levamisole , an anthelmintic agent that targets the nicotinic acetylcholine receptors , is usually used as an immunostimulant in combination with 5-fluorouracil ( 5-fu ) to treat colorectal cancer since 1990 .
it has been shown that combination of these two drugs decrease the risk of clinical recurrence and to increase survival in patients with stage iii adenocarcinoma of the colon . 
 
, we describe multifocal inflammatory leukoencephalopathy in a patient with accidentally consumption of levamisole after 8 months of gastric lavage of the drug .
a 53-year - old man was admitted to the neurology department of farabi hospital ( kermanshah , iran ) with walking inability and recognition disorder .
patient history showed that he had referred to hospital with vomiting , vertigo and headache 8 months before after consumption of two sachet of levamisole ( for veterinary use ) which each sachet contained 1.5 gram of levamisole hydrochloride .
one month later , he had been stricken by progressive walking inability and recognition disorder up to administration to our hospital .
the patient had not any previous illness . on neurologic examination , he was confused and did not establish a good relationship with the bystander . on mental and cognitive power examinations , using the mini mental state examination ( mmse ) , he earned 17 points ( out of a total score of 30 ) with no signs of meningeal irritation ( such as stiffness of neck ) .
the power of limbs was within normal range but deep tendon reflexes in all of four limbs had increased in conjunction with extensor plantar response and reduced abdominal skin reflex .
on cerebellar examination , finger to nose test and heel to shin was impaired and the gait was ataxic . on the initial laboratory tests , complete blood count ( cbc ) ,
in cerebrospinal fluid analysis , color , pressure , cells , and sugar were normal but protein was increased ( 69 mg / dl ) .
on electroencephalography ( eeg ) , bilateral paroxysmal slow waves were seen . in visual evoked potential ( vep ) , there was a bilaterally prolonged p100 latency .
brain magnetic resonance imaging ( mri ) showed mild cerebral atrophy and multiple focal lesions distributed in periventricular and cerebellar white matter and also in pons and midbrain ( figure 1 ) .
these lesions had low - signal intensity on t1-weighted images and high - signal intensity in fluid - attenuated inversion recovery ( flair ) view and t2-weighted images .
initial brain mri in the patient with multifocal demyelinating leukoencephalopathy after accidental consumption of levamisole ; a : brain mri on t1wi revealed multifocal subcortical white matter lesions in the periventricular ; b and c : brain mri on t2wi revealed multifocal subcortical white matter lesions in the periventricular , cerebellar and pons ; d and e : brain mri on flair revealed multifocal subcortical white matter lesions in the periventricular area , cerebellum and pons following clinical examinations and ruling out of other causes , including infectious and vascular causes , trauma and metabolic , central nervus system ( cns ) vasculitis and paraneoplastic syndromes ; and according to the patient 's history , the patient was diagnosed as multifocal inflammatory leukoencephalopathy following levamisole consumption .
the patient was treated with intravenous methylprednisolone ( 500 mg ) every 12 hours for 7 days followed by two weeks oral consumption of the prednisolone ( 50 mg / day ) during hospitalization .
no change was noticed in cerebellar signs and gait disorder but a brief improvement was seen in mentality and cognition after 1 and 3 months . after a month of treatment
( figure 2 ) the follow - up brain mri in patient with multifocal demyelinating leukoencephalopathy , after 1 month treatment with methylprednisolone disclosed no recovery of the subcortical white matter lesions ; a : brain mri on t1wi revealed multifocal subcortical white matter lesions in the periventricular area ; b : brain mri on t1wi with contrast revealed multifocal subcortical white matter lesions in the periventricular area and no evidence of enhancement ; c : brain mri on t2wi revealed multifocal subcortical white matter lesions in the periventricular area ; d , e and f : brain mri on flair revealed multifocal subcortical white matter lesions in the periventricular area , cerebellum and pons
this paper reported the clinical features and mri changes that were occurred suddenly after consumption of high dose levamisole and 8 months later .
clinical investigations and also mri imaging showed the drug induced toxicity in the brain after 8 months of treatment .
toxicity of levamisole is generally mild , even when levamisole is used alone , and is negligible in a series of patients in whom it is associated with 5-fu (  leucovorin ) .
the spectrum of side effects ( partly dose - dependent ) includes myalgia , arthralgia , fatigue , fever , chills , skin rash , nausea , vomiting , anorexia and neurological symptoms .
the latter mainly consist of depression , anxiety , insomnia , difficulty in concentration , headache and vertigo . 
 
clinical investigations of the patient showed memory loss , confusion , ataxia , dysarthria , and hyperreflexia that can not be considered as the side effects of the drug alone but are the main symptoms of multifocal inflammatory leukoencephalopathy . here , it seems that if a case subjected to only one but high dose of levamisole , the catastrophic effect is such prominent that may induce multifocal inflammatory leukoencephalopathy .
on the other hand , mri imaging showed inflammation in many parts of the brain that led us to diagnose the patient as multifocal inflammatory leukoencephalopathy .
multifocal inflammatory leukoencephalopathy , a central nervous system disorder characterized by demyelination with perivascular inflammation , has recently been reported in several patients treated with the combination of fluorouracil and levamisole chemotherapy . 
 
it has been suggested that the neurotoxicity derived by combination of these two drugs was mainly due to 5-fu rather than levamisole alone .
however , some authors confirmed that multifocal inflammatory leukoencephalopathy could be induced by levamisole alone . in parallel with these studies
, we also suggest that levamisole alone can induce multifocal inflammatory leukoencephalopathy . on the other hand , in previous studies
, levamisole was administered as a drug choice and there was no document in the literature for monitoring the effect of this drug following accidental consumption .
in addition , gastric lavage followed by delayed treatment of the patient with methylprednisolone can not diminish the neurotoxicity of levamisole .
these data highlights the fact that the drug must be unavoidable to children and the usage of the drug must be used vigilantly .
 levamisole is an anthelmintic agent and also immunostimulant drug which is used to treat colorectal cancer . the present study aimed to show accidental consumption of levamisole alone induced multifocal inflammatory leukoencephalopathy . 
 a 53-year - old male was admitted to the neurology department of farabi hospital ( kermanshah , iran ) with walking inability and recognition disorder . following clinical examinations , the patient diagnosed as multifocal inflammatory leukoencephalopathy following 
 levamisole consumption.the patient was treated with intravenous methylprednisolone followed by prednisolone . 
 the magnetic resonance imaging ( mri ) was done 1 month later and did not show a reduction or remission in the lesions . 
 history of the patient showed that he had accidentally consumed levamisole 8 months ago . 
 it seems that the consumption of levamisole can induce multifocal inflammatory leukoencephalopathy and delayed treatment of the patient with corticosteroid can not diminish the neurotoxicity of levamisole . 
 in addition , the cytotoxic dose of levamisole induces irreversible multifocal inflammatory leukoencephalopathy . 
Introduction
Case report
Discussion