Abstract Introduction We present a unique case of Type B lactic acidosis, which is a rare but life-threatening presentation of hematologic malignancies. The patient declined rapidly and required critical care support. He recovered remarkably once chemotherapy was initiated. Case Presentation A 78-year-old man with no significant past medical history was admitted with acute mental status changes and presumed sepsis. Labs were notable for lactic acid of 6.3, leukocytosis of 14 K, and urinalysis suggestive of a urinary tract infection. Despite broad-spectrum antibiotics, both lactic acidosis and leukocytosis continued to worsen, peaking at 14 and 37 K, respectively. Other workup including CT chest/abdomen/pelvis, CT head, MRI brain, and lumbar puncture were unrevealing. The patient rapidly deteriorated and was escalated to the intensive care unit. He required mechanical ventilation, four vasopressors, stress-dose steroids, and eventually developed acute kidney injury requiring continuous renal replacement therapy (CRRT). With persistent lactic acidosis despite aggressive treatment, the hematology team was consulted for escalated work up. Bone marrow biopsy revealed a hypercellular marrow with 70-80 % involvement by triple-expressor and negative FISH DLBCL. Chemotherapy with R-miniCHOP (without vincristine) was initiated. The lactic acidosis quickly improved and resolved within two days of chemotherapy. By day nine of chemotherapy, the patient was successfully weaned off CRRT and extubated. He was downgraded to the hematology floor and discharged after completing two cycles of R-miniCHOP. Discussion This case demonstrates the uncommon presentation of Type B lactic acidosis as the initial manifestation of DLBCL and the success of early initiation of chemotherapy in an ICU setting. Prior systemic analyses have indicated that early initiation of chemotherapy is the strongest modifiable predictor of survival (Zhang et al., 2025) for hematologic malignancies with type B lactic acidosis. The diagnosis of DLBCL in our patient was initially thought to be unlikely as his disease primarily involved the bone marrow in which imaging and CSF studies were negative for extra-nodal disease or lymphadenopathy. In addition, with 70-80 % bone marrow involvement, our patient maintained normal hemoglobin and platelet counts. Our patient’s lymphoma is a primary bone marrow DLBCL (PBM DLBCL), which is a rare and atypical presentation that account for approximately 1.16 % of all lymphomas and 2.65 % of DLBCL cases. Conclusion This case report highlights the importance of early diagnosis and initiation of chemotherapy in a patient whose initial presentation of hematologic malignancies such as PBM DLBCL was lactic acidosis. This abstract is funded by: None
Leatheng et al. (Fri,) studied this question.