Respiratory Diseases — MCQs

A seven-year-old child presents with recurrent chest infections and exocrine pancreatic insufficiency, raising suspicion for cystic fibrosis. Sweat chloride levels have been measured between 40-60 mmol/l on two separate occasions. Which of the following tests should be performed next to support the diagnosis of cystic fibrosis?

Q150Medium

A 16-year-old asthmatic uses a salbutamol inhaler twice a week on average and frequently wakes up coughing. She is compliant with her treatment regimen and has good inhaler technique. Which of the following would be the most appropriate next step in managing her asthma?

Respiratory Diseases Indian Medical PG Practice Questions and MCQs

Question 141: What is the commonest sign of an intrabronchial foreign body in children?

A. Cough (Correct Answer)
B. Wheeze
C. Dyspnoea
D. Stridor

Explanation: **Explanation:** Foreign body aspiration (FBA) is a common pediatric emergency, most frequently occurring in children aged 1–3 years. **Why Cough is the Correct Answer:** **Cough** is the most common clinical sign and symptom of an intrabronchial foreign body, present in approximately **80–95% of cases**. When a foreign object enters the tracheobronchial tree, it triggers the cough reflex via the sensory receptors of the vagus nerve located in the larynx, trachea, and carina. While the initial "penetration syndrome" (choking and gasping) is classic, a persistent, unexplained cough remains the most consistent finding during the clinical presentation. **Analysis of Incorrect Options:** * **B. Wheeze:** While common, it is often localized or monophonic. It occurs due to partial airway obstruction but is less frequent than a cough. It is often misdiagnosed as asthma. * **C. Dyspnoea:** Shortness of breath occurs if the foreign body is large or causes significant lung collapse/obstructive emphysema, but it is not as universally present as a cough. * **D. Stridor:** This is a sign of **upper airway** (laryngeal or tracheal) obstruction. Since the question specifies an **intrabronchial** (lower airway) location, stridor is less likely than wheezing or coughing. **Clinical Pearls for NEET-PG:** * **Classic Triad:** Cough, wheezing, and diminished breath sounds (found in only ~40% of patients). * **Most Common Site:** The **Right Main Bronchus** (due to it being wider, shorter, and more vertical than the left). * **Radiology:** Most foreign bodies are **radiolucent** (e.g., peanuts). Look for indirect signs like obstructive emphysema (hyperinflation) or atelectasis. * **Gold Standard Diagnosis/Management:** Rigid Bronchoscopy.

Question 142: Pneumatoceles are seen in which of the following conditions?

A. Klebsiella pneumonia (Correct Answer)
B. Pneumococcal pneumonia
C. Mycoplasma pneumonia
D. Streptococcal pneumonia

Explanation: ### Explanation **Pneumatoceles** are thin-walled, air-filled cavities within the lung parenchyma that typically develop as a complication of necrotizing pneumonia. They occur due to a "check-valve" mechanism where inflammation in the small airways allows air to enter the interstitial space during inspiration but prevents it from leaving during expiration. **Why Klebsiella pneumonia is correct:** * *Klebsiella pneumoniae* is a classic cause of necrotizing pneumonia, especially in patients with underlying debilitation or chronic lung disease. It is characterized by significant tissue destruction, abscess formation, and the development of **pneumatoceles**. * *Note:* While **Staphylococcus aureus** is the most common cause of pneumatoceles in children globally, among the options provided, *Klebsiella* is the most associated with these cavitary lesions. **Why the other options are incorrect:** * **B. Pneumococcal pneumonia:** Caused by *Streptococcus pneumoniae*, this typically presents as lobar pneumonia. While it is the most common cause of community-acquired pneumonia, it is rarely necrotizing and seldom leads to pneumatocele formation. * **C. Mycoplasma pneumonia:** This causes "atypical pneumonia" characterized by interstitial infiltrates. It does not typically cause parenchymal necrosis or air-filled cysts. * **D. Streptococcal pneumonia:** Group A Streptococcus can cause severe pneumonia with empyema, but it is a much less common cause of pneumatoceles compared to *Klebsiella* or *S. aureus*. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of pneumatoceles:** *Staphylococcus aureus* (especially in infants). * **Klebsiella hallmark:** "Red currant jelly" sputum and the "Bulging Fissure Sign" on X-ray due to heavy inflammatory exudate. * **Management:** Most pneumatoceles are asymptomatic and resolve spontaneously; surgical intervention is only required if they become tension pneumatoceles or get secondarily infected.

