[A case of acute sensory neuropathy]

We report a 50-year-old man who developed sensory neuropathy of acute onset. It affected position and vibration senses very severely, and superficial sensations mildly. There were athetoid movements of the outstretched left arm when the eyes were closed. The upper limbs were more severely affected than the lower limbs. There was no weakness or atrophy in the limb muscles. Nerve conduction study and somato-sensory evoked potential showed normal function of motor nerves and axonopathy of the sensory nerves. Sural nerve biopsy disclosed fibrosis and marked loss of myelinated fibers, especially of large ones, and many fibers with myelin balls in teased preparations, indicating severe axonopathy. Electronmicroscopy confirmed severe degeneration and loss of myelinated axons with abundant myelin figures in schwann cells. There were no malignancy or other diseases that could cause sensory neuropathy, and he was diagnosed as having acute sensory neuropathy (ASN) of Windebank et al. ASN, a distinct syndrome characterized by axonal type neuropathy, should be segregated from acute and chronic inflammatory demyelinaiting neuropathies although the clinical features and CSF findings look alike.