Pulmonary injury is one of themost common complications of stem cell transplantation and a major cause ofmorbidity and mortality. Damage to the lungs can be multifactorial,including infection, chemotherapy toxicity, graft-versus-host disease(GVHD), radiation injury, hemorrhage, and immune reactions. Potentialetiology can be determined by carefully considering timing of pulmonarycomplications and whether the radiographic studies are focal or diffuse.Important also to consider is history including exposure to infectiousagents, current and recent prophylaxis regimen, cytomegalovirus (CMV) statusof patient and donor, prior treatment and exposure to pulmonary/cardiotoxictherapy, and current and recent immunosuppression therapy.

All patients should havebaseline pulmonary function tests (PFTs) before transplantation, and anaggressive diagnostic approach should be taken early after transplantationif there are pulmonary problems.

In general, patients withdyspnea and normal chest X-ray (CXR) should undergo PFTs and arterial bloodgas analysis. Restrictive physiology should prompt a chest CT (to look forinterstitial disease). In patients with normal PFTs and CXR, cardiac causessuch as pulmonary hypertension and cardiac dysfunction should beexcluded.

Bronchoscopy withbronchoalveolar lavage (BAL) should be performed early in the search for adiagnosis. If no diagnosis is made, lung biopsy if possible should beconsidered. Patients with focal ini ltrates should be given empiricantibiotics plus or minus fungal therapy and assessed for a response beforeinvasive measures are taken.