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• Not all that doesn't wheeze isn't not asthma
  Alisa B Lipson
  Published on: 9 January 2022
• Exercise-induced dyspnea; if not asthma, then what?
  Miles Weinberger
  Published on: 9 January 2022

• Published on: 9 January 2022

  Not all that doesn't wheeze isn't not asthma

  • Alisa B Lipson, physician

  Dear Editor,

  While the paper by Drs. Seear and Wensley makes an interesting and important point regarding the over-diagnosis of exercise induced asthma, it is well to remember that the authors are reporting a case series of patients who have been referred to them in a specialty respiratory clinic. The children who are referred are often those whose clinical course or symptoms are atypical, though not necessarily v...

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  Dear Editor,

  While the paper by Drs. Seear and Wensley makes an interesting and important point regarding the over-diagnosis of exercise induced asthma, it is well to remember that the authors are reporting a case series of patients who have been referred to them in a specialty respiratory clinic. The children who are referred are often those whose clinical course or symptoms are atypical, though not necessarily very severe. Indeed, it is often the child who has little to find on examination who is the most puzzling. Most children with moderate exercise induced asthma are straightforward in that they have clear symptoms, often accompanied by objective wheeze relieved by therapy, and they never need specialist referral. I would suggest that the authors are seeing a skewed population of children who do not represent the majority; the external validity of their sample is thus very limited.

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  Conflict of Interest:
  None declared.

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• Published on: 9 January 2022

  Exercise-induced dyspnea; if not asthma, then what?

  • Miles Weinberger, Professor of Pediatrics

  The report by Seear et al found that most children referred to their clinic with a history of exercise-induced asthma (EIA) did not have asthma.(1) These investigators conclude that the majority of exercise associated respiratory complaints can be diagnosed and managed without the need for exercise testing. The accompanying editorial concurs with that view.(2) Our own study recently published is supportive of the ove...

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  The report by Seear et al found that most children referred to their clinic with a history of exercise-induced asthma (EIA) did not have asthma.(1) These investigators conclude that the majority of exercise associated respiratory complaints can be diagnosed and managed without the need for exercise testing. The accompanying editorial concurs with that view.(2) Our own study recently published is supportive of the overdiagnosis of asthma as a cause of exercise-induced dyspnea (EID).(3) However, I would argue against the conclusion that formal exercise testing is not indicated. In fact, our experience demonstrated the value of full cardiopulmonary evaluation with breath-by-breath analysis of oxygen consumption and carbon dioxide production for such children during exercise sufficient to reproduce their symptoms.

  By reproducing EID in 117 patients, most of whom had been previously diagnosed and treated for asthma, while continuously monitoring their cardiopulmonary physiology, we identified only 11 who had EIA during reproduction of their EID. Fifteen had flattening of the inspiratory portion of the flow-volume loop at the time of reproduction of symptoms. Direct visualization with a flexible laryngoscope while symptoms were present distinguished 2 who had exercise-induced laryngomalacia from with vocal cord dysfunction. There were other patients who had what sounded like inspiratory stridor at very high minute ventilation who did not have evidence for upper airway obstruction but simply moved sufficient air through a normal variant airway that an inspiratory sound could be reproduced during maximal exercise. We also identified 15 who, when their EID was reproduced, attained their maximal minute ventilation with a decreased maximal tidal volume and abnormally high respiratory rate consistent with a component of chest wall restriction not apparent at rest. One patient had simply exercise induced hyperventilation, a phenomena we previously reported in others.(4) Supraventricular tachycardia demonstrable by ECG in association was identified in a well- conditioned highly competitive teen-age athlete whose heart rate jumped suddenly to 220 during maximal exercise in association with his EID. He underwent a successful ablation by our cardiac electophysiologist which completely eliminated this young athlete’s EID enabling him to complete a full basketball game without having to repeatedly stop to recover. Since our publication, we have identified another teenager whose EID was associated with supraventricular tachycardia, also only present during vigorous exercise. Both of these adolescents had been previously treated unsuccessfully for EIA. Of the 117 in whom we reproduced their EID during the treadmill exercise, 74 had only normal physiologic exercise limitation, with cardiovascular conditioning among them about equally divided between poor, average, and above average cardiovascular conditioning.

  Our experience is that simply identifying the absence of EIA is not sufficient. Even for the 74 with no physiologic abnormality, we were able to counsel those with poor cardiovascular conditioning regarding the means to improve exercise ability and could counsel those even with excellent cardiovascular conditioning about the need for training to learn how to manage normal exercise limitation. Moreover, since dyspnea from any cause is anxiety producing, identifying the cause of the EID and providing recommendations for a potential solution relieves that anxiety component which was likely to be a factor in seeking medical care and receiving inappropriate treatment in the first place.

  In the study by Saeer et al, one wonders if even all 8 children identified as having EIA actually had asthma as the cause of their EID since the diagnosis was based on an FEV1 decrease >10% but <15% in 6, decreases which may be within normal limits for non-asthmatics.(5) In contrast to the 21% of children with no diagnosis for their EID, we were able to identify the cause of EID in all of our patients in whom full cardiopulmonary monitoring was performed in association with sufficient exercise to reproduce their symptoms.

  Thus, while we certainly agree with the publication and accompanying editorial that EIA is overdiagnosed, our experience would argue for exercise testing that reproduces the symptoms of EID during continuous cardiopulmonary monitoring for those whose history is otherwise atypical for asthma.

  References

  1. Seear M, Wensley D, West N. How accurate is the diagnosis of exercise induced asthma among Vancouver school children. Arch Dis Child 2005;90:898-902.

  2. Helms PJ. Exercise induced asthma: real or imagined? Arch Dis Child 2005;90:886-887.

  3. Abu-Hasan M, Tannous B, Weinberger M. Exercise-induced dyspnea in children and adolescents: if not asthma then what? Ann Allergy Asthma Immunol 2005;94:366-71.

  4. Hammo AH, Weinberger M. Exercise induced hyperventilation: a pseudoasthma syndrome. Annals of Allergy, Asthma, and Immunology 82:574- 578, 1999.

  5. Kattan M, Keens TG, Mellis CM, Levison H. The response to exercise in normal and asthmatic children. J Pediatr 1978;92:718-21.

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  Conflict of Interest:
  None declared.

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