Neuro Emergencies: Seizures Flashcards
Acute Symptomatic Seizures can occur from the following?
Head Trauma
Brain Tumors
Intracranial Infection
Congenital brain malformations
Hypo/hyperglycemic
Hyper/hyponatremia
Hypocalcemia
Hypomagnesemia
Withdrawal states
Hypoxic brain injury
Stroke
Vascular malformations
Eclampsia
Hypertensive encephalopathy
Hyperthyroidism
Toxic/metabolic
AED non-compliance
Differential Diagnosis for seizure like symptoms
Syncope
Tremors
Rigors
Nonepileptic seizures
Dyskinesia
TIA
Types of Generalized Seizures
Convulsive
Absence
Tonic
Atonic
Myoclonic
Types of Generalized Absence Seizures
Typical
Myoclonic Absence
With eyelid myoclonia
Atypical
Types of Generalized Myoclonic Seizures
Negative Myoclonus
Myoclonic-Atonic
A generalized seizure is conceptualized as originating at some point within, and rapidly engaging, bilaterally distributed networks
Can include cortical and subcortical structures, but do not necessarily include the entire cortex
Although individual seizure onsets can appear localized, the location and lateralization are not consistent from one seizure to another
Can be asymmetric
What type of Seizure?
Generalized
Typically bilateral and symmetric although variants with asymmetry including head and eye deviation can be seen
A tonic clonic seizure is a seizure consisting of a tonic and a clonic phase, typically in this order, however variations such as clonic-tonic-clonic are also seen
A clonic seizure is a seizure involving bilaterally rhythmic jerking and may occur alone or in combination with tonic activity where there is bilaterally increased tone of the limbs typically lasting seconds to a minute
The jerking in a clonic seizure is more sustained and rhythmic than seen in a myoclonic seizure
What type of Seizure?
convulsive
Seizure is a generalized seizure with abrupt onset and offset of altered awareness which can vary in severity
Memory for events during the seizures is usually impaired although there may be some retained awareness particularly for adolescents
Clonic movements of eyelids, head, eyebrows, chin, perioral or other facial parts may occur
Myoclonus of limbs can rarely occur
Oral and manual automatisms are common and there may be perseveration of behaviors occurring prior to seizure onset
Absence seizures were previously known as ‘petit mal’ seizures
Absence status epilepticus can occur
What type of Absence Seizure?
Typical
Rhythmic myoclonic jerks of the shoulders and arms with tonic abduction that results in progressive lifting of the arms during the seizure
The myoclonic jerks are typically bilateral but may be unilateral or asymmetric
Perioral myoclonias and rhythmic jerks of the head and legs may occur
Seizures last 10-60 seconds and typically occur daily
Level of awareness varies from complete loss of awareness to retained awareness
What type of Absence Seizure?
Myoclonic Absence Seizure
Absence seizures accompanied by brief, repetitive, often rhythmic, fast (4-6 Hz) myoclonic jerks of the eyelids with simultaneous upward deviation of the eyeballs and extension of the head
Seizures are typically very brief (<6s in duration) and multiple seizures occur on a daily basis
Mostly awareness is retained
What type of Absence Seizure?
Absence with eyelid myoclonia seizure
Seizure has less abrupt onset and offset of loss of awareness than typical absence seizures
They are often associated with other features such as loss of muscle tone of the head, trunk or limbs (often a gradual slump) and subtle myoclonic jerks
Often occur in individuals with intellectual impairment
The loss of awareness may be minimal with the patient continuing an activity, but more slowly or with mistakes
What type of Absence Seizure?
Absence Atypical Seizure
Involves bilaterally increased tone of the limbs typically lasting seconds to a minute
They often occur out of sleep and in runs of varying intensity of tonic stiffening
The individual is unaware during these events
At the beginning with more intense stiffening, individuals may make an expiratory sound
More severe and prolonged seizures may have a vibratory component which may be confused with clonic jerking
Often occur in individuals with intellectual impairment
What type of seizure?
Tonic Seizure
Involves sudden loss or diminution of muscle tone without apparent preceding myoclonic or tonic features
Very brief (<2 seconds) and may involve the head, trunk or limbs
Often occur in individuals with intellectual impairment
What type of seizure?
