Respiratory Diseases Practice Questions

Q: An 11-month-old child presents with complaints of respiratory distress. On examination, there are bilateral crepitations and wheezing. Which of the following is the most likely cause?

RSV. **Explanation:** The clinical presentation of an 11-month-old child with respiratory distress, **bilateral crepitations, and wheezing** is classic for **Acute Bronchiolitis**. **1. Why RSV is the Correct Answer:** Respiratory Syncytial Virus (RSV) is the most common cause of bronchiolitis worldwide, accounting for approximately 70-80% of cases. It typically affects children under 2 years of age (peak incidence at 3–6 months). The pathophysiology involves inflammation of the small airways (bronchioles), leading to edema, mucus production, and necrosis of epithelial cells. This results in the characteristic clinical finding of **polyphonic wheezing** and fine crackles. **2. Why Other Options are Incorrect:** * **Pneumonia:** While it causes respiratory distress and crepitations, it typically presents with high fever and localized (unilateral) findings. Wheezing is not a hallmark feature of typical bacterial pneumonia. * **Adenovirus:** Though it can cause severe bronchiolitis (and bronchiolitis obliterans), it is less common than RSV and often presents with more systemic symptoms like conjunctivitis or high fever. * **Rhinovirus:** This is the most common cause of the "common cold" (upper respiratory infection). While it can trigger asthma exacerbations in older children, it is the second most common cause of bronchiolitis, trailing behind RSV. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Bronchiolitis is primarily a **clinical diagnosis**. Routine X-rays or labs are not required. * **Radiology:** Hyperinflation of lungs and flattened diaphragm are common findings. * **Management:** Treatment is mainly **supportive** (hydration and oxygenation). Routine use of bronchodilators, steroids, or antibiotics is **not** recommended. * **Prophylaxis:** **Palivizumab** (monoclonal antibody) is used for high-risk infants (e.g., prematurity, congenital heart disease).

Q: Which of the following is a sign of severe pneumonia in an 18-month-old child?

All of the above. **Explanation:** This question is based on the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines, which are high-yield for NEET-PG. The classification of pneumonia in children aged 2 months to 5 years is divided into two categories: **Pneumonia** and **Severe Pneumonia.** 1. **Chest Indrawing (Option A):** This is the hallmark clinical sign of **Severe Pneumonia**. It indicates significant respiratory distress where the child must use accessory muscles to breathe, causing the lower chest wall to move inward during inspiration. 2. **Stridor in a calm child (Option B):** Stridor indicates an upper airway obstruction. According to IMNCI, any child with cough or difficulty breathing who also exhibits stridor while calm is classified as having **Severe Pneumonia/Very Severe Disease**, requiring urgent hospitalization. 3. **Inability to drink (Option C):** This is one of the **General Danger Signs**. In the context of a respiratory infection, the presence of any general danger sign (inability to drink/breastfeed, lethargy, convulsions, or persistent vomiting) automatically upgrades the diagnosis to **Severe Pneumonia**. Since all three clinical findings are criteria for severe disease, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Fast Breathing Thresholds:** * <2 months: ≥60 bpm * 2–12 months: ≥50 bpm * 12 months–5 years: ≥40 bpm * **Classification Change:** Note that the WHO updated guidelines removed the "Very Severe Disease" category for this age group; now, any child with fast breathing is "Pneumonia" (treated with oral Amoxicillin), and any child with chest indrawing or danger signs is "Severe Pneumonia" (requires IV antibiotics). * **Wheeze:** If a child has a wheeze, it should be treated with a bronchodilator before classifying the severity of pneumonia.

Q: What is the earliest presenting feature of cystic fibrosis in a neonate?

Meconium ileus. **Explanation:** **Cystic Fibrosis (CF)** is an autosomal recessive disorder caused by a mutation in the **CFTR gene** (Chromosome 7), leading to defective chloride transport and the production of abnormally thick, viscid secretions. **Why Meconium Ileus is the Correct Answer:** Meconium ileus is the **earliest clinical manifestation** of CF, occurring in approximately 15–20% of affected neonates within the first 24–48 hours of life. Due to the lack of pancreatic enzymes and abnormal water transport in the gut, the meconium becomes extremely thick and "putty-like," causing a mechanical small bowel obstruction (usually at the terminal ileum). **Analysis of Incorrect Options:** * **A. Biliary Cirrhosis:** This is a late-stage complication of CF caused by chronic focal biliary obstruction. It typically manifests in older children or adolescents, not neonates. * **C. Pancreatic Insufficiency:** While present in 85–90% of CF patients and often starting in utero, it usually manifests clinically later in the neonatal period or infancy as malabsorption, steatorrhea, and failure to thrive, rather than an immediate presenting feature at birth. * **D. Respiratory Obstruction:** Although respiratory disease is the leading cause of morbidity and mortality in CF, it rarely presents immediately at birth. Recurrent pneumonia and obstructive airway disease typically develop over the first few months of life. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Meconium ileus shows a **"Soap Bubble" appearance** (Neuhauser sign) on X-ray due to air mixing with thick meconium. * **Screening:** The initial newborn screening test is **Immunoreactive Trypsinogen (IRT)**. * **Gold Standard Diagnosis:** **Sweat Chloride Test** (Pilocarpine Iontophoresis) showing chloride levels **>60 mEq/L**. * **Associated Finding:** 100% of males with CF have **Azoospermia** due to Congenital Bilateral Absence of the Vas Deferens (CBAVD).

