P. 562

An Urban Experience
M. Berendtm1
1Department of Veterinary Clinical Sciences, Dyrlaegevej 16, 1870 Frb. C, Denmark
Epilepsy is a disease of the brain characterized by recurrent seizures originating from the brain. The signs
of epilepsy are episodic, and epilepsy can become inactive for a period of time or even disappear.
Seizure activity arises as a sequel to abnormal hyper synchronous electrical activity, which stems from a group of local cerebral neurons or from the whole cortex in collaboration with subcortical structures.
Epilepsy is characterized by a sudden loss of control and paroxysmal manifestations with seizures which suddenly occur and suddenly cease. Seizures are transient and seldom last longer than 2-3 minutes. Seizures typically follow a repetitive pattern where signs and sequence are identical from episode to episode in the individual animal. Signs may include motor-, sensory- and autonomic elements and behavioural disturbances. Consciousness may be altered or lost. In some individuals with epilepsy, seizures can be provoked by external factors such as e.g. excitement, agitation,  ashes of light, and sleep deprivation.
Factors involved in epileptogenesis may be e.g. neuroplasticity/synaptic plasticity, decreased GABA (gamma amino butyric acid) activity, increased glutamate activity, new formation of excitatory circuits, receptor alterations, ion channelopathies, dysfunction of glia cells, cortical dysgenesis, and primary brain disease causing seizures such as in ammatory or neoplastic disease.
The prevalence of epilepsy in dogs in general has been estimated in an epidemiological study to be 0.76%. The prevalence of epilepsy in cats is believed to be lower, although no true epidemiological studies exist
to document this. Several dog breeds are however associated with a much higher prevalence caused by an identi ed genetic or suspected genetic background for epilepsy. This leads to an unfortunate accumulation of epileptic individuals within such breeds. In the Lagotto Romagnolo a genetic background for epilepsy has
been fully identi ed and in the Belgian shepherd partially identi ed. In other breeds, an accumulation of epileptic individuals within families, have been documented by epidemiological studies (Labrador Retriever, Belgian Shepherd and Petit Basset Griffon Vendeen), or by pedigree studies (Keeshound, Labrador Retriever, Vizla,
Shetland Sheepdog, Irish Wolfhound, English Springer Spaniel, Australian Shepherd and Border collie among others).
Classi cation of epilepsy and epileptic seizures
The present presentation of epilepsy classi cation
in veterinary medicine is based on the consensus statements which have recently been published by the International Veterinary Epilepsy Task Force (IVETF). This consensus statement group involves veterinary and human neurologists and neuroscientists, practitioners, neuropharmacologists and neuropathologists.
Classi cation of epilepsy
Epilepsy is classi ed into categories based on known or presumed aetiology. Structural epilepsy (former known as symptomatic epilepsy) refers to epilepsy caused by a known/identi ed disorder of the CNS (cerebral pathology identi ed with e.g. CT, MRI or CSF examination). The term suspected structural epilepsy is used if brain pathology is strongly suspected (based on anamnestic information or abnormal  ndings on the neurological examination or both, signalling a focal brain lesion),
but has not been con rmed. Idiopathic epilepsy refers
to epilepsy where no structural cerebral pathology is identi ed, and where an identi ed or suspected genetic component is involved in the aetiology. Finally, a number of epilepsies are of unexplained origin (epilepsy of unexplained origin). In these cases, the epileptic seizures are however the only sign of disease. There is nothing in the history and no  ndings on clinical and neurological examination indicating intracranial pathology, and there are no abnormalities on specialized neuro-diagnostic tests (CT, MRI and CSF) suggesting intracranial pathology.
Note that epilepsy classi cation is continuously under revision and will be changed as our understanding of epilepsy aetiology in animals expand.
Classi cation of Epileptic Seizures
The clinical manifestation of epileptic seizures is directly related to the amount and distribution of abnormal electrical activity in the brain. Epileptic seizures are classi ed as generalized epileptic seizures, focal epileptic seizures (previously termed partial seizures) and focal seizures which evolve into generalized epileptic seizures.
With generalized epileptic seizures, there is a sudden outburst of abnormal electrical activity throughout both cerebral hemispheres. Without warning, the patient collapses with tonic, clonic, or tonic-clonic seizures. With focal epileptic seizures, the abnormal electrical activity arises in a localized group of neurons (the epileptic focus). The clinical signs re ect the functions of the area

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