A Case of Sensory-Motor Polyneuropathy in Hashimoto Thyroiditis

Abstract

Background & Significance: It is well known that thyroid dysfunction may be associated with entrapment neuropathy or polyneuropathy. We represents a case of acute sensory-motor polyneuropathy which occurred in the background of Hashimoto’s thyroiditis. Case: A 60-year-old female was referred to department of neurology for gait disturbance and whole extremity sensory change. Her symptoms started 1 week before admission to the hospital. She has been treated with levothyroxine for hypothyroidism for 7 years. Gun biopsy was performed 3 months ago because of the thyroid mass found accidently and confirmed lymphocytic thyroiditis. She was diagnosed with Hashimoto thyroiditis due to positive reaction for antithyroglobulin antibody. After then, gait disturbance and whole extremity weakness and tingling sensation developed. On neurologic examination, there was bilateral symmetric lower extremity paraparesis with decreased knee jerk and ankle jerk. She had distal dominant both lower limb hypesthesia and paresthesia. Her gait was wide-based ataxic gait pattern, and limb ataxia such as dysmetria and decomposition was also observed bilaterally. NCS findings showed prolonged terminal latencies and decreased motor and sensory conduction velocity on whole limbs and EMG findings emonstrated positive sharp waves and fibrillation potentials on whole limb distal muscles suggesting sensory-motor polyneuropathy pattern. There were no remarkable laboratory findings about diabetes mellitus, connective tissue disease, heavy metals and tumor markers except thyroid function. Cerebral spinal fluid study was also normal. Malignancy work-up was performed, but no evidence of malignancy was seen. Whole body PETCT demonstrated right thyroid nodule without significant FDG uptake. Thyroid lobectomy was done to confirm whether hidden malignancy was present on thyroid gland. Thyroid biopsy showed adenomatous hyperplasia suggesting Hashimoto thyroiditis. We started oral prednisolone therapy. The patient’s clinical symptoms responded to prednisolone, and improved to walk on herself. Conclusions or Commentes: There were some reports about polyneuropathy in Hashimoto thyroiditis and the main mechanisms remain uncertain. We report a patient who had a sensorymotor polyneuropathy with Hashimoto thyroiditis based on eletrophysiologic and laboratory findings.