Bronchoprovocation test in the normal and in asthmatics.
The bronchoprovocation test has been widely used in diagnosis of bronchial asthma. Forty-eight cases under tentative diagnosis of bronchial asthma, with complaints of cough, shortness of breath, and wheezing, were studied by using histamine and methacholine. Their baseline pulmonary functions were all normal. Among the Fourteen cases, histamine and methacholine provocation tests were both negative in 14 cases (29%) (Group 1). There were 18 cases (37%) of allergic asthmatics with positive challenge to either histamine (2 cases) or methacholine (1 case) or both (15 cases) (Group 2). There were 16 cases (34%) of nonallergic asthmatics with positive challenge to either histamine (2 cases) or methacholine (3 cases) or both (11 cases) (Group 3). In Group 2, the average PD20 FEV1 for methacholine and histamine was 25.8 +/- 8.2 BU and 22.9 +/- 7.1 BU respectively; the average PD25 FEF25-75 for methacholine and histamine was 19.4 +/- 7.0 BU and 21.1 +/- 7.1 BU respectively. The sensitivities, compared between both agents, were nearly the same. In Group 3, the average PD20 FEV1 for methacholine and histamine was 35.1 +/- 9.0 BU and 54.5 +/- 9.6 BU respectively; the average PD25 FEF25-75 for methacholine and histamine was 27.9 +/- 8.6 BU and 50.2 +/- 9.6 BU respectively. Methacholine is more sensitive in detecting airway hyperreactivity in this group. When these two groups of asthmatics were compared, Group 2 patients were more sensitive to challenges with histamine and methacholine (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)