Seizures as a manifestation of intracranial disease with particular regard to brain tumours in dogs

Michieletto, Alberta (2001) Seizures as a manifestation of intracranial disease with particular regard to brain tumours in dogs. MVM(R) thesis, University of Glasgow.

Abstract

Seizures are one of the most common neurological disorders encountered in the canine patient. The susceptibility of the brain to a wide spectrum of structural and metabolic disorders means that the occurrence of seizures is indicative of an underlying condition of cerebrocortical dysfunction, not of a specific aetiology. However, all the pathological processes resulting in seizures may also occur without being accompanied by seizure activity. In addition, seizure activity in humans with brain tumours most commonly originates from cortical tissue that is distant from the tumour. This dissertation focuses on seizures as a sign of intracranial dysfunction and through the presentation of selected canine clinical cases highlights the reasons and times at which seizures may be a clinical feature of intracranial neoplasia. The majority of brain tumours associated with seizures affect the rostrotentorial structures, especially the frontal, olfactory, and parietal lobes. Of the sixteen cases presented here, ten had seizures as admitting complaint. Of these, two were diagnosed with idiopathic epilepsy, one with hydrocephalus and intracranial arachnoid cyst, and seven with brain tumours. All but one of these seven dogs had tumours located in the rostral fossa. Unexpectedly, one dog had a caudal fossa tumour. In this case, post mortem examination revealed the presence of metastasis within the forebrain. At the time of presentation to a veterinarian, seizures may be the only clinical manifestation of an intracranial tumour. However, in most instances interictal neurological abnormalities are present. Conversely, animals affected with idiopathic epilepsy typically do not manifest interictal neurological deficits. In the case material here reported, two of the seven dogs presented for evaluation of seizure disorders and diagnosed with brain tumour did not exhibit interictal neurological abnormalities. These findings emphasise that a normal interictal neurological examination does not exclude the possibility that a structural brain abnormality is the cause of the observed seizure activity. Overall, changes in mental status, behavioural derangement and ataxia are the neurological abnormalities most frequently observed in patients with intracranial neoplasia. Signs of vestibular dysfunction are a common manifestation of tumours affecting the caudal fossa structures. In the series here reported, two of the three dogs diagnosed with hindbrain neoplasia exhibited signs of vestibular dysfunction at the time of presentation. Combining the results of this study with a broad review of the literature pertaining to seizure disorders in dogs, this dissertation emphasises the non-specificity of seizures as a sign of intracranial disease / dysfunction and the need for a logical and systematic diagnostic evaluation.

• Item Type: Thesis (MVM(R))
• Qualification Level: Masters
• Keywords: Veterinary science.
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Anderson, Dr. T.J.
• Date of Award: 2001
• Depositing User: Enlighten Team
• Unique ID: glathesis:2001-73244
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 12 Nov 2021 12:55
• URI: https://theses.gla.ac.uk/id/eprint/73244