Since over 23 percent of patients with a persistent, troublesome cough who are referred to a cough specialist are diagnosed with "psychogenic cough," experts caution physicians to resist this diagnosis initially. They say that the most common diseases associated with cough lasting two months or more are postnasal drip syndrome, asthma, and gastroesophageal reflux disease. These illnesses should be considered first despite what appears to be even more "obvious" causes such as smoking or chronic interstitial pneumonia. According to the experts, a troublesome cough can be due to more than one condition 93 percent of the time and more than two conditions up to 53 percent of the time. Moreover, because chronic cough so adversely affects psychological health, clinicians should be cautious when concluding that any psychosocial dysfunction is the cause rather than the consequence of the cough. The "Clinical Commentary" appears in the first issue for June of the American Thoracic Society's peer- reviewed American Journal of Respiratory and Critical Care Medicine.
ASTHMA AIRWAY REMODELING STARTS IN
CHILDHOOD AND CONTINUES INTO ADULTHOOD
Airway remodeling in asthma, which, over time, slowly becomes less reversible and manifests itself in impaired lung function, begins in childhood and continues into adult life, according to Canadian and New Zealand researchers. For over a decade, the investigators studied a birth cohort of 1,037 New Zealand children born from 1972 to 1973. The youngsters received lung function tests at ages 9,11, 13, 15, 18, 21, and 26 years as part of an effort to determine the extent of airway remodeling. The researchers developed a lung function test ratio to serve as an airway caliber index. "Normal" study members with no history of asthma, no wheezing in the last year, and no smoking ever were used to determine sex- and age-specific base reference values for the remodeling ratio. According to the authors, failure to achieve a ratio within the normal range despite the use of a bronchodilator suggested the presence of structural abnormalities in the airway wall, indicating a lack of full reversibility. Airway remodeling in this way occurred in 7.4 percent of the cohort at age 18 and 6.4 percent at age 26. This problem occurred in up to one-third of the patients with asthma. Remodeling was associated with male sex, low lung function values, asthma, and, in childhood, airway hyperresponsiveness. The research appears in the first issue for June of the American Thoracic Society's peer- reviewed American Journal of Respiratory and Critical Care Medicine.
CANADIAN INVESTIGATORS DISCOVER RARE
NEW INFANT DEVELOPMENTAL DISORDER
Canadian investigators have identified a new neonatal interstitial lung disease they call "pulmonary interstitial glycogenosis," which they believe is an infant developmental disorder rather than one caused by infection or inflammation. To develop their conclusion, the physician researchers looked at the clinical, radiologic, and pathologic findings from lung biopsies in seven infants with atypical noninfective respiratory disorders during their neonatal period. The authors believe that the pathology they saw had not been described previously and could represent a unique form of interstitial lung disease. Six of the seven infants showed favorable outcomes after being treated primarily with corticosteroids. One infant died from complications associated with extreme prematurity. Three of the cases were followed by the researchers for 6 years. Over that time, these three children showed both a clinical resolution of their problem and improved radiographic results. The study appears in the first issue for June of the American Thoracic Society peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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