Asthma Exacerbations In Adults Research Articles

Respiratory viruses and exacerbations of asthma in adults.

To study the role of respiratory viruses in exacerbations of asthma in adults. Longitudinal study of 138 adults with asthma. Leicestershire Health Authority. 48 men and 90 women 19-46 years of age with a mean duration of wheeze of 19.6 years. 75% received regular treatment with bronchodilators; 89% gave a history of eczema, hay fever, allergic rhinitis, nasal polyps, or allergies; 38% had been admitted to hospital with asthma. Symptomatic colds and asthma exacerbations; objective exacerbations of asthma with > or = 50 l/min reduction in mean peak expiratory flow rate when morning and night time readings on days 1-7 after onset of symptoms were compared with rates during an asymptomatic control period; laboratory confirmed respiratory tract infections. Colds were reported in 80% (223/280) of episodes with symptoms of wheeze, chest tightness, or breathlessness, and 89% (223/250) of colds were associated with asthma symptoms. 24% of 115 laboratory confirmed non-bacterial infections were associated with reductions in mean peak expiratory flow rate > or = 50 l/min through days 1-7 and 48% had mean decreases > or = 25 l/min. 44% of episodes with mean decreases in flow rate > or = 50 l/min were associated with laboratory confirmed infections. Infections with rhinoviruses, coronaviruses OC43 and 229E, influenza B, respiratory syncytial virus, parainfluenza virus, and chlamydia were all associated with objective evidence of an exacerbation of asthma. These findings show that asthma symptoms and reductions in peak flow are often associated with colds and respiratory viruses; respiratory virus infections commonly cause or are associated with exacerbations of asthma in adults.

Viral respiratory tract infection and exacerbations of asthma in adult patients.

The role of viral respiratory tract infections in acute exacerbations of asthma was studied prospectively in 31 patients with atopic asthma aged 15-56 years. Patients recorded symptom scores for asthma and peak expiratory flow rate daily for 11 months. In addition, they reported for detailed clinical, functional, and virological study every four weeks and as soon as possible after the onset of worsening asthma or symptoms suggesting a respiratory tract infection. Thirty viral identifications were made, of which 18 (60%) were associated with an exacerbation of asthma. Viral respiratory tract infection was identified in 18 (10%) of the 178 exacerbations of asthma, and in 10 (36%) of the 28 severe exacerbations. The frequency of viral identifications in 16 non-asthmatic, control subjects during the same period was similar. It is concluded that viral respiratory tract infections may cause or be associated with exacerbations of asthma in adults, and that they are an important factor in severe exacerbations.

Exacerbations of asthma in adults during experimental rhinovirus infection.

To determine the incidence of wheezing in adult asthmatics with rhinovirus infection, we exposed 21 asthmatic volunteers to 1 of 2 rhinovirus serotypes. Symptoms, spirometry, and histamine inhalation challenge were assessed prior to, daily during, and 3 wk after the rhinovirus infection. Four volunteers had fiberoptic bronchoscopy performed on the fourth study day. Nineteen volunteers became infected with rhinovirus; 17 of 19 had typical coryzal symptoms. Volunteers did not have significant changes in spirometry or histamine sensitivity during rhinovirus infection when taken as a group or when categorized by severity of asthma or severity of the clinical illness. A subgroup of 4 volunteers was identified that had a 10% or greater decrease in FEV1 and a parallel increase in histamine sensitivity during rhinovirus infection; these 4 volunteers were not otherwise distinguishable from the group as a whole. Rhinovirus was recovered from bronchoscopy specimens of 1 of the 4 infected volunteers bronchoscoped. Thus, exacerbations of wheezing occurred in the minority of experimental rhinovirus infections in adult asthmatics, suggesting that other viral pathogens may play a more important role in precipitating asthma attacks.

Alterations in Pulmonary Function Following Respiratory Viral Infection

Respiratory viral illness is a major cause of morbidity in both adults and children. This report focuses on both the acute and chronic effects on respiratory function of these ubiquitous infections. Infant airways are particularly vulnerable due to the relatively low conductance in immature peripheral airways. Bronchiolitis, caused predominantly by respiratory syncytial virus, is the most important of these viral illnesses and is emerging as a major risk factor for the subsequent development of obstructive airway disease in adults, possibly by interference with normal alveolar proliferation. The basic pathogenic mechanism involved in adult respiratory viral infection is bronchial hyperreactivity, presumably secondary to epithelial damage and resultant sensitization of rapidly adapting airway receptors. In addition, there may be virus-related alterations in the autonomic and humoral regulation of airway tone. Viral infections may alter the effects of common air pollutants on respiratory function.