolitis obliterans. **Explanation:** **Bronchiolitis Obliterans (BO)** is a chronic obstructive lung disease following a severe lower respiratory tract insult (usually viral, like Adenovirus). The clinical hallmark is a **"biphasic" course**: an initial acute episode (fever, cough, stridor) that shows partial improvement, followed by persistent or progressive symptoms of airway obstruction (wheeze, productive cough, and exercise intolerance). * **Why it is correct:** The presence of persistent wheezing and productive cough after an initial infection, combined with **hyperlucency** on X-ray (due to air trapping) and an **obstructive pattern** on PFTs, is classic for BO. The initial "improvement" followed by chronic obstruction is the key diagnostic clue. **Why other options are incorrect:** * **Post-viral syndrome:** This typically presents as a transient hyper-reactive airway (cough/wheeze) that resolves over a few weeks without the permanent obstructive changes or hyperlucency seen in BO. * **Pulmonary alveolar microlithiasis:** A rare genetic disorder characterized by calcium deposits in alveoli. Radiography would show a "sandstorm" appearance (diffuse fine opacities), not hyperlucency. * **Follicular bronchitis:** Usually associated with immunodeficiency or connective tissue disorders; it presents with nodules on CT rather than the classic post-infectious obstructive picture. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Adenovirus (Types 3, 7, and 21) is the most frequent trigger for post-infectious BO. * **Radiology:** Look for the **"Mosaic Perfusion"** pattern on HRCT (areas of air trapping interspersed with normal lung). * **Diagnosis:** Primarily clinical and radiological; lung biopsy is the gold standard but rarely required. * **Management:** Supportive care, bronchodilators, and sometimes pulses of corticosteroids.

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: Which one of the following is not a common feature of cystic fibrosis?

Polyneuropathy. **Explanation:** Cystic Fibrosis (CF) is an autosomal recessive multisystem disorder caused by mutations in the **CFTR gene** (most commonly **ΔF508**), leading to defective chloride transport and thick, viscous secretions in various organs. **Why Polyneuropathy is the Correct Answer:** Polyneuropathy is **not** a feature of Cystic Fibrosis. CF primarily affects epithelial surfaces (lungs, pancreas, sweat glands, and reproductive tract). While chronic vitamin E deficiency (due to malabsorption) can rarely lead to neurological symptoms like ataxia or loss of vibratory sense, a generalized polyneuropathy is not a recognized clinical manifestation of the disease. **Analysis of Incorrect Options:** * **Exocrine Pancreatic Insufficiency:** Seen in >85% of patients. Thick secretions obstruct pancreatic ducts, leading to acinar atrophy and fibrosis. This results in malabsorption of fats and fat-soluble vitamins (A, D, E, K) and steatorrhea. * **Azoospermia:** Occurs in >95% of males due to **Congenital Bilateral Absence of the Vas Deferens (CBAVD)**. Spermatogenesis is usually normal, but the transport mechanism is absent. * **Distal Gastrointestinal Obstruction (DIOS):** Formerly called "meconium ileus equivalent," DIOS involves the accumulation of viscid chyme in the terminal ileum and cecum, causing intestinal obstruction in older children and adults. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Sweat Chloride Test (>60 mEq/L on two occasions). * **Most common cause of death:** Progressive respiratory failure (common pathogens: *S. aureus* in early childhood, *P. aeruginosa* in adults). * **Newborn Screening:** Immunoreactive Trypsinogen (IRT) levels. * **GI Manifestation:** Meconium ileus is the earliest clinical sign (seen in 15-20% of newborns).

Q: Which genetic mutation is most commonly associated with congenital central hypoventilation syndrome?

Mutation in the paired like homeobox 2B gene. **Explanation:** **Congenital Central Hypoventilation Syndrome (CCHS)**, historically known as "Ondine’s Curse," is a rare disorder characterized by the failure of autonomic control of breathing. **1. Why Option B is Correct:** The hallmark of CCHS is a mutation in the **PHOX2B (Paired-like homeobox 2B) gene** located on chromosome 4p12. This gene is crucial for the development of the autonomic nervous system. Most cases (approx. 90%) involve **polyalanine repeat expansion mutations (PARMs)**. The severity of the hypoventilation, especially during sleep, is often correlated with the length of these repeats. **2. Why Other Options are Incorrect:** * **Option A:** Mutations in the sodium channel alpha 1 subunit (**SCN1A**) are associated with **Dravet Syndrome** (Severe Myoclonic Epilepsy of Infancy), not respiratory control disorders. * **Option C:** Mutations in the **outer dynein arm** (e.g., DNAH5, DNAI1) result in **Primary Ciliary Dyskinesia (PCD)** or Kartagener Syndrome, leading to chronic respiratory infections and situs inversus, but not central apnea. **3. High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Newborns typically present with cyanosis and hypercapnia during sleep (shallow breathing) but may breathe normally while awake. * **Associated Conditions:** CCHS is frequently associated with other disorders of neural crest derivation, most notably **Hirschsprung disease** (15-20% of cases) and **neuroblastoma**. This triad is sometimes referred to as **Haddad Syndrome**. * **Diagnosis:** Gold standard is genetic testing for the *PHOX2B* mutation. * **Management:** Lifelong ventilatory support (CPAP/BiPAP or mechanical ventilation) is required, as the hypercapnic ventilatory response is absent.

