Abstract

Nine patients in whom subacute myelo-opticoneuropathy (SMON) was diagnosed with varying degrees of confidence are discussed. The cases were discovered after a retrospective examination of our records for the period 1967-71, and a prospective search from March 1972 to date. Subacute myelopathy with predominant dysaesthesiae and greater involvement of the pyramidal tracts was seen more often than fully developed SMON. Subacute myelopathy was seen in six instances, opticomyelopathy in two and myeloneuropathy only once. Clioquinol could not be excluded as an aetiological agent. The difference in the reported prevalence of SMON between Japan and India is noted, and factors which may account for this difference are discussed. Problems related to the diagnosis of SMON outside Japan, and particularly in India, are stressed.