Bronchiolitis obliterans and bronchiolitis obliterans synd

This code represents a rare, severe, and progressive lung disease characterized by irreversible obstruction of the small airways (bronchioles) due to inflammation and fibrosis. It encompasses both bronchiolitis obliterans, a specific pathological finding, and bronchiolitis obliterans syndrome (BOS), a clinical diagnosis often seen in lung transplant recipients or after toxic inhalations. The condition leads to significant airflow limitation and respiratory compromise.

Use this code for patients diagnosed with either bronchiolitis obliterans or bronchiolitis obliterans syndrome, regardless of the underlying cause. This code is appropriate when documentation clearly states the diagnosis, often supported by pulmonary function tests showing obstructive ventilatory defects and/or lung biopsy findings. It is commonly seen in post-transplant patients (lung, bone marrow), those with autoimmune diseases, or individuals with a history of toxic fume exposure.

• Distinguish from acute bronchiolitis (J21.-), which is typically a viral infection in infants and young children.
• Always look for the underlying cause or associated condition, such as post-transplant status (T86.81-), and code it as a secondary diagnosis if applicable.
• Ensure documentation specifies "obliterans" to differentiate from other forms of bronchiolitis.