Q: A 3-year-old girl presents with a high fever, anorexia, and discomfort. She is leaning forward with significant drooling. A cervical radiograph is shown. What is the most likely explanation for this finding?

Thumb sign. ***Thumb sign*** - The **thumb sign** on lateral cervical X-ray is **pathognomonic for acute epiglottitis**, showing an enlarged, swollen epiglottis resembling a thumb. - Classic presentation includes the **"4 D's"**: **drooling**, **dysphagia**, **distress**, and **dysphonia** with **tripod positioning** (leaning forward). *Batwing sign* - The **batwing sign** refers to bilateral **pulmonary edema** seen on chest X-ray, appearing as butterfly-shaped opacities around the hilum. - This finding is associated with **congestive heart failure** or **acute respiratory distress syndrome**, not epiglottitis. *Air-fluid levels* - **Air-fluid levels** are seen in conditions with **fluid accumulation** in hollow organs like **pneumonia with pleural effusion** or **bowel obstruction**. - This finding would not explain the **neck symptoms** and **tripod positioning** characteristic of epiglottitis. *Honeycombing* - **Honeycombing** represents **end-stage pulmonary fibrosis** with **cystic airspaces** and **thickened septa** on chest imaging. - This chronic lung finding is unrelated to **acute epiglottitis** and would not cause the presented symptoms.

Q: A previously well 1-year-old infant has had a runny nose and has been sneezing and coughing for 2 days. Two other members of the family had similar symptoms. Four hours ago, his cough became much worse. On physical examination, he is in moderate respiratory distress with tachypnea and nasal flaring. Upon auscultation, he has easily audible wheezing with scattered crackles bilaterally. His arterial blood gas on room air revealed a pH of 7.46, a PaCO2 of 34 mm Hg, and a PaO2 of 75 mm Hg. His chest radiograph shows bilateral hyperinflation with flattened diaphragms and peribronchial thickening, without focal consolidation. Which of the following is the appropriate next course of action?

Monitoring oxygenation and fluid status. ***Monitoring oxygenation and fluid status*** - This 1-year-old infant presents with classic **bronchiolitis** (likely **RSV**) given the viral **upper respiratory prodrome**, family clustering, and bilateral **wheeze with crackles**. - **AAP guidelines** recommend supportive care with **oxygen monitoring** and **fluid management** as first-line treatment, avoiding unnecessary interventions in mild-moderate cases. *Inhaled epinephrine and a single dose of steroids* - **Epinephrine** is indicated for **croup** (barking cough, stridor), not bronchiolitis with bilateral wheeze and crackles. - **Steroids** have no proven benefit in **bronchiolitis** and are not recommended by current pediatric guidelines. *Acute-acting bronchodilators and a short course of oral steroids* - **Bronchodilators** (albuterol/salbutamol) show minimal benefit in **bronchiolitis** and are not routinely recommended in infants under 2 years. - **Oral steroids** are ineffective in viral **bronchiolitis** and may increase risk of secondary bacterial infections. *Emergent intubation, mechanical ventilation, and antibiotics* - Patient has **moderate respiratory distress** but **normal pH** (7.46) and **adequate oxygenation** (PaO2 75 mmHg), not requiring immediate intubation. - **Antibiotics** are not indicated as this is a **viral illness** (bronchiolitis) without evidence of bacterial superinfection.

Q: A 7.5-year-old girl presents with a non-productive cough and mild stridor for 3 months. Her condition was improving, but she suddenly developed wheeze, productive cough, and mild fever. Chest X-ray shows hyperlucency, and pulmonary function tests reveal an obstructive pattern. What is the most probable diagnosis?

