Bronchiolitis: Causes, Symptoms, Diagnosis, and Treatment

Bronchiolitis is a common lower respiratory tract infection that primarily affects infants and young children. It is most often caused by respiratory syncytial virus, or RSV, and is especially important in infants because their small airways can become obstructed quickly by inflammation, mucus, and cellular debris.

Although many cases are mild and improve with supportive care, bronchiolitis can become serious in premature infants, young infants, and children with underlying heart, lung, or immune conditions.

Understanding bronchiolitis helps respiratory therapy students and clinicians recognize respiratory distress, support oxygenation, and identify signs of deterioration.

What Is Bronchiolitis?

Bronchiolitis is an acute infection of the lower respiratory tract that affects the small bronchi and bronchioles. These are the narrow airways that help carry air deeper into the lungs. When these airways become infected and inflamed, they swell and produce secretions. Mucus, inflammatory fluid, and cellular debris can then narrow or obstruct the airway lumen.

This obstruction makes it harder for the infant to move air in and out of the lungs. Because infants have naturally small airways, even a small amount of swelling can produce a major increase in airway resistance. This is why bronchiolitis can progress from what looks like a simple cold to significant respiratory distress within a short period of time.

Bronchiolitis is most commonly associated with RSV, but other respiratory viruses can also cause it. The condition is most common in infants younger than 2 years old, especially those younger than 1 year. The peak age for hospitalization is usually between 2 and 6 months.

In respiratory care, bronchiolitis is important because it can cause wheezing, tachypnea, hypoxemia, dehydration, apnea, and respiratory failure. The main clinical focus is not routine medication use, but careful assessment and supportive management.

Why Bronchiolitis Is Common in Infants

Infants are especially vulnerable to bronchiolitis because of their airway size and developmental anatomy. Their bronchioles are narrow, so inflammation and mucus can obstruct airflow more easily than in older children or adults.

The infant chest wall is also more compliant, meaning it is softer and more flexible. This can make breathing less efficient during respiratory distress. Infants also have limited respiratory reserve, so they may tire quickly when the work of breathing increases.

Another factor is that young infants depend heavily on nasal breathing, especially during feeding. Nasal congestion can interfere with feeding, increase respiratory effort, and contribute to dehydration. When an infant has bronchiolitis, even upper airway secretions can worsen the overall clinical picture.

Bronchiolitis often occurs during seasonal RSV outbreaks. These epidemics commonly occur during the winter months, often from December through March. During these periods, infants may be exposed through respiratory droplets, contaminated surfaces, daycare settings, or close household contact.

Causes of Bronchiolitis

The most common cause of bronchiolitis is respiratory syncytial virus. RSV is highly contagious and spreads through respiratory secretions. It can be transmitted by coughing, sneezing, direct contact, or touching contaminated surfaces and then touching the eyes, nose, or mouth.

Bronchiolitis often begins as an upper respiratory infection. At first, the infant may have nasal congestion, mild cough, and a slight fever. After several days, the virus may spread into the lower airways, where it causes inflammation of the bronchioles.

Although RSV is the most common cause, other viruses may also be involved. These can include rhinovirus, parainfluenza virus, influenza virus, adenovirus, and human metapneumovirus. However, in most textbook discussions and board exam contexts, bronchiolitis is strongly linked with RSV.

Note: Bronchiolitis is not primarily a bacterial disease. This is why antibiotics are not routinely recommended unless there is evidence of a bacterial infection, such as bacterial pneumonia, otitis media, or another identified bacterial focus.

Pathophysiology of Bronchiolitis

The pathophysiology of bronchiolitis centers on inflammation and obstruction of the small airways. When a virus infects the bronchioles, the airway lining becomes inflamed. This inflammatory response causes swelling of the airway wall, increased mucus production, and movement of fluid into the airway and surrounding tissues.

As inflammation progresses, epithelial cells may slough into the airway lumen. These cells can mix with mucus and inflammatory debris, forming plugs that partially or completely obstruct the small airways. In severe cases, the airway lumina may become filled with impacted cellular debris.

This obstruction increases airway resistance and makes airflow more difficult, especially during exhalation. When air cannot exit normally, air trapping occurs. This can lead to lung hyperinflation, flattened hemidiaphragms on chest radiograph, and increased work of breathing.

In some areas of the lung, obstruction may be complete. When air cannot reach those alveoli, atelectasis may occur. In other areas, partial obstruction may cause overinflation. This uneven ventilation can contribute to ventilation-perfusion mismatch and hypoxemia.

