Bronchiolitis


Article Author:
Nathaniel Justice


Article Editor:
Jacqueline Le


Editors In Chief:
Timothy Craig
Yoon Kim
Robert Hostoffer


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Steve Bhimji
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes
Tehmina Warsi


Updated:
2/23/2019 11:55:48 AM

Introduction

Bronchiolitis is a common lung infection in young individuals. The viral infection involves the lower respiratory tract and can present with signs of mild to moderate respiratory distress. Bronchiolitis is a mild, self-limited infection in the majority of children but may sometimes progress to respiratory failure in infants. Bronchiolitis is managed supportively with hydration and oxygen. No specific medications treat the infection.

It is important to know that respiratory syncytial virus is just one cause of bronchiolitis. The infection can occur in individuals of any age, but overall, the most severe symptoms tend to be common in infants.[1][2][3]

Etiology

The most common virus associated with bronchiolitis is the respiratory syncytial virus. However, over the years many other viruses have been found to cause the same infection, and they include  the following:

  • Human rhinovirus
  • Coronavirus
  • Human metapneumovirus
  • Adenovirus
  • Parainfluenza virus

RSV accounts for the majority of cases, although in about 30% of infants, there may be 2 viruses present at the same time.

Epidemiology

Bronchiolitis is most common in children less than 2 years of age. During the first year of life, the incidence has been reported to be about 11% to 15%. Depending on the severity of the infection, there are at least 5 hospitalizations for every 1000 children younger than 2 years of age. Bronchiolitis is classically a seasonal disorder that is most common during autumn and winter, but sporadic cases may occur throughout the year. Some of the risk factors that have been identified for severe infections include the following:

  • History of prematurity (less than 32 to 34 weeks gestational age)
  • Age younger than 3 months
  • Neuromuscular disease
  • Congenital heart disease
  • Chronic lung illness
  • Immunodeficiency

Pathophysiology

The clinical features of bronchiolitis are primarily due to airway obstruction and diminished lung compliance. The virus infects the epithelial cells in the airways and induces an inflammatory reaction, that leads to ciliary dysfunction and cell death. The accumulated debris, edema of the airways, and narrowing of the airways due to the release of cytokines eventually leads to symptoms and lowered lung compliance. The patient then tries to overcome the decreased compliance by breathing harder.[4][5][6]

History and Physical

Once RSV is acquired, the symptoms of an upper respiratory tract infection appear and include a cough, fever, and rhinorrhea. Within 48 to 72 hours, the acute infection involving the lower airways will become evident. During the acute stage, the infant may develop small airway obstruction that leads to symptoms of respiratory distress. The physical exam will reveal crackles, wheezing, and rhonchi. The severity of respiratory distress may vary from infant to infant. Some infants may have mild disease with only tachypnea, but others may show severe retractions, grunting, and cyanosis. The course of the illness may last 7 to 10 days, and the infant may become irritable and not feed. However, most infants improve within 14 to 21 days, as long as they are well hydrated.

Evaluation

The diagnosis of bronchiolitis is made clinically. Blood work and imaging studies are only needed to rule out other causes. Ordering serology and other laboratory tests to identify the virus is only of academic purpose. The presence of the virus in the blood does not correlate with symptoms or the course of the disease. Laboratory assays in bronchiolitis are useful for epidemiological studies and have little practical application.

A chest x-ray should only be ordered if there is clinical suspicion of a complication such as pneumothorax or bacterial pneumonia. Urine cultures may be obtained in children who have no other source of infection and continue to spike temperatures. Concomitant urinary tract infections are known to occur in about 5% to 10% of cases.

Treatment / Management

The hallmark of management for children with bronchiolitis is symptomatic care. All infants and children who are diagnosed with bronchiolitis should be carefully assessed for adequacy of hydration, respiratory distress, and presence of hypoxia.[7][8][9][10]

Children who present with mild to moderate symptoms can be treated with interventions like nasal saline, antipyretics, and a cool mist humidifier. Those children with severe symptoms of acute respiratory distress, signs of hypoxia and/or dehydration should be admitted and monitored. These children need aggressive hydration. The use of beta-adrenergic agonists like epinephrine or albuterol, or even steroids, has not been shown to be effective in children with bronchiolitis. Instead, these children should be provided with humidified oxygen and nebulized hypertonic saline. Ensuring that the infant is well hydrated is key, especially for those who cannot eat. Oxygen therapy to maintain saturations just above 90% is adequate.

