Bronchiolitis

Airway instrumentation provokes it - Manipulating the airway when the bronchi are hyperresponsive can worsen obstruction and hypercapnia, so weigh hard whether an elective case can wait out the illness.

Severity at the bedside - Tachypnea, intercostal and subcostal retractions, nasal flaring, grunting, prolonged expiration, wheezes, crackles, rhonchi, and cyanosis. The children who decompensate are those under 12 weeks, born preterm, with chronic lung disease, hemodynamically significant congenital heart disease, neuromuscular disease that impairs airway clearance, airway anomalies, or immunodeficiency. A palivizumab prophylaxis history flags exactly that group.

Diagnosis is clinical - No routine labs or films. Get a chest x-ray only when you suspect a complication such as pneumothorax or bacterial pneumonia; expect nonspecific hyperinflation, patchy atelectasis, and peribronchial thickening, which are hard to separate from bacterial pneumonia.

Bronchodilators and steroids do not work here - Albuterol, nebulized racemic and parenteral epinephrine, and corticosteroids are not recommended in bronchiolitis. A Cochrane review of 30 randomized trials found no improvement in oxygen saturation, hospitalization rate, length of stay, or time to resolution. In ventilated infants with RSV bronchiolitis, bronchodilators dropped peak inspiratory pressure only trivially while causing significant tachycardia.

What actually helps - Supportive care: suction the nose and upper airway, keep the child hydrated, humidified oxygen. Supplemental oxygen is not routine unless saturations sit below 90%. Escalation runs high-flow nasal cannula, then CPAP, then intubation and mechanical ventilation. Nebulized hypertonic saline is an option in hospitalized children but not in the ED, and it can itself provoke bronchospasm, so it is usually given with an inhaled bronchodilator.

Secretions and plugging - Ciliary dysfunction plus mucus and cellular debris obstruct the small airways, so plan for frequent suctioning. Children have poorly developed collateral ventilation, so a plugged bronchus collapses the segment behind it — treat a sudden desaturation or rising peak pressure as a plug until proven otherwise.

If bronchospasm is the problem - Ketamine has bronchodilatory effects and works as both sedative and bronchodilator during noninvasive or invasive support. Inhaled volatile anesthetics are potent bronchodilators but sit at the end of the line, at the cost of myocardial depression, arrhythmias, cerebral vasodilation, and volatile exposure in an MH-susceptible child.

Ventilating obstructed small airways - Air trapping raises the risk of pneumothorax and pneumomediastinum. Use a lung-protective strategy and tolerate permissive hypercapnia; refractory hypoxia or hypercapnia may require extracorporeal life support.

Isolation - RSV spreads by respiratory droplet. Contact precautions, gowns and gloves, and hand hygiene between rooms. Infected children are contagious 3 to 8 days, and infants or immunocompromised children can shed for up to 4 weeks after symptoms stop.

Not the same as bronchiolitis obliterans - Obliterative (constrictive) bronchiolitis is fibrosis of terminal and distal bronchioles with fixed airflow obstruction on spirometry, seen after lung or hematopoietic stem cell transplant, toxic inhalation, autoimmune disease, and sometimes after childhood adenovirus or RSV. Its dyspnea and cough are progressive over weeks to months rather than episodic, and it does not resolve with supportive care.

Bronchiolitis is acute viral inflammation of the bronchioles and the most common lower respiratory tract infection in children under two. Respiratory syncytial virus (RSV) causes most cases, with adenovirus, human metapneumovirus, influenza, and parainfluenza behind it; it peaks in winter and early spring.

The virus infects airway epithelial cells and causes ciliary dysfunction, cell necrosis, mucus production, and airway edema. Accumulated debris and edema narrow the small airways and lung compliance falls. Because airflow resistance is inversely related to the fourth power of the airway radius, a small amount of edema in an infant's bronchiole creates a large obstruction, and the child compensates by breathing harder.

Most children run 7 to 10 days of illness and recover in 14 to 21 days if kept hydrated, but young infants can progress to hypoxia, apnea, and respiratory failure.