Template:Short description Template:Distinguish Template:Use dmy dates Template:Use American English Template:Infobox medical condition (new) Bronchiolitis is inflammation of the small airways also known as the bronchioles in the lungs. Acute bronchiolitis is caused by a viral infection, usually affecting children younger than two years of age.<ref name="Ryu">Template:Cite journal</ref> Symptoms may include fever, cough, runny nose or rhinorrhea, and wheezing.<ref name=Fri2014/> More severe cases may be associated with nasal flaring, grunting, or respiratory distress.<ref name=Fri2014/> If the child has not been able to feed properly due to the illness, signs of dehydration may be present.<ref name=Fri2014/>
Chronic bronchiolitis is more common in adults and has various causes, one of which is bronchiolitis obliterans.<ref name="Ryu"/><ref name="Robbins">Template:Cite book</ref> Often when people refer to bronchiolitis, they are referring to acute bronchiolitis in children.<ref name="Ryu" />
Acute bronchiolitis is usually the result of viral infection by respiratory syncytial virus (RSV) (59.2% of cases) or human rhinovirus (19.3% of cases).<ref name=":5">Template:Cite journal</ref> Diagnosis is generally based on symptoms.<ref name=Fri2014>Template:Cite journal</ref> Tests such as a chest X-ray or viral testing are not routinely needed, but may be used to rule out other diseases.<ref name=Sch2014/>
There is no specific medicine that is used to treat bronchiolitis.<ref name=Han2017>Template:Cite journal</ref><ref name=Kir2019>Template:Cite journal</ref> Symptomatic treatment at home is generally effective and most children do not require hospitalization.<ref name=Fri2014/> This can include antipyretics such as acetaminophen for fever and nasal suction for nasal congestion, both of which can be purchased over the counter.<ref name="Fri2014" /> Occasionally, hospital admission for oxygen, particularly high flow nasal cannula, or intravenous fluids is needed in more severe cases of disease.<ref name=Fri2014/>
About 10% to 30% of children under the age of two years are affected by bronchiolitis at some point in time.<ref name=Fri2014/><ref name=Sch2014>Template:Cite journal</ref> It commonly occurs in the winter season in the Northern Hemisphere.<ref name=Fri2014/> It is the leading cause of hospitalizations in those less than one year of age in the United States.<ref name=Ral2014>Template:Cite journal</ref><ref name=Kir2019 /> The risk of death among those who are admitted to hospital is extremely low at about 1%.<ref name=Ken2012>Template:Cite book</ref> Outbreaks of the condition were first described in the 1940s.<ref>Template:Cite book</ref>
Signs and symptomsEdit
Bronchiolitis typically presents in children under two years old and is characterized by symptoms of a respiratory illness.<ref name="Fri2014" />{{#invoke:Listen|main}}Signs of the disease include:<ref name="Ral2014" />
- fever
- rhinorrhea
- cough
- wheeze
- mild tachypnea or increased breathing
Some signs of severe disease include:<ref>Template:Cite book</ref>
- increased work of breathing (such as use of accessory muscles of respiration, rib & sternal retraction, tracheal tug)
- severe chest wall recession (Hoover's sign)
- presence of nasal flaring and/or grunting
- severe tachypnea or increased breathing
- hypoxia (low oxygen levels)
- cyanosis (bluish skin)
- lethargy and decreased activity
- poor feeding (less than half of usual fluid intake in preceding 24 hours)
These symptoms can develop over one to three days.<ref name="Fri2014" /> Crackles or wheeze are typical findings on listening to the chest with a stethoscope. Wheezes can occasionally be heard without a stethoscope. The child may also experience apnea, or brief pauses in breathing, but this can occur due to many conditions that are not just bronchiolitis. After the acute illness, it is common for the airways to remain sensitive for several weeks, leading to recurrent cough and wheeze.<ref name="Fri2014" />
CausesEdit
Bronchiolitis is most commonly caused by respiratory syncytial virus<ref name=":5" /> (RSV, also known as human pneumovirus). Other agents that cause this illness include, but are not limited to, human metapneumovirus, influenza, parainfluenza, coronavirus, adenovirus, rhinovirus and mycoplasma.<ref name="Bourke11">Template:Cite journal</ref><ref name=":6" />