The infant responds by breathing faster. Tachypnea is an attempt to maintain minute ventilation and gas exchange. However, as the disease worsens, the infant may no longer be able to compensate. A rising PaCO₂ despite tachypnea is an important warning sign that ventilation is failing.

Common Signs and Symptoms

Bronchiolitis often begins with symptoms that resemble a common cold. Early findings may include nasal congestion, runny nose, mild fever, and intermittent cough. These upper respiratory symptoms may seem minor at first.

As the infection moves into the lower airways, the infant may develop signs of respiratory distress. Common clinical findings include:

• Tachypnea
• Wheezing
• Cough
• Coryza
• Retractions
• Nasal flaring
• Grunting
• Dyspnea
• Poor feeding
• Irritability
• Hypoxemia

Wheezing occurs because air moves through narrowed bronchioles. The wheezing may be inspiratory, expiratory, or both, but expiratory wheezing is especially common in obstructive lower airway disease.

Auscultation may reveal diffuse coarse crackles or rales. Some descriptions compare these sounds to “Velcro” rales because they may sound sticky or coarse. Wheezes may occur along with these crackles.

Note: Symptoms often peak around 48 to 72 hours after the illness worsens. This is a clinically important period because an infant who initially appears stable may deteriorate as airway obstruction, hypoxemia, and fatigue progress.

Severe Bronchiolitis

Severe bronchiolitis can become life-threatening. The most concerning signs include apnea, cyanosis, worsening hypoxemia, poor feeding, dehydration, lethargy, exhaustion, and rising carbon dioxide levels.

Apnea is especially important in very young infants. Premature infants and those with a history of apnea or cardiorespiratory disease are at higher risk. In some cases, apnea may be the presenting sign of RSV infection.

Poor feeding is another significant finding. Infants with respiratory distress may not be able to feed effectively because they must coordinate sucking, swallowing, and breathing. When nasal congestion and tachypnea are present, feeding becomes even more difficult. Poor intake can quickly lead to dehydration.

Dehydration can worsen the clinical situation by making secretions thicker and harder to clear. It may also contribute to fatigue and poor perfusion.

Cyanosis is a late and concerning sign. It suggests significant hypoxemia and may indicate impending respiratory failure. Clinicians should not wait for cyanosis before escalating care, because oxygenation and work of breathing should be assessed continuously.

A rising arterial carbon dioxide level is another major warning sign. If the PaCO₂ rises above 45 mm Hg despite tachypnea, the infant may be losing the ability to maintain adequate ventilation. This should prompt preparation for respiratory support, including possible intubation and mechanical ventilation.

Risk Factors for Severe Disease

Although bronchiolitis can affect any infant, some patients are at higher risk for severe illness, hospitalization, respiratory failure, and death.

Important risk factors include:

• Premature birth
• Age younger than 6 months
• Chronic lung disease
• Bronchopulmonary dysplasia
• Cystic fibrosis
• Congenital heart disease
• Pulmonary hypertension
• Immunodeficiency
• Exposure to passive smoke
• Crowded living conditions
• Daycare attendance

Premature infants are vulnerable because their lungs and immune systems may be immature. Infants with bronchopulmonary dysplasia or other chronic lung diseases already have reduced pulmonary reserve. Children with congenital heart disease, especially those with pulmonary hypertension or cardiovascular compromise, may not tolerate hypoxemia well.

Infants with immunodeficiency may have more severe or prolonged infection because their immune systems cannot clear the virus effectively. Passive smoke exposure can irritate the airways and increase the risk of more severe respiratory symptoms.

Note: Recognizing risk factors helps clinicians decide which infants need closer monitoring, hospitalization, or early escalation of care.

Diagnosis of Bronchiolitis

The diagnosis of bronchiolitis is primarily clinical. This means it is based mainly on the patient’s age, history, symptoms, physical examination, season, and pattern of illness.

A typical case may involve an infant during RSV season who begins with upper respiratory symptoms and then develops cough, wheezing, tachypnea, increased work of breathing, and hypoxemia.

The physical exam should focus on the infant’s respiratory status and overall appearance. Important assessment findings include respiratory rate, heart rate, oxygen saturation, work of breathing, retractions, nasal flaring, grunting, breath sounds, mental status, hydration, and feeding ability.

Laboratory testing may be used to confirm RSV or another viral infection. Samples are often collected through nasopharyngeal aspirate or nasal lavage. RSV may be identified by viral culture, antigen detection assays, enzyme-linked immunosorbent assays, or immunofluorescent assay. Some tests can provide same-day results.

Note: Testing may help guide infection-control measures, especially in hospitals, but not every mild case requires viral confirmation. In many cases, the clinical presentation is enough to guide management.

