Clinical results of a cross-over treatment with pyridoxine and placebo of the carpal tunnel syndrome.

Clinical evaluation was made of cross-over treatments by pyridoxine and a placebo of patient 22 having the carpal tunnel syndrome. Extraordinary monitoring of the specific activities of the erythrocyte glutamic oxaloacetic transaminase proved a severe vitamin B6 deficiency, which was partially corrected by the Recommended Dietary Allowance of 2 mg, and completely corrected by 100 mg. The severity of the syndrome diminished on the Recommended Dietary Allowances and the patient was asymptomatic at the higher dosage. On placebo, both the vitamin B6 deficiency and syndrome reappeared. Retreatment with 100 mg again corrected both the deficiency and syndrome. Measurements (total n = 19) of flexion of proximal interphalangeal joints of the index fingers by a goniometer, and of pinch by the Preston gauge revealed objective normalization. Scores of 17 symptoms revealed reductions at both the 2- (P less than 0.01) and 100-mg (P less than 0.001) dosages. Conduction through the carpal tunnels had improved by electromyography. These and previous data on a total of 22 patients showed the concomitant presence of a deficiency of vitamin B6 and the carpal tunnel syndrome; a causal relationship is apparent.