Indirect bronchial provocation tests in childhood asthma
| PhD ceremony: | Ms E.T.G. (Elin) Kersten |
| When: | July 01, 2015 |
| Start: | 12:45 |
| Supervisor: | prof. dr. E.J. Duiverman |
| Co-supervisor: | dr. B.J. Thio |
| Where: | Academy building RUG |
| Faculty: | Medical Sciences / UMCG |
In this thesis, we used indirect bronchial provocation tests to monitor treatment changes in asthmatic children. Indirect bronchial provocation tests assess the response of the airways to stimuli that act on inflammatory cells present in the airways. The response to indirect stimuli is greater in children with uncontrolled asthma.
A well-known indirect bronchial provocation test is the exercise challenge test, but it is time consuming, requires strenuous exercise and can potentially cause severe bronchoconstriction. The mannitol test was developed as an alternative; it mimics the dehydrating effect of exercise on the airways by inhalation of dry powder mannitol. We concluded that this test is a suitable alternative for children, especially to rule out exercise induced bronchoconstriction (EIB).
Regular use of β2-agonists (bronchodilators) can lead to an increased bronchial hyperresponsiveness to indirect stimuli. Therefore, we studied the effect of stepping down combination therapy by the cessation of the long-acting β2-agonist. This step down turned out to reduce EIB and to shorten recovery time after a mannitol test.
Asthma and allergic rhinitis frequently co-exist, but nasal symptoms often remain unrecognized and undertreated. We demonstrated that treatment with a corticosteroid nasal spray reduces EIB in asthmatic children.
Montelukast provides a protective effect against EIB after a single dose. We found that this effect only modestly predicts the effect of longer treatment. The acute effect of montelukast on EIB is stronger than the longer term effect, implying that a high adherence is essential to profit from the full protective effect.