|Classification and external resources|
Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs. It usually occurs in children less than two years of age with the majority being aged between three and six months.1 It presents with coughing, wheezing and shortness of breath which can cause some children difficulty feeding. This inflammation is usually caused by respiratory syncytial virus (70% of cases)2 and is much more common in the winter months. Treatment is typically supportive and may involve the use of nebulized epinephrine or hypertonic saline. Bronchiolitis is common with up to one third of children being affected in their first year of life.
In a typical case, an infant under two years of age develops cough, wheeze, and shortness of breath over one or two days. Crackles and/or wheeze are typical findings on listening to the chest with a stethoscope. 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.
Some signs of severe disease include:3
- poor feeding (less than half of usual fluid intake in preceding 24 hours)
- history of apnea
- respiratory rate >70/min
- presence of nasal flaring and/or grunting
- severe chest wall recession
The term usually refers to acute viral bronchiolitis, a common disease in infancy. This is most commonly caused by respiratory syncytial virus4 (RSV, also known as human pneumovirus). Other viruses which may cause this illness include metapneumovirus, influenza, parainfluenza, coronavirus, adenovirus, and rhinovirus.
Studies have shown there is a link between voluntary caesarean birth and an increased prevalence of bronchiolitis. A recent study by Perth's Telethon Institute for Child Health Research has shown an 11% increase in hospital admissions for children delivered this way.5 Children born prematurely (less than 35 weeks), with a low birth weight or who suffer from congenital heart disease may have higher rates of Bronchiolitis and are more likely to require hospital admission. There is evidence that breastfeeding provides some protection against bronchiolitis.6
Testing for the specific viral cause can be done but has little effect on management and thus is not routinely recommended.7 RSV testing by direct immunofluorescence testing on nasopharyngeal aspirate had a sensitivity of 61% and specificity of 89%.8 Identification of those who are RSV-positive can help for: disease surveillance, grouping ("cohorting") people together in hospital wards 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).
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). In addition to good hygiene an improved immune system is a great tool for prevention. One way to improve the immune system is to feed the infant with breast milk, especially during the first month of life.10 Immunizations are available for premature infants who meet certain criteria (some cardiac and respiratory disorders) such as Palivizumab (a monoclonal antibody against RSV). Passive immunization therapy requires monthly injections every winter.
Treatment and management of bronchiolitis is usually focused on the symptoms instead of the infection itself (supportive therapies) since the infection will run its course and complications are typically from the symptoms themselves.11
Currently other medications do not yet have evidence to support their use.13
Ribavirin is an antiviral drug which does not appear to be effective for bronchiolitis.14 Antibiotics are often given in case of a bacterial infection complicating bronchiolitis, but have no effect on the underlying viral infection.14 Corticosteroids have no proven benefit in bronchiolitis treatment and are not advised.14 DNAse has not been found to be effective.15
90% of the patients are aged between 1 and 9 months old. Bronchiolitis is the most common cause of hospitalization up to the first year of life. It is epidemic in winters.
- Paediatric Society of New Zealand. (2005). "Best Practice Evidence Based Guideline: Wheeze and Chest Infection in Infants Under 1 Year". The Society.
- Papadopoulos NG; Moustaki M, Tsolia M, Bossios A, Astra E, Prezerakou A (2002). Am J Respir Crit Care Med.
- BRONCHIOLITIS IN CHILDREN (Sign Guideline 91). Scottish Intercollegiate Guidelines Network. 2006. ISBN 9781905813018.
- Smyth RL, Openshaw PJ (July 2006). "Bronchiolitis". Lancet 368 (9532): 312–22. doi:10.1016/S0140-6736(06)69077-6. PMID 16860701.
- Carbonell-Estrany X, Figueras-Aloy J, (2004). "Identifying risk factors for severe respiratory syncytial virus among infants born after 33 through 35 completed weeks of gestation: different methodologies yield consistent findings.". . Pediatr Infect Dis J 2004;23(11 Suppl):S193-201.
- Zorc, JJ; Hall, CB (2010 Feb). "Bronchiolitis: recent evidence on diagnosis and management". Pediatrics 125 (2): 342–9. doi:10.1542/peds.2009-2092. PMID 20100768.
- 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.
- Ralston, S; Hill, V, Waters, A (2011 Oct). "Occult serious bacterial infection in infants younger than 60 to 90 days with bronchiolitis: a systematic review.". Archives of pediatrics & adolescent medicine 165 (10): 951–6. doi:10.1001/archpediatrics.2011.155. PMID 21969396.
- Belderbos ME, Houben ML, van Bleek GM, et al. (February 2012). "Breastfeeding modulates neonatal innate immune responses: a prospective birth cohort study". Pediatric Allergy and Immunology : Official Publication of the European Society of Pediatric Allergy and Immunology 23 (1): 65–74. doi:10.1111/j.1399-3038.2011.01230.x. PMID 22103307.
- Wright, M; Mullett CJ, Piedimonte G et al. (October 2008). "Pharmacological management of acute bronchiolitis". Veterinary Research 4 (5): 895–903. PMC 2621418. PMID 19209271.
- Hartling L, Bialy LM, Vandermeer B, Tjosvold L, Johnson DW, Plint AC et al. (2011). "Epinephrine for bronchiolitis.". Cochrane Database Syst Rev (6): CD003123. doi:10.1002/14651858.CD003123.pub3. PMID 21678340.
- Hartling, L; Fernandes, RM, Bialy, L, Milne, A, Johnson, D, Plint, A, Klassen, TP, Vandermeer, B (2011 Apr 6). "Steroids and bronchodilators for acute bronchiolitis in the first two years of life: systematic review and meta-analysis". BMJ (Clinical research ed.) 342: d1714. doi:10.1136/bmj.d1714. PMC 3071611. PMID 21471175.
- Bourke, T; Shields, M (2011 Apr 11). "Bronchiolitis". Clinical evidence 2011. PMID 21486501.
- "BestBets: Do recombinant DNAse improve clinical outcome in an infant with RSV positive bronchiolitis?".
- Bronchiolitis. Patient information from NHS Choices
- PDF (1.74 MB) from the Scottish Intercollegiate Guidelines Network
- Diagnosis and Management of Bronchiolitis from the AAP
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