Bronchiolitis is the inflammation of the lung’s smallest airways, the bronchioles, causing swelling and mucus buildup that restricts airflow. While commonly recognized as a seasonal illness in infants, its presentation in adults is rare and often signifies a more serious underlying process. Adult bronchiolitis can be a transient, acute infection or a chronic, progressive, and irreversible disease, requiring distinct medical management. This article focuses on the diagnostic and therapeutic strategies employed when treating this condition in adults.
Understanding Bronchiolitis in Adults
Bronchiolitis in adults is medically distinct from common bronchitis, which affects the larger bronchial tubes. It presents in two primary forms requiring different treatment paths. Acute infectious bronchiolitis is often caused by common respiratory viruses, such as respiratory syncytial virus (RSV), influenza, or adenovirus, or may result from bacterial infections or toxic inhalation. This form typically presents with fever, a dry cough, and wheezing, and is generally self-limited, though it can progress rapidly to respiratory failure in vulnerable patients.
The second, more severe presentation is chronic constrictive bronchiolitis, also known as Bronchiolitis Obliterans (BO), involving irreversible scarring and narrowing of the small airways. This progressive form is commonly linked to autoimmune diseases like rheumatoid arthritis, complications following lung or bone marrow transplantation, or prolonged exposure to toxic fumes. The larger size of adult airways can mask the severity of the small airway damage until significant obstruction occurs, often leading to a delayed diagnosis.
Medical Diagnosis and Acute Care
Diagnosis begins with a thorough medical history, investigating potential exposures, autoimmune conditions, or recent infections, since symptoms often overlap with asthma or chronic obstructive pulmonary disease (COPD). Pulmonary function tests (PFTs), specifically spirometry, show an obstructive ventilatory defect. This defect does not significantly improve after using an inhaled bronchodilator, indicating fixed airflow obstruction. High-resolution computed tomography (HRCT) scans are frequently used to visualize the lungs, often revealing characteristic signs such as air trapping on expiration, which indicates small airway obstruction.
For a definitive diagnosis of chronic disease, a surgical lung biopsy may be required, as the small size of the affected airways makes transbronchial biopsy less sensitive. Acute or severe cases require immediate medical intervention focused on supportive care and addressing the underlying cause. Supplemental oxygen therapy is administered to counteract low blood oxygen levels, and mechanical ventilation may be necessary in cases of severe respiratory distress.
Specific pharmacological treatment depends on the form and cause of the inflammation. If the cause is infectious, antiviral medications may be administered early in the illness, though antibiotics are reserved only for confirmed bacterial infections. For inflammatory or autoimmune-related bronchiolitis, high-dose systemic corticosteroids, such as prednisone, are a first-line treatment to suppress the immune response and reduce airway inflammation. Immunosuppressive agents may also be used, particularly in post-transplant patients where the condition is viewed as chronic rejection.
Symptom Management and Home Treatments
While medical treatment targets the underlying pathology, supportive measures are implemented to manage symptoms and facilitate recovery at home. Adequate rest is encouraged to reduce the body’s oxygen demand and conserve energy for healing, especially during periods of fever or breathlessness. Maintaining a high fluid intake is important for thinning mucus secretions, helping clear the blocked small airways.
The use of a cool-mist humidifier can add moisture to the air, which soothes irritated airways and may help ease the discomfort of a persistent, dry cough. Over-the-counter medications like acetaminophen can be used to manage fever and general body aches associated with the acute infectious phase. Home management also involves strictly avoiding environmental irritants, including tobacco smoke, strong chemical fumes, and air pollution, as these can exacerbate inflammation and damage the recovering airway epithelium.
Managing Chronic Bronchiolitis and Follow-Up
For patients diagnosed with the chronic, irreversible form (Bronchiolitis Obliterans), management shifts to slowing the progression of lung function decline. Regular follow-up appointments with a pulmonologist are required, including periodic PFTs to monitor the forced expiratory volume in one second (FEV1) as a measure of disease stability. Long-term specialized therapies may include inhaled bronchodilators to help relax any remaining muscle around the airways, providing temporary relief from shortness of breath.
In some cases, specific medications like the macrolide antibiotic azithromycin are prescribed, not for their antibacterial effects, but for their anti-inflammatory properties that may help stabilize lung function. Pulmonary rehabilitation programs are often recommended, combining supervised exercise training, breathing techniques, and patient education to improve physical capacity and quality of life. When the disease is severe and progressively limits daily life, leading to respiratory failure, lung transplantation remains the final therapeutic option.