The Value of the Chest X-Ray in Making the Diagnosis of Bronchial Asthma

Article excerpt

INTRODUCTION

Although bronchial asthma is one of the most common chronic illnesses of children and young adults (Kaliner, Eggleston, & Mathews, 1987; Proceedings of the Asthma Mortality Task Force, 1987), with a prevalence of 3-5% (Proceedings of the Asthma Mortality Task Force, 1987), it remains underdiagnosed (Anderson, Bailey, Cooper, et al., 1981; Spaight, Lee, & Hey, 1983). Underdiagnosis of asthma can lead to excess morbidity as well as missed days of school or work. Any test that would enhance diagnosis clearly would be of value.

Currently, spirometry is the standard diagnostic test for bronchial asthma at the primary care level. However, between 1952 and 1974, the chest X-ray also was considered important in making the diagnosis of asthma (Royle, 1952; Simon, 1970; Rebuck, 1970; Simon, Connolly, Littlejohns, et al., 1973; Hodson, Simon, & Batten, 1974; Eggleston, Ward, Pierson, et al., 1974); but since 1976, the chest X-ray as a useful diagnostic test has fallen into disfavor (Snider, 1976; Janower, 1976; Findley & Sahn, 1981; Zieverink, Harper, Holden, et al., 1982; Gershel, Goldman, Stein, et al., 1983; Kaliner, Eggleston, & Mathews, 1987). For example, in 1987, the Primer on Allergic and Immunologic Diseases asserted that "chest roentgenograms are not particularly valuable . . . |and~ are indicated only when complications are suspected" (Kaliner, Eggleston, & Mathews, 1987). In 1991, the U.S. Department of Health and Human Services issued a special expert panel report (Guidelines for the Diagnosis and Management of Asthma, 1991); its judgment on the chest X-ray was no less favorable: "|The chest X-ray is useful only to~ rule out other causes of airway obstruction . . . |which~ is especially important for children." It is curious that prior to 1976, the chest X-ray was considered valuable in making the diagnosis of asthma, but since 1976 it has not been considered valuable even though no evidence was produced to evoke this radical change in view. Clearly, the value of the chest X-ray for diagnosing asthma needs to be resolved.

The purpose of this paper is to assess the value of the chest X-ray. This was done by comparing chest X-ray and spirometric findings among asthmatic, bronchitic, and normal patients with the goal of improving the sensitivity of diagnostic criteria in making the diagnosis of bronchial asthma at the primary care level.

METHOD

We studied a nonselected sample of the medical records of three groups of patients, aged 18-40, seen at the Harvard University Health Services (UHS) from 1982 to 1987, in which there were reports in the records of chest X-rays taken at UHS during the same period and in which one of the following three diagnoses was noted: (1) bronchial asthma, (2) bronchitis, or (3) normal or healthy. The group of patients with bronchial asthma (also known as "asthma," "bronchospasm," or "reactive airway syndrome") consisted of 70 cases. Curiously, the diagnosis was not made on the basis of spirometric findings or on chest X-ray findings; in fact, in not a single case did a clinical note even make reference to these. Rather it seemed to have been made on the basis of symptomatology and/or clinical response to bronchodilators or anti-inflammatory agents. We made no attempt to include or exclude patients on the basis of any set of diagnostic criteria; we simply accepted the diagnoses of the UHS clinicians who had taken the histories and examined the patients. We did exclude patients with the following diagnoses: specifically induced asthmatic syndromes (such as exercise-induced, seasonally associated, or cat-induced asthma), cardiac asthma, asthma with associated pectus excavatum, "chest pain syndrome," "chest wall syndrome," pneumonia, pneumothorax, and pneumomediastinum.

Our group of asthmatic patients may best be described as having mild to moderate asthma because only 18 of 70 (26%) had a history of ever coming to an emergency room for asthma; only 7 of these 18, or 7 of 70 (10%), had a history of ever having been hospitalized for asthma; only 10 of 70 (14%) had ever used oral steroids; and none had been referred to a pulmonologist or an asthma treatment center. …