Seronegative Lyme neuroborreliosis in a patient on treatment for chronic lymphatic leukemia

We report on a patient who developed seronegative Lyme neuroborreliosis complicating chemotherapy for chronic lymphatic leukemia. After the fifth cycle of chemotherapy (FCR: fludarabine, cyclophosphamide, rituximab and prednisone) the 63-year-old patient developed night sweat, arthralgia in elbows, wrists, proximal interphalangeal joints (PIPs) and strong neuropathic pain in both legs, followed by paresthesia and hypesthesia in the feet, arms and face. Laboratory analysis revealed an elevated C-reactive protein (CRP), a slight elevation of liver enzymes and decreased IgG levels. Cerebrospinal fluid (CSF) analysis showed a lymphomononuclear pleocytosis and an elevation of protein. A broad diagnostic work-up was negative including a negative Borrelia IgG and IgM ELISA. The patient did not remember recent tick bites, but after specific questioning he recollected a transient erythema on his leg developing just before the start of the last cycle of chemotherapy. As the combination of neuropathic pain and arthralgia, the transient erythema and the lymphomononuclear pleocytosis raised the suspicion of Lyme neuroborreliosis, the patient was treated for 3 weeks with ceftriaxone. On therapy all symptoms resolved and CRP normalized. Retrospective PCR analysis of a CSF sample confirmed the clinical diagnosis by detecting Borrelia garinii DNA. This case demonstrates that in immunosuppressed patients borrelial serology may be negative and that additional diagnostic approaches (including tests for direct Borrelia detection) may be needed to demonstrate borrelial infection.