Asthma Control, Viral Infections, and Severity of Asthma Exacerbation Symptoms in Children Seen in the Emergency Department.

RATIONALE: While rhinovirus (RV) infection is shown to be associated with asthma exacerbations, prior research has not identified reliable predictors of acute symptom severity in virus-related asthma exacerbations. We enrolled 97 subjects with asthma exacerbations in the emergency department (ED) to evaluate the effect of pre-existing asthma control on the severity of current illness.

METHODS: We prospectively enrolled children with physician diagnosed asthma and current wheezing who presented to Arkansas Children’s Hospital ED. The Asthma Control Test (ACT) was used to stratify well- (ACT>19) and poorly-controlled (ACT≤19) asthma, while Pediatric Respiratory Symptoms Score (PRSS) and Modified Jackson Criteria (MJC) were used to assess current symptoms. Nasopharyngeal swab samples were obtained for viral PCR and genome sequencing.

RESULTS: There were 28 well-controlled and 69 poorly-controlled asthmatics. Sixty-seven percent tested positive for a viral infection, RV most commonly (39.2%). Of those with poor control, 71.4% were infected vs. 60.7% of those with good control. In virally infected subjects, those who were poorly-controlled demonstrated more acute symptoms as compared to those who were well-controlled as measured with PRSS and MJC (p<0.05). The PRSS detected more acute symptoms in the poorly-controlled asthmatics with viral infection than those poorly-controlled asthmatics without infection. Subjects with well-controlled asthma and RV-induced exacerbations had higher viral loads than those with poor control (p<0.05).

CONCLUSIONS: Virally infected poorly-controlled asthmatics demonstrate more symptoms during exacerbations by PRSS and MJC, even when compared to uninfected poorly-controlled asthmatics. With RV infection, those with well-controlled asthma have higher viral loads than those with poorly-controlled, suggesting intact immune responses.