Respiratory Diseases Practice Questions

Q: What is true about cystic fibrosis?

It is caused by a genetic defect on chromosome 7.. ### Explanation **Correct Option: D. It is caused by a genetic defect on chromosome 7.** Cystic Fibrosis (CF) is an **autosomal recessive** disorder caused by a mutation in the **CFTR (Cystic Fibrosis Transmembrane Conductance Regulator)** gene. This gene is located on the **long arm of chromosome 7 (7q31.2)**. The most common mutation is the deletion of phenylalanine at position 508 (**ΔF508**). The defect leads to abnormal chloride transport, resulting in thick, viscid secretions in the lungs, pancreas, and intestines. **Analysis of Incorrect Options:** * **A. Nasal polyposis is absent:** This is incorrect. Nasal polyposis is a common clinical feature of CF (occurring in ~25% of patients). In the pediatric population, the presence of nasal polyps should always raise suspicion for Cystic Fibrosis. * **B. Sweat chloride levels > 30 mmol/L are diagnostic:** This is incorrect. For a definitive diagnosis, sweat chloride levels must be **≥ 60 mmol/L** on two separate occasions. Levels between 30–59 mmol/L are considered intermediate/borderline and require further genetic testing. * **C. Staphylococcus is the most common pathogen in adults:** This is incorrect. While *Staphylococcus aureus* is the most common pathogen in **infants and young children**, ***Pseudomonas aeruginosa*** becomes the predominant pathogen in **adults** and is associated with a decline in lung function. **High-Yield Clinical Pearls for NEET-PG:** * **Meconium Ileus:** The earliest clinical manifestation of CF (seen in 15-20% of newborns). * **Infertility:** 95% of males are infertile due to **Congenital Bilateral Absence of Vas Deferens (CBAVD)**; females have reduced fertility due to thick cervical mucus. * **Vitamin Deficiencies:** Malabsorption of fat-soluble vitamins (A, D, E, K) occurs due to pancreatic insufficiency. * **Screening:** Immunoreactive Trypsinogen (IRT) is used for newborn screening.

Q: Which of the following statements is not true regarding spasmodic croup?

History of fever is present.. ### Explanation: Spasmodic Croup **Spasmodic Croup** (also known as "Midnight Croup") is a clinical variant of croup characterized by sudden-onset respiratory distress, primarily occurring at night. **1. Why Option A is the Correct Answer (The "Not True" Statement):** Unlike Acute Laryngotracheobronchitis (Viral Croup), which is preceded by a prodrome of fever, coryza, and sore throat, **Spasmodic Croup is non-inflammatory and non-infectious.** It is believed to have an allergic or psychological component. Therefore, a **history of fever is typically absent**, and the child appears perfectly healthy during the day before the episode. **2. Analysis of Other Options:** * **Option B (Metallic Cough):** This is a classic feature. The sudden subglottic edema causes a characteristic "barking" or metallic cough, often accompanied by inspiratory stridor. * **Option C (Pale and Edematous Larynx):** On direct laryngoscopy, the laryngeal mucosa in spasmodic croup appears pale, watery, and edematous. This contrasts with viral croup, where the mucosa is typically erythematous (red) and inflamed. * **Option D (Occurs at Night):** This is a hallmark of the condition. The child typically wakes up suddenly at night with respiratory distress, which often resolves rapidly with exposure to cool night air or humidified steam. ### NEET-PG High-Yield Pearls: * **Age Group:** Most common between 1–3 years of age. * **Recurrence:** Spasmodic croup has a high tendency to recur (recurrent croup). * **Management:** Most cases are self-limiting. Management includes reassurance and humidification. Severe cases may require a single dose of corticosteroids (Dexamethasone). * **Key Differentiator:** If the question mentions **fever and toxicity**, think **Viral Croup** or **Bacterial Tracheitis**. If the child is **afebrile** and the episode is **sudden/nocturnal**, think **Spasmodic Croup**.

Q: A 10-year-old child presents with a history of chronic sinusitis, multiple nasal polyps, recurrent chest infections, and malabsorption syndrome. Which one of the following tests would be useful for diagnosis?

