Respiratory Diseases Practice Questions

Q: Which of the following is TRUE about Cystic Fibrosis?

Positive sweat test. **Explanation:** Cystic Fibrosis (CF) is an autosomal recessive multisystem disorder caused by mutations in the **CFTR gene** on chromosome 7. The gold standard for diagnosis remains the **Sweat Chloride Test** (Pilocarpine Iontophoresis). * **Why Option B is correct:** A positive sweat test is defined as a chloride concentration **>60 mmol/L** on two separate occasions. This occurs because the defective CFTR protein fails to reabsorb chloride from the sweat duct lumen, leading to "salty sweat." * **Why Options C and D are technically incorrect in this context:** While CF is indeed caused by a CFTR mutation and can present as meconium ileus, the question likely follows the pattern of identifying the **diagnostic hallmark** or is a "single best answer" type where the clinical confirmation (Sweat Test) is prioritized. *Note: In many modern exams, if multiple options are factually true, the most specific diagnostic or definitive feature is chosen.* * **Why Option A is incorrect:** The incidence of 1:2000-3000 is specific to **Caucasian populations**. In India and other Asian countries, the incidence is much lower (estimated at 1:10,000 to 1:40,000), making it a relatively rare diagnosis in the Indian subcontinent. **High-Yield Clinical Pearls for NEET-PG:** * **Most common mutation:** ΔF508 (Class II mutation - protein misfolding). * **Earliest manifestation:** Meconium ileus (seen in 15-20% of newborns). * **Pancreas:** Exocrine insufficiency leading to steatorrhea and Vitamin A, D, E, K deficiency. * **Lungs:** Recurrent infections with *Staphylococcus aureus* (early childhood) and *Pseudomonas aeruginosa* (most common overall). * **Infertility:** 95% of males are infertile due to Congenital Bilateral Absence of Vas Deferens (CBAVD).

Q: A child presents with a running nose and breathlessness, with a positive family history. What is the most likely diagnosis?

Bronchial asthma. **Explanation:** The clinical presentation of breathlessness associated with upper respiratory symptoms (running nose) and a **positive family history** strongly points towards **Bronchial Asthma**. **1. Why Bronchial Asthma is correct:** Asthma is a chronic inflammatory airway disease characterized by reversible airway obstruction. In pediatric cases, it is frequently triggered by viral upper respiratory infections (the "running nose"). The most significant diagnostic clue here is the **positive family history** of atopy or asthma, which reflects the genetic predisposition (Type I Hypersensitivity) central to the diagnosis. Recurrent episodes of wheezing and breathlessness triggered by common colds are hallmark features. **2. Why other options are incorrect:** * **Bronchiolitis:** While it presents with a runny nose and breathlessness (wheezing), it typically occurs in infants (<2 years old), most commonly due to RSV. It is an acute, first-time episode and is not typically associated with a strong family history of asthma. * **Viral Pneumonia:** This usually presents with high-grade fever, prominent cough, and toxic appearance. While it causes breathlessness, the absence of a "wheeze" and the lack of correlation with family history make it less likely than asthma in this scenario. **Clinical Pearls for NEET-PG:** * **Diagnosis:** In children >5 years, Spirometry showing reversibility (>12% improvement in FEV1) is the gold standard. * **Risk Factors:** The **Asthma Predictive Index (API)** is used to predict if a wheezing child will develop persistent asthma. A major criterion is a parental history of asthma. * **Management:** Inhaled Corticosteroids (ICS) are the most effective long-term preventive medications. * **Rule of Thumb:** "All that wheezes is not asthma, but recurrent wheeze with atopy usually is."

Q: A 2-year-old child presents to the emergency department at 3 AM with fever, barking cough, and stridor that is only present while crying. The child is able to drink normally. On examination, the respiratory rate is 36/min and the temperature is 39.6°C. What will be your next step?

