Bithalamic lesions of butane encephalopathy.

Butane inhalation can cause serious medical complications and is particularly toxic to the nervous system. This is a report of an acutely encephalopathic youth with prominent abulia. MRI revealed severe bithalamic injury attributed to butane toxicity. Clinical issues, including particular radiologic findings, related to butane inhalation are reviewed.

Epileptic encephalopathies and their relationship to developmental disorders: do spikes cause autism?

Epileptic encephalopathies are progressive clinical and electroencephalographic syndromes where deterioration is thought to be caused by frequent seizures and abundant EEG epileptiform activity. Seizures occur in approximately 10-15% of children with pervasive developmental disorders (PDD) and 8-10% have epileptiform EEG abnormalities without seizures. Thirty percent of children with PDD have regression of social behavior and language at 2-3 years of age. Some authors speculate that the regression is caused by epileptiform activity even in the absence of overt clinical seizures ("autism with epileptic regression") and suggest that elimination of the epileptiform activity, either medically or surgically, should lead to improvement in behavior. This review examines the data showing that interictal epileptiform discharges are associated with transient clinical dysfunction and discusses the implications of these observations for autistic behavioral abnormalities. The results of resective surgery, vagal nerve stimulation, and multiple subpial transaction on children with autism and epileptiform EEG abnormalities are also discussed. I conclude that there is no evidence that interictal discharges per se cause (or contribute to) the complex behavioral phenotype of autism. There is no justification to support the use of anticonvulsant medication or surgery in children with PDD without seizures; that is, there is no evidence that treatment to eliminate EEG spikes will have a therapeutic effect on the behavioral abnormalities of PDD and autism.

Neonatal seizures and syndromes.

Neonatal seizures frequently accompany neonatal encephalopathies. Seizures occur in approximately 1.8-5/1,000 live births in this country and are caused by virtually any condition that affects neonatal brain function. This review provides a simple classification of seizures and emphasizes that many abnormal intermittent behaviors in this age group are not accompanied by ictal EEG patterns. Additionally, < or =50% of neonatal seizures are not associated with abnormal clinical behavior. This is a common phenomenon, particularly after anticonvulsant treatment in which the clinical seizures are suppressed but electrographic seizures continue unabated. Seizures also may be caused by genetic disorders, several of which are benign, familial, and caused by channelopathies involving potassium channels. The review also discusses the epileptic syndromes seen in neonates, including early myoclonic encephalopathy, Ohtahara syndrome, pyridoxine dependency, and glucose transporter type 1 syndrome.