Background: During induction treatment, acute myeloid leukemia patients may develop pulmonary infiltrates due to infectious or noninfectious etiologies. The risk association and the clinical outcome of such pulmonary infiltrates are poorly characterized in the literature.
Methods: We retrospectively reviewed 363 cases of acute myeloid leukemia patients who received induction therapy as inpatients over a period of 11 years at William Beaumont Health System. Of these 363 patients, 120 developed pulmonary infiltrates during induction therapy, those patients were divided into 2 groups based on distribution of the infiltrate presenting as localized or diffuse in nature. Data on patients characteristics, leukemia subtype, cytogenetic risk, microorganism type, white blood cell count at diagnosis, neutrophil count at the time the infiltrate was reported, response to antibiotic and/or antifungal therapy, using respiratory support, and mortality rate were retrieved through chart review.
Results: Thirty-three percent of patients developed pulmonary infiltrates during their induction therapy. Sixty-three patients (52.5%) had a localized infiltrates and 57 patients (47.5%) had diffuse infiltrates. Of the 120 patients with pulmonary infiltrates, 48 (40%) had at least 1 pathogenic microorganism identified, and 58 (48.7%) required intubation and ventilatory support. Patients with localized pulmonary infiltrates were more likely to have positive pathogenic microorganisms (68.3% vs. 8.8%, P<0.001), to be neutropenic (96.8% vs. 21%, P<0.001), and tended to have potentially reversible infiltrates after treatment (87.3% vs. 21%, P<0.001). Whereas patients with diffuse infiltrates were more like to require intubation (78.9% vs. 21%, P<0.001), to have leukocytosis (white blood cell >100 billions/L) at diagnosis (54.4% vs. 0%, P<0.001), and had a higher mortality rate (70.2% vs. 9.5%, P<0.001).
Conclusions: The radiologic patterns of pulmonary infiltrates showed specific etiological and prognostic associations. Diffuse infiltrates are an unfavorable characteristic with overall dismal outcome.