Bronchiolitis
| Bronchiolitis | |
|---|---|
| Classification and external resources | |
|
File:Bronchiolitis chest X-ray.jpg A chest X-ray demonstrating lung hyperinflation with a flattened diaphragm and bilateral atelectasis in the right apical and left basal regions in a 16-day-old infant with severe bronchiolitis. | |
| ICD-10 | J21. |
| ICD-9 | 466.1 |
| DiseasesDB | 1701 |
| MedlinePlus | 000975 |
| eMedicine | emerg/365 |
| MeSH | D001988 |
Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs. This inflammation is usually caused by viruses.
Contents
Causes
The term usually refers to acute viral bronchiolitis, a common disease in infancy. This is most commonly caused by respiratory syncytial virus (RSV, also known as human pneumovirus). Other viruses which may cause this illness include metapneumovirus, influenza, parainfluenza, coronavirus, adenovirus, and rhinovirus.
The American Academy of Pediatrics has published a clinical practice guideline for the Diagnosis and Management of Bronchiolitis, including a review of the evidence and recommendations.
Diagnosis and Recovery
In a typical case, an infant under two years of age develops cough, wheeze, and shortness of breath over one or two days. The diagnosis is made by clinical examination. Chest X-ray is sometimes useful to exclude pneumonia, but not indicated in routine cases.
Testing for specific viral cause (e.g. RSV by nasopharyngeal aspirate) can be done but has little effect on management. In a systematic review, RSV testing by direct immunofluorescence testing on nasopharyngeal aspirate had a sensitivity of 61% and specificity of 89%. [1]Identification of RSV-positive patients can be helpful for:
- disease surveillance
- grouping ("cohorting") patients together in hospital wards as to prevent cross infection
- predicting whether the disease course has peaked yet
- reducing the need for other diagnostic procedures (by providing confidence that a cause has been identified).
The infant may be breathless for several days. After the acute illness, it is common for the airways to remain sensitive for several weeks, leading to recurrent cough and wheeze.
There is a possible link with later asthma: possible explanations are that bronchiolitis causes asthma by inducing long term inflammation, or that children who are destined to be asthmatic are more susceptible to develop bronchiolitis.
Rarely, bronchiolitis obliterans occurs, that is, when bronchitis presents with concomitant non-reversible obstruction due to the bronchioles (small airway branches) becoming compressed and narrowed by fibrosis (scar tissue) and/or inflammation.[2] This form of bronchiolitis is life-threatening and has various causes.
Treatment
There is no effective specific treatment for bronchiolitis. Therapy is principally supportive.[3]
Conservative measures
Frequent small feeds are encouraged to maintain hydration as evidenced by good urine output, and sometimes oxygen may be required to maintain blood oxygen levels. Suction of the nasopharynx is often performed to maintain a clear airway. In severe cases the infant may need to be fed via a nasogastric tube or it may even need intravenous fluids. In extreme cases, mechanical ventilation (for example, using CPAP) might be necessary.
Bronchodilators
Bronchodilator drugs such as salbutamol/albuterol or ipratropium are no longer recommended, but many clinicians offer a trial dose to see if there is any benefit (especially if there is a family history of asthma, since it can be difficult to clinically distinguish bronchiolitis from a viral-induced asthma). Racemic epinephrine is another drug that is sometimes given.
Hypertonic saline
There is some interest in the use of hypertonic saline in bronchiolitis. Initially recommended for use in cystic fibrosis patients, it is speculated to increase hydration of secretions, thus facilitating their removal. [4] In a study of emergency room patients with bronchiolitis, a comparison of nebulized 3% saline/epinephrine with 0.9% saline/epinephrine showed no difference in effectiveness.[5] However, in another study looking at the inpatient population, aerosolized 3% saline soln/1.5mg epinephrine was shown to reduce the length of hospital stay among non-asthmatic, non-severely ill infants with viral bronchiolitis as compared to aerosolized 0.9% saline soln/1.5mg epinephrine according to a randomized controlled trial. Length of stay for aerosolized 3% saline soln/1.5mg epinephrine was 3 +/- 1.2 days, which was significantly shorter (by 25%) than length of stay for patients treated with 0.9% saline soln/1.5mg epinephrine which was 4 +/- 1.9 days (p < 0.05).[6]
Non effective
Ribavirin is an antiviral drug which has a controversial role in treating RSV infection. There is no proven benefit but it is used sometimes for infants with pre-existing lung, heart or immune disease. Antibiotics are often given in case of a bacterial infection complicating bronchiolitis, but have no effect on the underlying viral infection.
Corticosteroids have no proven benefit in bronchiolitis treatment and are not advised.
DNAse has not been found to be effective.[7]
Complications
Middle ear bacterial infection
Development of asthma later (bronchial hyperactivity)
Prevention
In general, prevention of bronchiolitis relies 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).
Premature infants, and others with certain major cardiac and respiratory disorders, can receive passive immunization with Palivizumab (a monoclonal antibody against RSV). This form of passive immunization therapy requires monthly injections every winter. Whether it could benefit infants with lung problems secondary to muscular dystrophies and other vulnerable groups is currently unknown
See also
References
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- Bronchiolitis. Patient information from NHS Direct
- Bronchiolitis in children - A national clinical guidelinePDF (1.74 MiB) from the Scottish Intercollegiate Guidelines Network
es:Bronquiolitis fr:Bronchiolite he:דלקת סימפונונות mg:Bronchiolite nl:Bronchiolitis pl:Ostre zapalenie oskrzelików
sv:Bronkiolit- ↑ Bordley WC, Viswanathan M, King VJ, Sutton SF, Jackman AM, Sterling L; et al. (2004). "Diagnosis and testing in bronchiolitis: a systematic review". Arch Pediatr Adolesc Med. 158 (2): 119–26. doi:10.1001/archpedi.158.2.119. PMID 14757603.
- ↑ Merriam-Webster Medical Dictionary > bronchiolitis obliterans Retrieved on August, 2010
- ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
- ↑ B. Kuzik, S. Al Qadhi, S. Kent, M. Flavin, W. Hopman, S. Hotte, S. Gander Nebulized Hypertonic Saline in the Treatment of Viral Bronchiolitis in Infants The Journal of Pediatrics, Volume 151, Issue 3, Pages 266-270.e1
- ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
- ↑ Mandelberg A, Tal G, Witzling M, Someck E, Houri S, Balin A; et al. (2003). "Nebulized 3% hypertonic saline solution treatment in hospitalized infants with viral bronchiolitis". Chest. 123 (2): 481–7. doi:10.1378/chest.123.2.481. PMID 12576370.
- ↑ "BestBets: Do recombinant DNAse improve clinical outcome in an infant with RSV positive bronchiolitis?".
