A Case of Acute Sensory Neuropathy Associated with Contrast Enhancement of the Cauda Equina on Magnetic Resonance Imaging

A 46-year-old woman experienced dysesthesia and pain in the lower limbs one week after cold-like symptoms. On admission, she presented with superficial sensation disturbance without deep sensation disturbance. Bilateral tendon areflexia was observed, but muscle strength was maintained at the normal level, and no dysautonomia including vesicorectal disturbance was observed. Her cerebrospinal fluid CSF showed albuminocytologic dissociation. Peripheral nerve conduction velocity was normal in motor nerves, while sensory conduction velocity was absent in the peroneal and sural nerves. T1-weighted lumbar spine magnetic resonance imaging with gadolinium revealed enhancement of the cauda equina. From these findings, the patient was diagnosed as having acute sensory neuropathy. Her symptoms subsequently progressed; sensory disturbance extended to her upper limbs after four weeks from onset. Following the administration of steroids and intravenous immunoglobulin, sensory disturbance and CSF abnormalities improved. The enhancement also disappeared within two months. In this case, blood-nerve barrier of the cauda equina was extensively disrupted. Abnormal immunological mechanisms may be involved in the pathogenesis of the disease.