A 67-year-old woman was sent to emergency department because of fever and sore throat.
Her medical history included ESRD with regular hemodialysis 3 times per week for 15 years, hyperuricemia and gout.
She also had comorbidity such as dyslipidemia, hypertension, secondary hyperparathyroidism, and diabetes.
The hemogram revealed a white blood cell count (WBC) of 700/μL, with 2% neutrophils, 94% lymphocytes and 2% monocytes, hemoglobin 11.1 g/dL, and platelet count, 131,000/μL.
Under the impression of febrile neutropenia and acute pharyngitis, she was admitted to our hematologic ward for further survey and management.
Broad-spectrum antibiotics with piperacillin 2 g and tazobactam 0.25 gm i.v.
q8h had been administered and her infection sign resolved gradually.
Upon admission, we reviewed her oral medication: glipizide 5 mg tid, saxagliptin 2.5 mg qd, fenofibrate 600 mg qd, aluminum hydroxide 324 mg tid, folic acid 5 mg qd, calcium carbonate 1000 mg tid, and febuxostat 40 mg qd.
Besides, she also received epoetin-beta 2000 iu i.v.tiw.
Except for febuxostat, all the other drugs had been used for more than 1 year.
Febuxostat was administered 2½ months before admission for inadequate serum uric acid control by allopurinol 50 mg qd.
Two weeks before febuxostat exposure, routine laboratory test revealed WBC 6000/μL and serum uric acid level 9.8 mg/dL.
Febuxostat was discontinued thereafter due to the causal relationship of agranulocytosis cannot be excluded.
Besides, we also surveyed viral infection and autoimmune disorder.
There were no clinical or laboratory evidence of Epstein–Barr virus, cytomegalovirus, or human immunodeficiency virus infections; antinuclear antibody (ANA) and antiextractable nuclear antigen (anti-ENA) were both negative.
Bone marrow examination during hospitalization showed hypocellular marrow with a marked decrease in myeloid component but no evidence of hematologic neoplasms.
Chromosome analysis of bone marrow was normal karyotype.
The patient denied history of radiation or chemicals exposure.
After stopping febuxostat for 17 days, her neutropenia improved significantly (WBC 2100/μL, and neutrophil 66%), without any granulocyte colony-stimulating factor (G-CSF) support.
After discharge, her WBC and differential count was completely normal during follow-up (Fig.1).
This study was approved by our institutional review board.