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Risk factorsEdit
Children are at an increased risk for progression to severe respiratory disease if they have any of the following additional risk factors:<ref name="Kir2019" /><ref name="Ral2014" /><ref name=":6" /><ref name=":7">Template:Cite journal</ref>
- Preterm infant (gestational age less than 37 weeks)
- Younger age at onset of illness (less than 3 months of age)
- Congenital heart disease
- Immunodeficiency
- Chronic lung disease
- Neurological disorders
- Tobacco smoke exposure
DiagnosisEdit
The diagnosis is typically made by a provider through clinical history and physical exam. Chest X-ray is sometimes useful to exclude bacterial pneumonia, but not indicated in routine cases.<ref name="Fri2014" /> Chest x-ray may also be useful in people with impending respiratory failure.<ref name=":3">Template:Cite journal</ref> Additional testing such as blood cultures, complete blood count, and electrolyte analyses are not recommended for routine use although may be useful in children with multiple comorbidities or signs of sepsis or pneumonia.<ref name="Kir2019" /><ref name=":3" /> Electrolyte analyses may be performed if there is concern for dehydration.<ref name="Fri2014" />
Testing for the specific viral cause can be done but has little effect on management and thus is not routinely recommended.<ref name="Peds10">Template:Cite journal</ref> The COVID pandemic has led to more viral testing to exclude COVID as a cause of the infection. At that point providers often also add on a flu and RSV test for completeness. <ref name=":10" /> RSV testing by direct immunofluorescence testing of a swab of the nose had a sensitivity of 61% and specificity of 89%, so it is not alway accurate.<ref name=":6">Template:Cite journal</ref><ref name=":3" /> Identification of those who are RSV-positive can help providers recommend isolation precautions in the hospital or at home to avoid the infection spreading to others. <ref name="Kir2019" /> Identification of the virus may help reduce the use of antibiotics because antibiotics are not recommended for viral illnesses such as bronchiolitis.<ref name=":3" />
It is extremely rare for infants to be co-infected with a bacterial illness while having bronchiolitis. Infants with bronchiolitis between the age of two and three months have a second infection by bacteria (usually a urinary tract infection) less than 6% of the time.<ref>Template:Cite journal</ref> When further evaluated with a urinalysis, infants with bronchiolitis had an accompanying UTI 0.8% of the time.<ref name=":4">Template:Cite journal</ref>
Differential diagnosisEdit
There are many childhood illnesses that can present with respiratory symptoms, particularly persistent cough, runny nose, and wheezing.<ref name="Ral2014" /><ref name=":2" /> Bronchiolitis may be differentiated from some of these by the characteristic pattern of preceding febrile upper respiratory tract symptoms lasting for 1 to 3 days with associated persistent cough, increased work of breathing, and wheezing.<ref name=":2" /> However, some infants may present without fever (30% of cases) or may present with apnea without other signs or with poor weight gain prior to onset of symptoms.<ref name=":2" /> In such cases, additional laboratory testing and radiographic imaging may be useful.<ref name="Ral2014" /><ref name=":2" /> The following are some other diagnoses to consider in an infant presenting with signs of bronchiolitis:<ref name="Fri2014" />
- Upper Respiratory Infection
- Asthma and reactive airway disease
- Bacterial pneumonia
- Whooping cough
- Foreign body aspiration
- Congenital heart disease
- Allergic reaction
- Vascular ring
- Heart failure
- Cystic fibrosis
- Chronic pulmonary disease
PreventionEdit
Prevention of bronchiolitis relies strongly on measures to reduce the spread of the viruses that cause respiratory infections (that is, handwashing, and avoiding exposure to those symptomatic with respiratory infections).<ref name=Kir2019 /><ref name="Ral2014" /> Guidelines are mixed on the use of gloves, aprons, or personal protective equipment.<ref name=Kir2019 />
