Greeting and Introduction to Activities
Subacute myelo-optico neuropathy (SMON) is a neurological disease characterized by abdominal symptoms such as stomachache and diarrhea followed by specific numbness starting at the toe and ascending throughout the lower extremities or to the chest/abdominal area. In addition to such sensory impairments, SMON causes lower limbs cramps (spasticity) or weakness, and in severe cases may lead to blindness due to impaired visual acuity, or even death in some cases from brain-stem disorder. SMON often occurred in Japan during the 1960s and became a social problem because it was suspected to be a new infectious disease, and it occurred concurrently in various locations.
In 1970, it was proposed that SMON was caused by adverse effects of chinoform (clioquinol), an antiflatulent, with no new patients detected since its use was banned in Japan by the Central Pharmaceutical Affairs Council. Based on patient medication records, chinoform is the apparent cause of SMON epidemiologically. There were 9,249 patients at the end of 1972, with an estimate of more than 12,000 patients during the peak period. As of the spring of 2014, approximately 1,639 people were identified as SMON patients, but it is assumed the actual number is slightly higher. The Research Committee on SMON, organized by the Research on Intractable Diseases Policy of the Ministry of Health, Labour and Welfare (MHLW) implements a program of annual health check-ups for patients nationwide. Aggregate data compiled from the check-up results are utilized to improve treatment for patients. Given that persistent sequelae and symptoms are exacerbated in SMON patients due to secondary concurrent disease, MHLW has reflected this in its measures, for instance, improving the medical expenses support system and considering symptoms of abnormal sensation when making a determination under the nursing-care insurance system.
We hope that this website is helpful in preventing SMON and the knowledge acquired about drug-induced diseases from being forgotten, and facilitate the medical care and welfare of SMON patients.
Representative of the Research Committee on SMON
Director, National Hospital Organization Suzuka National Hospital
Masaaki Konagaya
- Research Committee on SMON
- Research representative:
Masaaki Konagaya, Director, NHO Suzuka National Hospital
3-2-1 Kasado, Suzuka-shi, Mie-ken, 513-8501
Phone: +81-59-378-1321