Sweat chloride. ### Explanation The clinical presentation of **chronic sinusitis, nasal polyps, recurrent respiratory infections, and malabsorption** (suggestive of pancreatic insufficiency) is a classic triad for **Cystic Fibrosis (CF)**. **Why Sweat Chloride is the Correct Answer:** Cystic Fibrosis is an autosomal recessive disorder caused by a mutation in the **CFTR gene** (Chromosome 7). This defect leads to thick, viscid secretions in the lungs and pancreas, and impaired reabsorption of chloride in sweat ducts. The **Pilocarpine Iontophoresis Sweat Chloride Test** remains the gold standard for diagnosis. A chloride concentration **>60 mmol/L** on two separate occasions is diagnostic of CF. **Analysis of Incorrect Options:** * **A. Total IgE estimation:** While IgE is elevated in Allergic Bronchopulmonary Aspergillosis (ABPA)—a common complication of CF—it is not a diagnostic test for the primary disease itself. * **B. ESR:** This is a non-specific marker of inflammation and does not aid in the definitive diagnosis of a genetic multisystem disorder. * **C. ACE Levels:** Elevated serum Angiotensin-Converting Enzyme (ACE) levels are characteristic of **Sarcoidosis**, which typically presents in adults with bilateral hilar lymphadenopathy, not childhood malabsorption. **High-Yield Clinical Pearls for NEET-PG:** * **Nasal Polyps in Children:** Always rule out Cystic Fibrosis. * **Most Common Mutation:** ΔF508. * **Earliest Manifestation:** Meconium ileus (seen in 15-20% of newborns). * **Common Pathogens:** *Staphylococcus aureus* (early childhood) and *Pseudomonas aeruginosa* (most common cause of chronic infection in older children). * **Infertility:** 95% of males are infertile due to Congenital Bilateral Absence of the Vas Deferens (CBAVD).

Q: Which of the following are seen in Bronchiolitis?

Symptomatic treatment is given. **Explanation:** **Bronchiolitis** is an acute viral infection of the lower respiratory tract, primarily affecting the small airways (bronchioles). It is the most common cause of wheezing in infants. **1. Why Option D is Correct:** The management of bronchiolitis is primarily **supportive/symptomatic**. Since the etiology is viral, antibiotics are not indicated. The mainstay of treatment includes maintaining hydration, nasal suctioning for secretions, and supplemental oxygen if saturation drops below 90-92%. Routine use of bronchodilators, steroids, or chest physiotherapy is generally not recommended by current AAP guidelines. **2. Why Other Options are Incorrect:** * **Option A:** Bronchiolitis typically affects children **under 2 years of age**, with a peak incidence between **2 to 6 months**. It is rare in children older than 2 years due to the increased diameter of their airways. * **Option B:** The most common causative agent is **Respiratory Syncytial Virus (RSV)** (approx. 75% of cases). Other causes include Rhinovirus, Parainfluenza, and Adenovirus. *Streptococcus pneumoniae* is a common cause of bacterial pneumonia, not bronchiolitis. * **Option C:** While Chest X-ray (CXR) often shows hyperinflation and patchy atelectasis, it is **not routinely recommended** for diagnosis. Diagnosis is primarily **clinical**. CXR is reserved for severe cases or to rule out secondary bacterial pneumonia. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** RSV. * **Clinical presentation:** Starts as a viral URI (coryza), progressing to lower respiratory signs like tachypnea, wheezing, and subcostal retractions. * **Modified Wood’s Clinical Score:** Used to assess the severity of bronchiolitis. * **Prophylaxis:** **Palivizumab** (monoclonal antibody against RSV) is indicated for high-risk infants (preterm, congenital heart disease). * **Risk Factor:** Lack of breastfeeding and exposure to cigarette smoke.

Q: What is the most common organism associated with cystic fibrosis?

