Bronchiolitis
477474
221942373
2008-06-26T20:09:02Z
Stevenfruitsmaak
247845
+pic
{{Infobox_Disease
| Name = Bronchiolitis
| Image = Bronchiolitis chest X-ray.jpg
| Caption = 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.
| DiseasesDB = 1701
| ICD10 = {{ICD10|J|21||j|20}}
| ICD9 = {{ICD9|466.1}}
| ICDO =
| OMIM =
| MedlinePlus = 000975
| eMedicineSubj = emerg
| eMedicineTopic = 365
| MeshID = D001988
}}
'''Bronchiolitis''' is inflammation of the [[bronchiole]]s, the smallest air passages of the lungs.
==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). ({{ICD10|J|21|0|j|20}})
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 '''[http://aappolicy.aappublications.org/cgi/content/full/pediatrics;118/4/1774 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]]) is common, but has little effect on management. 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.
==Treatment==
There is no effective specific treatment for bronchiolitis. Therapy is principally supportive. 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 [[Continuous positive airway pressure|CPAP]]) might be necessary.
[[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.
[[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.
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.
==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 majory 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 dystrophy|muscular dystrophies]] and other vulnerable groups is currently unknown.
==See also==
*[[Respiratory syncytial virus]]
==External links==
*[http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=479 Bronchiolitis]. Patient information from [[NHS Direct]]
*{{PDF|[http://www.sign.ac.uk/pdf/sign91.pdf Bronchiolitis in children - A national clinical guideline]|1.74 [[Mebibyte|MiB]]<!-- application/pdf, 1833126 bytes -->}} from the [[Scottish Intercollegiate Guidelines Network]]
{{Respiratory pathology}}
{{Common Cold}}
[[Category:Viral diseases]]
[[Category:Inflammations]]
[[Category:Pediatrics]]
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