Methacholine inhalation challenge in patients with chronic cough induced by angiotensin-converting enzyme inhibitors.

Angiotensin-converting enzyme inhibitors (ACEI) cause cough in some patients, but the mechanism of this side effect is not clear. Five patients (group I) who had developed chronic cough induced by ACEI were evaluated to determine the bronchial hyperreactivity (BHR) by challenge with methacholine inhalation using a reservoir method at Respiratory Unit, Chulalongkorn Hospital University. Five patients (group II) who did not experience coughing associated with ACEI were also challenged as controls. The results revealed that two patients (40%) in group I demonstrated BHR with the mean PC20 at 15 mg/ml of methacholine solution. On the other hand, none of the patients in group II disclosed BHR. We concluded that coughing during ACEI therapy may be due to an increased inflammatory state in the airway in some susceptible subjects.

Effect of inhaled corticosteroids on bronchial hyperresponsiveness in patients with mild asthma.

We studied the effect of inhaled budesonide on bronchial hyperresponsiveness (BHR) in twenty mild asthmatic patients. The study was conducted as a randomized, double-blind, placebo-controlled study. Before entering the study, the patients performed methacholine inhalation challenge (MIC) using a reservoir method to assess BHR. Then, they were randomly allocated to receive budesonide turbuhaler (200 micrograms/dose) or placebo turbuhaler two inhalations, twice daily for eight weeks. During the study, each patient recorded daily asthma score and daily number of puffs of beta 2 agonist and they were assessed at weeks 4 and 8. At the end of the treatment, MIC was repeated again. Patients receiving budesonide showed a significant improvement in airway responsiveness compared with those receiving placebo (p < 0.05). They also showed a significant improvement in asthma severity score and a significant decrease in beta 2 agonist bronchodilator use. This study also suggested that inhaled corticosteroids may be the primary treatment in patients, even with mild asthmatic and well-controlled symptoms.

Methacholine inhalation challenge in patients with post-Mycoplasma pneumoniae pneumonia.

We studied methacholine bronchial inhalation challenge in 12 patients at 4th week and 12th week after recovered from Mycoplasma pneumoniae pneumonia, compared with 12 healthy subjects as controls. The aerosolized methacholine was produced by an atomized nebulizer of the Provocationtest I, Pari-Starnberg, Germany and the aerosol was kept into a reservoir bag. Then, it was inhaled slowly by a subject. Increasing concentration of methacholine solutions (0, 0.5, 1, 5, 10, and 25 mg/ml) were used. The results revealed that 67% of the patients had bronchial reactivity to methacholine at the first time of challenge with a mean concentration of methacholine producing a fall in FEV1 of 20% from baseline (PC20) of 12.3 +/- 6.44 mg/ml. Fifty percent of the patients were still positive to the test on the second time of challenge with a mean PC20 of 20.1 +/- 6.89 mg/ml. None of the healthy subjects had bronchial hyperreactivity (PC20 > 25 mg/ml). Two patients experienced wheezing and asthmatic attacks requiring bronchodilator therapy during acute phase pneumonia. They were also diagnosed as having bronchial asthma for the first time. Many patients had prolonged coughing during the recovery phase lasting more than 4 weeks. This prolonged coughing seemed to have a correlation with the development of bronchial hyperresponsiveness (BHR). We concluded that M. pneumoniae could induce BHR which may be transient or persistent. The effect of mycoplasma respiratory tract infection may result in airway inflammations and asthmatic attacks.