Question 143: All of the following criteria classify a child aged 11 months as having severe pneumonia, except:

A. Inability to drink or breastfeed
B. Nasal flaring
C. Breathing rate > 40 per minute (Correct Answer)
D. Grunting

Explanation: This question tests your knowledge of the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines for classifying respiratory infections in children aged 2 months to 5 years. ### **Why Option C is the Correct Answer** In a child aged 11 months, a breathing rate of **>40 per minute** is considered normal or "fast breathing" depending on the age bracket, but it does not define "Severe Pneumonia." According to IMNCI: * **Fast breathing** for an 11-month-old is defined as **≥50 breaths per minute**. * A rate of >40 per minute is only considered "fast breathing" for children aged **1 to 5 years**. * More importantly, tachypnea alone classifies a child as having **Pneumonia**, not **Severe Pneumonia**. ### **Analysis of Incorrect Options (Signs of Severe Pneumonia)** Options A, B, and D are all "General Danger Signs" or signs of severe respiratory distress that upgrade the classification to **Severe Pneumonia/Very Severe Disease**: * **Inability to drink or breastfeed (A):** A general danger sign indicating the child is too weak or distressed to maintain hydration/nutrition. * **Nasal flaring (B) and Grunting (D):** These are signs of significant respiratory distress. Grunting, specifically, is an expiratory sound produced against a partially closed glottis to maintain Functional Residual Capacity (FRC). * **Other signs include:** Chest indrawing (subcostal/intercostal), central cyanosis, lethargy, or convulsions. ### **High-Yield Clinical Pearls for NEET-PG** * **Fast Breathing Cut-offs:** * <2 months: ≥60/min * 2–12 months: ≥50/min * 12 months–5 years: ≥40/min * **Classification Shift:** Under the revised WHO criteria, "Chest Indrawing" now classifies a child as **Pneumonia** (treated with oral Amoxicillin), whereas "Severe Pneumonia" requires IV antibiotics and hospitalization due to the presence of general danger signs or severe distress (grunting/cyanosis).

Question 144: What is the most frequent pulmonary pathogen in cystic fibrosis?

A. Klebsiella
B. Enterococci
C. Staphylococci
D. Pseudomonas (Correct Answer)

Explanation: **Explanation:** In Cystic Fibrosis (CF), the defect in the CFTR protein leads to thick, dehydrated secretions that impair mucociliary clearance, creating a niche for chronic bacterial colonization. **Why Pseudomonas is the correct answer:** While the initial colonizer in early childhood is often *Staphylococcus aureus*, **Pseudomonas aeruginosa** is the most frequent and significant pulmonary pathogen overall, especially as patients age. By late adolescence and adulthood, up to 80% of CF patients are colonized with *Pseudomonas*. Its ability to form **biofilms** (mucoid strains) makes it incredibly difficult to eradicate, leading to progressive bronchiectasis and respiratory failure, which is the leading cause of mortality in CF. **Why the other options are incorrect:** * **A. Klebsiella:** While it can cause pneumonia in debilitated or alcoholic patients, it is not a characteristic or frequent pathogen in the CF airway. * **B. Enterococci:** These are typically commensals of the GI tract and are rarely implicated in CF pulmonary exacerbations. * **C. Staphylococci:** *S. aureus* is the most common pathogen in **infants and young children** with CF. However, it is eventually surpassed by *Pseudomonas* in prevalence and clinical impact as the child grows older. **High-Yield Clinical Pearls for NEET-PG:** * **Most common overall/Adults:** *Pseudomonas aeruginosa*. * **Most common in Children (<5-10 years):** *Staphylococcus aureus*. * **Burkholderia cepacia complex:** Associated with "Cepacia syndrome" (rapid clinical decline) and is often a contraindication for lung transplantation. * **Drug of Choice for Pseudomonas:** Antipseudonal penicillins (Piperacillin-Tazobactam), Ceftazidime, or Aminoglycosides (Tobramycin).

Question 145: A 4-year-old child with bronchial asthma presents with 3 or more episodes of wheezing during the daytime in a week and 2 wheezing episodes during the night in a month. How will you grade this asthma?

