Understanding Bronchiolitis Obliterans Syndrome

What is Bronchiolitis Obliterans Syndrome?

Bronchiolitis obliterans syndrome (BOS), also known as obliterative bronchiolitis (OB), is a condition where the small airways in the lungs become scarred and blocked. This scarring and blockage limits airflow to and from the lungs and reduces the ability of lungs to work properly. BOS is generally considered an orphan disease due to its rarity. It usually develops after stem cell or lung transplantation but can also occur after other types of injuries to the lungs.

Causes and Risk Factors of BOS

The exact causes of BOS are still not fully understood. However, some potential causes and risk factors that have been identified include:

– Lung transplantation: BOS is a common complication that can develop after lung transplantation. The underlying cause is thought to be an abnormal immune response following transplantation where the donor lungs are attacked by the recipient’s immune system.

– Infections: Certain viral infections like adenovirus are considered a significant risk factor for developing BOS after lung transplantation. Bacterial and fungal infections can also potentially trigger BOS.

– Graft-versus-host disease: This occurs when immune cells from the donor organ (graft) attack the recipient’s body (host). It is a risk factor for BOS in stem cell transplant recipients.

– Noncompliance with immunosuppressive medications: Not following the medication regimen prescribed to prevent rejection can increase the risks of developing BOS.

– Tobacco smoke exposure: Smoking has been linked to worse outcomes and more rapid onset of BOS in lung transplant patients.

– Genetic factors: Some evidence suggests genetic variations in human leukocyte antigens (HLAs) and other genes may influence risks.

Symptoms of Bronchiolitis Obliterans Syndrome

The symptoms of Bronchiolitis obliterans syndrome usually develop gradually over weeks to months. Common signs and symptoms include:

– Shortness of breath during exercise or activities that did not previously cause breathlessness

– Dry cough

– Fatigue

– Decreased ability to exercise or be physically active

– Wheezing sounds while breathing

– Chest tightness

– Production of thick or tenacious sputum

As the obstruction in the small airways progresses, symptoms may worsen and include shortness of breath even at rest, respiratory failure, and cor pulmonale (enlargement and failure of the right side of the heart).

*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it