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N18 Neurology
Stroke is the most common cause of late-onset (>50 yr) seizures, accounting for 50-80% of cases
Seizure Disorders and Epilepsy Toronto Notes 2019 Seizure Disorders and Epilepsy
Seizure
Definitions
• seizure:transientoccurrenceofsignsand/orsymptomsduetoabnormalexcessiveorsynchronous neuronal brain activity
■ can be symptom of acute insult to the brain such as: alcohol and illicit drug use/withdrawal,
brain injury/abnormality (tumour, trauma, vascular), CNS infection, fever (children), metabolic (hypoglycemia, electrolyte abnormalities, liver/renal failure), medications, or be a manifestation of epilepsy
• epilepsy:disorderofthebraincharacterizedbyanenduringpredispositiontogenerateepileptic seizures, and by the neurobiologic, cognitive, psychological, and social consequences of this condition.
■ diagnosis of an epilepsy syndrome requires:
1) at least two unprovoked (or reflex) seizures occurring more than 24 hours apart
2) one unprovoked (or reflex) seizure and a probability of further seizures similar to the general
recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years ■ etiologies: genetic, structural (e.g. prior stroke, tumour, meningo/encephalitis, perinatal insult,
vascular malformation, malformation of cortical development, neurodegenerative), or unknown
Seizures and Dementia
Neurodegenerative diseases can underlie seizures; conversely, seizures can be a cause of dementia
Classification
Focal Onset
Aware / Impaired Awareness
Seizure
Generalized Onset
Unknown Onset*
Motor
Automatisms Atonic
Clonic
Epileptic spasms Hyperkinetic Myoclonic
Tonic
Nonmotor Focal to bilateral tonic-clonic
Autonomic Behaviour arrest Cognitive Emotional Sensory
Motor
Tonic-clonic
Clonic
Tonic
Myoclonic Myclonic-tonic-clonic Myoclonic-atonic Atonic
Epileptic spasms
Nonmotor (absence)
Typical Atypical Myoclonic Eyelid myoclonia
Motor
Tonic-clonic Epileptic spasms
Nonmotor
Behaviour arrest
Unclassified‡
Temporal lobe epilepsy is suggested
by an aura of fear, olfactory or gustatory hallucinations, and visceral or déjà vu sensations
Frontoparietal cortex seizures are suggested by contralateral focal sensory or motor phenomena
Antiepileptic Drug Monotherapy for Epilepsy: A Network Meta-analysis of Individual Participant Data
Cochrane DB Syst Rev 2017;CD011412 Carbamazepineandlamotriginearesuitable first-line treatments for partial onset seizures with levetiracetam as a suitable alternative. Evidence supports sodium valproate as first-line treatment for generalized tonic-clonic seizures with lamotrigine and levetiracetam as suitable alternatives.
• focal(partial)seizures
■ focal can secondarily generalize, or focal (simple) → focal with impaired awareness (complex) →
generalized seizures
■ focalwithintactawareness(simplepartial)
◆ motor: postural, phonatory, forceful turning of eyes and/or head, focal muscle rigidity/jerking ± Jacksonian march (spreading to adjacent muscle groups)
◆ sensory: unusual sensations affecting vision, hearing, smell, taste, or touch
◆ autonomic: epigastric discomfort, pallor, sweating, flushing, piloerection, pupillary dilatation
◆ psychiatric: symptoms rarely occur without impairment of consciousness and are more
commonly complex partial
■ focalwithimpairedawareness(complexpartial)
◆ patient may appear to be awake but with impairment of awareness
◆ classic complex seizure is characterized by automatisms such as chewing, swallowing, lip-
smacking, scratching, fumbling, running, disrobing, and other stereotypic movements
◆ other forms: dysphasic, dysmnesic (déjà vu), cognitive (disorientation of time sense), affective
(fear, anger), illusions, structured hallucinations (music, scenes, taste, smells), epigastric fullness • generalizedseizures
■ absence(petitmal):usuallyseeninchildren,unresponsivefor5-10switharrestofactivity,staring, blinking or eye-rolling, no post-ictal confusion; 3 Hz spike and slow wave activity on EEG
■ clonic:repetitiverhythmicjerkingmovements ■ tonic:musclerigidityinflexionorextension
■ tonic-clonic(grandmal)
◆ may have prodrome of unease or irritability hours to days before the episode (aura)
◆ tonic ictal phase: muscle rigidity
◆ clonic ictal phase: repetitive violent jerking of face and limbs, tongue biting, cyanosis, frothing,
*Unknown Onset not characteristic of the seizure, but an indication of ignorance.
‡ Unclassified comprises both seizures with patterns that do not fit other categories or lack information.
Figure 16. Classification of seizures
Clinical Features
incontinence