Pseudomonas aeruginosa (non mucoid). **Explanation:** In patients with **Cystic Fibrosis (CF)**, the respiratory tract is predisposed to chronic bacterial colonization due to thick, inspissated mucus. **Pseudomonas aeruginosa** is the most common pathogen overall, particularly in adolescents and adults. While *Staphylococcus aureus* is the most common organism in early childhood, *Pseudomonas* eventually colonizes the majority of patients. Initially, the infection involves **non-mucoid** strains; however, over time, these transition into **mucoid** phenotypes (producing alginate), which are associated with biofilm formation, increased antibiotic resistance, and a more rapid decline in pulmonary function. **Analysis of Options:** * **A. Pseudomonas aeruginosa (non-mucoid):** Correct. It is the hallmark pathogen of CF lung disease. * **B. Burkholderia cepacia:** While highly significant in CF, it is less common than *Pseudomonas*. It is associated with "Cepacia syndrome" (rapid clinical deterioration) and is often a contraindication for lung transplantation. * **C & D. Pleisomonas and Aeromonas:** These are primarily water-borne Gram-negative rods associated with gastroenteritis or wound infections and are not typical pathogens in Cystic Fibrosis. **Clinical Pearls for NEET-PG:** * **Most common organism (Overall/Adults):** *Pseudomonas aeruginosa*. * **Most common organism (Infants/Children):** *Staphylococcus aureus*. * **Most common cause of death in CF:** Respiratory failure due to chronic infection. * **Diagnostic Gold Standard:** Sweat Chloride Test (>60 mEq/L). * **Genetics:** Autosomal Recessive; mutation in the **CFTR gene** on **Chromosome 7** (most common mutation: **ΔF508**).

Q: The sudden appearance of pneumothorax in a child suffering from pneumonia points to which etiology?

Staphylococci. **Explanation:** The correct answer is **Staphylococci (Option A)**. **Underlying Medical Concept:** *Staphylococcus aureus* is a highly pyogenic and tissue-destructive organism. It produces specific toxins and enzymes (such as hyaluronidase and panton-valentine leukocidin) that lead to **necrosis of the pulmonary parenchyma**. This necrosis often results in the formation of **pneumatoceles** (thin-walled, air-filled cysts). When these subpleural pneumatoceles rupture into the pleural space, they cause a sudden **pneumothorax** or pyopneumothorax. This rapid progression from consolidation to cavitation and pleural complications is a hallmark of Staphylococcal pneumonia in children. **Analysis of Incorrect Options:** * **B. Streptococci:** *Streptococcus pneumoniae* is the most common cause of community-acquired pneumonia in children. While it frequently causes large pleural effusions or empyema, it is typically non-necrotizing and rarely causes pneumatoceles or sudden pneumothorax. * **C. Mycoplasma:** This causes "Atypical Pneumonia," characterized by interstitial infiltrates and constitutional symptoms. It does not cause tissue destruction or pneumothorax. * **D. Klebsiella:** While *Klebsiella* can cause necrotizing pneumonia and lung abscesses (classically the "bulging fissure sign"), it is a much rarer cause of pneumonia in the pediatric age group compared to Staphylococci and is more commonly seen in chronic alcoholics or diabetic adults. **High-Yield Clinical Pearls for NEET-PG:** * **Staphylococcal Pneumonia:** Look for keywords like "pneumatoceles," "pyopneumothorax," and "rapid radiological progression." * **Most common complication:** Empyema is frequently associated with Staph pneumonia. * **Treatment:** Cloxacillin or Vancomycin (if MRSA is suspected). * **Age group:** It is particularly common in infants under 1 year of age.

Q: "Steeple sign" is seen in which of the following conditions?