High-dose dexamethasone injection. **Explanation:** The clinical presentation of a **barking cough, fever, and inspiratory stridor** in a toddler is classic for **Croup (Laryngotracheobronchitis)**, most commonly caused by the Parainfluenza virus. To determine the management, we assess the severity using the **Westley Croup Score**. This child has **mild-to-moderate croup** because the stridor is only present when agitated (crying) and there are no signs of respiratory distress (the child can drink and the respiratory rate is within acceptable limits for a febrile 2-year-old). 1. **Why Option B is correct:** Corticosteroids are the mainstay of treatment for all severities of croup. A single dose of **Dexamethasone (0.15 mg/kg to 0.6 mg/kg)** reduces airway edema, decreases the need for hospitalization, and shortens the duration of symptoms. It is the "next step" to prevent progression. 2. **Why Option A is incorrect:** Nebulized Racemic Epinephrine is reserved for **moderate-to-severe croup** (stridor at rest, significant retractions). Since this child only has stridor when crying, epinephrine is not yet indicated. 3. **Why Option C is incorrect:** Croup is a clinical diagnosis. Viral testing (RSV/Influenza) does not change the immediate management of the airway. 4. **Why Option D is incorrect:** Croup is viral. Antibiotics are indicated for **Epiglottitis** or **Bacterial Tracheitis**, but the "barking cough" and ability to drink (no drooling) point strongly away from these diagnoses. **High-Yield Pearls for NEET-PG:** * **X-ray finding:** "Steeple Sign" (subglottic narrowing) on AP view of the neck. * **Most common pathogen:** Parainfluenza Type 1. * **Dexamethasone:** Has a long half-life (36–72 hours), making a single dose highly effective. * **Differential:** If the child looks toxic, has high fever, and no barking cough, suspect **Epiglottitis** (Thumbprint sign) or **Bacterial Tracheitis**.

Q: A 3-month-old child presents with moderate fever, non-productive cough, and mild dyspnea. Following a course of antibiotics, the child showed transient improvement but then developed high fever, productive cough, and increased respiratory distress. Chest X-ray 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 resulting from an inflammatory injury to the small airways (bronchioles), leading to luminal narrowing or total occlusion by fibrotic tissue. 1. **Why it is correct:** The clinical history is classic for **Post-infectious BO**. It typically follows a severe lower respiratory tract infection (often Adenovirus). The "biphasic" presentation is key: an initial acute insult followed by a period of relative improvement, then a secondary deterioration with persistent cough, wheezing, and respiratory distress. The **Chest X-ray** showing **hyperlucency** (due to air trapping) and **PFTs** showing a fixed **obstructive pattern** are hallmark diagnostic features. 2. **Why the other options are incorrect:** * **Alveolar microlithiasis:** A rare genetic disorder characterized by widespread intra-alveolar calcification. X-ray shows a "sand-storm" appearance, not hyperlucency. * **Postviral syndrome:** This is a vague term for lingering symptoms after a virus. It does not typically present with severe obstructive PFTs or localized hyperlucency on X-ray. * **Follicular bronchitis:** This is a lymphoproliferative disorder often associated with immunodeficiency or connective tissue diseases. It typically presents with a nodular pattern on imaging rather than pure hyperlucency. **Clinical Pearls for NEET-PG:** * **Most common cause:** Adenovirus (Types 3, 7, and 21) is the most frequent trigger for post-infectious BO in children. * **Radiology:** Look for the **"Mosaic Perfusion"** pattern on HRCT, which is the gold standard for diagnosis. * **Swyer-James-MacLeod Syndrome:** A radiological variant of BO characterized by a unilateral hyperlucent lung and a small pulmonary artery. * **Management:** Treatment is largely supportive (bronchodilators, oxygen) as the airway fibrosis is generally irreversible.

Q: A 5-year-old girl presents with rhinorrhea, barking cough, and sore throat. Examination reveals laboured respiration. Her siblings are well. What is the most probable viral cause of her symptoms?

Parainfluenza virus. **Explanation:** The clinical presentation of a **barking cough**, rhinorrhea, and labored respiration in a young child is classic for **Croup (Laryngotracheobronchitis)**. **Why Parainfluenza virus is correct:** **Parainfluenza virus (Type 1 and 2)** is the most common cause of Croup, accounting for nearly 75% of cases. The virus causes subglottic edema and inflammation, leading to the characteristic "barking" or "brassy" cough, inspiratory stridor, and hoarseness. The prodrome of rhinorrhea and sore throat is typical of the viral upper respiratory infection that precedes the laryngeal symptoms. **Why other options are incorrect:** * **Adenovirus:** Commonly causes pharyngoconjunctival fever (sore throat, fever, and conjunctivitis) or pneumonia, but is a less frequent cause of isolated croup. * **Influenza virus:** While it can cause severe croup, it typically presents with high-grade fever, significant myalgia, and systemic toxicity. * **RSV (Respiratory Syncytial Virus):** This is the primary pathogen for **Bronchiolitis** in children under 2 years, characterized by wheezing rather than a barking cough. **Clinical Pearls for NEET-PG:** * **X-ray Finding:** The classic radiological sign for Croup is the **"Steeple Sign"** (subglottic narrowing) seen on an AP view of the neck. * **Management:** Mild cases are managed with a single dose of **Dexamethasone** (0.6 mg/kg). Severe cases with stridor at rest require **Nebulized Epinephrine** (L-epinephrine or Racemic) for rapid vasoconstriction and reduction of edema. * **Age Group:** Croup typically affects children aged 6 months to 3 years; presentation at age 5 is still common, but always rule out Epiglottitis if the child appears toxic or is drooling.

