RHINOVIRUS-ASSOCIATED WHEEZING IN INFANCY: SIMILARITIES AND DIFFERENCES WITH RESPIRATORY SYNCYTIAL VIRUS BRONCHIOLITIS Kotaniemi-Syrjänen A, 1 Korppi M, 1 Waris M, 2 Vainionpää R, 2 Reijonen TM. 1 1 The Department of Paediatrics, Kuopio University and Kuopio University Hospital, and 2 The Department of Virology, Turku University, Finland. INTRODUCTION There is increasing evidence that rhinoviruses are associated with wheezing illnesses in infants, and that rhinoviral wheezing carries an increased risk for later childhood asthma (Table 1). 1 Less is known on the clinical picture of rhinovirus-associated wheezing. In the present study, clinical characteristics of rhinovirus- associated wheezing were compared with respiratory syncytial virus (RSV) bronchiolitis in younger than 2-year old children, all hospitalized either with rhinovirus (n=26) or with RSV (n=24) infection-associated wheezing in RESULT I Baseline data of the 50 study children with either rhinovirus or RSV infection etiology. Rhinovirus RSV Baselineinfectioninfection data(n=26)p(n=24)OR (95%CI) ____________________________________________________________________________________ Age >12 months17 (65%)<0.001 # 2 (8%) Gender (boys / girls)18/ # 13/11 Atopic dermatitis14 (54%)0.006 ¤ 4 (17%)15.61 ( ) Blood eosinophilia a 14 (56%)0.045 ¤ 2 (9%)6.78 ( ) Elevated total serum IgE b 8 (31%)0.763 ¤ 3 (14%)1.38 ( ) ____________________________________________________________________________________ a Blood eosinophil count of >0.45 x10 9 /L (data available for 25 rhinovirus positive and 22 RSV positive children). b Total serum IgE of >60 kU/L (data available for 26 rhinovirus positive and 22 RSV positive children). # Chi-squared test ¤ Logistic regression adjusted for age ( 12 months) and gender (OR vs. RSV group as a reference). RESULT II Results of the clinical examination on hospital admission in the 50 study children with rhinovirus or RSV infection etiology. VariableRhinovirus infectionRSV infection (n=26)(n=24) _____________________________________________________________________________________ Respiratory rate /min [median (range)]49 (36-80) 53 (36-72) Heart rate /min [median (range)] a 161 ( ) # 146 ( ) Oxygen saturation [median (range)] 95 (90-98) 92 (87-97) ¤ RDAI score [median (range)] 9 (2-14) 8 (4-14) RACS from 0 to 90 min [median (range)] b 5 (-1 to 17) 4 (-2 to 13) _____________________________________________________________________________________ a Data available for 26 children with rhinovirus and for 23 children with RSV infection. b Data available for 24 children with rhinovirus and for 24 children with RSV infection. RACS = RDAI(0 min)-RDAI(90 min) + respiratory rate change from 0 to 90 min (10% decrease = +1 unit; 10% increase = -1 unit). A positive RACS figure means clinical improvement, and a negative figure clinical deterioration. # p=0.001 vs. children with RSV etiology (age-adjusted linear regression). ¤ p=0.027 vs. children with rhinovirus etiology (age-adjusted linear regression). TABLE 2. Respiratory distress assessment instrument (RDAI) (according to Lowell et al. 1987) 3 Points ___________________________________ Maximum Findings1234points _____________________________________________________________________ Wheezing ExpirationEnd½¾All 4 InspirationPartAll Location SegmentalDiffuse Retractions SupraclavicularMildModerateMarked--- 3 IntercostalMildModerateMarked--- 3 SubcostalMildModerateMarked--- 3 Total 17 ________________________________________________________________________________ CONCLUSION Rhinovirus-associated wheezing seem to be a clinical entity different from RSV bronchiolitis, and the illnesses can be preliminary separated by age. However, virological studies are essential for definitive separation. Markers on allergy, and especially eosinophilia during viral infection, are helpful for prediction of the outcome. Our results suggest that the use of the diagnosis of bronchiolitis should be restricted only to infants younger than 12 months (or even younger than 6 months) of age, and wheezy (obstructive) bronchitis (or even asthma) is the preferable diagnostic term to over 12 months old wheezers, and also to younger infants who wheeze in association with verified rhinovirus infection. REFERENCES 1.Kotaniemi-Syrjänen A, Vainionpää R, Reijonen TM, Waris M, Korhonen K, Korppi M. Rhinovirus-induced wheezing in infancy – the first sign of childhood asthma. J Allergy Clin Immunol 2003; 111: Reijonen T, Korppi M, Pitkäkangas S, Tenhola S, Remes K. The clinical efficacy of nebulized racemic epinephrine and albuterol in acute bronchiolitis. Arch Pediatr Adolesc Med 1995; 149: Lowell D, Lister G, von Koss H, McCarthy P. Wheezing in infants: the response to epinephrine. Pediatrics 1987; 79: METHODS Polymerase chain reaction (PCR) was used to confirm rhinoviral etiology (in frozen nasopharyngeal aspirates in 2000), 1 and antibody and antigen assays (in ) 2 and PCR (in frozen nasopharyngeal aspirates in 2002) to confirm RSV etiology. Clinical data, registered prospectively on admission, included respiratory rate, oxygen saturation, clinical scores (RDAI, respiratory distress assessment instrument (Table 2)) and RACS, respiratory assessment change scores), physician-diagnosed atopic dermatitis, total serum immunoglobulin E (IgE), and blood eosinophil counts. TABLE 1. Viruses associated with wheezing in infancy and asthma at early school age. (modified from Kotaniemi-Syrjänen et al. 2003) 1 Asthma at early school age ___________________________ Viral findingsPresentNot present (n=27)(n=39) ____________________________________________________________________________ Single viral findings1824 Rhinovirus14 # 6 RSV19 Other39 Multiple viral findings28 No viral findings77 ________________________________________________________________________________________ # p=0.047; OR 4.13; 95% CI vs. RV-negative cases, determined by logistic regression with adjustment for age sex and atopic dermatitis on entry to the study.