Chest X-Ray Findings

A chest x-ray is not always required in mild bronchiolitis. However, it may be used when the diagnosis is uncertain, symptoms are severe, oxygenation is poor, or another condition needs to be ruled out.

Common chest radiograph findings include hyperinflation and flattened hemidiaphragms. These findings reflect air trapping due to small airway obstruction.

Some chest x-rays may show areas of atelectasis, collapse, or consolidation. Atelectasis can occur when mucus and debris completely obstruct small airways. Consolidation may be present when inflammation or secondary infection affects portions of the lung.

Note: It is important to interpret chest x-ray findings within the clinical context. Radiographic changes alone do not determine severity. The infant’s oxygenation, work of breathing, hydration status, mental status, and ventilatory status are more important for treatment decisions.

Supportive Treatment

Treatment of bronchiolitis is largely supportive. The main goals are to maintain oxygenation, support hydration, reduce airway obstruction from secretions, monitor for deterioration, and escalate respiratory support when needed.

Supportive care may include:

• Oxygen therapy
• Nasal suctioning
• Nasopharyngeal suctioning
• Hydration
• Monitoring of respiratory status
• High-flow nasal cannula when needed
• Noninvasive support in selected cases
• Mechanical ventilation for respiratory failure

Oxygen therapy is used when the infant has hypoxemia. It may be delivered by nasal cannula, high-flow nasal cannula, or other appropriate devices depending on severity.

Hydration is important because infants may feed poorly during respiratory distress. Some infants may require intravenous fluids or enteral support if oral intake is inadequate. Hydration also helps prevent secretions from becoming overly thick.

Suctioning can be helpful because infants often have nasal congestion and secretions that increase work of breathing and interfere with feeding. Nasal or nasopharyngeal suctioning may improve airflow and comfort, especially before feeding or sleep.

Note: The clinician should continue reassessing the infant. Bronchiolitis can worsen during the first few days, so monitoring trends is essential.

Medications and Therapies

Many therapies have been studied in bronchiolitis, but routine medication use is limited. The reason is that bronchiolitis is primarily a viral inflammatory and obstructive small airway disease, and many medications do not consistently improve outcomes.

Bronchodilators

Bronchodilators are not routinely recommended for all infants with bronchiolitis. Ipratropium bromide and theophylline have not shown proven benefit as bronchodilators for bronchiolitis.

Albuterol may be considered in selected situations, especially when hypertonic saline is given for the first time because acute bronchospasm can occur. A one-time as-needed albuterol order may be used with the first dose of hypertonic saline, particularly in patients who may have known or unrecognized reactive airway disease.

Note: Bronchiolitis should not be treated as asthma by default. Wheezing in bronchiolitis comes from inflammation, mucus, debris, and small airway obstruction, not necessarily bronchospasm alone.

Corticosteroids

Although airway inflammation is present, systemic or inhaled corticosteroids given early in the symptomatic phase generally do not improve outcomes in bronchiolitis.

Inhaled corticosteroids may sometimes be used when recovery is delayed, but improvement in those cases may reflect another underlying respiratory tendency, such as recurrent wheezing or asthma. For typical acute viral bronchiolitis, corticosteroids are not a routine therapy.

Hypertonic Saline

Nebulized 3% hypertonic saline has been discussed as a potentially effective and safe treatment for infants with mild to moderate respiratory distress. It may reduce bronchiolitis scores and has been associated with reduced length of stay in some settings.

One regimen described includes treatments every 2 hours for three doses, then every 4 hours for five doses, then every 6 hours until discharge. However, the optimal inpatient dosing schedule remains unclear.

The first dose requires close monitoring because acute bronchospasm can occur, especially in children with known or unrecognized asthma. This is why a one-time as-needed albuterol order may be recommended with the first dose.

Antibiotics

Antibiotics are not recommended for routine viral bronchiolitis. They should be used only when there is an identified or suspected bacterial infection.

If a child with bronchiolitis also has bacterial pneumonia, otitis media, sepsis, or another bacterial focus, that infection should be treated appropriately. However, antibiotics should not be given simply because the infant has bronchiolitis.

Note: Routine antibiotic use can increase cost, cause side effects, and contribute to antibiotic resistance.

Cough and Cold Medications

Antihistamines, oral decongestants, and over-the-counter cough and cold medications are not recommended for routine bronchiolitis therapy. These medications can cause adverse effects and may not improve the illness.

The FDA warning against cough and cold products in children younger than 2 years is especially important. Infants should not be treated with these medications without appropriate medical direction.

Ribavirin

Ribavirin, also known as Virazole, is an antiviral medication associated with severe RSV infection in selected high-risk infants and young children. It is not used routinely for every case of bronchiolitis.

