EXPERIMENTAL TOXIC ENCEPHALOMYELOPATHY (Diffuse sclerosis following subcutaneous injections of potassium cyanide)

The author, after re- viewing the various theories to explain the etiology of diffuse or multiple sclerosis, used KCN subcut. in varying doses on 14 cats and 4 monkeys. This substance interferes seriously with oxidation in tissues. As much as 35 mgm. was given daily. Clinical symptoms included hyperpnea, vomiting, twitchings, nystagmus, hyperre-flexia, spasticity, spastic paralysis oi hind legs, blindness, convulsions. The brain showed widespread de-myelination, more pronounced in the frontal and occipital region. The areas are not sharply defined. The degree oi demyelination varies from paleness to destruction. The spinal cord is similarly involved. Axis cylinders are also destroyed in places. The optic nerve showed demyelination and diffuse gliosis. There seemed to be a predilection for the gliosis in the periventricular regions. Areas of softening were encountered. In only 2 animals were there evidences of inflammatory reactions, extending from the white substance to the meninges with peri-vascular lymphocytic infiltration. Spinal roots were somewhat demyelinated. Cortical cells were degenerated in a few. Comments were made on the similarity between the experimental lesions produced and diffuse or multiple sclerosis. The author regards multiple sclerosis as a toxic manifestation but admits that toxins may occasionally produce histologic pictures resembling inflammation. The possibility of cyanide production in the body metabolism is discussed.