A. Mild Persistent (Correct Answer)
B. Moderate Persistent
C. Severe Persistent
D. Mild Intermittent

Explanation: ### Explanation The classification of asthma severity in children is based on the frequency of daytime symptoms, nighttime awakenings, and the use of rescue medications. This grading is essential for determining the initial step of management. **1. Why "Mild Persistent" is correct:** According to the GINA (Global Initiative for Asthma) and standard pediatric guidelines, asthma is classified as **Mild Persistent** when: * **Daytime symptoms:** Occur >2 times per week (but not daily). * **Nighttime symptoms:** Occur 3–4 times per month (for ages 5+) or **1–2 times per month (for ages <5)**. In this case, the child has >3 daytime episodes/week and 2 nighttime episodes/month, fitting the criteria for Mild Persistent asthma. **2. Why other options are incorrect:** * **Mild Intermittent:** Symptoms occur ≤2 days per week and nighttime awakenings are ≤2 times per month (for ages 5+) or 0 times (for ages <5). This child’s daytime frequency exceeds this. * **Moderate Persistent:** Symptoms occur **daily** and nighttime awakenings occur >1 time per week (but not nightly). * **Severe Persistent:** Symptoms occur **throughout the day** and nighttime awakenings occur **7 times per week (nightly)**. **3. Clinical Pearls for NEET-PG:** * **Step-up Therapy:** For Mild Persistent asthma, the preferred treatment is **Step 2**: Low-dose Inhaled Corticosteroids (ICS) as daily controller therapy. * **Rule of Two:** If a patient uses a rescue inhaler >2 times/week or has >2 nighttime awakenings/month, their asthma is likely not well-controlled and requires a step-up in therapy. * **PFTs:** In children >5 years, FEV1 or PEFR is 80% predicted in Mild Persistent, 60-80% in Moderate, and <60% in Severe Persistent asthma.

Question 146: A 3-month-old child presents with biphasic stridor and barking cough. All of the following are true regarding this condition EXCEPT:

A. Hypopharyngeal dilation and subglottic stenosis may be seen on X-ray.
B. The condition most commonly involves the subglottis.
C. Males are involved more commonly than females.
D. Antibiotics are used as an initial treatment. (Correct Answer)

Explanation: ### Explanation The clinical presentation of **biphasic stridor** and a **barking cough** in an infant is characteristic of **Croup (Laryngotracheobronchitis)**. **1. Why Option D is the Correct Answer (The "Except"):** Croup is primarily caused by **viruses**, most commonly the **Parainfluenza virus (Type 1)**. Since the etiology is viral, **antibiotics are not indicated** as initial treatment. Management focuses on maintaining the airway using humidified oxygen, nebulized adrenaline (to reduce mucosal edema), and corticosteroids (Dexamethasone) to reduce inflammation. **2. Analysis of Other Options:** * **Option A:** On an Anteroposterior (AP) X-ray of the neck, the characteristic finding is the **"Steeple Sign"** due to subglottic narrowing. Additionally, lateral views may show hypopharyngeal dilation as the child attempts to compensate for the narrowed airway. * **Option B:** The subglottis is the narrowest part of the pediatric airway. In Croup, inflammation and edema are most intense in the **subglottic region**, leading to the classic stridor. * **Option C:** Epidemiologically, Croup shows a slight **male predominance** (approx. 1.5:1 ratio) and typically affects children between 6 months and 3 years of age. **Clinical Pearls for NEET-PG:** * **Most common cause:** Parainfluenza virus Type 1. * **X-ray Sign:** Steeple Sign (Subglottic narrowing). * **Westley Croup Score:** Used to classify severity (Mild, Moderate, Severe). * **Drug of Choice:** Dexamethasone (0.15–0.6 mg/kg) is the mainstay of treatment. * **Differential Diagnosis:** If the child is toxic-looking with high fever and no barking cough, suspect **Acute Epiglottitis** (Thumb sign on X-ray) or **Bacterial Tracheitis**.

Question 147: In a 3-year-old child, what respiratory rate is classified as Pneumonia?

