Pediatric Respiratory - 2026 Asthma & RSV Management

1. According to Poiseuille's law, how does the resistance to airflow in a child's airway compare to that of an adult when mucosal edema occurs? A. Resistance increases linearly with the decrease in airway radius B. Resistance is inversely proportional to the fourth power of the airway radius, meaning a 1 mm reduction in a child's small airway increases resistance exponentially (by up to 16-fold) C. Children have larger airways relative to body size, so they are less affected by edema D. Edema decreases airway resistance in children by widening the larynx Correct Answer: B. Resistance is inversely proportional to the fourth power of the airway radius, meaning a 1 mm reduction in a child's small airway increases resistance exponentially (by up to 16-fold) Rationale: In a small child, the airway is narrow. According to Poiseuille's law, resistance is inversely proportional to the radius to the fourth power ($R propto 1/r^4$). Mucosal edema that reduces the lumen by 1 mm increases resistance by 16-fold in an infant, compared to only a 3-fold increase in an adult with larger starting airway diameters. 2. Which anatomical difference in the pediatric respiratory system explains why infants under 4-6 months are highly vulnerable to nasal obstruction? A. They have very large nasal passages that collect debris B. They are obligate nose-breathers due to the anatomical position of the epiglottis and larynx C. Their trachea is highly rigid, preventing mouth-breathing D. They lack a gag reflex to clear oral secretions Correct Answer: B. They are obligate nose-breathers due to the anatomical position of the epiglottis and larynx Rationale: Young infants are obligate nose-breathers because their high-riding epiglottis and larynx sit close to the soft palate, creating a seal. Mucus or swelling in the nasal passages can cause significant respiratory distress since they do not naturally switch to mouth-breathing when congested. Nasal suctioning is a critical intervention. 3. Why are "retractions" (sinking of soft tissues around the ribs) commonly observed in young children during respiratory distress? A. Because their intercostal muscles are hyperactive and pull the ribs inward B. Because the pediatric chest wall is highly compliant (floppy, cartilaginous) and is sucked inward by the high negative intrapleural pressure generated to inhale C. Because children breathe primarily using their upper chest muscles D. It is a sign of rib cage calcification Correct Answer: B. Because the pediatric chest wall is highly compliant (floppy, cartilaginous) and is sucked inward by the high negative intrapleural pressure generated to inhale Rationale: The ribs and chest wall in infants and young children are mostly cartilaginous and highly flexible. When airway resistance increases, the infant must generate high negative pressures to draw air in, which pulls the flexible chest wall inward, resulting in retractions (subcostal, intercostal, substernal, suprasternal). 4. In a child, the narrowest portion of the larynx/airway is located at which anatomical structure? A. The vocal cords B. The cricoid cartilage (subglottic space) C. The epiglottis D. The thyroid cartilage Correct Answer: B. The cricoid cartilage (subglottic space) Rationale: Unlike adults, in whom the narrowest part of the airway is the glottic opening (vocal cords), in infants and children under 8-10 years of age, the narrowest point is the cricoid cartilage, which forms a complete ring in the subglottic space. Swelling here (as in Croup) rapidly compromises the airway. 5. What is the physiological mechanism of "head bobbing" in a dyspneic infant? A. A neurological tremor triggered by hypoxia B. The infant is using accessory neck muscles (scalene and sternocleidomastoid) to lift the chest wall during inspiration, causing the head to pull backward, then fall forward on expiration C. A voluntary sign of distress to attract the caregiver's attention D. Rapid exhaustion of the diaphragm leading to neck spasm Correct Answer: B. The infant is using accessory neck muscles (scalene and sternocleidomastoid) to lift the chest wall during inspiration, causing the head to pull backward, then fall forward on expiration Rationale: Head bobbing is a sign of severe respiratory distress in infants. They use the neck muscles to assist with inspiration, pulling the head back as they inhale; when they exhale and the muscles relax, the head bobs forward. It indicates impending respiratory failure. 