Eucapnic voluntary hyperventilation test in children.

BACKGROUND: In children, exercise-induced dyspnea is a common symptom that can be due to dysfunctional breathing. EVH test has bee used especially in elite athletes as bronchoprovocation test. Currently, there are only few studies on the EVH test. New research methods are required alongside the traditionally used tests especially due to dysfunctional breathing disorder. PURPOSE: The purpose of the "pilot study" was to study the usability of the EVH test with real time biofeedback in children of 10-16 years of age in the diagnostics of exercise-induced dyspnea. METHODS: Six 10-16-year-old teenagers with history of exercise-induced dyspnea and three healthy control subjects were selected for the study. A 6-minute EVH test with realtime biofeedback was performed on the patients and the diagnosis was confirmed on the basis of clinical findings and spirometry follow-up either as normal, asthma or dysfunctional breathing. RESULTS: The study was successful in the patients. In the spirometry follow-up, three patients had bronchoconstriction (FEV1 decline over 10%), dysfunctional breathing condition was observed in three patients and three control patients experienced no symptoms. Only two DFB-patients didn't reach the target level of minute ventilation due to a clinical symptom (inspiratory stridor). CONCLUSION: The EVH test was successful in the 10-16-year-old children having participated in the study and the test was well tolerated. Through the study, it was possible to provoke both dysfunctional breathing disorder and bronchoconstriction in the symptomatic patients. Based on the pilot study, EVH test seems to be usable in the diagnostics of pediatric exercise-induced dyspnea but larger studies are warranted to confirm our preliminary findings.

Exercise-induced asthma: nutritional management.

Exercise-induced asthma (EIA) refers to the transient narrowing of the airways following strenuous exercise in asthmatic and otherwise healthy individuals. Despite the heterogeneous treatment options for patients with EIA, there remains a substantial burden of unaddressed disease, even with optimal treatment. Epidemiological studies indicate that patients frequently resort to complementary and alternative therapies while being treated for asthma and other chronic health conditions. There is now convincing evidence that many dietary factors such as increased omega-3 polyunsaturated fatty acids, antioxidant intake and caffeine, and a sodium-restricted diet can reduce the severity of EIA. It is important that these dietary therapies be safe, effective, and likely to be used by individuals with EIA. This review will critically examine whether dietary modification represents a beneficial intervention for asthmatic individuals with EIA.

Exercise-induced bronchoconstriction and atopy in Tunisian athletes.

BACKGROUND: This study is a cross sectional analysis, aiming to evaluate if atopy is as a risk factor for exercise induced bronchoconstriction (EIB) among Tunisian athletes. METHODS: Atopy was defined by a skin prick test result and EIB was defined as a decrease of at least 15% in forced expiratory volume in one second (FEV1) after 8-min running at 80-85% HRmaxTheo. The study population was composed of 326 athletes (age: 20.8 +/- 2.7 yrs - mean +/- SD; 138 women and 188 men) of whom 107 were elite athletes. RESULTS: Atopy was found in 26.9% (88/326) of the athletes. Post exercise spirometry revealed the presence of EIB in 9.8% of the athletes including 13% of the elite athletes. Frequency of atopy in athletes with EIB was significantly higher than in athletes without EIB [62.5% vs 23.1%, respectively]. CONCLUSION: This study showed that atopic Tunisian athletes presented a higher risk of developing exercise induced bronchoconstriction than non-atopic athletes.

Advances in pediatric asthma in 2008: where do we go now?

This year's summary focuses on recent advances in pediatric asthma as reported in Journal publications in 2008. New National Asthma Education and Prevention Program asthma guidelines were released in 2007 with a special emphasis on asthma control. Attention was redirected to methods that could reduce impairment, specifically symptom control, and minimize risk, including exacerbations. Journal theme issues in 2008 focused on several relevant asthma topics including asthma exacerbations, exercise-induced bronchospasm, asthma and obesity, and occupational asthma. This review highlights Journal articles and related articles that reinforce principles of the guidelines and also direct us to new information that will advance asthma care for children. A major step forward will be finding ways to implement the asthma guidelines.

