RESUMO
In children and adults with asthma, infections with common cold viruses such as respiratory syncytial virus and rhinovirus frequently cause exacerbations of asthma. Recent studies suggest that these and other respiratory viruses infect the lower airways, and that the infected epithelial cells help to initiate immune responses to the virus. These immune responses have antiviral effects, but also enhance airway inflammation and may add to cold symptoms and airway obstruction. Moreover, there are data to suggest that there may be specific interactions between allergic and virus-induced inflammatory responses that contribute to lower airway dysfunction in asthma. Finally, impaired T-helper type 1-like lymphocyte responses during viral infections may be a risk factor for more severe viral illnesses in patients with allergies and asthma. It is hoped that these advances in our understanding of the relationship between viral infections and exacerbations of asthma will translate into new therapeutic targets for virus-induced exacerbations of asthma.
Assuntos
Asma , Resfriado Comum/virologia , Asma/imunologia , Asma/fisiopatologia , Asma/virologia , Criança , Resfriado Comum/complicações , Humanos , Vírus Sincicial Respiratório Humano , Rhinovirus , Fatores de Risco , Viroses/imunologiaRESUMO
In asthmatic children with persistent symptoms, maintenance therapy with nedocromil sodium, inhaled corticosteroids, or montelukast is associated with a decreased rate of asthma exacerbations. The greatest benefit is seen with use of regular inhaled corticosteroids in preschool- or school-age children, in whom asthma exacerbations, the need for rescue oral corticosteroids, unscheduled urgent medical visits, and hospitalizations are all decreased by approximately 50%. However, maintenance therapy is not beneficial in children with intermittent respiratory virus-induced wheezing without persistent symptoms.
Assuntos
Agonistas Adrenérgicos beta/uso terapêutico , Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Asma/virologia , Glucocorticoides/uso terapêutico , Antagonistas de Leucotrienos/uso terapêutico , Infecções Respiratórias/complicações , Infecções Respiratórias/virologia , Doença Aguda , Administração por Inalação , Corticosteroides/uso terapêutico , Criança , Resfriado Comum/complicações , Resfriado Comum/tratamento farmacológico , Resfriado Comum/virologia , Humanos , Sons RespiratóriosAssuntos
Asma/fisiopatologia , Asma/virologia , Resfriado Comum/complicações , Resfriado Comum/virologia , Doença Aguda , Asma/tratamento farmacológico , Criança , Humanos , Infecções por Vírus Respiratório Sincicial/complicações , Vírus Sincicial Respiratório Humano , Infecções Respiratórias/complicações , Infecções Respiratórias/virologiaAssuntos
Antialérgicos/uso terapêutico , Hiper-Reatividade Brônquica , Antagonistas dos Receptores Histamínicos H1/uso terapêutico , Loratadina/uso terapêutico , Hipersensibilidade Respiratória , Sistema Respiratório/fisiopatologia , Infecções Respiratórias/prevenção & controle , Alérgenos/efeitos adversos , Antialérgicos/farmacologia , Asma/complicações , Hiper-Reatividade Brônquica/epidemiologia , Hiper-Reatividade Brônquica/etiologia , Quimiotaxia de Leucócito/efeitos dos fármacos , Criança , Pré-Escolar , Resfriado Comum/complicações , Eosinófilos/efeitos dos fármacos , Feminino , Antagonistas dos Receptores Histamínicos H1/farmacologia , Humanos , Imunoglobulina E/imunologia , Lactente , Molécula 1 de Adesão Intercelular/fisiologia , Estudos Longitudinais , Loratadina/farmacologia , Masculino , Modelos Imunológicos , Selectina-P/fisiologia , Recidiva , Hipersensibilidade Respiratória/epidemiologia , Hipersensibilidade Respiratória/etiologia , Hipersensibilidade Respiratória/prevenção & controle , Infecções Respiratórias/complicações , Rhinovirus/imunologia , Viroses/complicaçõesRESUMO
Episodes of acute otitis media are commonly associated with viral upper respiratory tract infections. Rhinoviruses account for approximately 40% of these infections, and were previously shown to alter eustachian tube function and middle ear pressures. However, progression to otitis media has not been prospectively documented. In the present study, changes in tympanometric pressures and otoscopic findings resulting from experimental intranasal rhinovirus type-39 inoculation were documented in 60 adult volunteers. Fifty-seven (95%) subjects became infected and 34 (60%) of these had a clinical cold. Prior to viral inoculation, 3 (5%) subjects had middle ear pressures of less than -100 mm H2O and two of these subjects developed middle ear effusions following infection. In all, 22 (39%) subjects developed middle ear pressures of less than -100 mm H2O. No subject with normal middle ear pressures prior to infection developed evidence of effusion. This study extends the otologic manifestations of rhinovirus infection to include otitis media. Furthermore, these results support the hypothesized relationship between upper respiratory tract infections, eustachian tube dysfunction, and otitis media.
Assuntos
Resfriado Comum/complicações , Otopatias/etiologia , Testes de Impedância Acústica , Adolescente , Adulto , Ensaios Clínicos Controlados como Assunto , Otopatias/diagnóstico , Orelha Média , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Otite Média/diagnóstico , Otite Média/etiologia , Pressão , Estudos ProspectivosRESUMO
To determine whether a viral upper respiratory tract infection can alter the responsiveness of the nasal mucosa, paired intranasal histamine and cold air challenge sessions were performed before and after (8 to 13 days) experimental rhinovirus infection in 18 nonallergic subjects and 20 subjects with seasonal allergic rhinitis. The nasal response to the challenges was measured as symptom scores for rhinorrhea and congestion, counts for sneezing, weight for expelled secretions, and inspiratory conductance for nasal patency. For both sessions, a greater response was observed in allergic subjects for sneezing, symptoms of rhinorrhea and congestion, secretion weights provoked by histamine challenge, and secretion weights provoked by cold air challenge when compared with the nonallergic subjects. A comparison of the responses to the paired challenge sessions showed greater responses for sneezing, secretion weight and rhinorrhea to histamine and for secretion weight to cold air challenges performed after rhinovirus infection. No differences were observed between allergic and nonallergic subjects with respect to the degree of enhanced responsiveness secondary to viral infection. These results document an increased responsiveness of the nose to these stimuli during the postsymptomatic period of a rhinovirus infection in both allergic and nonallergic subjects.