Airway-Centered Granulomatous Fibrinous and Organizing Pneumonia as a Manifestation of Sirolimus-A Reversible Pulmonary Toxicity

Abstract

Sirolimus is a potent immunosuppressant medication and is used in renal transplant patients to prevent acute graft rejection. Various pulmonary toxicities in patients treated with sirolimus include cough, desquamative interstitial pneumonia (DIP), diffuse interstitial pneumonia, diffuse alveolar damage (DAD), diffuse alveolar hemorrhage (DAH), alveolar phospholipoproteinosis and pulmonary hypertension with features of hemolytic uremic syndrome (HUS). We describe a case of a patient with an insidious development of chest X-ray (CXR), computed tomography of the chest (CT chest) and pulmonary function (PFT) (mainly the DLCO) abnormalities. When this progressed, an open lung biopsy was performed revealing granulomatous inflammation consistent with a hypersensitivity reaction. The abnormalities on imaging and pulmonary function testing improved after drug discontinuation. We suggest that patients using this drug have yearly DLCOs as their pulmonary symptoms may be few. If the DLCO declines significantly then a high resolution CT Chest should be performed. If abnormal, biopsy is warranted.