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The Diagnosis of Seizures in Dogs

What is a seizure?

A seizure is caused by an abnormal burst of electrical activity within the brain,commonly in one of the cerebral hemispheres (focal/partial seizure). A focal/ partialseizure is one in which the jerking or twitching is limited (at least initially) too aparticular part of the body. More often, the electrical activity spreads out andinvolves both sides of the brain, which results in a generalized (grand mal) seizure.Generalized seizures last less than two minutes and are characterized by collapsewith rigid extension of the legs. This is followed by rhythmic jerking of the legs(which resembles running or paddling). Some dogs also chomp, chew, drool orurinate and defecate. As the dog regains consciousness there is a post-seizure statecharacterized by disorientation and confusion. The dog may stumble into walls andappear blind. The post-seizure state can persist for minutes or hours.There are other causes of neurological episodes, which can appear similar toseizures but are not, including: syncope, narcolepsy, vestibular/ vertigo spells andsome pain-related behavior.

Diagnosis of Seizures

Since seizures can be caused by any process that alters the normal neurological function, the goal of the veterinarian is todistinguish between primary and secondary causes of seizures. This is done through examination, the taking of a thoroughpatient history and often includes further medical tests (bloodwork, x-rays, blood pressure), advanced imaging (brain MRI)and/or spinal fluid analysis, if necessary. With this information, the veterinarian can create a plan for the management andtreatment of the patient's seizures.

Most Likely Causes of Seizures

Dog is less than 1 year of age

Metabolic (liver shunt), infection/inflammatory (encephalitis), toxin, congenital malformation

Dog is 1-5 years of age

Idiopathic Epilepsy, infectious/inflammatory (encephalitis), vascular/stroke

Dog is Greater than 5 years of age

Brain tumor, infection/inflammatory (encephalitis), vascular/stroke, metabolic (glucose regulation)

Girl Laughing and Holding a Brown Dog

Treatment of Seizures

Following a definitive diagnosis, treatment of the specific condition should beconsidered. In the case of diagnosis of Idiopathic Epilepsy (seizures forwhich no underlying abnormality can be identified), the treatment ofseizures centers on control with anticonvulsant drugs. Other identifiedcauses of seizures vary in their treatment and prognosis and may involvemanagement with additional specific medications or surgery in some cases.