Bronchiolitis obliterans. **Explanation:** **Bronchiolitis Obliterans (BO)** is a chronic obstructive lung disease resulting from an insult to the lower respiratory tract, leading to inflammation and fibrosis of the small airways (bronchioles). 1. **Why it is correct:** The clinical presentation follows a classic pattern: an initial acute insult (often viral like Adenovirus or Mycoplasma) followed by a period of relative improvement, and then the development of chronic symptoms like **non-productive cough, persistent wheeze, and stridor**. The **hyperlucency** on Chest X-ray (due to air trapping) and the **obstructive pattern** on PFTs are hallmark findings of BO in children. 2. **Why other options are incorrect:** * **Hemosiderosis:** Presents with a triad of hemoptysis, iron deficiency anemia, and diffuse parenchymal infiltrates (not hyperlucency). * **Pulmonary Alveolar Microlithiasis:** A rare genetic disorder characterized by "sand-like" calcifications (microliths) within alveoli. X-ray shows a classic "sandstorm" appearance, not hyperlucency. * **Follicular Bronchitis:** Usually associated with immunodeficiency or connective tissue disorders; it typically presents with a nodular pattern on CT rather than isolated hyperlucency and obstructive PFTs. **Clinical Pearls for NEET-PG:** * **Post-infectious BO:** The most common cause in children is **Adenovirus** (Types 3, 7, and 21). * **Radiology:** Look for the **"Mosaic attenuation"** pattern on HRCT, which is the gold standard for diagnosis. * **Swyer-James-MacLeod Syndrome:** A sequela of post-infectious BO where one lung or lobe remains hyperlucent and small due to obliterated vascularity and air trapping.

Question 1

A 7.5-month-old child presents with cough and mild stridor, initially treated with oral antibiotics showing improvement. Subsequently, the child developed wheeze, productive cough, and mild fever. Radiography reveals hyperlucency, and pulmonary function tests demonstrate an obstructive pattern. What is the most probable diagnosis?

Accepted Answer

Bronchiolitis obliterans

Answer

Post-viral syndrome

Answer

Pulmonary alveolar microlithiasis

Answer

Follicular bronchitis

Question 2

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 3

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

Accepted Answer

Helical CT

Answer

Bronchography

Answer

MRI

Answer

Bronchoscopy

Question 4

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 5

Which one of the following is not a common feature of cystic fibrosis?

Accepted Answer

Polyneuropathy

Answer

Exocrine pancreatic insufficiency

Answer

Azoospermia

Answer

Distal gastrointestinal obstruction

Question 6

Which genetic mutation is most commonly associated with congenital central hypoventilation syndrome?

Accepted Answer

Mutation in the paired like homeobox 2B gene

Answer

Mutation in the sodium channel alpha 1 subunit

Answer

Mutation in the outer dynein arm

Answer

All of the above

Question 7

A 3-year-old girl presents with a high fever, anorexia, and discomfort. She is leaning forward with significant drooling. A cervical radiograph is shown. What is the most likely explanation for this finding?

Accepted Answer

Thumb sign

Answer

Batwing sign

Answer

Air-fluid levels

Answer

Honeycombing

Question 8

A previously well 1-year-old infant has had a runny nose and has been sneezing and coughing for 2 days. Two other members of the family had similar symptoms. Four hours ago, his cough became much worse. On physical examination, he is in moderate respiratory distress with tachypnea and nasal flaring. Upon auscultation, he has easily audible wheezing with scattered crackles bilaterally. His arterial blood gas on room air revealed a pH of 7.46, a PaCO2 of 34 mm Hg, and a PaO2 of 75 mm Hg. His chest radiograph shows bilateral hyperinflation with flattened diaphragms and peribronchial thickening, without focal consolidation. Which of the following is the appropriate next course of action?

Accepted Answer

Monitoring oxygenation and fluid status

Answer

Inhaled epinephrine and a single dose of steroids

Answer

Acute-acting bronchodilators and a short course of oral steroids

Answer

Emergent intubation, mechanical ventilation, and antibiotics

Question 9

A 4-month-old infant presents with cough and a respiratory rate greater than 60/min, without retractions. What is the appropriate management according to the Integrated Management of Childhood Illness (IMNCI) protocol?

Accepted Answer

Administer oral antibiotic, explain danger signs, and arrange for follow-up.

Answer

Administer IM antibiotic and refer urgently.

Answer

Explain danger signs and arrange for follow-up.

Answer

Administer IM antibiotic and hospitalize.

Question 10

A 7.5-year-old girl presents with a non-productive cough and mild stridor for 3 months. Her condition was improving, but she suddenly developed wheeze, productive cough, and mild fever. Chest X-ray shows hyperlucency, and pulmonary function tests reveal an obstructive pattern. What is the most probable diagnosis?

Accepted Answer

Bronchiolitis obliterans

Answer

Hemosiderosis

Answer

Pulmonary alveolar microlithiasis

Answer

Follicular bronchitis

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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