Clinical prognosis of patients with diagnosed chronic solvent intoxication.

The clinical symptoms and signs of 80 patients with chronic organic solvent intoxication were evaluated after 3-9 years (mean 5.8 years) of follow-up. Thirty-one of the patients had slight clinical neurological signs at the time of diagnosis while the rest of the patients had only neurophysiological or psychological disturbances. The most common subjective symptoms were headache, tiredness and memory disturbances. Of the clinical signs, disturbances occurred frequently in cerebellar functions, gait and station and fine motorics. In addition, psycho-organic alteration and neurasthenic signs were often found. After the follow-up clinical signs of impairment in the nervous system were present in 42 cases. At the group level, the subjective symptoms decreased during the follow-up but the objective clinical signs increased and worsened. Only the prognosis of disturbances in gait and station correlated with the duration and intensity of exposure. The present results emphasize the great difficulties arising in occupational neurology regarding chronic organic solvent intoxications. No clear-cut clinical picture exists and reliable estimation of prognosis in general cannot be made on the basis of the present knowledge.