Croup. **Explanation:** The **"Steeple sign"** (also known as the wine bottle sign) is a classic radiological finding seen on an **Anteroposterior (AP) view of the neck X-ray**. It represents the subglottic narrowing caused by edema and inflammation in **Croup** (Laryngotracheobronchitis). The narrowing of the subglottic airway gives the appearance of a tapered church steeple. **Why the other options are incorrect:** * **Acute Epiglottitis:** Characterized by the **"Thumb sign"** on a **Lateral neck X-ray**, representing a swollen, enlarged epiglottis. It is a medical emergency caused typically by *H. influenzae* type B. * **Laryngomalacia:** The most common cause of congenital stridor. Diagnosis is clinical (inspiratory stridor worsening when supine) and confirmed via laryngoscopy showing "omega-shaped" epiglottis; X-rays are usually unremarkable. * **Quinsy (Peritonsillar Abscess):** Presents with a "hot potato voice," uvular deviation to the opposite side, and trismus. Imaging (CT or Ultrasound) would show a localized collection in the peritonsillar space, not subglottic narrowing. **High-Yield Clinical Pearls for NEET-PG:** * **Croup Etiology:** Most commonly caused by **Parainfluenza virus Type 1**. * **Clinical Triad:** Barking cough (seal-like), inspiratory stridor, and hoarseness. * **Management:** Nebulized adrenaline (for immediate relief of stridor) and Dexamethasone (mainstay of treatment). * **Westley Croup Score** is used to assess severity. * **Distinction:** Unlike Epiglottitis, children with Croup usually do *not* have high fever, drooling, or a toxic appearance.

Q: An 8-year-old girl presents with mild respiratory distress, a history of allergies to cats and wool, and recurrent upper respiratory tract infections. Physical examination reveals expiratory wheezes, use of accessory respiratory muscles, and a hyperresonant chest to percussion. Arterial blood gases show respiratory alkalosis, and the peripheral eosinophil count is increased. What is the most appropriate diagnosis?

Asthma. **Explanation:** The clinical presentation is classic for **Bronchial Asthma**, a chronic inflammatory airway disease characterized by reversible airway obstruction and bronchial hyperreactivity. **Why Option B is Correct:** * **Clinical Triad:** The patient exhibits the hallmark signs: expiratory wheezing, accessory muscle use (indicating distress), and hyperresonance (due to air trapping/hyperinflation). * **Atopy:** A history of allergies (cats, wool) and recurrent infections are strong triggers for extrinsic asthma. * **Laboratory Findings:** Peripheral eosinophilia is a common marker of allergic (Type 1 hypersensitivity) asthma. * **ABG Pattern:** In early or mild-to-moderate asthma exacerbations, hyperventilation leads to low $PaCO_2$ and high pH, resulting in **respiratory alkalosis**. (Note: A "normal" $PaCO_2$ in a severe attack is an ominous sign of impending respiratory failure). **Why Other Options are Incorrect:** * **A. Acute Bronchiolitis:** Typically occurs in children **<2 years old** (peak age 3–6 months), usually caused by RSV. It is rare in an 8-year-old. * **C. Cystic Fibrosis:** While it presents with recurrent infections and wheezing, it usually involves chronic productive cough, malabsorption (steatorrhea), and failure to thrive. * **D. Usual Interstitial Pneumonia (UIP):** A restrictive lung disease presenting with fine "velcro" inspiratory crackles and honeycombing on CT, not expiratory wheezing and hyperresonance. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Spirometry is the gold standard (shows reversibility: $\ge$12% and 200ml increase in $FEV_1$ post-bronchodilator). * **Pulsus Paradoxus:** May be seen in severe acute asthma. * **Chest X-ray:** Usually shows hyperinflation with flattening of the diaphragm. * **Drug of Choice:** Inhaled Corticosteroids (ICS) are the mainstay for long-term control; SABA (Salbutamol) for acute relief.

Q: A 5-year-old female presents with dry cough and progressive breathlessness of two years duration. Examination reveals clubbing, cyanosis, and bibasilar crepitations. What is the probable diagnosis?

