The most important differential diagnoses to exercise-induced asthma and bronchial hyper-responsiveness in adolescent athletes
| Diagnosis | Clinical presentation in the athlete | Diagnostic procedure |
|---|---|---|
| EIA | Symptoms with expiratory dyspnoea typically start shortly after (sometimes during) physical exercise. By auscultation: Rhonchi and sibilating rhonchi. Respiratory retractions. Gradual improvement spontaneously or after inhaled bronchodilator. | Standardised submaximal exercise test. Mannitol inhalation test. |
| Bronchial hyper-responsiveness | Regular EIA or cough, phlegm occurring typically after intense or repeated competitions/intensive training bouts. | Metacholine bronchial challenge (PC20 or PD20). Eucapnic voluntary hyperpnoea. |
| Exercise-induced vocal cord dysfunction | Symptoms during maximum exertion disappear when exercise is stopped unless continuous hyperventilation. Inspiratory dyspnoea with audible inspiratory sounds from the laryngeal area and no signs of bronchial obstruction. No effect of inhaled bronchodilator before exercise. | Maximal exercise test. Observe inspiratory stridor during maximum exercise. Continuous laryngoscopic exercise test. |
| Exercise-induced arterial hypoxaemia | Occurs in well-trained athletes with high maximum oxygen uptake. Possibly due to diffusion limitations and ventilation–perfusion inequality or rapid red blood cell transit time through the pulmonary capillaries. | Exercise test with the recording of arterial oxygen saturation or arterial oxygen tension. |
| Swimming-induced pulmonary oedema | Occurs rarely. Reported after heavy swimming exercises. Symptoms: Haemoptysis, cough and respiratory distress. Reduced diffusion capacity (TLCO) for up to weeks afterwards. | |
| Other chronic lung diseases | Reduced physical fitness and performance due to reduced baseline air flow and lung volumes. | Exercise test with determination of maximum oxygen uptake and recording of tidal flow volume loops during exercise (flow limitation during exercise) |
| Other chronic disease | Chronic heart diseases and other general disorders. | Regular medical examination. |
| Poor physical fitness | High heart rate after low grade exercise load. | Exercise test with fitness assessment. |
EIA, exercise-induced asthma; TLCO, transfer factor for carbon monoxide.