Four Cases Of Dyskinesia Caused By Acute Methyi Bromide Intoxication And Literature Review

BackgroundMethyl bromide(MeBr)is a kind of high-toxic gas which is colorless,odorless as well as evaporable.MeBr is widely used because of the effect of killing pests,fungi and keeping fruits fresh.People or animals may have MeBr intoxication when they inhale or contact it.MeBr often destroy human's respiratory system and neurological system.The symptoms include fatigue,nausea,vomiting,visual disturbance,dysarthria,paralysis,muscles pain and myasthenia.And ataxia,high fever,lethargy as well as tremor,myoclonus,delirium,insanity also appears as the manifestations.A large amount of MeBr inhalation leads to inspiratory failure,renal failure,seizures and coma.The recovery of nonfatal acute intoxication is very slow,and some neurological and mental sequels do happen frequently.Most patients are young adults who are afflicted intoxication in their works and these dyskinesia will influent both their daily life and work.MeBr intoxication is not common at home and abroad.The dyskinesia caused by acute MeBr intoxication is seldom reported.Nowadays,the relevant treatment is still symptomatic treatment and rehabilitation training.The investigation and reports about the treatment and prognosis of dyskinesia caused by MeBr intoxication are rare.Clinical medical practitioners in China are lack of knowledge of this disease.ObjectiveTo study the manifestations,accessory examination changes,proper treatment and the prognosis of the dyskinesia caused by acute methyl bromide intoxication.MethodReport four cases of dyskinesia caused by acute MeBr intoxication and follow up to the 3 cases.Using Activity of Daily Living Scale(ADL)and Fahn-Tolosa-Marin Tremor Rating Scale(FTMTRS)to evaluate the impairment of patients' ability of daily activity and the characteristics of their tremor.Review literatures related to the MeBr intoxication and the dyskinesia caused by it.ConclusionFour patients in these cases are right-handed males.The onset ages are between 21 to 40 years old,average age is 34.5 years.As of March 8,2017,their courses are between 11 to 144 months.The average course is 56 months.The patients showed coma,seizures,followed by clumsy action,hand tremor,difficulty in holding things and handwriting,with or without unstable gait and slurred speech.Their daily life and work are influenced greatly.We give them treatment to control epilepsy,promote nerve growth,improve metabolism and give nutrition to neurons.In case 2,the patient's tremor nearly disappears after 10months and his handwriting is improved markedly while the other 3 patients shows no significant changes after our treatment.The patient in case 3 recovers from severe disability after the MeBr intoxication in the past 11 years,but the symptoms are still exist.The head magnetic resonance imaging(MRI)of patient in case 2 showed symmetric abnormal signals in dentate nucleus in cerebellum,medulla oblongata,periventricular area of the fourth ventricle and the globus pallidus.One patient's electromyography(EMG)and another patient's electroencephalogram(EEG)are abnormal.The average ADL scores of patients in case 1-3 is 21.33,the damaged abilities include washing clothes,cooking and house-work.Average FRMTRS scores is 37.67 and the intention tremor in upper extremities is prominent.The handwriting is impaired.The treatment includes symptomatic treatment,nutritional supplements to nerves and rehabilitation.The young patient who received immediately treatment for the intoxication and early treatment to help nerves-recovery and promote circulation recovered faster than these who are elder and don't get treatments as soon as possible.The recovery of dyskinesia caused by acute MeBr intoxication is slow and the disability persists for a long time.The prognosis is not good.Conclusion1.The four patients in this article all have tremor in both hands,with or without unstable gait and slurred speech after the acute intoxication of MeBr.2.The tremor after acute MeBr intoxication appears in the upper extremities and intention tremor is prominent.The tremor with posture holding is lesser.No rest tremor are observed.3.The ability of daily life activity is decreased,especially the abilities of washing clothes,cooking and doing housework.The handwriting performance is also destroyed markedly.4.This is the first report of MRI changes of head after acute MeBr poisoning in China.Some acute MeBr poisoned patients reveals symmetric abnormal signals in head MRI in dentate nucleus in cerebellum,medulla oblongata,periventricular area of the fourth ventricle and the globus pallidus.5.Some patients have abnormal changes in electromyography and electroencephalogram which indicate the destroys of peripheral nerves and cortex of brain.6.The treatment of dyskinesia caused by acute MeBr intoxication is under the basement of the treatment of acute intoxication of MeBr and the former rely on the symptomatic treatment and rehabilitation training.7.The prognosis is related to the patient's age,the severity of intoxication,the emergent treatment after the poisoning as well as the rehabilitation training.The recovery is slow and the disability persists for a long time.In conclusion,prognosis is not good.