When used, ribavirin is delivered by aerosol for prolonged periods, often 12 to 18 hours per day for 3 to 7 days. It must be administered with a small-particle aerosol generator, or SPAG, because the device is designed to create particles small enough for lower airway penetration.

A scavenging system is required to reduce healthcare worker exposure to aerosolized medication. This safety requirement is an important respiratory therapy exam point.

Note: Ribavirin is most relevant in severe RSV bronchiolitis or RSV pneumonia involving very sick, high-risk infants, especially those with prematurity or cardiopulmonary disease.

Airway Clearance

Routine chest physiotherapy is not strongly supported for acute bronchiolitis. Airway clearance techniques have minimal to no benefit in typical acute infant bronchiolitis, so they should not be used automatically.

The most useful secretion-management intervention in hospitalized infants is often nasal or nasopharyngeal suctioning. This helps relieve upper airway obstruction and may improve feeding and breathing comfort.

It is also important to distinguish acute viral bronchiolitis from bronchiolitis obliterans. Bronchiolitis obliterans is a different condition and may be associated with secretion-retention strategies such as positive expiratory pressure therapy in selected older patients. That does not mean PEP therapy is routinely indicated for infants with acute RSV bronchiolitis.

Respiratory Support and Mechanical Ventilation

Most infants with bronchiolitis do not require mechanical ventilation. However, severe cases may progress to respiratory failure and require advanced support. Signs that respiratory support may be needed include worsening hypoxemia, recurrent apnea, exhaustion, altered mental status, severe retractions, poor perfusion, and rising PaCO₂.

High-flow nasal cannula may be used in hospitalized infants with moderate to severe disease. It can provide heated, humidified gas, reduce work of breathing, and support oxygenation. Noninvasive support may be considered in selected patients, depending on the clinical setting and severity.

If respiratory failure develops, intubation and mechanical ventilation may be required. Since bronchiolitis is an obstructive disease, ventilator settings must account for air trapping. The patient needs enough expiratory time to exhale adequately.

Ventilator strategies may include lower respiratory rates, longer expiratory times, and careful use of PEEP. Excessive rates or insufficient expiratory time can worsen dynamic hyperinflation and air trapping. The goal is to support ventilation while avoiding additional lung injury or worsening obstruction.

Prevention of RSV Bronchiolitis

Prevention is especially important for high-risk infants. RSV prophylaxis may be recommended for selected infants who are at increased risk for severe disease.

High-risk groups may include infants with chronic lung disease, premature infants born at very low gestational age, and infants with congenital heart disease and cardiovascular compromise. The goal of RSV prophylaxis is not to treat active bronchiolitis, but to reduce the risk or severity of RSV disease.

General prevention also includes infection-control measures. These include hand hygiene, avoiding exposure to sick contacts, cleaning contaminated surfaces, reducing smoke exposure, and limiting exposure during peak RSV season when appropriate.

Note: In hospital settings, identifying RSV may help guide isolation precautions and reduce transmission to other vulnerable infants.

Bronchiolitis and Board Exam Preparation

Bronchiolitis is an important topic for respiratory therapy students because it may appear in pediatric patient-care scenarios. The condition requires the therapist to recognize lower airway disease, assess severity, identify signs of respiratory failure, and choose supportive interventions.

A typical exam scenario may describe an infant with recent cold symptoms who now has tachypnea, wheezing, retractions, poor feeding, and low oxygen saturation. The correct approach is to gather relevant clinical information, assess oxygenation and ventilation, evaluate work of breathing, and support the patient appropriately.

Important assessment data include age, prematurity history, congenital heart disease, chronic lung disease, apnea, feeding ability, hydration status, respiratory rate, breath sounds, oxygen saturation, and blood gas values when available.

For decision making, students should remember that bronchiolitis is usually viral and supportive care is the primary treatment. Routine antibiotics, corticosteroids, antihistamines, decongestants, and cough medications are not standard treatment for uncomplicated bronchiolitis.

Note: You should also recognize when the case has become severe. Apnea, cyanosis, lethargy, worsening hypoxemia, and rising PaCO₂ despite tachypnea are major red flags.

Role of the Respiratory Therapist

Respiratory therapists play an important role in bronchiolitis management. Their responsibilities include assessing the infant’s respiratory status, monitoring oxygenation, assisting with secretion clearance, delivering oxygen therapy, supporting ventilation, and recognizing deterioration.

The respiratory therapist should evaluate work of breathing, breath sounds, oxygen saturation, response to oxygen therapy, and signs of fatigue. In hospitalized patients, repeated assessment is essential because bronchiolitis can worsen during the peak phase of illness.