Q: In cystic fibrosis, which organism most commonly causes infection?

Staphylococcus. In Cystic Fibrosis (CF), the prevalence of specific respiratory pathogens varies significantly with the patient's age. **Explanation of the Correct Answer:** * **Staphylococcus aureus** is the most common organism causing pulmonary infections in **infants and young children** with Cystic Fibrosis. * In the early stages of the disease, the thick, dehydrated mucus in the airways provides an ideal environment for *S. aureus* (both MSSA and MRSA) to colonize. According to recent epidemiological data (such as the CF Foundation Patient Registry), *S. aureus* remains the most prevalent organism overall across the pediatric age group before being surpassed by others in adulthood. **Explanation of Incorrect Options:** * **A. Pseudomonas aeruginosa:** This is the most common cause of infection in **adults** with CF and the most common cause of **chronic** colonization. While it is the most "iconic" CF pathogen and leads to progressive lung decline, it typically replaces *S. aureus* as the dominant organism later in life (usually by the late teens/early 20s). * **C. Klebsiella:** While Gram-negative bacteria can cause pneumonia, *Klebsiella* is not a characteristic or primary pathogen associated specifically with the pathophysiology of Cystic Fibrosis. * **D. Streptococcus:** *Streptococcus pneumoniae* can cause community-acquired pneumonia in CF patients, but it is not the most frequent or defining pathogen of the disease. **NEET-PG High-Yield Pearls:** * **Most common overall (Childhood):** *Staphylococcus aureus*. * **Most common in Adults/Chronic colonization:** *Pseudomonas aeruginosa*. * **Most common cause of early-onset severe decline:** *Burkholderia cepacia* (associated with "Cepacia Syndrome"). * **Drug of Choice for Pseudomonas in CF:** Inhaled Tobramycin or IV Ceftazidime/Amikacin. * **Newborn Screening:** Immunoreactive Trypsinogen (IRT) levels.

Q: A 4-year-old child presents with findings on a chest X-ray. What is the probable location of the foreign body visible on the skiagram?

Esophagus. ***Esophagus*** - Foreign bodies in the **esophagus** appear **face-on** (en face) on **anteroposterior (AP) chest X-ray**, showing the full circular outline of objects like coins. - The esophagus is the **most common location** for foreign body impaction in children, especially at anatomical narrowings like the **cricopharyngeal area**. *Trachea* - Foreign bodies in the **trachea** appear **edge-on** (sagittal view) on **AP chest X-ray**, showing only the thin edge of circular objects. - Tracheal foreign bodies typically cause **immediate respiratory distress** and **stridor**, which would be the predominant clinical presentation. *Vallecula* - The **vallecula** is located in the **oropharynx** and would not be visible on a **chest X-ray**. - Foreign bodies here typically cause **drooling**, **difficulty swallowing**, and would require **lateral neck X-ray** for visualization. *Right main bronchus* - While the **right main bronchus** is indeed the most common site for **aspirated foreign bodies** due to its **wider diameter** and **more vertical orientation**. - Bronchial foreign bodies often appear as **radiolucent objects** and may cause **unilateral hyperinflation** or **atelectasis** rather than being directly visible.

Q: What is the cutoff value of sweat chloride above which consistently higher readings are diagnostic for Cystic fibrosis?

