INTRODUCTION Ethylene glycol (EG) is a common household toxic found in anti-freeze, brake fluid and other industrial products, odorless and with a sweet taste; it is very often accidentally ingested by children and pets. Even though all animals are susceptible to EG poisoning it is most commonly encountered in dogs and cats, being associated with antifreeze ingestion. Symptoms may appear after consuming only a small quantity of this fluid, for an average size dog a tablespoon being enough to cause fatal kidney failure. Early symptoms may occur within 30 minutes of ingestion, but it can take even up to 12 hours for the first signs of poisoning to manifest (1, 7, 12). EG itself is not toxic, but due to its biotransformation in the liver in the presence of alcohol dehydrogenase, toxic metabolites are formed that cause metabolic disorders and renal damage. Being dependent on the doses and the time elapsed after ingestion the clinical signs can be divided in those caused by non-metabolized EG and those cause by its breakdown products (3, 7). After ingestion EG is completely absorbed from the gastro-intestinal (GI) tract in a period of one to three hours, this is when the first signs of poisoning start showing that resemble alcohol intoxication, the animal may look inebriated, ataxic or simply become inactive (7, 12). Eventually the signs may improve, even without treatment, this is when the EG passes to liver and begins its transformation in glycoaldehyde via alcohol dehydrogenase, other major metabolites are than formed such as glycolic, Dogs’ Brain Electric Activity in Ethylene Glycol Poisoning Paula Maria SAFTENCU, Gabriela Dumitriţa STANCIU, Mihai MUSTEAŢĂ, Sorin Ioan BEŞCHEA CHIRIAC, Sorin Aurelian PAŞCA, Gheorghe SOLCAN* Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine “Ion Ionescu de la Brad” 8 Sadoveanu Alley, Faculty of Veterinary Medicine, Iaşi, Romania Corresponding author: gsolcan@uaiasi.ro Bulletin UASVM Veterinary Medicine 72(1) / 2015, Print ISSN 1843-5270; Electronic ISSN 1843-5378 DOI:10.15835/buasvmcn-vm: 10520 Abstract Ethylene glycol (EG) poisoning is one of the most common toxicosis in dogs, even a small amount being lethal if the antidote is not administered on time. Once ingested the breakdown products of the toxic cause acute renal failure. Neurological signs include dizziness, ataxia, and seizures similar to those from idiopathic epilepsy or other neurologic disorder. The aim of this study was to describe electroencephalographic changes in dogs suffering from EG toxicosis using a repeated short time electroencephalographic (EEG) recording. EEGs was performed on 5 mixed breed with ages between 4 and 9 years old suffering from EG poisoning, free of other neurologic disorders or previous seizures. Electroencephalographic recording was obtained using five subdermal needle electrodes placed using the Redding model. The EEG was recorded with sensitivity = 70μV/cm; time constant = 0.3 seconds impedance of all electrodes < 10 kΩ. Each patient was EEG analysed at every 24 hours. The EEG trace was normal in the initial state. With toxicosis progression different EEG anomalies were observed. The EEG traces slightly voltated presented an initially slowed background activity of 5-7 cycles/second, above which synchronous bilateral diffuse delta waves where registered, as an expression of cortical or subcortical neuronal hyperexcitability state. In advanced stages, when the patients elicit seizures clinically, the EEG recording trace became irregular and arrhythmic with epileptic abnormalities. Keywords: dog, electroencephalogram, ethylene glycol poisoning.