Summary about Disease
Viral-induced asthma, also sometimes called virus-triggered asthma exacerbation, describes the onset of asthma symptoms or a worsening of existing asthma symptoms that are triggered by a viral respiratory infection, such as the common cold (rhinovirus), influenza (flu), or respiratory syncytial virus (RSV). These infections irritate and inflame the airways, leading to constriction and increased mucus production, characteristic of asthma. While not a distinct type of asthma, it's a common trigger for asthma exacerbations, particularly in children.
Symptoms
Symptoms mimic typical asthma symptoms but often occur during or shortly after a viral respiratory infection. Common symptoms include:
Wheezing (a whistling sound when breathing)
Coughing
Shortness of breath
Chest tightness
Increased mucus production
Fast breathing
Use of accessory muscles to breathe (e.g., neck muscles pulling in)
Fatigue
Causes
The primary cause is a viral respiratory infection. Common viruses include:
Rhinovirus (the most frequent cause)
Respiratory Syncytial Virus (RSV)
Influenza viruses (Flu viruses A and B)
Parainfluenza viruses
Adenoviruses
Human Metapneumovirus These viruses infect the respiratory tract, causing inflammation and airway hyperresponsiveness. This inflammation makes the airways more sensitive to other triggers and causes them to narrow, leading to asthma symptoms.
Medicine Used
Medications used to manage viral-induced asthma exacerbations include:
Bronchodilators (e.g., Albuterol): These medications relax the muscles around the airways, opening them up and making it easier to breathe. They are typically delivered via an inhaler or nebulizer.
Inhaled Corticosteroids (e.g., Fluticasone, Budesonide): These reduce inflammation in the airways and help prevent future attacks. They can be used as a maintenance therapy or during an exacerbation.
Oral Corticosteroids (e.g., Prednisone): Used for more severe exacerbations to reduce inflammation quickly. They are typically taken for a short period (5-10 days).
Combination Inhalers (e.g., Fluticasone/Salmeterol, Budesonide/Formoterol): These contain both a bronchodilator and an inhaled corticosteroid for both immediate relief and long-term control.
Antivirals (e.g., Oseltamivir (Tamiflu) for influenza): These may be prescribed if the viral infection is identified early and is amenable to antiviral treatment.
Is Communicable
Yes, the viral infection that triggers the asthma symptoms is communicable. These respiratory viruses spread through respiratory droplets produced when an infected person coughs or sneezes. Asthma itself is not contagious, but the viral trigger is.
Precautions
Preventing viral infections is crucial. Precautions include:
Frequent Handwashing: Wash hands thoroughly with soap and water for at least 20 seconds.
Avoid Touching Face: Avoid touching your eyes, nose, and mouth.
Social Distancing: Maintain distance from people who are sick.
Vaccination: Get vaccinated against influenza and, if eligible, COVID-19 and RSV.
Clean and Disinfect Surfaces: Regularly clean and disinfect frequently touched surfaces.
Avoid Sharing Personal Items: Don't share utensils, drinks, or towels.
Stay Home When Sick: If you're feeling unwell, stay home to avoid spreading the virus.
Asthma Action Plan: Follow your asthma action plan and take your medications as prescribed.
How long does an outbreak last?
The duration of the viral infection typically lasts from a few days to a couple of weeks (7-14 days). Asthma symptoms can persist for longer, even after the viral infection has cleared, sometimes lasting several weeks. The exact duration depends on the severity of the infection, the individual's asthma control, and how promptly treatment is initiated.
How is it diagnosed?
Diagnosis involves:
Medical History: A detailed history of asthma, triggers, and recent respiratory symptoms.
Physical Exam: Listening to lung sounds (wheezing, crackles), assessing breathing effort.
Pulmonary Function Tests (PFTs): Spirometry measures how well the lungs are functioning. This may be difficult during an acute exacerbation, especially in young children.
Viral Testing: Nasal swabs or washes can identify specific viruses (e.g., RSV, influenza, rhinovirus) causing the infection. This is not always routinely done.
Chest X-ray: May be performed to rule out other conditions like pneumonia, especially if symptoms are severe.
Assessment of Asthma Control: Based on symptom frequency, nighttime awakenings, use of rescue inhaler, and limitations on activity.
Timeline of Symptoms
The symptom timeline typically unfolds as follows:
Day 1-3: Initial viral symptoms (sore throat, runny nose, fatigue). Asthma symptoms may start subtly.
Day 3-7: Asthma symptoms worsen (wheezing, coughing, shortness of breath). Viral symptoms may also peak during this time.
Day 7-14: Viral symptoms begin to subside. Asthma symptoms may persist or improve with treatment, but can linger even after the virus is gone.
Weeks 2-4: Gradual resolution of asthma symptoms. Some individuals may experience lingering airway hyperreactivity for several weeks. This is a general timeline; individual experiences may vary.
Important Considerations
Asthma Action Plan: Having a written asthma action plan is crucial. It outlines steps to take when symptoms worsen, including medication adjustments and when to seek medical care.
Early Intervention: Prompt treatment with bronchodilators and corticosteroids is essential to prevent severe exacerbations.
Monitoring: Closely monitor symptoms and lung function (if possible).
Comorbidities: Other conditions, such as allergies or sinusitis, can worsen asthma symptoms.
Pediatric Considerations: Viral-induced asthma is particularly common in children due to their smaller airways and developing immune systems.
Long-Term Management: Regular asthma check-ups and adherence to prescribed maintenance medications are important for preventing future exacerbations.
Severe Asthma: Patients with severe asthma may require more aggressive treatment and closer monitoring during viral infections.