A 60-year-old man six months post-heart transplant presents with shortness of breath, low-grade fever and a non-productive cough. His current medications include sirolimus, mycophenolate mofetil, prednisone, Septra, enteric-coated ASA, amlodipine, hydrochlorothiazide, atorvastatin, calcium carbonate, vitamin D and omeprazole. His chest X-ray shows diffuse interstitial infiltrates. He is started on broad-spectrum antibiotics but does not improve. An ECG and echocardiogram are unremarkable. He is seen by Respirology, who suggest, “Consider pneumocystis pneumonia or interstitial pneumonitis secondary to sirolimus.”
What are the characteristics of sirolimus-associated lung disease?