RESUMEN
PURPOSE: Case reports with a comprehensive review of the current literature concerning subacute combined degeneration induced by nitrous oxide inhalation. A differential diagnosis should be considered when young patients present with progressive myelopathy because that the misuse of nitrous oxide has potentially serious outcomes. CASES REPORT: Three young patients aged from 18 to 24, one male and two females, were diagnosed with progressive ascending numbness in four limbs or both legs and ataxia. They all had been inhaling nitrous oxide from whipped-cream containers for several months. A cervicothoracic magnetic resonance imaging scan revealed long segmental hyperintensity changes at the posterior column of the spinal cord. Serological examination showed a low level of vitamin B12. Subacute combined degeneration of the spinal cord was diagnosed and the etiology was considered related to nitrous oxide misuse. Their neurological status, neuroimage, and neurophysiologic condition improved after vitamin B12 supplementation and cessation of nitrous oxide inhalation. CONCLUSION: Iatrogenic usage of nitrous oxide apparently resulted in subacute combined degeneration in our three patients. Recently, nitrous oxide misuse has increased among young people. Subacute combined degeneration of the spinal cord should be considered as a possible outcome of such abuse.
Asunto(s)
Óxido Nitroso/envenenamiento , Enfermedades de la Médula Espinal/inducido químicamente , Degeneración Combinada Subaguda/inducido químicamente , Adolescente , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Enfermedades de la Médula Espinal/complicaciones , Degeneración Combinada Subaguda/complicaciones , Vitamina B 12/metabolismo , Adulto JovenRESUMEN
BACKGROUND: Myeloneuropathy from chronic exposure to nitrous oxide has been described. Nitrous oxide irreversibly alters B(12) activation, causing signs and symptoms of B(12) deficiency. OBJECTIVES: We describe a case of myeloneuropathy secondary to acute use of high-dose nitrous oxide. CASE REPORT: A 24-year-old man presented to the Emergency Department complaining of numbness and tingling of his hands and feet, as well as worsening clumsiness and gait disturbances after escalating use of nitrous oxide in the prior 2 weeks. He was found to have dysmetria, poor proprioception, decreased sensation to vibration and light touch over his extremities, and a mildly positive Romberg sign. Laboratory test values revealed a normal B(12) level but increased methylmalonic acid and homocysteine levels. The patient was admitted to the hospital and started on a course of B(12) injections. He was discharged after 3 days with daily B(12) supplementation. CONCLUSIONS: This case demonstrates myeloneuropathic changes secondary to acute high-dose nitrous oxide exposure.
Asunto(s)
Anestésicos por Inhalación/envenenamiento , Enfermedades Desmielinizantes/inducido químicamente , Óxido Nitroso/envenenamiento , Deficiencia de Vitamina B 12/etiología , Humanos , Masculino , Adulto JovenRESUMEN
Two cases of severe myeloneuropathy and macrocytic anemia associated with a low serum level of vitamin B12 after prolonged exposure to nitrous oxide are reported. In both cases, the neurological manifestations worsened initially despite B12 supplementation, although in one case the use of methionine seemed to arrest the progression of the disease and accelerate recovery. This offers further support for the biochemical hypothesis of methionine synthetase inhibition by nitrous oxide and reproduces in man previously reported animal studies with methionine. Methionine may be an important first-line therapy in the initial treatment of neuropathy and myeloneuropathy induced by nitrous oxide, and has a hypothetical role in the treatment of subacute combined degeneration of the cord.