(1557) Leukocytosis and Thrombocytosis After Splenectomy: Expected Finding, Infection, or Something Else

Introduction: Leukocytosis and thrombocytosis often follow splenectomy in blunt trauma patients, complicating the post-operative identification of infection. While the platelet count (PC) to white blood cell (WBC) ratio provides diagnostic assistance to discern between expected laboratory alterations and infection, diagnoses such as leukemia are often overlooked.

Description: A 53-year-old male presented with abdominal pain, nausea, tachycardia, and focal peritonitis four days after being assaulted and struck multiple times in the abdomen. Initial WBC was 38.4 x10^9/L, PC 691 x10^9/L and lipase 55 U/L. Computed tomography (CT) abdomen/pelvis demonstrated a hematoma encasing the distal pancreas, and abutting the stomach and colon. Emergent laparotomy revealed a nearly transected pancreas and devascularized colon necessitating a distal pancreatectomy, splenectomy, and colon resection with primary anastomosis. Post operatively, he had a persistently elevated leukocytosis, thrombocytosis, segmented neutrophils, eosinophilia and basophilia (peak at 70, 2293, 64, 1.1, and 1.2 x10^9/L respectively). Despite sepsis workup including repeat CT, no source was identified. Hematology/oncology was consulted for concern for hematologic etiology with bone marrow biopsy performed consistent with BCR-ABL positive chronic myeloid leukemia (CML). The patient was treated with hydroxyurea and transitioned to Imatinib.

Discussion: Thrombocytosis following splenectomy is a common complication and PC/WBC < 20 indicates infectious etiology. A significantly elevated WBC count (>50x10^9/L) and thrombocytosis (>2000x10^9/L) may suggest something more ominous including CML, particularly when elevated granulocyte counts are present. CML workup includes peripheral smear, bone marrow aspiration, and determination of Philadelphia chromosome. Post splenectomy vaccines are still indicated within 14 days; however, the timing of immunization with cancer treatment must be considered. Tyrosine kinase inhibitors (TKI) are first line therapy and benefits of pretreatment with hydroxyurea for cytoreduction remain under investigation. Additionally, TKIs have been associated with gastrointestinal perforation and impaired wound healing necessitating heightened attention in patients with a new bowel anastomosis.