Abstract Introduction Acute lymphoblastic leukemia (ALL) is a clonal hematopoietic stem cell disorder of B or T cell origin, accounting for ∼30% of childhood cancers but 1% of leukemias in adults over 60. Older adults often exhibit vague and nonspecific symptoms. Cytopenia may be misattributed to infection, medications, or autoimmune disease, delaying diagnosis. Thrombocytopenia in this population has a broad differential, including drug-induced, immune-mediated, marrow infiltration, and consumptive coagulopathies. Diffuse alveolar hemorrhage (DAH), defined as bleeding into the alveolar spaces, is a rare pulmonary complication of hematologic malignancies, typically associated with profound thrombocytopenia and high mortality rate. We report an elderly patient who initially presented with presumed infection and was later diagnosed with ALL following catastrophic DAH. Case Presentation An 84-year-old female with scleroderma, essential tremor, transient global amnesia, and prior hysterectomy presented with fever, chills, abdominal pain, diarrhea progressing to constipation, and fatigue. She was on day nine of nitrofurantoin for presumed urinary tract infection (UTI). On admission, she was febrile and tachycardic, with leukocytosis (WBC 17 × 10³/µL), 5% blasts, elevated lactate, and urinalysis suggesting UTI; IV ceftriaxone was initiated. Platelets were 28 × 10³/µL, thought secondary to drug-induced thrombocytopenia, but fell to 7 × 10³/µL within 48 hours. Peripheral smear showed no schistocytes. Hematology initiated evaluation including coagulation profile and flow cytometry. Despite IVIG, dexamethasone, and platelet transfusions, counts dropped to 3 × 10³/µL. She developed acute kidney injury and hypoxemic respiratory failure. CT chest revealed bilateral infiltrates, and bronchoscopy confirmed DAH. Pulse-dose methylprednisolone was initiated. Flow cytometry confirmed ALL. Given her age, comorbidities, and poor functional reserve, she was not a candidate for chemotherapy. After family discussions, life-sustaining measures were withdrawn. Discussion This case illustrates an unusual presentation of acute lymphoblastic leukemia (ALL) in an elderly patient, in whom infection initially masked the underlying malignancy. Severe thrombocytopenia led to diffuse alveolar hemorrhage (DAH), a rare and devastating complication. In older adults, cytopenias are often attributed to infection, autoimmune disease, or medication effects, which can obscure timely diagnosis. Although flow cytometry remains the gold standard for confirming ALL, in this case the diagnosis was delayed until after the onset of respiratory failure and multiorgan dysfunction. DAH associated with hematologic malignancies carries poor outcomes, particularly when mechanical ventilation is required. Earlier recognition and consideration of hematologic malignancy in elderly patients with unexplained cytopenias could enable more timely diagnosis, multidisciplinary management, and informed goals-of-care discussions. This abstract is funded by: None
Shahid et al. (2026) studied this question.