Discussion of interesting or befuddling cases related to pulmonary and critical care medicine.
Tuesday, May 02, 2006
Exercise-induced asthma
What's the best way to diagnose exercise-induced asthma in a patient where the history seems to fit and baseline spiro is negative: methacholine challenge or post-exercise spirometries?
Anecdotally, I have recently had a patient with normal baseline spiro, negative methacholine with significant decline in FVC and FEV1 at peak exercise...
In keeping with the differential asthma with exercise as a trigger and more isolated exercise-induced bronchospasm (EIB) I have come across two references looking at different levels of exhaled NO in asthma vs EIB: Scollo M et al Am J Respir Crit Care Med 2000 Mar;161(3 Pt 1):1047-50 and De Gouw HW et al J Appl Physiol 2001 Feb;90(2):586-92
I have also found a reference (though I can't get the abstract online) for an old study showing that there is a difference in response to exercise and to methacholine in those with just exercise-induced symptoms.
Yes, I also was under the impression that methacholine was not as sensitive for exercise-induced as it was for the atopic, and that a post-exercise spiro would be more applicable....
The 1999 ATS guidelines for methacholine and exercise challenge testing.(A J Respir Crit care med. Vol 161, #1 Jan 2000, 309-3290 states that AIB cannot be excluded by methacholine challenge.This conforms with my experiences that the way to diagnose exercise asthma (or bronchospasm-realizing there may be a distinction between the 2) is with exercise testing.
6 comments - CLICK HERE to read & add your own!:
Anecdotally, I have recently had a patient with normal baseline spiro, negative methacholine with significant decline in FVC and FEV1 at peak exercise...
In keeping with the differential asthma with exercise as a trigger and more isolated exercise-induced bronchospasm (EIB) I have come across two references looking at different levels of exhaled NO in asthma vs EIB:
Scollo M et al Am J Respir Crit Care Med 2000 Mar;161(3 Pt 1):1047-50 and
De Gouw HW et al J Appl Physiol 2001 Feb;90(2):586-92
I have also found a reference (though I can't get the abstract online) for an old study showing that there is a difference in response to exercise and to methacholine in those with just exercise-induced symptoms.
Yes, I also was under the impression that methacholine was not as sensitive for exercise-induced as it was for the atopic, and that a post-exercise spiro would be more applicable....
The 1999 ATS guidelines for methacholine and exercise challenge testing.(A J Respir Crit care med. Vol 161, #1 Jan 2000, 309-3290 states that AIB cannot be excluded by methacholine challenge.This conforms with my experiences that the way to diagnose exercise asthma (or bronchospasm-realizing there may be a distinction between the 2) is with exercise testing.
Welcome, James. I have had the same experience. Come back and comment often.
Post a Commenttest post a comment