Abstract
RATIONALE: Granulocyte colony-stimulating factors (G-CSFs) are used in treating chemotherapy-induced neutropenia or in healthy stem cell donors before collection since they mobilize hematopoietic stem cells from the bone marrow into the peripheral blood. Reported side effects of these drugs include bone pain, fatigue, and, rarely, splenic rupture. However, G-CSFs were not previously associated with isolated hyperbilirubinemia. PATIENT CONCERNS: We describe the case of a previously healthy 42-year-old female who presented to the emergency department with fever and chills. Initial laboratory investigations revealed pancytopenia along with normal liver, renal, and bilirubin levels. DIAGNOSES: A peripheral smear showed an elevated blast cell count, and subsequent bone marrow cytology and flow cytometry confirmed the diagnosis of acute myelogenous leukemia. INTERVENTIONS: The patient was started on induction chemotherapy and subsequently developed febrile neutropenia, for which G-CSF was initiated to promote neutrophil recovery. OUTCOMES: Following G-CSF initiation, the patient demonstrated a progressive rise in total bilirubin, while liver enzymes (alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transpeptidase) and other markers of liver function remained within normal limits. Extensive evaluation for alternative causes of hyperbilirubinemia was unremarkable, so given the temporal association and lack of other identifiable etiologies, G-CSF-induced isolated hyperbilirubinemia was suspected. LESSONS: This case highlights a potential and previously unreported adverse effect of G-CSF. Clinicians should be aware of this possible association, particularly in patients undergoing treatment for hematologic malignancies.