Page 807 - Problem-Based Feline Medicine

36 – THE CAT WITH SEIZURES, CIRCLING AND/OR CHANGED BEHAVIOR 799

dling. This is often accompanied by jaw champing, Seizures must be differentiated from seizure-like
facial twitching and autonomic signs (e.g. mydriasis, events such as syncopes, sleep disorders (e.g. excessive
hypersalivation, piloerection, micturition). dream-like movements), movement disorders (e.g.
● In partial (focal) seizures with secondary general- myoclonia, tremors-tetany), narcolepsy-cataplexy,
ization, the seizure is preceded by behavioral episodic behavioral disorders (e.g. fly catching, feline
change (aura) or localized or lateralized motor signs hyperesthesia), dysphoric and agitated anesthetic
or followed by motor deficits. recovery, and paddling associated with decerebration.
Partial (focal) seizures have a focal onset in one cere- Compulsive circling is usually accompanied by men-
bral hemisphere and a limited propagation within one tal confusion with either depression or agitation. It is
or both hemispheres. often associated with wandering, pacing and sometimes
● They manifest with variable degrees of alteration of with an abnormal posture (head and eye deviation or
consciousness ranging from normal to totally turning, leaning).
absent awareness and responsiveness. ● Compulsive circling must be differentiated from
● Partial (focal) seizures have motor signs that may vestibular circling which is due to marked loss of
be either lateralized to one side of the body, local- balance.
ized to one part of the body, or may even be gener- – The cat with compulsive circling does not have
alized but not violent enough to cause complete a head tilt (its head may however be turned), loss
recumbency (e.g. mild tremors of the whole body). of balance, nystagmus and other vestibular signs.
– Lateralized signs include unilateral facial It usually has a normal gait (no detectable ataxia
twitching, tonic or clonic movements of one or nor paresis) and often can walk in a straight line
both limbs on one side, and spasmodic turning when it is motivated to do so (e.g. reach a spe-
of the head to one side. cific goal such as a food plate).
– Signs localized to one part of the body include
Personality and behavioral changes due to forebrain
hindlimb weakness causing difficulty or inabil-
diseases must be differentiated from pure behavioral
ity walking, and bilateral facial twitching with or
disorders.
without spasmodic head bobbing.
● Partial (focal) seizures of cats are often subtle
WHERE?
and/or bizarre and may be difficult to recognize as
being seizure activity. Forebrain (thalamocortex) diseases can cause any of
● Some partial (focal) seizures previously called psy- the following signs:
chomotor seizures mainly manifest with bizarre ● Mentation abnormalities ranging from depression
stereotypical and behavioral activities (e.g. halluci- to semi-stupor, or confusion.
natory prey or predator behavior with running fits). ● Subtle personality changes (e.g. loss of good or
● Seizures preceded by an aura (behavioral changes bad habits) to obvious behavioral abnormalities
within a few seconds or minutes of the ictus onset) or (e.g. dementia, aggression).
followed by localized post-ictal motor deficits (e.g. ● Abnormal activities such as wandering, propulsive
hemiparesis) are partial in onset, even if they appear pacing, head pressing and compulsive circling.
to be generalized from the beginning of the ictus. ● Seizures.
● Partial (focal) seizures may secondarily general- ● Mild contralateral hemiparesis and proprioceptive
ize to tonic-clonic generalized seizures and this may loss causes either subtle gait abnormalities (e.g.
occur so quickly that their initial partial phase may knuckling) or is only detected as postural reaction
not be observed clinically; most generalized deficits (e.g. proprioceptive positioning, hopping,
seizures of cats are probably within that category. lateral tactile limb placing).
● The occurrence of partial seizures usually indicates ● Central visual loss either causes the cat to bump
that there is a focal forebrain lesion which into things, or is only detected by a deficit in the
excludes the possibility of idiopathic (genetic) menace response together with normal pupillary
epilepsy and extracranial (metabolic and toxic) light reflexes in the contralateral eye when the
causes of seizures. affected eye is tested.