SOLVENT VAPOR ABUSE LEUKOENCEPHALOPATHY - COMPARISON TO AD ADRENOLEUKODYSTROPHY

Chronic organic solvent vapor inhalation can cause permanent damage to the central nervous system. Clinical features and radiologic abnormal ities are well known, but pathology has not been definitely establishe d. This study describes the gross, microscopic and ultrastructural cha nges and fatty acid composition of cholesterol esters in the brain of two chronic paint sniffers as well as the electron microscopic finding s from a third, all with permanent neurological impairment. The abnorm alities which were the same in all cases consisted of a demyelinating process which grossly manifested itself as brain atrophy and subtle di scoloration of the cerebral and cerebellar white matter. Periodic acid -Schiff-positive macrophages in the absence of foamy macrophages were the histological hallmark of this process. Electron microscopy reveale d oval membrane-bound cytoplasmic bodies filled with bundles of trilam inar inclusions composed of 3 nm paired dense leaflets separated by a space 3-7 nm wide in macrophages. Biochemical analysis showed an incre ase of very long chain fatty acids in the white matter cholesterol est ers. This study defines the morphologic substrate of solvent vapor abu se leukoencephalopathy. The novel ultrastructural observations in conj unction with biochemical findings provide a link with adrenoleukodystr ophy and raise the possibility of similar mechanisms of myelin degrada tion in both.