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.

Question 1

Which of the following is TRUE about Cystic Fibrosis?

Accepted Answer

Positive sweat test

Answer

Incidence is 1:2000

Answer

Mutation in CFTR gene

Answer

May present as meconium ileus

Question 2

A 7.5-month-old child presents with cough and mild stridor, initially treated with oral antibiotics with some improvement. Later, the child developed wheeze, productive cough, and mild fever. Radiographic findings show hyperlucency, and pulmonary function tests reveal an obstructive pattern. What is the most probable diagnosis?

Accepted Answer

Bronchiolitis obliterans

Answer

Post-viral syndrome

Answer

Follicular bronchitis

Answer

Pulmonary alveolar microlithiasis

Question 3

A 4-year-old child presents with a history of chronic left lower lobe pneumonitis. On contrast bronchography, the area involved with the pneumonitis does not fill, whereas the surrounding area does fill. What is the most likely diagnosis?

Accepted Answer

Pulmonary sequestration

Answer

Asthma

Answer

Cystic fibrosis

Answer

Bronchopulmonary dysplasia

Question 4

A child presents with a running nose and breathlessness, with a positive family history. What is the most likely diagnosis?

Accepted Answer

Bronchial asthma

Answer

Bronchiolitis

Answer

Viral pneumonia

Answer

None of the above

Question 5

A 2-year-old child presents to the emergency department at 3 AM with fever, barking cough, and stridor that is only present while crying. The child is able to drink normally. On examination, the respiratory rate is 36/min and the temperature is 39.6°C. What will be your next step?

Accepted Answer

High-dose dexamethasone injection

Answer

Racemic epinephrine nebulization

Answer

Nasal wash for influenza or RSV

Answer

Antibiotics and blood culture

Question 6

A 3-month-old child presents with moderate fever, non-productive cough, and mild dyspnea. Following a course of antibiotics, the child showed transient improvement but then developed high fever, productive cough, and increased respiratory distress. Chest X-ray reveals hyperlucency, and Pulmonary Function Tests demonstrate an obstructive pattern. What is the most probable diagnosis?

Accepted Answer

Bronchiolitis obliterans

Answer

Alveolar microlithiasis

Answer

Postviral syndrome

Answer

Follicular bronchitis

Question 7

A child suffering from acute asthma with intermittent bronchospasm is brought to a hospital ER, and oxygen is administered to establish a Pao2>60 mm Hg. Which of the following statements about the further management of this patient is most accurate?

Accepted Answer

Frequent high-dose delivery of an inhaled beta2 agonist is indicated.

Answer

Benzodiazepines should be given for sedation.

Answer

Inhaled steroids are drugs of choice in acute asthma.

Answer

Aminophylline is always used if bronchospasm is present.

Question 8

A 5-year-old girl presents with rhinorrhea, barking cough, and sore throat. Examination reveals laboured respiration. Her siblings are well. What is the most probable viral cause of her symptoms?

Accepted Answer

Parainfluenza virus

Answer

Adenovirus

Answer

Influenza virus

Answer

RSV

Question 9

A 2-year-old female child presented with fever, cough, and respiratory distress. Chest X-ray showed consolidation in the right lower lobe. She improved with antibiotics, but on follow-up at 8 weeks, she was found to have increasing consolidation in the right lower lobe and recurrent fever. What would be your next investigation?

Accepted Answer

Bronchoscopy

Answer

Bacterial culture of the nasopharynx

Answer

CT scan of the chest

Answer

Allergen sensitivity test

Question 10

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

Accepted Answer

Rhinosinusitis

Answer

Bronchiolitis

Answer

Croup

Answer

Pneumonia

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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