6. Why are infants and toddlers prone to rapid oxygen desaturation during periods of apnea or airway obstruction compared to adults? A. They have a lower metabolic rate and consume less oxygen B. They have a high metabolic rate (consuming 6-8 mL/kg/min of oxygen vs. 3-4 mL/kg/min in adults) and a low functional residual capacity (FRC) representing smaller oxygen reserves C. Their hemoglobin has a lower affinity for oxygen D. Their alveoli are twice as large as adult alveoli, losing gas quickly Correct Answer: B. They have a high metabolic rate (consuming 6-8 mL/kg/min of oxygen vs. 3-4 mL/kg/min in adults) and a low functional residual capacity (FRC) representing smaller oxygen reserves Rationale: Young children have a metabolic rate double that of adults, meaning they consume oxygen very quickly. Concurrently, their FRC (the air remaining in the lungs at the end of expiration that serves as an oxygen reservoir) is small. This combination leads to rapid desaturation when breathing stops. 7. What is the functional impact of a child's floppy, U-shaped epiglottis compared to the adult flat epiglottis? A. It is less likely to become infected B. It is longer, more flexible, and projects backward, making it easier to collapse and obstruct the airway during airway inflammation or negative pressure inspiration C. It prevents the aspiration of liquids completely D. It sits lower in the throat, protecting the larynx Correct Answer: B. It is longer, more flexible, and projects backward, making it easier to collapse and obstruct the airway during airway inflammation or negative pressure inspiration Rationale: The pediatric epiglottis is long, narrow, and floppy (omega- or U-shaped) and projects at a more acute angle. When inflamed (Epiglottitis) or under high inspiratory pressures (Laryngomalacia), it can easily flap backward and cause complete airway obstruction. 8. During respiratory distress, an infant exhibits "nasal flaring. " What is the physiological purpose of this sign? A. To cool down the body temperature B. To decrease upper airway resistance and increase the volume of inspired air C. To sneeze out obstructing secretions D. To indicate an allergic reaction Correct Answer: B. To decrease upper airway resistance and increase the volume of inspired air Rationale: Nasal flaring is an involuntary reflex where the nostrils dilate during inspiration. This flares the nares, decreasing resistance at the nasal valve and allowing more air to enter, which is a key clinical sign of respiratory distress. 9. Why is a child's right mainstem bronchus a more common site for foreign body aspiration than the left mainstem bronchus? A. The right mainstem bronchus is longer and narrower B. The right mainstem bronchus is wider, shorter, and branches off the trachea at a steeper, more vertical angle than the left C. The left mainstem bronchus is completely closed by a valve in children D. The right lung has only two lobes, creating less pressure Correct Answer: B. The right mainstem bronchus is wider, shorter, and branches off the trachea at a steeper, more vertical angle than the left Rationale: Anatomically, the right mainstem bronchus is wider and more vertical than the left bronchus, which branches off at a sharper angle to clear the heart. Inhaled objects are therefore more likely to travel straight down the trachea into the right lung. 10. What is the definition of "expiratory grunting" in a pediatric patient, and what does it indicate? A. A vocalization of anger or agitation B. Breathing out against a partially closed glottis to increase end-expiratory pressure, keeping the alveoli open to prevent atelectasis C. Spasms of the vocal cords during inspiration D. A normal sound heard during deep sleep Correct Answer: B. Breathing out against a partially closed glottis to increase end-expiratory pressure, keeping the alveoli open to prevent atelectasis Rationale: Grunting is a compensatory mechanism used by infants with alveolar collapse (e.g., RDS or severe pneumonia). By exhaling against a closed glottis, they create a physiological "CPAP" effect, maintaining positive end-expiratory pressure (PEEP) to keep alveoli open for gas exchange. It indicates severe lung disease. 11. What is the underlying pathophysiology of a pediatric asthma attack? A. Alveolar destruction and loss of lung elasticity B. Chronic airway inflammation, bronchial smooth muscle bronchoconstriction, and excessive mucus production leading to reversible airway obstruction C. Bacterial infection of the bronchial wall causing tissue necrosis D. Congenital narrowing of the pulmonary artery Correct Answer: B. Chronic airway inflammation, bronchial smooth muscle bronchoconstriction, and excessive mucus production leading to reversible airway obstruction Rationale: Asthma is characterized by a triad: 1) airway inflammation (triggered by IgE-mediated responses), 2) airway hyperresponsiveness causing smooth muscle spasm (bronchoconstriction), and 3) hypersecretion of thick mucus, leading to airflow obstruction. A key feature is that the obstruction is typically reversible (spontaneously or with bronchodilators). 