From the Guidelines
The likely cause of asthma exacerbation in a marathon trainee who developed symptoms 3 hours after training is an upper respiratory infection, given the history of recent training in cold air and upper respiratory infection symptoms. The patient's history of upper respiratory infection symptoms strongly suggests a viral upper respiratory infection as the trigger, as viral infections are among the most common precipitants of asthma exacerbations, causing inflammation of the airways, increased mucus production, and bronchial hyperresponsiveness 1. While exercise and cold air exposure can trigger asthma symptoms, the presence of preceding upper respiratory symptoms makes the viral infection the most likely culprit in this scenario.
Asthma Exacerbation Triggers
- Upper respiratory infections are a common trigger for asthma exacerbations
- Exercise and cold air exposure can also trigger asthma symptoms, but are less likely in this scenario given the patient's history of upper respiratory infection symptoms
- The patient's recent training in cold air may have contributed to the exacerbation, but is not the primary cause
Worsening of Exacerbation and Intubation
The patient's subsequent worsening of exacerbation, intubation, and hypotension can be attributed to the positive pressure ventilation decreasing venous return to the heart, as well as the use of sedative medications during intubation, which can cause vasodilation and further contribute to hypotension 1. Additionally, the development of auto-PEEP (intrinsic positive end-expiratory pressure) in patients with obstructive airway disease can further compromise hemodynamic stability.
Management of Asthma Exacerbations
The management of asthma exacerbations should follow the guidelines outlined by the National Asthma Education and Prevention Program Expert Panel Report 3, which recommends immediate care, close observation for deterioration, frequent treatment, and repeated measurement of lung function 1. The use of oxygen, inhaled b2-agonists, and systemic corticosteroids is recommended, with the dose and frequency of administration dependent on the severity of the exacerbation.
From the Research
Likely Cause of Asthma Exacerbation
- The likely cause of asthma exacerbation in a marathon trainee who developed symptoms 3 hours after training, given a history of recent training in cold air and upper respiratory infection symptoms, is a viral respiratory infection, particularly rhinovirus 2, 3, 4, 5, 6.
- Respiratory viruses are well recognized as major triggers of acute exacerbations of asthma in children and adults, resulting in frequent outpatient visits and hospitalizations 2.
- The fact that the trainee developed symptoms 3 hours after training suggests that the physical exertion may have triggered the exacerbation, possibly in combination with the viral infection and cold air exposure.
Probable Reason for Worsening of Exacerbation
- The probable reason for the subsequent worsening of exacerbation, intubation, and hypotension is the severe inflammatory response triggered by the viral infection, which can lead to impaired antiviral immunity and prolonged symptoms 2, 4.
- The impaired antiviral immunity to rhinovirus may lead to impaired viral clearance, resulting in more severe consequences of the lower respiratory tract infection 2.
- The combination of viral infection, physical exertion, and cold air exposure may have contributed to the severity of the exacerbation, leading to intubation and hypotension.
Role of Viral Infections in Asthma Exacerbations
- Viral infections, particularly rhinovirus, are a major cause of morbidity and mortality in asthma, and are associated with asthma exacerbations 2, 3, 4, 5, 6.
- The severity of viral infections in asthma patients can be influenced by factors such as impaired immune responses, environmental exposures, and nutritional deficiencies 4.
- Early treatment or prevention of viral infections might significantly reduce the rate of asthma exacerbation, which is one of the key points of disease management 3.