Interstitial lung disease. ### Explanation **Correct Answer: C. Interstitial Lung Disease (ILD)** The clinical triad of **progressive breathlessness, digital clubbing, and bibasilar end-expiratory crepitations (Velcro crackles)** is the hallmark of Interstitial Lung Disease [1]. In children, ILD (often termed chILD) presents with a chronic dry cough and restrictive lung physiology [1]. The presence of **cyanosis** indicates significant ventilation-perfusion mismatch and impaired gas exchange across the thickened alveolar-capillary membrane, reflecting the progressive nature of the fibrosis [1]. **Why other options are incorrect:** * **A. Bronchiectasis:** While it presents with clubbing and crepitations, the cough is typically **productive** with copious purulent sputum (not dry). Crepitations are usually coarse and may change with coughing. * **B. Lung Abscess:** This is an acute to subacute condition characterized by high-grade fever and the expectoration of foul-smelling sputum. While it can cause clubbing, it does not present with progressive breathlessness over two years or bilateral basal crepitations. * **C. Pulmonary Tuberculosis:** In children, TB usually presents with constitutional symptoms (fever, weight loss, night sweats). While it can cause chronic cough, bilateral basal crepitations and early clubbing are not its typical primary presentations. **High-Yield Clinical Pearls for NEET-PG:** * **Velcro Crackles:** Fine, high-pitched, end-expiratory crepitations are pathognomonic for ILD/Pulmonary Fibrosis [1]. * **Clubbing in Pulmonology:** Common causes include Suppurative lung diseases (Bronchiectasis, Abscess, Empyema), Bronchogenic Carcinoma, and ILD [1]. **Note:** Simple Chronic Bronchitis and Asthma do *not* typically cause clubbing. * **Diagnosis:** The gold standard for diagnosing the pattern of ILD is **HRCT (High-Resolution Computed Tomography)**, which shows reticular opacities or ground-glass appearance [1].

Question 1

What is true about cystic fibrosis?

Accepted Answer

It is caused by a genetic defect on chromosome 7.

Answer

Nasal polyposis is absent.

Answer

Sweat chloride levels > 30 mmol/L are diagnostic.

Answer

Staphylococcus is the most common pathogen causing infection in cystic fibrosis in adults.

Question 2

Which of the following statements is not true regarding spasmodic croup?

Accepted Answer

History of fever is present.

Answer

Cough is metallic.

Answer

The larynx is pale and edematous.

Answer

It occurs mostly at night.

Question 3

A 10-year-old child presents with a history of chronic sinusitis, multiple nasal polyps, recurrent chest infections, and malabsorption syndrome. Which one of the following tests would be useful for diagnosis?

Accepted Answer

Sweat chloride

Answer

Total IgE estimation

Answer

ESR

Answer

Level of angiotensin converting enzyme

Question 4

Which of the following are seen in Bronchiolitis?

Accepted Answer

Symptomatic treatment is given

Answer

Seen in children 5 months to 3 years of age

Answer

Caused by Streptococcus pneumoniae

Answer

Chest X-ray shows hyperinflation bilaterally

Question 5

What is the most common organism associated with cystic fibrosis?

Accepted Answer

Pseudomonas aeruginosa (non mucoid)

Answer

Burkholderia cepacia

Answer

Pleisomonas

Answer

Aeromonas

Question 6

The sudden appearance of pneumothorax in a child suffering from pneumonia points to which etiology?

Accepted Answer

Staphylococci

Answer

Streptococci

Answer

Mycoplasma

Answer

Klebsiella

Question 7

"Steeple sign" is seen in which of the following conditions?

Accepted Answer

Croup

Answer

Acute epiglottitis

Answer

Laryngomalacia

Answer

Quinsy

Question 8

An 8-year-old girl presents with mild respiratory distress, a history of allergies to cats and wool, and recurrent upper respiratory tract infections. Physical examination reveals expiratory wheezes, use of accessory respiratory muscles, and a hyperresonant chest to percussion. Arterial blood gases show respiratory alkalosis, and the peripheral eosinophil count is increased. What is the most appropriate diagnosis?

Accepted Answer

Asthma

Answer

Acute bronchiolitis

Answer

Cystic fibrosis

Answer

Usual interstitial pneumonia

Question 9

A 5-year-old female presents with dry cough and progressive breathlessness of two years duration. Examination reveals clubbing, cyanosis, and bibasilar crepitations. What is the probable diagnosis?

Accepted Answer

Interstitial lung disease

Answer

Bronchiectasis

Answer

Lung abscess

Answer

Pulmonary tuberculosis

Question 10

A child requires repeated short-acting bronchodilators. What could be the next line of management?

Accepted Answer

Short-acting budesonide

Answer

Methylxanthines

Answer

Oral prednisolone

Answer

Montelukast

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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