The prevalence of allergic asthma and rhinitis in children of Polichni, Thessaloniki.

AIM: To define the prevalence of asthma and rhinitis in primary school children in the Polichni Municipality of the city of Thessaloniki. METHODS AND RESULTS: The parents of 2005 students living in the area of Polichni completed a questionnaire for the detection of pulmonary disease in childhood. Of 493 children who gave positive answers to the questions about allergies, asthma and rhinitis, 203 were excluded after an interview with the parents, because they suffered from either atopic dermatitis or drug allergy or had normal lgE levels. Of the remaining children, 290 were further examined: methacholine test was positive in 109, exercise test was positive in 67, nasal provocation test with histamine was positive in 244, and rhinodilation test with tramazoline was positive in 206. Skin prick tests were positive in 142 children (90 to grass-cereal pollen, 66 to acarea and 59 to Parietaria officinalis). CONCLUSIONS: We found that 168 children suffered from rhinitis, 84 from both asthma and rhinitis concurrently and 38 from asthma alone. Only 37 % of the parents knew that their children suffered from asthma, while even fewer (32 %) knew that their children had rhinitis. The prevalence of asthma was 6.1 % and that of rhinitis was 12.6 % among children aged 9-12 years in the area of Polichni, Thessaloniki. Childhood rhinitis and asthma seem to be frequently underdiagnosed and undertreated.

Omega-3 Fatty acids and airway hyperresponsiveness in asthma.

Despite the progress that has been made in the treatment of asthma, the prevalence and burden of this disease has continued to increase. Exercise is a powerful trigger of asthma symptoms and reversible airflow obstruction and may result in the avoidance of physical activity by patients with asthma, resulting in detrimental consequences to their health. Approximately 90% of patients with asthma are hyperresponsive to exercise and experience exercise-induced bronchoconstriction (EIB). While pharmacologic treatment of asthma is usually highly effective, medications often have significant side-effects or exhibit tachyphylaxis. Alternative therapies for treatment (complementary medicine) that reduce the dose requirements of pharmacologic interventions would be beneficial, and could potentially reduce the public health burden of this disease. There is accumulating evidence that dietary modification has potential to influence the severity of asthma and reduce the prevalence and incidence of this condition. A possible contributing factor to the increased incidence of asthma in Western societies may be the consumption of a proinflammatory diet. In the typical Western diet, 20- to 25-fold more omega- 6 polyunsaturated fatty acids (PUFA) than omega-3 PUFA are consumed, which causes the release of proinflammatory arachidonic acid metabolites (leukotrienes and prostanoids). This review analyzes the existing literature on omega-3 PUFA supplementation as a potential modifier of airway hyperresponsiveness in asthma and includes studies concerning the efficacy of omega-3 PUFA supplementation in EIB. While clinical data evaluating the effect of omega-3 PUFA supplementation in asthma has been equivocal, it has recently been shown that pharmaceutical-grade fish oil (omega-3 PUFA) supplementation reduces airway hyperresponsiveness after exercise, medication use, and proinflammatory mediator generation in nonatopic elite athletes with EIB. These findings are provocative and suggest that dietary omega-3 PUFA supplementation may be a viable treatment modality and/or adjunct therapy in airway hyperresponsiveness. Further studies are needed to confirm these results and understand their mechanism of action.

Fish oil supplementation reduces severity of exercise-induced bronchoconstriction in elite athletes.