One way to improve the immune system is to feed the infant with breast milk, especially during the first month of life.<ref name=":7" /><ref name="pmid22103307">Template:Cite journal</ref> Respiratory infections were shown to be significantly less common among breastfed infants and fully breastfed RSV-positive hospitalized infants had shorter hospital stays than non or partially breastfed infants.<ref name="Ral2014" /> Guidelines recommend exclusive breastfeeding for infants for the first 6 months of life to avoid infection with bronchiolitis.<ref name="Ral2014" />
The US Food and Drug Administration (FDA) has currently approved two RSV vaccines for adults ages 60 and older, Arexvy (GSK plc) and Abrysvo (Pfizer).<ref name="FDARSV">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Abrysvo is also approved for "immunization of pregnant individuals at 32 through 36 weeks gestational age for the prevention of lower respiratory tract disease (LRTD) and severe LRTD caused by respiratory syncytial virus (RSV) in infants from birth through 6 months of age."<ref name=":9">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is unclear how effective these vaccines will be in preventing infection with bronchiolitis since they are new, although the FDA has approved them due to the clear benefit that they have shown in clinical trials.<ref name=":9" />
Nirsevimab, a monoclonal antibody against RSV, is approved by the FDA for all children younger than 8 months in their first RSV season.<ref name="FDARSV" /> Additionally, children aged 8 to 19 months who are at increased risk may be recommended to receive Nirsevimab as they enter their second RSV season if they have increased risk factors for infection with RSV.<ref>Template:Cite news</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
A second monoclonal antibody, Palivizumab, can be administered to prevent bronchiolitis to infants less than one year of age that were born prematurely and that have underlying heart disease or chronic lung disease of prematurity.<ref name="Ral2014" /> Otherwise healthy premature infants that were born after a gestational age of 29 weeks should not be administered Palivizumab, as the harms outweigh the benefits.<ref name="Ral2014" />
Tobacco smoke exposure has been shown to increase both the rates of lower respiratory disease in infants, as well as the risk and severity of bronchiolitis.<ref name="Ral2014" /> Tobacco smoke lingers in the environment for prolonged periods and on clothing even when smoking outside the home.<ref name="Ral2014" /> Guidelines recommend that parents be fully educated on the risks of tobacco smoke exposure on children with bronchiolitis.<ref name="Ral2014" /><ref name=":2" />
ManagementEdit
Treatment of bronchiolitis is usually focused on the hydration and symptoms instead of the infection itself since the infection will run its course. Complications of bronchiolitis are typically from the symptoms themselves.<ref name="Wright">Template:Cite journal</ref> Without active treatment, cases resolved in approximately eight to fifteen days.<ref>Template:Cite journal</ref> Children with severe symptoms, especially poor feeding or dehydration, may be considered for hospital admission.<ref name="Kir2019" /> Oxygen saturation under 90%-92% as measured with pulse oximetry is also frequently used as an indicator of need for hospitalization.<ref name="Kir2019" /> High-risk infants, apnea, cyanosis, malnutrition, and diagnostic uncertainty are additional indications for hospitalization.<ref name="Kir2019" />
Most guidelines recommend sufficient fluids and nutritional support for affected children along with frequent nasal suctioning. <ref name=Kir2019 /> Measures for which the recommendations were mixed include nebulized hypertonic saline, nebulized epinephrine, and chest physiotherapy. <ref name="Fri2014" /><ref name="Kir2019" /><ref name="Heliox inhalation therapy for bronc">Template:Cite journal</ref><ref name=":0">Template:Cite journal</ref><ref>Template:Cite journal</ref> Treatments which the evidence does not support include salbutamol, steroids, antibiotics, antivirals, and heliox.<ref name=Fri2014/><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
Outpatient ManagementEdit
NutritionEdit
Maintaining hydration is an important part of management of bronchiolitis.<ref name="Ral2014" /><ref name=":3" /><ref>Template:Cite journal</ref> Infants with mild pulmonary symptoms may require only observation if feeding is unaffected.<ref name="Ral2014" /> However, oral intake may be affected by nasal secretions and increased work of breathing.<ref name="Ral2014" /> Poor feeding or dehydration, defined as less than 50% of usual intake, is often cited as an indication for hospital admission.<ref name="Kir2019" />