RTs may assist with nasal suctioning, high-flow nasal cannula setup, oxygen titration, aerosol therapy when ordered, and preparation for escalation of support. If intubation becomes necessary, the respiratory therapist helps with airway management and mechanical ventilation.

Note: The respiratory therapist must also understand infection-control procedures because RSV spreads easily. Proper hand hygiene, equipment cleaning, isolation precautions, and protection of other vulnerable patients are all important.

Bronchiolitis Practice Questions

1. What is bronchiolitis?
Bronchiolitis is an acute lower respiratory tract infection that primarily affects the small bronchi and bronchioles, causing inflammation, obstruction, wheezing, and respiratory distress.

2. What virus is most commonly associated with bronchiolitis?
Respiratory syncytial virus, or RSV, is the virus most commonly associated with bronchiolitis.

3. What age group is most commonly affected by bronchiolitis?
Bronchiolitis most commonly affects infants and young children, especially those younger than 2 years old.

4. What is the peak age for hospitalization due to bronchiolitis?
The peak age for hospitalization is between 2 and 6 months.

5. Why are infants especially vulnerable to bronchiolitis?
Infants are vulnerable because their airways are small, so even mild swelling, mucus, or cellular debris can significantly increase airway resistance.

6. What is the primary pathophysiologic problem in bronchiolitis?
The primary problem is obstruction of the small airways due to inflammation, mucus, fluid, and cellular debris.

7. How does bronchiolitis affect airway resistance?
Bronchiolitis increases airway resistance by narrowing the bronchioles with swelling, secretions, and debris.

8. What causes air trapping in bronchiolitis?
Air trapping occurs when narrowed or obstructed bronchioles make exhalation difficult, allowing air to remain trapped in the lungs.

9. What chest x-ray finding is commonly associated with bronchiolitis?
A common chest x-ray finding is hyperinflation with flattened hemidiaphragms.

10. What other chest x-ray findings may be seen in bronchiolitis?
Chest x-rays may also show areas of collapse, atelectasis, or consolidation.

11. How does bronchiolitis often begin clinically?
Bronchiolitis often begins like an upper respiratory infection, with symptoms such as coryza, cough, nasal congestion, and mild fever.

12. What are common clinical signs of bronchiolitis?
Common signs include cough, wheezing, tachypnea, respiratory distress, retractions, poor feeding, and hypoxemia.

13. When do symptoms of bronchiolitis usually peak?
Symptoms usually peak around 48 to 72 hours after the illness worsens.

14. What breath sounds may be heard in bronchiolitis?
Breath sounds may include diffuse coarse rales, “Velcro” or “sticky” rales, and wheezes.

15. Why does wheezing occur in bronchiolitis?
Wheezing occurs because air moves through narrowed, inflamed, and obstructed small airways.

16. What is a serious symptom of bronchiolitis in very young infants?
Apnea is a serious symptom, especially in very young infants or those with prematurity or cardiorespiratory disease.

17. Why can poor feeding become dangerous in bronchiolitis?
Poor feeding can lead to dehydration, which may worsen secretion clearance, fatigue, and overall respiratory status.

18. What does cyanosis suggest in an infant with bronchiolitis?
Cyanosis is a warning sign of significant hypoxemia and may indicate impending respiratory failure.

19. What PaCO₂ finding suggests ventilatory failure in bronchiolitis?
A PaCO₂ rising above 45 mm Hg despite tachypnea suggests that the infant is no longer maintaining adequate ventilation.

20. What should be considered if an infant with bronchiolitis has rising PaCO₂ despite tachypnea?
Respiratory support should be prepared, including possible intubation and mechanical ventilation.

21. What infants are at higher risk for severe RSV bronchiolitis?
High-risk infants include those born prematurely, those with chronic lung disease, congenital heart disease, pulmonary hypertension, cystic fibrosis, or immunodeficiency.

22. How does passive smoke exposure affect bronchiolitis risk?
Passive smoke exposure increases the risk of more severe respiratory illness by irritating the airways and reducing respiratory reserve.

23. Why are infants with congenital heart disease at higher risk during bronchiolitis?
They may have less cardiopulmonary reserve and may not tolerate hypoxemia or increased work of breathing well.

24. How is bronchiolitis primarily diagnosed?
Bronchiolitis is primarily diagnosed clinically through history, physical examination, age, symptoms, season, and respiratory findings.

25. What samples may be used to confirm RSV bronchiolitis?
RSV may be confirmed using samples obtained by nasopharyngeal aspirate or nasal lavage.