In elite athletes, exercise-induced bronchoconstriction (EIB) may respond to dietary modification, thereby reducing the need for pharmacologic treatment. Ten elite athletes with EIB and 10 elite athletes without EIB (control subjects) participated in a randomized, double-blind crossover study. Subjects entered the study on their normal diet, and then received either fish oil capsules containing 3.2 g eicosapentaenoic acid and 2.2 g docohexaenoic acid (n-3 polyunsaturated fatty acid [PUFA] diet; n = 5) or placebo capsules containing olive oil (placebo diet; n = 5) taken daily for 3 weeks. Diet had no effect on preexercise pulmonary function in either group or on postexercise pulmonary function in control subjects. However, in subjects with EIB, the n-3 PUFA diet improved postexercise pulmonary function compared with the normal and placebo diets. FEV1 decreased by 3 +/- 2% on n-3 PUFA diet, 14.5 +/- 5% on placebo diet, and 17.3 +/- 6% on normal diet at 15 minutes postexercise. Leukotriene (LT)E4, 9alpha, 11beta-prostaglandin F2, LTB4, tumor necrosis factor-alpha, and interleukin-1beta, all significantly decreased on the n-3 PUFA diet compared with normal and placebo diets and after the exercise challenge. These data suggest that dietary fish oil supplementation has a markedly protective effect in suppressing EIB in elite athletes, and this may be attributed to their antiinflammatory properties.

Occurrence of exercise induced bronchospasm in elite runners: dependence on atopy and exposure to cold air and pollen.

OBJECTIVES: To study factors affecting the occurrence of exercise induced bronchospasm (EIB) in elite runners. METHODS: Fifty eight elite runners, 79% of them belonging to Finnish national teams, volunteered. The athletes answered a questionnaire on respiratory symptoms. Skin prick tests were used to investigate atopy, and spirometry to examine lung function at rest and after an exercise challenge test (ECT) at subzero temperature in the winter and after a similar ECT in the summer at the end of the birch pollen season. RESULTS: Definitive EIB (a post-exercise reduction of 10% or more in forced expiratory volume in one second (FEV1) was observed in five (9%) of the 58 runners. A subgroup consisting of 19 non-atopic symptom-free runners with no family history of asthma was used to establish a normal range for post-exercise reduction in FEV1. When this group's mean exercise induced change in FEV1 minus 2 SDs (a reduction of 6.5% or more in FEV1) was taken as the lower limit of the reference range, 15 (26%) of the runners had probable EIB in either the winter or the pollen season. The occurrence of probable EIB depended on atopy (odds ratio increased with number of positive skin prick test reactions, p < 0.05). Nine (22%) of the 41 runners, challenged in both the winter and the pollen season, had probable EIB only in the winter, and three (7%) had it only in the pollen season. Only one runner (2%) had EIB in both tests. CONCLUSIONS: Mild EIB is common in Finnish elite runners and is strongly associated with atopy. Seasonal variability affects the occurrence of EIB, and thus exercise testing should be performed in both cold winter air and the pollen season to detect EIB in elite runners.

[Immuno-biological diagnosis of food allergy]. / Diagnostic immuno-biologique de l'allergie alimentaire.

Food allergy is becoming more frequent, with 6% of asthmatics reporting an isolated food allergy, and 5 to 6% of atopic dermatitis patients also have either a single or multiple true food allergy. There is value in immuno-biological diagnosis by: Measurement of total serum IgE. Measurement of mono-allergen-specific IgE, following a measurement by a multi-allergen of the Trophatope type. A study of elimination of foods for 2 or 3 months followed by their re-introduction. Oral provocation tests in a hospital environment under clinical control and subsequent measurement of the mediators:-Plasma histamine, tryptase, and urinary methylhistamine to give proof of responsibility of the food allergen. Nowadays, it is perfectly possible to include in diagnosis the new technologies of the test of activation of basophils/or lymphocytes by means of flow cytometry.

Refractoriness of eucapnic hyperventilation-induced bronchoconstriction in rabbits.