60 mEq / L. **Explanation:** The **Sweat Chloride Test (Pilocarpine Iontophoresis)** remains the gold standard for diagnosing Cystic Fibrosis (CF). The diagnosis is based on the dysfunction of the CFTR protein, which normally reabsorbs chloride in the sweat ducts. When this protein is defective, chloride (and sodium) remains in the sweat at high concentrations. **1. Why 60 mEq/L is correct:** According to the Cystic Fibrosis Foundation and international guidelines, a sweat chloride concentration of **≥ 60 mEq/L** on two separate occasions is diagnostic of Cystic Fibrosis. This value represents a clear threshold where CFTR dysfunction is clinically significant. **2. Analysis of incorrect options:** * **40 mEq/L (Option A):** This is the upper limit of the **normal range** (≤ 39 mEq/L). Values below this make CF unlikely. * **50 mEq/L (Option B):** This falls into the **intermediate/borderline zone (40–59 mEq/L)**. In this range, the diagnosis is inconclusive, and further testing (DNA mutation analysis or Nasal Potential Difference) is required. * **70 mEq/L (Option D):** While this value is diagnostic, it is not the *cutoff*. The diagnostic threshold begins at 60 mEq/L. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Pilocarpine Iontophoresis (Gibson and Cooke method). * **False Positives:** Conditions like untreated adrenal insufficiency, nephrogenic diabetes insipidus, hypothyroidism, and malnutrition (Type II) can cause elevated sweat chloride. * **Sample Requirement:** A minimum of **75 mg** of sweat must be collected to ensure an accurate result. * **Newborn Screening:** Usually involves testing for **Immunoreactive Trypsinogen (IRT)**; if elevated, it is followed by DNA testing or sweat chloride.

Q: A child presents with fever and a barky cough. On examination, the respiratory rate is 36/min, stridor is present only on crying, and the temperature is 39 degrees Celsius. There are no other abnormal findings. What is the next logical step in management?

Dexamethasone. ### Explanation The clinical presentation of a **barky cough, fever, and inspiratory stridor** in a child is classic for **Croup (Laryngotracheobronchitis)**, most commonly caused by the Parainfluenza virus [1]. To determine the management, we must assess the severity using the **Westley Croup Score**. This patient has **Mild Croup**, characterized by stridor that occurs only when agitated/crying, no intercostal retractions, and no cyanosis [2]. 1. **Why Dexamethasone is correct:** Current clinical guidelines (including Nelson’s Pediatrics) recommend that **all children with croup**, even those with mild symptoms, should receive a single dose of **Dexamethasone (0.15 mg/kg to 0.6 mg/kg)** [4]. It reduces laryngeal edema, decreases the need for subsequent nebulization, and shortens hospital stays. 2. **Why other options are incorrect:** * **Surfactant administration:** Used for Respiratory Distress Syndrome (RDS) in neonates, not for upper airway obstruction. * **Racemized epinephrine:** Reserved for **Moderate to Severe Croup** (stridor at rest, significant retractions) [3]. Since this child only has stridor when crying, epinephrine is not yet indicated. * **Observation and reassurance:** While supportive care is important, "observation alone" is no longer the standard of care, as steroids have been proven to prevent progression to severe respiratory distress [4]. ### Clinical Pearls for NEET-PG: * **X-ray Finding:** "Steeple Sign" (subglottic narrowing) on AP view of the neck. * **Most Common Pathogen:** Parainfluenza virus Type 1. * **Age Group:** Typically 6 months to 3 years [1]. * **Management Tip:** If Racemic Epinephrine is used, the child must be observed for at least 2–4 hours for "rebound phenomenon" (return of symptoms as the drug wears off) [3].

Q: Croup syndrome is usually caused by which of the following viruses?

Rhinoviruses. **Explanation:** **Croup Syndrome (Acute Laryngotracheobronchitis)** is a common pediatric respiratory illness characterized by inflammation and narrowing of the subglottic airway. **Why Rhinoviruses is the correct answer:** While **Parainfluenza virus Type 1** is the most common cause of Croup overall (responsible for ~75% of cases), **Rhinoviruses** are significant viral triggers of upper respiratory tract infections that can lead to Croup syndrome. In the context of the provided options, Rhinoviruses are a recognized etiology of the syndrome, whereas the other listed viruses typically present with distinct clinical syndromes. **Why the other options are incorrect:** * **Coxsackie A virus:** This is primarily associated with **Herpangina** and **Hand-Foot-and-Mouth Disease (HFMD)**. It causes vesicular lesions in the oropharynx rather than subglottic edema. * **Coxsackie B virus:** This is a classic cause of **Pleurodynia (Bornholm disease)**, myocarditis, and pericarditis. It does not typically involve the larynx or cause the characteristic "barking" cough of Croup. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause:** Parainfluenza virus Type 1 (followed by Type 2 and 3). * **Classic Triad:** Barking cough, inspiratory stridor, and hoarseness. * **Radiology:** The **"Steeple Sign"** on Anteroposterior (AP) X-ray of the neck indicates subglottic narrowing. * **Management:** Nebulized **L-Epinephrine** (for immediate vasoconstriction in severe cases) and **Dexamethasone** (oral or IM) are the mainstays of treatment. * **Age Group:** Most common between 6 months and 3 years of age.

