P50-7 A case of Waldenstrom macroglobulinemia with severe systemic myalgia after rituximab treatment

Abstract

71-year-old female was diagnosed with Waldenstrom macroglobulinemia in 20XX-13. She was hospitalized in 20XX due to advanced anemia. Bone marrow examination revealed abnormal lymphocytes 27%. Computed tomography showed mild splenomegaly. After plasma exchange, bendamstine+rituximab , BR regimen was performed for one cycle. In January 20XX+1, she was hospitalized for second cycle of chemotherapy. After administration of rituximab, shoulder pain and ankle joint pain occurred. On the second day of illness, limb pain and muscle weakness occurred and she became unable to walk. No abnormalities were found in the cerebrospinal fluid examination, head MRI, and nerve conduction velocity examination. On the third day of illness, weakness and myalgia in the extremities and trunk further increased. No increase in muscle enzyme was observed. On the 4th day of illness, the pain improved with symptomatic treatment, and she became able to walk. She was diagnosed as myalgia due to infusion reaction of rituximab, grade 3. 5 cycles of bendamstine monotherapy were performed and remission was obtained. There are many mild cases such as fever and rash in the infusion reaction of rituximab, and rarely severe cases of decreased blood pressure, pulmonary edema, ARDS, and impaired consciousness. Although muscle complications are reported to be 2% as an adverse event of rituximab, we report a severe case of difficulty walking.