A. 30 breaths/min
B. 40 breaths/min (Correct Answer)
C. 50 breaths/min
D. 60 breaths/min

Explanation: This question tests your knowledge of the **WHO Integrated Management of Childhood Illness (IMCI)** guidelines, which are high-yield for NEET-PG. The classification of pneumonia in children is primarily based on the respiratory rate (RR) adjusted for age. ### **Why 40 breaths/min is correct:** According to IMCI criteria, "Fast Breathing" (Pneumonia) is defined based on the following age-specific thresholds: * **< 2 months:** ≥ 60 breaths/min * **2 – 12 months:** ≥ 50 breaths/min * **12 months – 5 years:** **≥ 40 breaths/min** Since the child in the question is **3 years old** (falling into the 12 months – 5 years category), a respiratory rate of **40 breaths/min** or more is the diagnostic cutoff for pneumonia. ### **Analysis of Incorrect Options:** * **Option A (30 breaths/min):** This is a normal respiratory rate for a 3-year-old. It does not meet the threshold for tachypnea. * **Option C (50 breaths/min):** This is the cutoff for infants aged **2 to 12 months**. While a 3-year-old with 50 breaths/min certainly has pneumonia, the *threshold* for classification starts at 40. * **Option D (60 breaths/min):** This is the cutoff for neonates and infants **under 2 months** of age. ### **Clinical Pearls for NEET-PG:** 1. **Classification Shift:** The WHO now classifies cases as either **Pneumonia** (fast breathing and/or chest indrawing) or **Severe Pneumonia** (presence of any "danger signs" like inability to drink, lethargy, or cyanosis). 2. **Counting Rule:** The respiratory rate must be counted for a **full 60 seconds** when the child is calm. 3. **Chest Indrawing:** If present, it signifies "Pneumonia" under revised guidelines, but if accompanied by danger signs, it is "Severe Pneumonia."

Question 148: A two-year-old child is classified as having pneumonia if the respiratory rate is more than:

A. 30 breaths/min
B. 40 breaths/min (Correct Answer)
C. 50 breaths/min
D. 60 breaths/min

Explanation: The classification of pneumonia in children, according to the **WHO Integrated Management of Childhood Illness (IMCI)** guidelines, relies primarily on the assessment of the respiratory rate to identify "fast breathing." ### **Why Option B is Correct** The threshold for fast breathing is age-dependent because the baseline respiratory rate decreases as a child matures. For a child aged **12 months to 5 years (which includes a two-year-old)**, the cutoff for fast breathing is **≥ 40 breaths per minute**. If a child in this age group presents with a cough or difficulty breathing and a respiratory rate of 40 or more, they are classified as having **Pneumonia**. ### **Analysis of Incorrect Options** * **Option A (30 breaths/min):** This is within the normal range for a two-year-old and does not meet the criteria for tachypnea. * **Option C (50 breaths/min):** This is the cutoff for infants aged **2 months to 12 months**. While a rate of 50 is technically "fast" for a two-year-old, the diagnostic threshold begins at 40. * **Option D (60 breaths/min):** This is the cutoff for neonates and young infants **less than 2 months of age**. ### **High-Yield Clinical Pearls for NEET-PG** * **WHO Classification Summary:** * **< 2 months:** ≥ 60 bpm (Fast breathing) * **2–12 months:** ≥ 50 bpm (Fast breathing) * **12 months–5 years:** ≥ 40 bpm (Fast breathing) * **Pneumonia vs. Severe Pneumonia:** Under revised WHO guidelines, "Pneumonia" is defined by fast breathing, while **"Severe Pneumonia"** is characterized by the presence of at least one danger sign (e.g., chest indrawing, cyanosis, inability to drink, lethargy, or convulsions). * **Measurement Tip:** The respiratory rate must be counted for a full **60 seconds** when the child is calm and not crying to be accurate.

Question 149: A seven-year-old child presents with recurrent chest infections and exocrine pancreatic insufficiency, raising suspicion for cystic fibrosis. Sweat chloride levels have been measured between 40-60 mmol/l on two separate occasions. Which of the following tests should be performed next to support the diagnosis of cystic fibrosis?