Breathing/ OxygenEdit
Children must be closely monitored for changes in ability to breathe. Nasal suction can be used at home in order to decrease nasal congestion and open the airways. <ref name="Fri2014" />
Inadequate oxygen supply to the tissue is one of the main concerns during severe bronchiolitis and oxygen saturation is often closely associated with both the need for hospitalization and continued length of hospital stay in children with bronchiolitis.<ref name=":3" /> However, oxygen saturation is a poor predictor of respiratory distress.<ref name="Ral2014" /> Accuracy of pulse oximetry is limited in the 76% to 90% range and there is weak correlation between oxygen saturation and respiratory distress as brief hypoxemia is common in healthy infants.<ref name="Ral2014" /><ref name=":3" /> Additionally, pulse oximetry is associated with frequent false alarms and parental stress and fatigue.<ref name="Ral2014" />
Nasal SuctionEdit
Infants are nose breathers and bronchiolitis causes congestion of the airways with secretions that can make it difficult to feed and breathe.<ref>Template:Cite journal</ref> Nasal suctioning is a very common supportive measure used at home to decrease nasal congestion.<ref name=":11">Template:Cite journal</ref> It has not been extensively studied in the literature, but can be used to decrease secretions in the nose and has been proven mildly effective in one experimental trial.<ref name=":11" /> A nasal suction bulb can be purchased over the counter and directions for its use can be explained by a provider or on the back of the box. Clinical guidelines state that routine suctioning is safe and can provide relief for infants which allows them to eat and sleep more comfortably.<ref name="Ral2014" />
In those same clinical guidelines, it is stated that deep suctioning, which is often performed in the hospital is not recommended as it may lead to increased length of hospital stay in children with bronchiolitis.<ref name="Ral2014" />
Inpatient/ Hospital ManagementEdit
Nutrition/ Fluid TherapyEdit
When children are experiencing poor feeding or dehydration, the child may be admitted to the hospital.<ref name="Ral2014" /><ref name=":2" /><ref name=":3" /> Approximately 50% of infants who are hospitalized due to bronchiolitis require fluid therapy.<ref name=":8">Template:Cite journal</ref> There are two main approaches to fluid therapy: intravenous (IV) fluid therapy and enteral tube fluid therapy (nasogastric or orogastric).<ref name=":8" /> Both approaches to fluid therapy are associated with a similar length of hospital stay.<ref name=":8" /> Enteral tube fluid therapy may reduce the risk of local complications, but the evidence for or against each approach is not clear.<ref name=":8" /> The risk of health care caused hyponatremia and fluid retention are minimal with the use of isotonic fluids such as normal saline.<ref name="Ral2014" />
OxygenEdit
If children are having trouble maintaining their oxygen saturations on room air, clinicians may choose to give additional oxygen to children with bronchiolitis if their oxygen saturation is below 90%.<ref name="Ral2014" /><ref name=":2" /><ref name=":3" /> Additionally, clinicians may choose to use continuous pulse oximetry in these people to monitor them.<ref name="Ral2014" />
The use of humidified, heated, high-flow nasal cannula may be a safe initial therapy to decrease work of breathing and need for intubation.<ref name="Ral2014" /><ref name=":1">Template:Cite journal</ref><ref>Template:Cite journal</ref> High flow nasal cannula may still be used in severe cases prior to intubation.<ref name=":2" /><ref>Template:Cite journal</ref> The use of CPAP has very limited evidence for improving breathing (a decreased respiratory rate) and does not reduce the need for mechanical ventilation.<ref>Template:Cite journal</ref>
Blood gas testing is not routinely recommended for people hospitalized with the disease.<ref name=":3" /><ref name=":2" /> However, people with severe worsening respiratory distress or impending respiratory failure may be considered for capillary blood gas testing.<ref name=":2" />
Contradicting EvidenceEdit
Hypertonic salineEdit