12. A 6-year-old child with asthma presents with worsening cough and wheezing. The nurse auscultates the lungs. Which phase of respiration is wheezing typically heard first in mild to moderate asthma? A. During inspiration only B. During expiration, as the airways naturally narrow during exhalation, exacerbating obstruction C. Equally during both phases from the start D. Only after a deep breath in Correct Answer: B. During expiration, as the airways naturally narrow during exhalation, exacerbating obstruction Rationale: During expiration, intrathoracic pressure increases, causing the airways to narrow slightly. In patients with asthma, this narrowing exacerbates the bronchoconstriction, making expiratory wheezing the classic initial finding. As the attack worsens, wheezing becomes biphasic (both inspiratory and expiratory). 13. During a severe asthma exacerbation, a child's wheezing stops suddenly, and the breath sounds become barely audible. The respiratory rate is 45 breaths/minute. What does this "silent chest" indicate? A. The asthma attack has resolved, and the child is recovering B. Severe airway obstruction with virtually no air movement, indicating impending respiratory failure and the need for emergency intervention C. The child has fallen asleep and is resting comfortably D. The child is hyperventilating due to anxiety only Correct Answer: B. Severe airway obstruction with virtually no air movement, indicating impending respiratory failure and the need for emergency intervention Rationale: A "silent chest" is an ominous clinical sign. It occurs when airway obstruction is so severe that the child cannot move enough air to generate a wheeze. The absence of wheezing in a severely dyspneic child indicates near-complete obstruction and imminent respiratory arrest, requiring immediate resuscitation (intubation or emergency drug escalation). 14. What are the common triggers for acute asthma bronchospasm in young children? A. Viral respiratory infections (e.g., rhinovirus, RSV), environmental allergens, cold air, exercise, and exposure to tobacco smoke B. High carbohydrate diets and lack of sleep C. Hot humid weather only D. Bacterial throat infections (e.g., Strep throat) Correct Answer: A. Viral respiratory infections (e.g., rhinovirus, RSV), environmental allergens, cold air, exercise, and exposure to tobacco smoke Rationale: Viral infections are the most common trigger for asthma exacerbations in children under 5. Other triggers include allergens (dust mites, pet dander), physical activity (exercise-induced bronchospasm), inhaled irritants (passive smoking, pollution), and sudden weather changes. 15. A child is diagnosed with "Mild Persistent" asthma. What criteria define this classification under standard asthma guidelines? A. Symptoms occur ≤ 2 days per week; no interference with normal activity B. Symptoms occur 2 days per week, but not daily; nighttime awakenings 3 to 4 times per month; minor limitation in activity C. Daily symptoms; weekly nighttime awakenings; moderate limitation in activity D. Symptoms throughout the day; nightly awakenings; severe limitation in activity Correct Answer: B. Symptoms occur 2 days per week, but not daily; nighttime awakenings 3 to 4 times per month; minor limitation in activity Rationale: Under EPR-3/GINA guidelines, Mild Persistent asthma is defined by symptoms 2 days/week but not daily, and nighttime awakenings 3-4 times/month. Step 1 (Intermittent) is ≤2 days/week. Step 3 (Moderate Persistent) is daily symptoms and weekly awakenings. Step 4 (Severe Persistent) features daily/constant symptoms and nightly awakenings. 16. What is the preferred rescue (quick-relief) medication class for acute bronchospasm, and what is its mechanism of action? A. Inhaled Corticosteroids (ICS); decreases mucosal edema B. Short-acting Beta-2 Agonists (SABA - e.g., Albuterol); binds to beta-2 adrenergic receptors on bronchial smooth muscle, causing rapid muscle relaxation and bronchodilation C. Leukotriene Receptor Antagonists (LTRA); blocks inflammatory pathways D. Long-acting Beta-2 Agonists (LABA); provides sustained bronchodilation Correct Answer: B. Short-acting Beta-2 Agonists (SABA - e.g., Albuterol); binds to beta-2 adrenergic receptors on bronchial smooth muscle, causing rapid muscle relaxation and bronchodilation Rationale: SABAs like albuterol or levalbuterol are the first-line rescue agents. They stimulate beta-2 receptors, causing relaxation of airway smooth muscle within 5-15 minutes. They do not treat the underlying inflammation, only the bronchoconstriction. 17. A child is prescribed an Inhaled Corticosteroid (ICS) like Fluticasone (Flovent) daily. What is the primary purpose of this controller medication? A. To use immediately during an asthma attack to stop wheezing B. To reduce chronic airway inflammation and hyperresponsiveness, preventing future asthma attacks C. To stimulate the immune system to fight respiratory viruses D. To relax the bronchioles for 24 hours Correct Answer: B. To reduce chronic airway inflammation and hyperresponsiveness, preventing future asthma attacks Rationale: ICS are the most effective daily controller medications. They reduce airway swelling, mucus production, and hypersensitivity to triggers. They must be taken daily, even when the child is asymptomatic. They have no bronchodilator effect and should not be used as rescue medicine during an attack.