A. Repeat sweat chloride levels on a different day
B. Perform a 72-hour fecal fat collection
C. Measure nasal potential difference (Correct Answer)
D. Perform DNA analysis for the F508 mutation

Explanation: **Explanation:** The diagnosis of Cystic Fibrosis (CF) is primarily clinical, supported by evidence of CFTR dysfunction. In this patient, the sweat chloride levels are in the **intermediate range (40–59 mmol/L)**. According to current diagnostic guidelines, if a patient has clinical features of CF but intermediate sweat chloride results, the next step is to perform tests that demonstrate CFTR dysfunction or identify two disease-causing mutations. **Why Nasal Potential Difference (NPD) is correct:** NPD is a functional assay that measures the voltage across the nasal epithelium. In CF, the lack of chloride secretion and increased sodium absorption create a characteristic "more negative" baseline potential and a specific response to amiloride and chloride-free solutions. It is the preferred "ancillary" test to confirm CFTR dysfunction when sweat tests are inconclusive. **Why other options are incorrect:** * **Option A:** Repeating the sweat chloride test is unlikely to be helpful as it has already been performed twice with consistent intermediate results. * **Option B:** Fecal fat collection confirms malabsorption but does not diagnose the underlying cause (CF). It is a supportive test for pancreatic insufficiency, not a diagnostic test for CF itself. * **Option D:** While DNA analysis is diagnostic, testing *only* for the ΔF508 mutation is insufficient. There are over 2,000 mutations; a negative ΔF508 test does not rule out CF. Full gene sequencing would be required, but NPD is the standard functional next step in the diagnostic algorithm. **Clinical Pearls for NEET-PG:** * **Sweat Chloride Cut-offs:** Normal: <30 mmol/L; Intermediate: 30–59 mmol/L; Diagnostic: ≥60 mmol/L (on two occasions). * **Gold Standard Diagnosis:** Sweat Chloride test (Pilocarpine Iontophoresis). * **Most Common Mutation:** ΔF508 (Class II mutation – protein misfolding). * **Newborn Screening:** Measures Immunoreactive Trypsinogen (IRT).

Question 150: A 16-year-old asthmatic uses a salbutamol inhaler twice a week on average and frequently wakes up coughing. She is compliant with her treatment regimen and has good inhaler technique. Which of the following would be the most appropriate next step in managing her asthma?

A. Budesonide 200mg BD (Correct Answer)
B. Theophylline 300mg sustained release
C. Montelukast 10mg
D. Salmeterol 50mg BD

Explanation: **Explanation:** The patient’s clinical presentation—using a SABA (Salbutamol) twice weekly and experiencing **nocturnal symptoms** (frequent coughing at night)—indicates that her asthma is **not well-controlled**. According to GINA (Global Initiative for Asthma) guidelines, the presence of nocturnal symptoms even once a week classifies the asthma as "Persistent," necessitating the initiation of **maintenance controller therapy**. **1. Why Budesonide is Correct:** Inhaled Corticosteroids (ICS), such as **Budesonide**, are the first-line maintenance therapy for persistent asthma. They address the underlying airway inflammation, reduce bronchial hyper-responsiveness, and are the most effective agents for preventing exacerbations and nocturnal symptoms. **2. Why the other options are incorrect:** * **Theophylline (B):** This is a methylxanthine with a narrow therapeutic index and significant side effects. It is considered an add-on therapy and is never the first-line choice for maintenance. * **Montelukast (C):** While Leukotriene Receptor Antagonists (LTRAs) can be used, they are generally considered less effective than ICS as monotherapy. ICS remains the "Gold Standard" for initial controller treatment. * **Salmeterol (D):** Long-Acting Beta-Agonists (LABA) should **never** be used as monotherapy in asthma due to the risk of life-threatening exacerbations. They must always be combined with an ICS. **Clinical Pearls for NEET-PG:** * **Step-up Criteria:** If a patient uses a SABA >2 times/week or has nocturnal awakenings >1-2 times/month, start Step 2 therapy (Low-dose ICS). * **Drug of Choice:** ICS is the most effective long-term medication for controlling asthma across all age groups. * **Side Effects:** Local side effects of ICS include oropharyngeal candidiasis and dysphonia (minimized by using a spacer and rinsing the mouth).

Practice by Chapter

Upper Respiratory Tract Infections

Practice Questions

Lower Respiratory Tract Infections

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Asthma Management

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Cystic Fibrosis

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Bronchiolitis

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Foreign Body Aspiration

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Sleep-Disordered Breathing

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Congenital Lung Malformations

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Pleural Diseases

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Tuberculosis in Children

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Chronic Lung Disease in Premature Infants

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Pulmonary Function Testing

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