The mechanism of refractoriness in bronchoconstriction after repeated hyperventilation was investigated in 18 sensitized rabbits. Rabbits were separated into three groups: an untreated control group (n = 7), a cimetidine-treated group (n = 6), and an indomethacin-treated group (n = 5). After anesthetization, hyperventilation was performed for 15 min (120 breaths/min, 7 ml/kg tidal volume) with dry air containing 5% CO2. Total lung resistance (RL) and dynamic compliance (Cdyn) were measured before (baseline) and after hyperventilation challenge. After RL and Cdyn had returned to baseline values, the hyperventilation challenge was repeated. In the control group maximal increase in percent RL (max %RL) was 49 +/- 9% after the first challenge, but 16 +/- 4% after the second challenge, indicating refractoriness. A similar tendency was observed in percent Cdyn. In the cimetidine- and indomethacin-treated groups, max %RL were 42 +/- 3% and 60 +/- 15% after the first challenge, and 35 +/- 8% and 60 +/- 7% after the second challenge, respectively, indicating no refractoriness. These results suggest that the H2-receptor and bronchodilating prostanoids play an important role in producing the refractoriness to bronchoconstriction observed in sensitized rabbits after repeated hyperventilation.

Seasonal variability of exercise-induced asthma especially outdoors. Effect of birch pollen allergy.

A study was made to determine whether natural allergenic exposure modulates exercise-induced asthma. Eighteen asthmatic men, ten non-allergic and eight allergic to birch pollen, underwent heart rate-monitored outdoor exercise tests during both the cold winter season and in the spring, the birch pollen season. The mean fall in FEV1 after the outdoor exercise test increased in the allergic group from 17 +/- 3% in the winter to 27 +/- 6% in the spring, while it decreased in the non-allergic group from 31 +/- 6% to 22 +/- 4%, respectively (P less than 0.01). Initial FEV1 and FCV values remained unchanged in both groups. The non-specific airway responsiveness to histamine did not change significantly in birch pollen allergic or non-allergic subjects during the spring, when compared with the winter values. We conclude that the exercise-induced asthma is aggravated in the birch pollen allergic asthmatics during the pollen season, when compared to the non-birch pollen allergic asthmatics, in whom the exercise-induced bronchoconstriction is attenuated as expected, because of the warmer and more humid weather in the spring.

Trachea-noise biofeedback in asthma: a comparison of the effect of trachea-noise biofeedback, a bronchodilator, and no treatment on the rate of recovery from exercise- and eucapnic hyperventilation-induced asthma.

We review some of the evidence that supports the existence of psychosomatic triggers to bronchospasm in asthmatics, and hypothesize that it may also be possible to consciously reverse bronchospasm using trachea-noise biofeedback. We precipitated significant levels of bronchospasm in 16 asthmatics using exercise or eucapnic-hyperventilation challenges on five occasions, and administered four different treatments and a no-treatment control. The treatments were trachea-noise biofeedback (TNBF), wrong-information TNBF, an inhaled adrenergic bronchodilator, and a placebo inhaler, all given double blind. Half of the subjects had 3 training days in the use of the TNBF device before study. Our results show that TNBF, in the trained subjects only, is associated with a detectable, but not statistically significant, increase in the rate of recovery from bronchospasm over that found with no treatment. We conclude that, although asthmatics seem to have a strong ability to consciously induce bronchospasm, conscious reversal of a full asthma attack using TNBF is limited. Despite contrary conclusions by other investigators, we believe that this study demonstrated little TNBF-assisted recovery from bronchospasm. We suggest that this is because its effect may be inhibited by humoral mechanisms that sustain the attack, but we believe further work is required to support this.

Exercise-induced asthma. Diagnostic clues with recommendation for treatment.

Exercise-induced bronchospasm, a very common component of asthma, may be quite bothersome and interfere with activities. The etiology appears to be related to the degree of heat loss in the tracheobronchial tree and to release of mediators from the mast cells. Exercise-induced asthma can be effectively treated, preferably with preventive medications such as beta 2 agonists or cromolyn (Intal). In the future, drugs such as nifedipine (Procardia) may also be useful, but as yet no calcium channel blocker has been approved for this indication.