Children who develop signs of severe respiratory distress may progress to respiratory failure. These children may require intensive care for mechanical ventilation or non-invasive support. A high-flow nasal cannula is an emerging modality of non-invasive support for children with bronchiolitis. Clinical trials are in progress.

Passive immunization against RSV is available with palivizumab for those who are at the greatest risk for severe illness. During the RSV season, this requires monthly injections of the drug, but this may not only be expensive but not also not practical for most infants.

Current recommendations by the American Academy of Pediatrics support the use of palivizumab during the first year of life for children with a gestational age less than 29 weeks, symptomatic congenital heart disease, chronic lung disease of prematurity, neuromuscular disorders that make it difficult to clear the airways, airway abnormalities, and immunodeficiency. Prophylaxis may be continued in the second year of life for children who require continued interventions for chronic lung disease of prematurity or those who remain immunosuppressed.

Differential Diagnosis

  • Asthma
  • Bacterial pneumonia
  • Gastroesophageal reflux disease (GERD)
  • Vascular ring
  • Croup
  • Foreign body aspiration
  • Pertussis

Prognosis

Bronchiolitis is a self-limited infectious process. It is commonly managed with supportive care, hydration, fever control, and oxygenation. When the disorder is recognized and treated, the prognosis is excellent. The majority of children recover without any adverse effects. Past studies suggest that infants with severe bronchiolitis will develop wheezing in future, but this has not been borne out by longitudinal studies.

About 3% of infants will require admission to the hospital, and the mortality rates vary from 0.5% to 7%. The large variation in mortality is because of different risk factors and lack of availability of intensive care units in certain countries.

Complications

Complications include:

  • Nosocomial infection in infants who are admitted
  • Barotrauma is ventilation is required
  • Arrhythmias induced by beta agonists
  • Nutritional deficiencies if there is persistent vomiting

Consultations

If an infant has been diagnosed with severe bronchiolitis, then a pediatrician and in infectious disease expert should be consulted regarding their management.

Deterrence and Patient Education

  • Maintain oral hydration
  • Control temperature
  • Avoid exposure to smoke in the home
  • Wash hands

Pearls and Other Issues

  • Bronchiolitis is a common lung infection in young individuals
  • The viral infection involves the lower respiratory tract and can present with signs of mild to moderate respiratory distress.
  • Bronchiolitis is a mild, self-limited infection in the majority of children but may sometimes progress to respiratory failure in infants.
  • The management of bronchiolitis is supportive hydration and oxygen. No specific medications treat the infection.

Enhancing Healthcare Team Outcomes

The diagnosis and management of bronchiolitis is with a multidisciplinary team that includes the emergency department physician, nurse practitioner, pediatrician, primary care giver and infectious disease consultant. The diagnosis is clinical and in most cases the treatment is supportive. While most children benefit from hydration, some may require antipyretics and a cool mist humidifer. About 1-3% of children with severe bronchiolitis may require admission for more aggressive respiratory support. When the disorder is recognized and treated, the prognosis is excellent. The majority of children recover without any adverse effects. Past studies suggest that infants with severe bronchiolitis will develop wheezing in future, but this has not been borne out by longitudinal studies.[11][12]

 


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Bronchiolitis - Questions

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Which is the most common cause of acute bronchiolitis in children?



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What therapy is most effective in patients with bronchiolitis?



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What disorder can develop in children who have bronchiolitis?



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A 9-month-old infant presents with a low-grade fever, increased work of breathing, grunting, and noisy breathing. On examination, the infant has bilateral wheezing and inspiratory crackles. What is the most likely cause of his illness?



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What is the treatment for acute bronchiolitis?



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What is the most common cause of bronchiolitis in children?



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A 5-month-old is admitted to the hospital with wheezing and respiratory distress in February. He has retractions, accessory muscle use, and tachypnea. His chest x-ray shows no infiltrates, and a diagnosis of bronchiolitis is given. The older brother has had a cough and rhinorrhea for several days. What is the most useful laboratory test to order next?



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Which of the following is the best management of bronchiolitis?



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What is the predominant causative organism in bronchiolitis?



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Which of the following is true about bronchiolitis?



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An 11-month-old infant was well until two days ago when she developed a cough and clear nasal discharge. The rest of her family has similar symptoms. Six hours ago the cough became worse, so the child was brought to the emergency department. On initial evaluation, the infant is in moderate respiratory distress with bilateral wheezing, abdominal thrusting, and nasal flaring. SpO2 is 89% on room air. Chest radiograph shows bilateral patchy infiltrates and flattened diaphragms. What is the most appropriate management?