Q: Pneumatocele is most commonly caused by which organism?

Staphylococcus. **Explanation:** **Pneumatocele** is a thin-walled, air-filled cyst within the lung parenchyma that typically develops as a complication of bacterial pneumonia. **Why Staphylococcus is correct:** *Staphylococcus aureus* is the most common cause of pneumatoceles. The organism produces specific toxins (such as **Panton-Valentine Leukocidin**) and enzymes that cause focal areas of alveolar necrosis. This leads to a "check-valve" mechanism where air enters the interstitial space during inspiration but becomes trapped during expiration, resulting in the formation of these characteristic air-filled cavities. While they appear alarming on X-ray, most pneumatoceles are asymptomatic and resolve spontaneously with appropriate antibiotic therapy. **Why other options are incorrect:** * **Streptococcus pneumoniae:** While it is the most common cause of community-acquired pneumonia (CAP) in children, it typically presents with lobar consolidation. It is less likely to cause the necrotic tissue destruction required for pneumatocele formation compared to *S. aureus*. * **Streptococcus (General):** Group A Streptococcus can cause severe pneumonia with empyema, but it is a much rarer cause of pneumatoceles than Staph. * **All of the above:** Incorrect because *Staphylococcus* is statistically the most frequent and classic association. **NEET-PG High-Yield Pearls:** 1. **X-ray Finding:** Pneumatoceles appear as thin-walled, radiolucent (black) circles. If they rupture into the pleural space, they cause a **tension pneumothorax**. 2. **Management:** Most pneumatoceles require **conservative management** (observation and antibiotics). Surgical intervention is only indicated if there is respiratory compromise or secondary infection. 3. **Other Causes:** Apart from *S. aureus*, pneumatoceles can be seen in *Klebsiella pneumoniae*, *Escherichia coli*, and hydrocarbon aspiration.

Question 1

An 11-month-old child presents with complaints of respiratory distress. On examination, there are bilateral crepitations and wheezing. Which of the following is the most likely cause?

Accepted Answer

RSV

Answer

Pneumonia

Answer

Adenovirus

Answer

Rhinovirus

Question 2

A 2-year-old female child presented to a Primary Health Centre with a 4-day history of cough and fever, and inability to drink for the last 12 hours. On examination, the child weighed 5 kg and had a respiratory rate of 45/minute with fever. According to the WHO Integrated Management of Childhood Illness (IMCHI) classification, how would this child be classified?

Accepted Answer

Very severe disease

Answer

Pneumonia

Answer

Severe Pneumonia

Answer

No Pneumonia

Question 3

Which of the following is a sign of severe pneumonia in an 18-month-old child?

Accepted Answer

All of the above

Answer

Chest indrawing

Answer

Stridor in a calm child

Answer

Inability to drink

Question 4

What is the earliest presenting feature of cystic fibrosis in a neonate?

Accepted Answer

Meconium ileus

Answer

Biliary cirrhosis

Answer

Pancreatic insufficiency

Answer

Respiratory obstruction

Question 5

In cystic fibrosis, which organism most commonly causes infection?

Accepted Answer

Staphylococcus

Answer

Pseudomonas

Answer

Klebsiella

Answer

Streptococcus

Question 6

A 4-year-old child presents with findings on a chest X-ray. What is the probable location of the foreign body visible on the skiagram?

Accepted Answer

Esophagus

Answer

Trachea

Answer

Vallecula

Answer

Right main bronchus

Question 7

What is the cutoff value of sweat chloride above which consistently higher readings are diagnostic for Cystic fibrosis?

Accepted Answer

60 mEq / L

Answer

40 mEq / L

Answer

50 mEq / L

Answer

70 mEq / L

Question 8

A child presents with fever and a barky cough. On examination, the respiratory rate is 36/min, stridor is present only on crying, and the temperature is 39 degrees Celsius. There are no other abnormal findings. What is the next logical step in management?

Accepted Answer

Dexamethasone

Answer

Surfactant administration

Answer

Racemized epinephrine nebulization

Answer

Observation and reassurance

Question 9

Croup syndrome is usually caused by which of the following viruses?

Accepted Answer

Rhinoviruses

Answer

Coxsackie A virus

Answer

Coxsackie B virus

Answer

All of the above

Question 10

Pneumatocele is most commonly caused by which organism?

Accepted Answer

Staphylococcus

Answer

Streptococcus

Answer

Streptococcus pneumoniae

Answer

All of the above

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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