Guidelines recommend against the use of nebulized hypertonic saline in the emergency department for children with bronchiolitis but it may be given to children who are hospitalized.<ref name="Ral2014" /><ref name=":3" />
Nebulized hypertonic saline (3%) has limited evidence of benefit and previous studies lack consistency and standardization.<ref name="Zh2017">Template:Cite journal</ref><ref name="Brook2016">Template:Cite journal</ref><ref>Template:Cite journal</ref> It does not reduce the rate of hospitalization when therapy is given in the emergency department or outpatient setting.<ref name="Ral2014" /> A 2017 review found tentative evidence that it reduces the risk of hospitalization, duration of hospital stay, and improved the severity of symptoms.<ref name="Zh2017" /><ref>Template:Cite journal</ref> Side effects were mild and resolved spontaneously.<ref name="Zh2017" />
BronchodilatorsEdit
Guidelines recommend against the use of bronchodilators in children with bronchiolitis as evidence does not support a change in outcomes with such use.<ref name="Ral2014" /><ref name=":2" /><ref name="gadomski" /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Additionally, there are adverse effects to the use of bronchodilators in children such as tachycardia and tremors, as well as adding increased cost to the medical visit.<ref>Template:Cite journal</ref><ref name="gadomski">Template:Cite journal</ref>
Several studies have shown that bronchodilation with β-adrenergic agents such as salbutamol may improve symptoms briefly but do not affect the overall course of the illness or reduce the need for hospitalization.<ref name="Ral2014" />
However, there are conflicting recommendations about the use of a trial of a bronchodilator, especially in those with history of previous wheezing.<ref name="Kir2019" /><ref name="Ral2014" /><ref name=":3" /> Bronchiolitis-associated wheezing is likely not effectively alleviated by bronchodilators anyway as it is caused by airway obstruction and plugging of the small airway diameters by luminal debris, not bronchospasm as in asthma-associated wheezing that bronchodilators usually treat well.<ref name="gadomski" /> If a clinician is concerned that reactive airway disease or asthma may be a component of the illness, a bronchodilator may be administered. <ref name="Ral2014" />
Anticholinergic inhalers, such as ipratropium bromide, have a modest short-term effect at best and are not recommended for treatment.<ref name=":2" /><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
EpinephrineEdit
The current state of evidence suggests that nebulized epinephrine is not indicated for children with bronchiolitis except as a trial of rescue therapy for severe cases.<ref name="Ral2014" /><ref name=":2" />
Epinephrine is an α and β adrenergic agonist that is used to treat other upper respiratory tract illnesses, such as croup, as a nebulized solution.<ref>Template:Cite journal</ref> Current guidelines do not support the outpatient use of epinephrine in bronchiolitis given the lack of substantial sustained benefit.<ref name="Ral2014" />
A 2017 review found inhaled epinephrine with corticosteroids did not change the need for hospitalization or the time spent in hospital.<ref>Template:Cite journal</ref> Other studies suggest a synergistic effect of epinephrine with corticosteroids but have not consistently demonstrated benefits in clinical trials.<ref name="Ral2014" /> Guidelines recommend against its use currently.<ref name="Ral2014" /><ref name=Kir2019 />
Non-effective TreatmentsEdit
- Ribavirin is an antiviral drug which does not appear to be effective for bronchiolitis.<ref name="Bourke11" />
- Antibiotics are often given in case of a bacterial infection complicating bronchiolitis, but have no effect on the underlying viral infection and their benefit is not clear.<ref name="Bourke11" /><ref name="pmid25300167">Template:Cite journal</ref><ref>Template:Cite journal</ref> The risks of bronchiolitis with a concomitant serious bacterial infection among hospitalized febrile infants is minimal and work-up and antibiotics are not justified.<ref name="Ral2014" /><ref name=":4" /> Azithromycin adjuvant therapy may reduce the duration of wheezing and coughing in children with bronchiolitis but has not effect on length of hospital stay or duration of oxygen therapy.<ref>Template:Cite journal</ref>