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A 3 month old child is brought to the emergency department with a low grade fever, coryza, and cough. Physical exam reveals tachypnea, retractions, and expiratory wheezes. Which of the following is needed to make the diagnosis of bronchiolitis?



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A four-month-old infant is brought in with difficulty breathing. Her illness began three days ago with a cough and runny nose. Her mother states that she began "breathing heavily" overnight, and her difficulty breathing has worsened progressively. On exam, there is a respiratory rate of 65 breaths per minute. Auscultation reveals diffuse, bilateral wheezes with scattered crackles. Mild intercostal retractions are present, and the remainder of her exam is unremarkable. Which of the following histories would raise concern for this child having a severe course?



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A 15-month-old male presents to the emergency department with intermittent wheezing for the past four days. His wheezing was preceded by a cough and runny nose, and he has maintained a steady fever of 101.5 F throughout this illness. On exam, the child is non-toxic with mild tachypnea. Auscultation reveals wheezing and coarse rhonchi scattered throughout his lungs. He has no grunting, nasal flaring or retractions. His tympanic membranes are erythematous symmetrically, but non-bulging. Of the following, which is the most common secondary infection to this viral illness?



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Bronchiolitis - References

References

Polack FP,Stein RT,Custovic A, The syndrome we agreed to call bronchiolitis. The Journal of infectious diseases. 2019 Feb 19;     [PubMed]
Jo YM,Kim J,Chang J, Vaccine containing G protein fragment and recombinant baculovirus expressing M2 protein induces protective immunity to respiratory syncytial virus. Clinical and experimental vaccine research. 2019 Jan;     [PubMed]
Oz-Alcalay L,Ashkenazi S,Glatman-Freedman A,Weisman-Demri S,Lowenthal A,Livni G, Hospitalization for Respiratory Syncytial Virus Bronchiolitis in the Palivizumab Prophylaxis Era: Need for Reconsideration of Preventive Timing and Eligibility. The Israel Medical Association journal : IMAJ. 2019 Feb;     [PubMed]
Soudani N,Caniza MA,Assaf-Casals A,Shaker R,Lteif M,Su Y,Tang L,Akel I,Muwakkit S,Chmaisse A,Homsi M,Dbaibo G,Zaraket H, Prevalence and characteristics of acute respiratory virus infections in pediatric cancer patients. Journal of medical virology. 2019 Feb 14;     [PubMed]
Supino MC,Buonsenso D,Scateni S,Scialanga B,Mesturino MA,Bock C,Chiaretti A,Giglioni E,Reale A,Musolino AM, Point-of-care lung ultrasound in infants with bronchiolitis in the pediatric emergency department: a prospective study. European journal of pediatrics. 2019 Feb 12;     [PubMed]
Lodeserto FJ,Lettich TM,Rezaie SR, High-flow Nasal Cannula: Mechanisms of Action and Adult and Pediatric Indications. Cureus. 2018 Nov 26;     [PubMed]
Stobbelaar K,Kool M,de Kruijf D,Van Hoorenbeeck K,Jorens P,De Dooy J,Verhulst S, Nebulised hypertonic saline in children with bronchiolitis admitted to the paediatric intensive care unit: A retrospective study. Journal of paediatrics and child health. 2019 Jan 6;     [PubMed]
Kusak B,Grzesik E,Konarska-Gabryś K,Pacek Z,Piwowarczyk B,Lis G, Bronchiolitis in children - do we choose wisely? Developmental period medicine. 2018;     [PubMed]
Gold J,Hametz P,Sen AI,Maykowski P,Leone N,Lee DS,Gagliardo C,Hymes S,Biller R,Saiman L, Provider Knowledge, Attitudes, and Practices Regarding Bronchiolitis and Pneumonia Guidelines. Hospital pediatrics. 2019 Feb;     [PubMed]
Picone S,Fabiano A,Roma D,Di Palma F,Paolillo P, Re-comparing of three different epidemic seasons of bronchiolitis: different prophylaxis approaches. Italian journal of pediatrics. 2018 Dec 12;     [PubMed]
Clayton JA,McKee B,Slain KN,Rotta AT,Shein SL, Outcomes of Children With Bronchiolitis Treated With High-Flow Nasal Cannula or Noninvasive Positive Pressure Ventilation. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies. 2019 Feb;     [PubMed]
Luo G,Stone BL,Nkoy FL,He S,Johnson MD, Predicting Appropriate Hospital Admission of Emergency Department Patients with Bronchiolitis: Secondary Analysis. JMIR medical informatics. 2019 Jan 22;     [PubMed]

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