Optic neuritis due to solvent abuse

Abstract

Solvent abuse is a public health problem in Brazil particularly among young adults and children. Inhalation of toluene-based products is popular with solvent sniffers because of the euphoric effect and easy availability of these substances. Chronic inhalation of toluene may result in a variety of neurologic complications like cerebellar dysfunction, optic atrophy, pyramidal tract signs, cranial nerve abnormalities. Also, personality changes, emotional instability and general cognitive decline have been attributed to its abuse 1 . We report an unusual case of acute optic neuritis induced by thinner sniffing. caseA 34-year-old man presented with an acute visual loss. He was admitted to the hospital reporting a sudden and progressive loss of visual acuity after sniffing a hole can of thinner during uninterrupted 48 hours. This homeless patient had a history of chronic solvent abuse for five years, moderate alcohol ingestion and tabagism, but denied other substances abuse. At the moment of the admission, 4 days after the beginning of the symptoms, he related to see only countenances. The physical examination and vital data were normal. The neurological examination was normal except for presenting bilateral mydriasis with severe reduction of the photomotor and consensual responses. Visual acuity was worse than 20/200. Ophthalmological examination demonstred bilateral papilledema, with normal ocular pressure and ocular movements. Other cranial nerves were normal. Laboratory examinations are listed in Table. Lumbar puncture showed 130 mmH 2 O opening pressure, 27 red blood cells/mm³, 1 leucocyte/mm³, glucose concentration 75 mg/dL, protein 39 mg/ dL and VDRL was negative. Magnetic resonance imaging (MRI) showed bilateral symmetric hyperintense lesions in the deep white matter, corpus callosum (splenium), centrum semiovale (Fig 1) and pons (Fig 2). EEG was irregular without specific pathological meanings. The patient was treated with methylprednisolone 1 gr/day for three days associated with replacement of B complex vitamins. Six days after the admission, the patient ran away from the hospital and one month later returned in the neurology clinic relating important improvement of the visual acuity. discussiOn Today, organic solvents contained in industrial and domestic products are the most commonly abused volatile substances. Formerly, benzene was the major organic solvent in paints, lacquers, and thinners. However, benzene is toxic to bone marrow and liver and has been replaced by n-hexane or toluene (methyl benzene), which are neuro-

Neuropatía óptica bilateral e irreversible por ingestión de disolvente de pintura

“…La OCT de CFNR peripapilar del OD (E) y del OS (F) muestra un aumento generalizado del espesor, menos acusado en los sectores temporales. tejido adiposo, la médula ósea, las glándulas adrenales, el hígado y el riñón 3,4 . Al ser inhalado como sustancia de abuso, se observa una rápida aparición (20-30 minutos) de efectos psicoactivos, como euforia, mareo, alucinaciones y alteraciones del habla, y después incoordinación, letargia, estupor y coma 3,5 .…”

“…Al ser inhalado como sustancia de abuso, se observa una rápida aparición (20-30 minutos) de efectos psicoactivos, como euforia, mareo, alucinaciones y alteraciones del habla, y después incoordinación, letargia, estupor y coma 3,5 . En las intoxicaciones agudas y graves son característicos los desequilibrios hidroelectrolíticos, como la acidosis metabólica hiperclorémica con anión gap normal (acidosis renal distal tipo I) y la hipopotasemia, que se manifiesta por debilidad muscular y arritmias cardiacas que pueden llegar a ser mortales 1,2,4,6 . El tolueno se puede excretar directamente (en orina o en aire pulmonar), pero la mayor parte se metaboliza en el hígado a ácido benzoico, el cual se conjuga con la glicina produciendo ácido hipúrico, que se excreta en orina 3 .…”

“…Generalmente son muy volátiles a temperatura ambiente, lo que facilita su entrada en el organismo por vía inhalatoria. Además, por su naturaleza lipófila, tienen una gran afinidad por los tejidos nerviosos y los recubrimientos de mielina, produciendo efectos neurotóxicos [1][2][3][4] .…”

“…La exposición ocupacional se suele producir de forma crónica, habitualmente a lo largo un tiempo prolongado (años) y a bajas dosis 1,2,4 . Sin embargo, entre los adolescentes y la población joven no es infrecuente la inhalación intencionada de pegamentos o disolventes de pintura con fines recreativos 3,5 .…”

Drugs of abuse and ocular effects

“…Occasional reports, with no proposed mechanism of pathophysiology, include combined third, fifth and sixth cranial nerve palsy, 138 bilateral internuclear ophthalmoplegia, 139 toxic maculopathy 140 and optic neuritis. 141…”