Bronchial asthma is a disease characterized by the condition of airway hyper-responsiveness, which serves to produce narrowing of the airway secondary to airway inflammation and/or various spasm-inducing stimulus. Nonspecific bronchoprovocation testing is an important method implemented for the purpose of diagnosing asthma; this test measures the actual degree of airway hyper-responsiveness and utilizes direct and indirect bronchoprovocation testing. Direct bronchoprovocation testing using methacholine or histamine may have superior sensitivity as these substances directly stimulate the airway smooth muscle cells. On the other hand, this method also engenders the specific disadvantage of relatively low specificity. Indirect bronchoprovocation testing using mannitol, exercise, hypertonic saline, adenosine and hyperventilation serves to produce reactions in the airway smooth muscle cells by liberating mediators with stimulation of airway inflammatory cells. Therefore, this method has the advantage of high specificity and also demonstrates relatively low sensitivity. Direct and indirect testing both call for very precise descriptions of very specific measurement conditions. In addition, it has become evident that challenge testing utilizing each of the various bronchoconstrictor stimuli requires distinct and specific protocols. It is therefore important that the clinician understand the mechanism by which the most commonly used bronchoprovocation testing works. It is important that the clinician understand the mechanism of action in the testing, whether direct stimuli (methacholine) or indirect stimuli (mannitol, exercise) is implemented, when the testing is performed and the results interpreted.
Adenosine ; Asthma ; Bronchial Provocation Tests ; Hand ; Histamine ; Hyperventilation ; Inflammation ; Mannitol ; Methacholine Chloride ; Methods ; Myocytes, Smooth Muscle ; Respiratory Hypersensitivity ; Sensitivity and Specificity

Current asthma is often excluded by the presence of normal bronchial hyperresponsiveness. We report two asthmatic patients with normal bronchial hyperresponsiveness and one asthmatic patient with mild bronchial hyperresponsiveness (methacholine PC20; 24 mg/ml) which was presumed to be caused by sensitization and exposure to Black GR, the most frequent sensitizer among reactive dyes. They all complained of lower respiratory symptoms after work as well as at the workstation. The bronchoprovocation test with Black GR revealed isolated immediate bronchoconstrictions in all 3 patients and all had high specific IgE antibodies to Black GR-human serum albumin conjugate. After one worker continued at work for 3 days, he experienced a marked drop of methacholine PC20, and it returned to the pre-exposure level during 1 week. The other patient whose initial methacholine challenge was negative developed bronchial hyperresponsiveness on the first day after the dye bronchoprovocation, and returned to normal bronchial hyperresponsiveness on the third day. These findings suggested that patients with occupational asthma caused by reactive dye may not always have bronchial hyperresponsiveness to methacholine, and the screening program utilizing methacholine challenges may not always identify these patients.
Adult ; Asthma/*chemically induced ; Bronchial Provocation Tests/methods ; Bronchoconstriction/*drug effects ; Dyes/*adverse effects ; Human ; Hypersensitivity, Delayed ; Immunoglobulin E/analysis ; Male ; Occupational Diseases/*chemically induced ; Skin Tests

BACKGROUND: Changes in airway mucosal osmolarity are an underlying mechanism of bronchoconstrictive responses to exercise and hypertonic saline (HS). The purpose of this study was to examine whether an osmotic challenge test using HS can predict exercise-induced bronchospasm (EIB) in asthma patients. METHODS: Thirty-six young male asthmatic patients underwent bronchial challenge tests based on 4.5% HS, exercise (> 24h later), and methacholine (MCh) at the Chonnam National University Hospital. The relationships between responses to HS and exercise, and between MCh and exercise were evaluated. RESULTS: The maximal fall in forced expiratory volume in one second following exercise was significantly higher in the HS-responders (n=19) than in the HS-nonresponders (n=17, 35.9+/-4.1% vs. 17.9+/-2.7%, p< 0.001), and there was a significant correlation between the severity of EIB and HS-airway hyperresponsiveness (AHR). When compared with the MCh-AHR test in terms of predicting EIB, the HS-AHR test showed higher specificity (71.4% vs. 42.9%), but a lower sensitivity (58.6% vs. 89.7%) and negative predictive value (29.4% vs. 50.0%). At the moderate AHR cutoff value, the MCh-AHR test had a specificity that was comparable with and predictive values that were higher than those of the HS-AHR test. CONCLUSIONS: The HS-AHR test was more specific than the MCh-AHR test, but was less sensitive and had a poorer negative predictive value, which in combination preclude the use of the HS-AHR test as a screening tool for EIB. The MCh-AHR test had a cutoff value for moderate AHR that may be more useful for predicting EIB in asthmatic patients.
Saline Solution, Hypertonic/*diagnostic use ; Predictive Value of Tests ; Methacholine Chloride/diagnostic use ; Male ; Humans ; Bronchoconstrictor Agents/diagnostic use ; Bronchial Provocation Tests/*methods ; Bronchial Hyperreactivity/*diagnosis ; Asthma, Exercise-Induced/*diagnosis ; Adult ; Adolescent

Aspirin and food additives are known to induce bronchoconstriction, angioedema or urticaria in susceptible patients. To evaluate the incidence of hypersensitivity to aspirin and food additives, 36 subjects with bronchial asthma, 33 of whom were non-allergic asthmatics and 3 were allergic asthmatics who had a history of aspirin sensitivity, were challenged orally with six compounds: acetylsalicylic acid (ASA), sodium bisulfite, tartrazine, sodium benzoate, 4-hydroxy benzoic acid, and monosodium L-glutamate. Significant bronchoconstrictions were found in 15 (41.7%) of the 36 subjects tested. Eight of the 15 subjects showed positive asthmatic responses to the aspirin, two showed asthmatic responses to the food additives, and five responded to both aspirin and the food additives. It is suggested that ASA and food additives could be causes of clinically significant bronchoconstriction in moderately severe non-allergic asthmatic patients.
Adolescent ; Adult ; Aged ; Aspirin/*immunology ; Asthma/*immunology ; Bronchial Provocation Tests/*methods ; Drug Hypersensitivity/*immunology ; Female ; Food Additives/*adverse effects ; Human ; Male ; Middle Age

Aspirin and food additives are known to induce bronchoconstriction, angioedema or urticaria in susceptible patients. To evaluate the incidence of hypersensitivity to aspirin and food additives, 36 subjects with bronchial asthma, 33 of whom were non-allergic asthmatics and 3 were allergic asthmatics who had a history of aspirin sensitivity, were challenged orally with six compounds: acetylsalicylic acid (ASA), sodium bisulfite, tartrazine, sodium benzoate, 4-hydroxy benzoic acid, and monosodium L-glutamate. Significant bronchoconstrictions were found in 15 (41.7%) of the 36 subjects tested. Eight of the 15 subjects showed positive asthmatic responses to the aspirin, two showed asthmatic responses to the food additives, and five responded to both aspirin and the food additives. It is suggested that ASA and food additives could be causes of clinically significant bronchoconstriction in moderately severe non-allergic asthmatic patients.
Adolescent ; Adult ; Aged ; Aspirin/*immunology ; Asthma/*immunology ; Bronchial Provocation Tests/*methods ; Drug Hypersensitivity/*immunology ; Female ; Food Additives/*adverse effects ; Human ; Male ; Middle Age