26. What laboratory methods may be used to identify RSV?
RSV may be identified by viral culture, antigen detection assays, enzyme-linked immunosorbent assays, or immunofluorescent assay.

27. Why is bronchiolitis usually managed with supportive care?
Bronchiolitis is usually viral, and most medications do not consistently improve outcomes, so treatment focuses on oxygenation, hydration, suctioning, and monitoring.

28. What are the major treatment goals for bronchiolitis?
The major goals are to maintain oxygenation, support hydration, monitor for deterioration, manage secretions, and prepare for escalation if respiratory failure develops.

29. Why is oxygen therapy used in bronchiolitis?
Oxygen therapy is used to correct hypoxemia caused by airway obstruction, air trapping, and ventilation-perfusion mismatch.

30. What oxygen delivery devices may be used for hospitalized infants with bronchiolitis?
Oxygen may be delivered by nasal cannula, high-flow nasal cannula, or other appropriate oxygen devices based on the infant’s severity.

31. Why is hydration important in bronchiolitis?
Hydration is important because infants may feed poorly during respiratory distress, and dehydration can make secretions thicker and harder to clear.

32. What airway clearance method is commonly used in hospitalized infants with bronchiolitis?
Nasal or nasopharyngeal suctioning is commonly used to help remove secretions and reduce upper airway obstruction.

33. Is routine chest physiotherapy strongly supported for acute bronchiolitis?
No. Routine chest physiotherapy has minimal to no benefit in acute bronchiolitis and is not strongly supported.

34. Why are antibiotics not routinely recommended for bronchiolitis?
Antibiotics are not routinely recommended because bronchiolitis is usually viral, and unnecessary antibiotics can cause side effects, increase cost, and contribute to resistance.

35. When may antibiotics be appropriate in a patient with bronchiolitis?
Antibiotics may be appropriate if there is an identified or suspected bacterial infection, such as bacterial pneumonia or another bacterial focus.

36. Are antihistamines recommended for routine bronchiolitis therapy?
No. Antihistamines are not recommended for routine bronchiolitis therapy because they do not treat the underlying disease and may cause adverse effects.

37. Why should over-the-counter cough and cold medications be avoided in young children with bronchiolitis?
They should be avoided because they may cause harmful adverse effects and are not recommended for children younger than 2 years.

38. Are corticosteroids routinely beneficial in acute bronchiolitis?
No. Systemic or inhaled corticosteroids given early in the illness generally do not improve outcomes in typical acute bronchiolitis.

39. Why should bronchiolitis not automatically be treated like asthma?
Bronchiolitis-related wheezing is usually caused by inflammation, mucus, fluid, and debris in the small airways, not simply bronchospasm.

40. What bronchodilators have not shown proven benefit in bronchiolitis?
Ipratropium bromide and theophylline have not shown proven benefit as bronchodilators for bronchiolitis.

41. What medication may be ordered with the first dose of hypertonic saline?
A one-time as-needed albuterol order may be used with the first dose because acute bronchospasm can occur.

42. What concentration of nebulized hypertonic saline is discussed for bronchiolitis?
Nebulized 3% hypertonic saline is discussed as a possible therapy for infants with mild to moderate respiratory distress.

43. What potential benefit has been associated with nebulized 3% hypertonic saline?
It may reduce bronchiolitis scores and has been shown in some settings to reduce hospital length of stay.

44. Why should the first dose of hypertonic saline be monitored closely?
The first dose should be monitored closely because acute bronchospasm can occur, especially in children with known or unrecognized asthma.

45. What is ribavirin?
Ribavirin, also known as Virazole, is an antiviral medication that may be used for severe RSV bronchiolitis or RSV pneumonia in selected high-risk infants.

46. Is ribavirin used routinely for all infants with bronchiolitis?
No. Ribavirin is not used routinely and is generally associated with very sick or high-risk infants with severe RSV disease.

47. How long may ribavirin be nebulized each day?
Ribavirin may be nebulized for 12 to 18 hours per day.

48. What is the typical ribavirin treatment course mentioned in the text?
The treatment course may involve 3 to 7 days of nebulization.

49. What device is required to administer aerosolized ribavirin?
A small-particle aerosol generator, or SPAG, is required to administer aerosolized ribavirin.

50. Why is a scavenging system needed during ribavirin therapy?
A scavenging system is needed to prevent aerosolized ribavirin particles from escaping into room air and exposing healthcare workers.

51. Why is the SPAG device used for ribavirin delivery?
The SPAG device is used because it produces small aerosol particles designed for lower airway and alveolar penetration.

52. What does RSV stand for?
RSV stands for respiratory syncytial virus.

53. How does RSV usually spread?
RSV usually spreads through respiratory secretions, close contact, contaminated hands, and contaminated surfaces.