- Corticosteroids, although useful in other respiratory disease such as asthma and croup, have no proven benefit in bronchiolitis treatment and are not advised.<ref name="Ral2014" /><ref name="Kir2019" /><ref name="Bourke11" /><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Additionally, corticosteroid therapy in children with bronchiolitis may prolong viral shedding and transmissibility.<ref name="Ral2014" /> The overall safety of corticosteroids is questionable.<ref>Template:Cite journal</ref>
- Leukotriene inhibitors, such as montelukast, have not been found to be beneficial and may increase adverse effects.<ref name="Kir2019" /><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
- Immunoglobulins are of unclear benefit.<ref>Template:Cite journal</ref>
Experimental TrialsEdit
Currently other medications do not yet have evidence to support their use, although they have been studied for use in bronchiolitis.<ref name="Ral2014" /><ref name=BMJ11>Template:Cite journal</ref> Experimental trials with novel antiviral medications in adults are promising but it remains unclear if the same benefit will be present.<ref name=":3"/>
- Surfactant had favorable effects for severely critical infants on duration of mechanical ventilation and ICU stay however studies were few and small.<ref>Template:Cite journal</ref><ref name="Bourke11"/>
- Chest physiotherapy, such as vibration or percussion, to promote airway clearance may slightly reduce duration of oxygen therapy but there is a lack of evidence that demonstrates any other benefits.<ref name="Ral2014" /><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> People with difficulty clearing secretions due to underlying disorders such as spinal muscle atrophy or severe tracheomalacia may be considered for chest physiotherapy.<ref name=":2">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- Heliox, a mixture of oxygen and the inert gas helium, may be beneficial in infants with severe acute RSV bronchiolitis who require CPAP but overall evidence is lacking.<ref name="Heliox inhalation therapy for bronc"/><ref>Template:Cite journal</ref>
- DNAse has not been found to be effective but might play a role in severe bronchiolitis complicated by atelectasis.<ref>Template:Cite journal</ref>
- There are no systematic reviews or controlled trials on the effectiveness of nasal decongestants, such as xylometazoline, for the treatment of bronchiolitits.<ref name="Bourke11"/>
- Overall evidence is insufficient to support the use of alternative medicine.<ref name="Ku2017">Template:Cite journal</ref> There is tentative evidence for Chinese herbal medicine, vitamin D, N-acetylcysteine, and magnesium but this is insufficient to recommend their use.<ref name="Ku2017" />
EpidemiologyEdit
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Bronchiolitis typically affects infants and children younger than two years, principally during the autumn and winter.<ref name=":3" /> It is the leading cause of hospital admission for respiratory disease among infants in the United States and accounts for one out of every 13 primary care visits.<ref name=Kir2019 /> Bronchiolitis accounts for 3% of emergency department visits for children under 2 years old.<ref name="Bourke11"/> Bronchiolitis is the most frequent lower respiratory tract infection and hospitalization in infants worldwide.<ref name=":3" />
COVID-19 PandemicEdit
The COVID-19 pandemic rapidly changed the transmission and presentation starting in late 2019.<ref name=":10">Template:Cite journal</ref> During the pandemic, there was a sharp decrease in cases of bronchiolitis and other respiratory illness, which is likely due to social distancing and other precautions.<ref name=":10" /> After social distancing and other precautions were lifted, there was increases in the cases of RSV and bronchiolitis worldwide to varying degrees. <ref name=":10" /> There is unclear evidence on how COVID-19 will affect bronchiolitis moving forward. Recent evidence suggests that bronchiolitis still poses a large disease burden to both primary care providers and emergency departments. <ref>Template:Cite journal</ref>
ReferencesEdit
External linksEdit
- Bronchiolitis. Patient information from NHS Choices
- {{#invoke:citation/CS1|citation
|CitationClass=web }} Template:Small from the Scottish Intercollegiate Guidelines Network
Template:Medical resources Template:Sister project Template:Respiratory pathology Template:Common Cold