Page 794 - Clinical Small Animal Internal Medicine

762 Section 8 Neurologic Disease

Diagnosis that causes feline infectious peritonitis is not recom-
VetBooks.ir The most important component in approaching a seizure mended, as the correlation between a positive titer and
active CNS infection is low.
case is acquiring a thorough and accurate history. The
purpose is to establish overall frequency, seizure type, Magnetic Resonance Imaging (MRI) Brain Scan
patterns of occurrence, relationship to daily activity (e.g.,
exercise, sleep) and severity of postictal effects. Inquiries ● All dogs 7 years of age or older and all cats with an ini-
regarding the seizure event should address a description tial onset of seizure(s), regardless of the seizure pattern
of the event, time of day, duration, and postictal effects. or frequency or outcome of neurologic examination.
Video segments of events can be extremely helpful for ● Patients with an abnormal interictal exam or behavior.
clinicians to determine whether an epileptic event has ● Drug‐resistant epileptic patients.
occurred. Owners should be encouraged to video an ● Cerebrospinal fluid (CSF) analysis is recommended in
event if possible and to try and distract the animal to any animal with multifocal neurologic deficits or lesions
determine whether the event can be terminated with observed on MRI scans or if the scan is normal.
external stimuli. Distractability often implies a nonepi-
leptic event. A charting technique measuring seizure fre- Electroencephalogram (EEG)
quency and severity should be developed to aid objective Electroencephalogram analysis is beneficial for identify-
evaluation of future therapeutic success. Owners should ing underlying epileptic foci in the dog but the overall
be provided with a calendar to record the frequency and usefulness of this test for determining diagnosis and
description of all observed and suspected seizures. treatment has yet to be proven.
The interictal status of cerebrocortical function
(between seizures and after the postictal period) can be
evaluated by asking questions concerning the animal’s Therapy
behavior, vision, gait, and sleep/wake patterns. For exam- Management of epilepsy in cats and dogs often requires
ple, if the dog is more withdrawn or attention seeking, a lifetime commitment by the owners. The owner must
showing any unusual episodes of aggression or irritabil- be willing to medicate their pet several times per day,
ity, or fails to follow simple commands, then a structural travel to emergency clinics at unpredictable times, follow
cerebral problem should be suspected. Likewise, subtle up with periodic reevaluations and diagnostic testing,
gait disturbances (stumbling up or down the stairs), vis- and watch their pet carefully for adverse effects of
ual disturbances (occasionally bumping into objects on therapy.
one side) and restless sleep patterns may indicate fore- Despite all the time, financial, and emotional commit-
brain problems. ment, a significant number of dogs may still continue to
The sequence of diagnostic testing for any animal with
seizures should proceed from the least to the most inva- have seizures. Thus, proper client education is critical in
preparing owners for understanding their pet’s condition
sive (and expensive) modality. A complete blood count and the potential associated lifestyle changes. In particu-
(CBC), biochemistry panel, urinalysis, and blood pres- lar, owners need to know that a diagnosis of epilepsy
sure measurement should be performed for all animals implies an increased risk of premature death with the
being evaluated for an epileptic seizure. prognosis dependent on a combination of veterinary
For dogs, additional testing is based upon the age,
breed, seizure type, seizure frequency, and neurologic expertise, therapeutic success, and owner motivation.
examination findings.
Decision‐Making Strategies for AED Therapy
The decision regarding when to start AED treatment is
Advanced Metabolic and Infectious Disease Testing based on a number of factors, including etiology, risk of
Pre‐ and postprandial serum bile acid study with serum recurrence, seizure type and its effect on the patient, as
ammonia levels in dogs less than 1 year of age and those well as the risk of treatment. Risk factors for seizure
being started on hepatic metabolized antiepileptic drug recurrence are not well established for cats and dogs. A
(AED) therapy. number of relative risk factors have been identified in
Other individual tests for toxin exposure (e.g., plasma epileptic people, including current or previously defined
lead, serum cholinesterase assay), parasitic or rickettsial cerebral lesions or trauma, the presence of interictal EEG
infection, or systemic illness are based on the clinical epileptic discharges (up to 90% recurrence rate) and a
picture at the time of presentation. For cats, basic screen- history of marked postictal adverse effects (Todd paraly-
ing should include a retroviral screen for feline leukemia sis). Evidence‐based guidelines from several interna-
and feline immunodeficiency virus and testing for serum tional groups are well established for humans based on
antibodies to Toxoplasma gondii. Testing for the virus the risk:benefit ratio and predictability factors of drug