54. During what months do RSV bronchiolitis epidemics commonly occur?
Seasonal epidemics commonly occur from December through March.

55. Why can bronchiolitis progress quickly in infants?
Bronchiolitis can progress quickly because infant airways are small, and even minor swelling or mucus buildup can significantly obstruct airflow.

56. What is coryza?
Coryza refers to cold-like upper respiratory symptoms, such as nasal congestion and runny nose.

57. How may bronchiolitis present differently in children older than 2 years?
Children older than 2 years may have more prominent nasal congestion and productive cough rather than classic infant bronchiolitis.

58. Why is tachypnea common in bronchiolitis?
Tachypnea occurs as the infant attempts to maintain ventilation and gas exchange despite narrowed and obstructed airways.

59. What does dyspnea indicate in bronchiolitis?
Dyspnea indicates difficulty breathing caused by increased airway resistance, increased work of breathing, and impaired gas exchange.

60. What causes hyperinflation in bronchiolitis?
Hyperinflation occurs when air becomes trapped behind partially obstructed small airways.

61. What causes atelectasis in some cases of bronchiolitis?
Atelectasis can occur when mucus, fluid, or cellular debris completely obstructs small airways and prevents ventilation to affected lung regions.

62. Why can bronchiolitis cause hypoxemia?
Bronchiolitis can cause hypoxemia because airway obstruction and uneven ventilation create ventilation-perfusion mismatch.

63. What is one reason infants with bronchiolitis may become agitated?
Infants may become agitated because of hypoxia, respiratory distress, discomfort, or difficulty feeding.

64. Why is apnea especially concerning in bronchiolitis?
Apnea is concerning because it may signal severe disease, especially in premature infants, very young infants, or those with cardiorespiratory problems.

65. What does a rising PaCO₂ suggest in a tachypneic infant?
A rising PaCO₂ suggests that the infant is tiring or failing to ventilate adequately despite an increased respiratory rate.

66. What is the relationship between bronchiolitis and respiratory failure?
Bronchiolitis can progress to respiratory failure when airway obstruction, hypoxemia, fatigue, or CO₂ retention becomes severe.

67. What should clinicians assess when evaluating hydration in bronchiolitis?
Clinicians should assess feeding ability, urine output, mucous membranes, weight changes, perfusion, and signs of dehydration.

68. Why is feeding ability important in bronchiolitis assessment?
Feeding ability is important because poor intake can indicate worsening respiratory distress and can lead to dehydration.

69. What is the role of nasal suctioning in bronchiolitis?
Nasal suctioning helps remove secretions, reduce nasal obstruction, improve comfort, and support feeding in infants.

70. Why is nasopharyngeal suctioning used cautiously?
Nasopharyngeal suctioning is used cautiously because excessive or aggressive suctioning can irritate the airway and increase distress.

71. What is one reason bronchiolitis is important for the board exam?
Bronchiolitis is important for the board exam because it may appear as a pediatric scenario requiring information gathering, severity assessment, and decision-making.

72. What information should a respiratory therapist gather in a bronchiolitis scenario?
The therapist should gather age, birth history, prematurity status, oxygen saturation, respiratory rate, breath sounds, work of breathing, feeding status, hydration status, and comorbidities.

73. What decision-making mistake should be avoided in bronchiolitis?
A key mistake is choosing routine medications or unnecessary therapies instead of focusing on supportive care and signs of deterioration.

74. What comorbid lung condition increases risk in infants with bronchiolitis?
Bronchopulmonary dysplasia increases the risk of severe bronchiolitis because it reduces pulmonary reserve.

75. Why does cystic fibrosis increase the risk of severe bronchiolitis?
Cystic fibrosis increases risk because thick secretions and underlying lung disease can worsen airway obstruction and impair gas exchange.

76. Why does pulmonary hypertension increase risk in infants with bronchiolitis?
Pulmonary hypertension increases risk because hypoxemia and increased work of breathing can place additional strain on the cardiopulmonary system.

77. Why are immunodeficient infants at higher risk for severe bronchiolitis?
Immunodeficient infants are at higher risk because they may have difficulty clearing the viral infection, leading to more severe or prolonged disease.

78. What is the main difference between acute bronchiolitis and bronchiolitis obliterans?
Acute bronchiolitis is usually a viral lower airway infection in infants, while bronchiolitis obliterans is a different chronic small-airway disorder.

79. Is PEP therapy routinely indicated for acute infant bronchiolitis?
No. PEP therapy is not routinely indicated for acute infant bronchiolitis and is more relevant to selected older patients with secretion-retention conditions such as bronchiolitis obliterans.

