Alveolitis

Alveolitis can be caused by infections, environmental exposures, and autoimmune disorders. Some cases of alveolitis are also idiopathic where the underlying cause remains unknown. Infections are the most common cause and can include viral pneumonia (e.g., influenza or COVID-19), bacterial pneumonia (e.g. Streptococcus pneumoniae), and fungal infections (e.g., histoplasmosis and aspergillosis).

Environmental factors also play a pivotal role. The inhalation of allergens, pollutants, chemicals, or toxins contributes to alveolitis and may cause hypersensitivity pneumonitis (HP), which is characterized by inflammation of the lung tissue due to an excessive response of the immune system to an extrinsic allergen. Moreover, autoimmune diseases (e.g., rheumatoid arthritis, systemic lupus erythematosus, and sarcoidosis) can also have lung manifestations and may present with inflammation within the alveoli. Connective tissue diseases, like scleroderma and systemic sclerosis, can also affect the lungs and cause alveolitis. Additionally, smoking tobacco poses a significant risk of developing alveolitis as it tends to induce chronic obstructive pulmonary disease (COPD) (e.g., chronic bronchitis or emphysema), which causes lung inflammation and erosion of the alveoli. 

The signs and symptoms of alveolitis vary depending on the underlying cause. One of the most common symptoms is shortness of breath, which may have a gradual onset and progressively worsen to the point of disrupting everyday activities. Additionally, individuals with alveolitis often present with a persistent, dry cough. Fatigue is a prevalent issue for those affected by alveolitis, manifesting as an overall sense of weariness. Furthermore, some individuals may experience chest discomfort or pain, particularly during deep inspiration, which is known as pleuritic pain. In certain cases, clubbing of the fingers and toes may develop, characterized by the enlargement of fingertips and curved nails.

In certain scenarios, a bronchoscopy may be recommended to collect lung tissue samples via biopsy or bronchoalveolar lavage (BAL) fluid for microscopic examination to rule out infections and other lung conditions.

The treatment of alveolitis is based on the underlying cause. Of note, certain subtypes of ILDs are characterized by a progressive and irreversible course, whereas others may be managed with effective treatment. The primary objectives of treatment strategies nonetheless are to alleviate distressing symptoms; slow the progression of the disease; and, whenever possible, address the root cause. Antibiotics (e.g., azithromycin, levofloxacin) or antifungal medications (e.g., fluconazole) are prescribed to treat infections. Efforts may also be made to minimize or eliminate environmental exposures to irritants (e.g., staying indoors, wearing a mask). Corticosteroids are also frequently prescribed to address lung inflammation. Prednisone, a corticosteroid, is the typical choice for ILDs that exhibit an autoimmune component, such as rheumatoid arthritis-associated ILD. In instances where autoimmune diseases are the underlying cause, immunosuppressive drugs like azathioprine, mycophenolate, or cyclophosphamide may be combined with corticosteroids to modulate the immune response effectively.

For ILDs marked by lung fibrosis, as seen in  idiopathic pulmonary fibrosis (IPF), antifibrotic drugs like pirfenidone and nintedanib are employed to halt disease advancement and alleviate symptoms.

Supplemental oxygen therapy can be administered to enhance oxygen levels in the bloodstream, offering relief to individuals with compromised lung function. Pulmonary rehabilitation programs, comprising tailored exercises and educational components, are pivotal for augmenting lung function and improving overall physical well-being.

In situations where conservative treatments are inadequate in severe ILD cases, lung transplantation may be necessary. Overall, regular follow-up care with a pulmonary specialist for monitoring disease progression and fine-tuning treatment approaches is essential for individuals with persistent alveolitis or ILDs.