Syncytial Virus


rate of bronchiolitis-associated deaths was highest among infants weighing less than 1,500g at birth compared with those with higher birth weights.


Management of Respiratory Syncytial Virus Disease


The AAP clinical practice guidelines2 provide an evidence-based


approach to the diagnosis and management of bronchiolitis in children between one month and two years of age. Based on guideline recommendations, a diagnosis of bronchiolitis should be made on the basis of a patient’s history and physical examination. These same parameters should be used to assess disease severity. Diagnosis of RSV-related bronchiolitis can be made in several ways, including virus isolation, detection of viral antigens, detection of viral RNA, and demonstration of a rise in serum antibodies. Most clinical laboratories use antigen detection assays to diagnose infection. There is currently no curative treatment for RSV, and there are mixed data on the available pharmacotherapies. In children with mild RSV disease, no specific treatment is necessary other than management of specific symptoms (e.g. acetaminophen to reduce fever).1


The AAP has detailed


recommendations on which therapies are appropriate for children with more severe RSV disease.2


assessing the impact of a patient’s respiratory symptoms on feeding and hydration.2


The AAP stresses the importance of


If the ability to take fluids remains unaffected, infants with mild respiratory distress may require only observation. However, significant morbidity can occur in infants with respiratory difficulty. When the respiratory rate exceeds 60 to 70 breaths per minute, feeding may become compromised, particularly when there are copious nasal secretions. Infants with respiratory difficulty are at an increased risk for aspirating food into the lungs, and these children may develop nasal flaring, increased intercostal or sternal retractions, and prolonged respiratory wheezing.29


To prevent dehydration, intravenous fluids


should be administered to children who have difficulty feeding safely due to respiratory distress.2


According to the AAP guidelines, the use of supplemental oxygen is indicated when the oxyhemoglobin saturation


(SPO2) level persistently falls below 90% in previously healthy infants.2 Adequate supplemental oxygen should be used to maintain the SPO2 level at ≥90%, and can be discontinued when an infant is in minimal


respiratory distress, is feeding well and the SPO2 level is ≥90%. Pulse oximeters are a convenient and safe way to measure oxygenation


status in the clinical setting and are accurate to ±2%; however,


continuous measurement of the SPO2 level is not routinely necessary as the child’s clinical course improves.


Premature or low-birth-weight infants and those with hemodynamically significant CHD or BPD often have abnormal baseline oxygenation, along with an inability to cope with the pulmonary inflammation that occurs with bronchiolitis. These infants may require special attention as they are at risk for developing severe illness requiring hospitalization and may experience more severe or prolonged hypoxia compared with normal infants. These factors should be takeninto account when developing strategies for using supplemental oxygen in these children, and close monitoring is required as oxygen is being weaned.2


The use of bronchodilators in children with RSV bronchiolitis remains controversial. A consistent benefit has not been observed in trials of


58


Jennifer L York, MD, is a Clinical Fellow in Pediatric Critical Care Medicine at St Louis Children’s Hospital and Washington University School of Medicine. Her research efforts focus on identifying, developing, and refining strategies to disseminate and implement research-tested diagnostic, treatment, and quality of life improvement interventions into clinical practice.


α-adrenergic and β-adrenergic agents, and most children treated with bronchodilators will not benefit from the use of these agents.30


Due to


these findings, the AAP does not recommend the routine use of bronchodilators for the management of bronchiolitis.2


However, a


carefully monitored trial of an α-adrenergic or β-adrenergic agent may be an option, and inhaled bronchodilators should be continued only if a documented clinical response is observed. Corticosteroids are routinely administered to infants admitted to the hospital for bronchiolitis.3 However, data from clinical trials do not provide sufficient evidence for their use in patients with RSV bronchiolitis.31,32


Therefore, routine use of


corticosteroids in the management of RSV bronchiolitis is not recommended in the AAP guidelines,2


and the AAP Redbook33 state that the use of this agent states


that corticosteroids are not effective or indicated for RSV bronchiolitis in previously healthy infants. Routine use of ribavirin is also not recommended. The AAP guidelines2


should be reserved for highly selected situations that involve patients who are at risk for severe disease (e.g. immunocompromised and/or hemodynamically significant cardiovascular disease) or in patients with severe RSV-associated bronchiolitis. Marginal benefit with the use of ribavirin has been observed in most patients, and this agent is associated with cumbersome delivery requirements, high cost, and potential health risks for caregivers.34–36


Antibacterial therapy is


frequently given to children with bronchiolitis because of concerns regarding the possibility of bacterial infection. However, no benefit has been observed in clinical trials of antibacterial therapy for the treatment of bronchiolitis.37


According to the AAP guidelines,2 the use of


antibacterial therapy should be reserved for children with specific indications of the coexistence of a bacterial infection. In these children, the antibacterial agent should be used in the same manner as in children without bronchiolitis.


Conclusion


There are currently no treatments directed specifically at RSV infection, and management of patients with RSV disease is primarily symptomatic and supportive. In addition, treatment options that exist for RSV disease have been proven suboptimal in many patients, and significant morbidity can occur in those with severe disease. Due to the limitations and challenges surrounding the management of RSV disease, prevention remains of paramount importance, especially in infants and young children at high risk for severe disease. n


Paul A Checchia, MD, is Chief of the Pediatric Cardiac Critical Care Service and Medical Co-director of the Pediatric Intensive Care Unit at St Louis Children’s Hospital. He is Associate Professor of Pediatric Critical Care Medicine and Cardiology at Washington University School of Medicine. His clinical research efforts focus on studies aimed at further understanding the complex pathophysiology of all forms of cardiac disease.


US RESPIRATORY DISEASE


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84