80. What is the purpose of RSV prophylaxis?
The purpose of RSV prophylaxis is to reduce the risk or severity of RSV disease in selected high-risk infants.

81. Is RSV prophylaxis used to treat active bronchiolitis?
No. RSV prophylaxis is used for prevention in selected high-risk infants, not to treat active bronchiolitis.

82. Which infants may qualify for RSV prophylaxis?
Selected high-risk infants may qualify, including some premature infants, infants with chronic lung disease, and infants with congenital heart disease and cardiovascular compromise.

83. Why are infection-control measures important in RSV bronchiolitis?
Infection-control measures are important because RSV is highly contagious and can spread quickly to other vulnerable infants.

84. What infection-control practices help reduce RSV transmission?
Hand hygiene, cleaning contaminated surfaces, limiting exposure to sick contacts, and following hospital isolation precautions help reduce RSV transmission.

85. Why may identifying RSV be helpful in the hospital?
Identifying RSV may help guide infection-control precautions and reduce transmission to other hospitalized infants.

86. What is the role of high-flow nasal cannula in bronchiolitis?
High-flow nasal cannula may support oxygenation, provide heated humidified gas, and reduce work of breathing in infants with moderate to severe bronchiolitis.

87. When may noninvasive support be considered in bronchiolitis?
Noninvasive support may be considered when the infant has worsening respiratory distress, hypoxemia, or increased work of breathing despite initial supportive care.

88. What signs may suggest the need for intubation in bronchiolitis?
Signs may include recurrent apnea, worsening hypoxemia, exhaustion, altered mental status, severe retractions, poor perfusion, or rising PaCO₂.

89. Why must ventilator management account for air trapping in bronchiolitis?
Ventilator management must account for air trapping because bronchiolitis is obstructive, and inadequate expiratory time can worsen dynamic hyperinflation.

90. What ventilator strategy may help prevent worsening air trapping?
Lower respiratory rates and longer expiratory times may help allow adequate exhalation and reduce air trapping.

91. Why should excessive respiratory rates be avoided during mechanical ventilation for bronchiolitis?
Excessive respiratory rates can shorten expiratory time, worsen air trapping, and increase the risk of dynamic hyperinflation.

92. How should PEEP be considered in ventilated patients with bronchiolitis?
PEEP should be used carefully because it may help support airway patency but can worsen hyperinflation if excessive.

93. What does flattened hemidiaphragms on chest x-ray suggest in bronchiolitis?
Flattened hemidiaphragms suggest hyperinflation caused by air trapping from obstructed small airways.

94. Why is repeated assessment important in bronchiolitis?
Repeated assessment is important because symptoms can worsen during the peak phase, and infants may deteriorate quickly.

95. What should respiratory therapists monitor in infants with bronchiolitis?
Respiratory therapists should monitor oxygen saturation, respiratory rate, breath sounds, work of breathing, feeding tolerance, hydration, mental status, and response to therapy.

96. What is the respiratory therapist’s role if bronchiolitis progresses to respiratory failure?
The respiratory therapist helps prepare for airway management, intubation, ventilatory support, oxygen delivery, and ongoing assessment.

97. Why should clinicians avoid unnecessary therapies in bronchiolitis?
Unnecessary therapies can delay appropriate supportive care, increase cost, cause side effects, and provide little clinical benefit.

98. What is the most important overall approach to bronchiolitis management?
The most important approach is supportive care with close monitoring, oxygenation, hydration, secretion management, and timely escalation when respiratory failure appears.

99. What are major red flags in an infant with bronchiolitis?
Major red flags include apnea, cyanosis, worsening hypoxemia, poor feeding, dehydration, lethargy, severe retractions, and rising PaCO₂.

100. What is the key takeaway about bronchiolitis for respiratory therapy students?
The key takeaway is that bronchiolitis is a common RSV-related infant lower airway disease that requires careful assessment, supportive care, and early recognition of respiratory failure.

Final Thoughts

Bronchiolitis is a common infant lower airway infection, usually caused by RSV, that can range from mild cold-like illness to severe respiratory failure. Its clinical importance comes from inflammation and obstruction of the small airways, which can cause wheezing, tachypnea, air trapping, hypoxemia, apnea, and ventilatory failure.

Most treatment is supportive, focusing on oxygenation, hydration, suctioning, monitoring, and escalation when needed. Routine medications are limited, and antibiotics are reserved for bacterial infection.

For respiratory therapy students and clinicians, the key is to recognize severity early, support breathing effectively, and respond quickly when signs of respiratory failure appear.