PANCE Blueprint Pulmonary (10%)

Acute bronchiolitis (ReelDx)

REEL-DX-ENHANCED-PAID-MEMBERS-ONLY

2-year-old with difficulty breathing

2 y/o with tachypnea, hypoxemia, and fever

Patient will present as → a 9-month-old infant presents with a three-day history of a mild respiratory tract infection with serous nasal discharge, fever of 38.5 C (101.4 F), and decreased appetite. Physical exam reveals a tachypneic infant with audible wheezing and a respiratory rate of 65. Flaring of the alae nasi, use of accessory muscles, and subcostal and intercostal retractions are noted. Expiratory wheezes are present.

Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs, which usually occurs in children less than two years of age

  • Respiratory syncytial virus (RSV) is the most common cause of acute bronchiolitis
  • Most common in the fall and winter months. CXR is often normal - may show air trapping and peribronchial thickening
  • Diagnosed with nasal washing for RSV culture and antigen assay
  • Hospitalization if O2 < 95%, age < 3 months, respiratory rate > 70 or atelectasis on chest radiograph

Diagnosed with nasal washing for RSV culture and antigen assay

  • CXR findings include hyperinflation, perihilar infiltrates, increased interstitial markings, and patchy atelectasis
RSV

A CXR of a child with bronchiolitis showing the typical bilateral perihilar fullness (arrows)

Treatment is supportive with nasal suctioning, humidified O2, and antipyretics

  • The only treatment demonstrated to improve bronchiolitis is oxygen
  • Treatment is supportive; bronchodilators sometimes relieve symptoms but probably do not shorten hospitalization, and systemic corticosteroids are not indicated in previously well infants with bronchiolitis
  • Ribavirin for severe lung or heart disease and in immunocompromised patients
  • Respiratory Syncytial Virus (RSV) Vaccine VIS (see current CDC guidelines)
  • Monoclonal antibodies to RSV (palivizumab) prophylaxis (once per month for five months beginning in November) for special populations (immunocompromised, premature infants, neuromuscular disorders)

Indications for hospitalization

  • If SpO2 is < 95% on room air
  • Toxic appearance, poor feeding, lethargy, or dehydration
  • Moderate to severe respiratory distress: nasal flaring; intercostal, subcostal, or suprasternal retractions; respiratory rate >70 breaths per minute; dyspnea; or cyanosis
  • Apnea
  • Parents who are unable to care for them at home

osmosis Osmosis
Question 1

Which of the following is the most common etiological agent of acute bronchiolitis in infants and young children?

A
Streptococcus pneumoniae
Hint:
This is not the most common cause
B
Mycoplasma pneumoniae
Hint:
This is not the most common cause
C
Parainfluenza virus
Hint:
This is not the most common cause
D
Respiratory syncytial virus (RSV)
E
Adenovirus
Hint:
This is not the most common cause
Question 1 Explanation: 
Respiratory syncytial virus (RSV) is the most common cause of acute bronchiolitis in infants and young children. Other viruses that cause bronchiolitis are adenoviruses, influenza virus, parainfluenza virus, and human metapneumovirus. A less common agent is Mycoplasma pneumoniae, which occurs sporadically.
Question 2
A 6-month-old infant presents with a three-day history of cough, wheezing, and difficulty feeding. On examination, the infant has nasal flaring and intercostal retractions. Which of the following is the most appropriate initial diagnostic test?
A
Chest X-ray
Hint:
May be used to rule out pneumonia but is not necessary for the initial diagnosis of bronchiolitis.
B
Nasopharyngeal swab for viral PCR
C
Complete blood count (CBC)
Hint:
Not specific for diagnosing bronchiolitis and typically shows nonspecific findings.
D
Pulmonary function tests
Hint:
Not feasible or practical in infants with acute respiratory distress.
E
Blood culture
Hint:
Indicated if there is a suspicion of bacterial sepsis, not for uncomplicated bronchiolitis.
Question 2 Explanation: 
A nasopharyngeal swab for viral PCR (polymerase chain reaction) is the most appropriate initial diagnostic test for an infant presenting with symptoms suggestive of acute bronchiolitis. This test can rapidly identify the presence of RSV and other viruses, aiding in the diagnosis and management of the condition.
Question 3
Which of the following is the most appropriate management for a mild case of acute bronchiolitis in an infant?
A
Oral corticosteroids
Hint:
Not recommended for the treatment of bronchiolitis as they have not been shown to improve outcomes.
B
Antibiotic therapy
Hint:
Not indicated unless there is a clear evidence of bacterial co-infection, which is uncommon in uncomplicated bronchiolitis.
C
Supportive care, including hydration and nasal suctioning
D
Nebulized albuterol treatments
Hint:
May be trialed in some cases, but evidence does not consistently show benefit in bronchiolitis.
E
Hospitalization and oxygen therapy
Hint:
Indicated for severe cases with significant respiratory distress or hypoxemia, not mild cases.
Question 3 Explanation: 
Supportive care, including ensuring adequate hydration and nasal suctioning to clear nasal secretions, is the most appropriate management for a mild case of acute bronchiolitis in an infant. Most cases of bronchiolitis are self-limiting and do not require specific antiviral treatment or antibiotics.
Question 4
Which of the following is NOT considered an indication for hospitalization in an infant diagnosed with bronchiolitis?
A
Respiratory rate > 70 breaths per minute
Hint:
A respiratory rate greater than 70 breaths per minute indicates significant respiratory distress and is a criterion for hospitalization to provide appropriate respiratory support and monitoring.
B
Temperature > 100.5°F (38°C)
C
Oxygen saturation (SpO2) < 95% on room air
Hint:
Infants with bronchiolitis showing an oxygen saturation less than 95% on room air may require supplemental oxygen, monitoring, and possibly further intervention, making this an indication for hospitalization.
D
Apnea
Hint:
Episodes of apnea in infants with bronchiolitis are a critical concern, especially in young infants or those with a history of prematurity. This condition requires immediate hospitalization for continuous monitoring and intervention.
E
Poor feeding and/or dehydration
Hint:
Difficulty feeding leading to dehydration is a common complication of bronchiolitis in infants that may necessitate hospitalization for fluid management and supportive care.
Question 4 Explanation: 
Patients with bronchiolitis will commonly present with a fever. Fever alone is not an indication for admission although you must be sure to rule out pneumonia based on your physical exam findings. All the rest of the options are reasons to hospitalize patients with bronchiolitis.
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References: Merck Manual · UpToDate

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