Bronchiolitis obliterans organizing pneumonia (BOOP)

Also known as cryptogenic organizing pneumonia, bronchiolitis obliterans organizing pneumonia, or BOOP, is an uncommon condition that affects the lungs. It happens when the bronchioles or small airways of the lungs, along with the alveoli or tiny air-exchange sacs become clogged up and inflammed with connective tissue.

Symptoms are generally pretty mild, ranging from an unproductive cough to shortness of breath. Symptoms are not always immediately present.

While there are many reasons a person may develop BOOP, for the sake of this entry we will look at BOOP as a consequence of anti-cancer treatment. Specifically, BOOP sometimes develops as a complication of a bone marrow transplantation.

BOOP in HSCTs

Bronchiolitis obliterans organizing pneumonia occurrs to between 2-14 % of all allogeneic bone marrow transplantation patients.

The factors that raise the risk of BOOP developing in these patients are

- Chronic GVHD
- Low immunoglobulin levels

Typically, BOOP would be treated with corticosteroid therapy, but in bone marrow transplant patients, response is considered pretty poor. Neither the corticosteroids nor bronchodilators can reliably improve the airflow through the lungs.

Therefore a prompt response to BOOP is critical for the patient's prognosis because there's no telling what kind of clinical course BOOP may take. In patients with advanced disease, a lung transplantation may become necessary.

Sources

- Boyiadzis, Michael M. et al. Hematology-Oncology Therapy. 2007. New York: McGraw Hill, Medical Publishing Division.
- Epler, Gary R MD. Bronchiolitis obliterans organizing pneumonia. Arch Intern Med. Vol 161 Jan22 2001.