(1126) Diffuse Alveolar Hemorrhage: A Rare Manifestation of Undiagnosed Acute Myeloid Leukemia

Introduction: Diffuse alveolar hemorrhage (DAH) is a life-threatening pulmonary condition that results from widespread damage to small vessels and disruption of the alveolar-capillary basement membrane, resulting in blood collection within alveolar spaces. We present a rare case of acute myeloid leukemia presenting as DAH.

Description: The patient was a 35 year old male without any known medical history who presented with progressively worsening dyspnea associated with fever and generalized weakness for 3 days duration. He reported one episode of hemoptysis. He was tachycardic and hypoxic on admission. Chest imaging revealed extensive bilateral patchy infiltrates. Labs were notable for a hemoglobin of 12.8 g/dL, platelet count of 67 x 10^3/uL, and potassium of 5.0 mmol/L. SARS-Cov-2 test was negative. He was admitted to the intensive care unit and started on broad spectrum antibiotics for suspected pneumonia. Over the next 24 hours, the patient's oxygen demands continued to increase and eventually he required intubation and mechanical ventilation due to worsening respiratory failure. Patient still exhibited refractory hypoxemia despite maximum ventilator support, with worsening bilateral infiltrates on chest imaging concerning for ARDS. Patient was started on venovenous ECMO.
Results of bronchoscopy revealed diffusely hemorrhagic airway mucosa. Serial aliquots of bronchoalveolar lavage were consistent with DAH. Patient was noted to have 10% blasts on peripheral smear with flow cytometric immunophenotyping consistent with newly diagnosed acute myeloid leukemia (CBFB/MYH11 subtype). All other potential causes of DAH were ruled out with laboratory testing. Induction chemotherapy was considered but the patient died of refractory shock, disseminated intravascular coagulation, and multi-system organ failure despite all maximum supportive measures.

Discussion: DAH in the setting of AML is a rare and potentially fatal complication of the disease. Diagnosis is challenging, as pulmonary infiltrates on imaging are non-specific. Further research is needed to reveal the definitive underlying pathophysiology of DAH, with the hope of identifying prospects for improving time to diagnosis and treatment.