Atonic Seizure
A single or series of jerks (brief muscle contractions)
Each jerk is typically milliseconds in duration
Status epilepticus of this type is characterized by ongoing (> 30 minutes) irregular jerking, often with partially retained awareness
What type of Seizure?
Myoclonic Seizure
Is a seizure with brief cessation of background muscle tone, lasting less than 500 milliseconds
The resulting movement produced can have two components, an initial loss of posture caused by the negative myoclonus, and a subsequent voluntary, compensatory movement to restore posture
May occur in isolation or in a series
What type of Seizure?
Negative Myoclonic Seizure
Is a myoclonic seizure followed by an atonic seizure
Sometimes a series of myoclonic jerks occurs prior to the atonia
The head and limbs are affected, typically resulting in rapid fall
The myoclonic jerk may be subtle
Myoclonic-Atonic Seizure
Focal Seizure features include
Aura
Motor
Autonomic
Dyscognitive
Focal seizures are conceptualized as originating within
networks limited to one hemisphere
Focal Seizures distribution may be?
discretely localized or more widely distributed
Focal seizures may originate in
subcortical structures
Focal Seizuers
For each seizure type, ictal onset is what?
with preferential propagation patterns that can involve what?
consistent from one seizure to another
the ipsilateral and/or contralateral hemisphere
Focal seizures can be described by their
semiology (features)
The features that occur may reflect the regional networks involved what?
often enabling what?
in the seizure origin or propagation
these areas of the brain to be identified
Some features allow identification of what?
others allow identification of what?
the hemisphere involved
the discrete area of the brain (for example a lobe) that is involved
Auras are subjective and may be?
sensory or experiential
Auras reflect the initial what?
seizure discharge
An aura may be an isolated phenomenon or progress to a focal seizure with
objective features (with or without altered awareness) or to a bilateral convulsion
An aura is also known as a?
Warning
A sensory aura involves what?
A sensation w/o an objective clinical sign
Characterized by sensory phenomena including tingling, numbness, electric-shock like sensation, pain, sense of movement, or desire to move
occur in seizures involving the sensorimotor cortex
Somatosensory Aura
Characterized by elementary visual hallucinations such as flashing or flickering lights, spots or other shapes, simple patterns, scotomata, or amaurosis
More complex hallucinations such as seeing formed images are considered experiential aura.
Occur in seizures involving the occipital lobe, and are often colored in nature
Visual Aura
Characterized by elementary auditory phenomena including buzzing, ringing, drumming or single tones
More complex hallucinations such as voices are considered experiential seizures
Occur in seizures involving auditory cortex in the lateral superior temporal lobe
Auditory Aura
Characterized by phenomena - usually an odor, which is often unpleasant
Occur in seizures involving the mesial temporal or orbitofrontal regions
Olfactory Aura
Characterized by taste phenomena including acidic, bitter, salty, sweet, or metallic tastes
Occur in seizures involving the parietal operculum and the insula
Gustatory Aura
Characterized by upper abdominal phenomena including discomfort, emptiness, tightness, churning and a sensation that may rise up to the chest or throat
Occur in seizures involving the mesial temporal lobe
Epigastric Aura
Characterized by a sensation in the head such as light-headedness or headache
Cephalic Aura
An experiential aura involves affective, mnemonic (memory) or perceptual subjective phenomena including depersonalization and hallucinatory events; these may appear alone or in combination Experiential aura include the following types
Affective
Mnemonic
Hallucinatory
Illusory
Characterized by phenomena such as fear, depression, joy and anger.
Affective Aura
Characterized by memory phenomena such as feelings of familiarity (déjà vu) and unfamiliarity (jamais vu)
Mnemonic Aura
Characterized by imagined complex sensory phenomena that may involve visual (e.g. formed images), auditory (e.g. hearing voices) or other sensory modalities, without change in awareness
The sensory phenomena may be accompanied by associated emotion or interpretation e.g. may be experienced as persecutory
Hallucinatory Aura
Characterized by an alteration of actual perception involving visual, auditory, somatosensory, olfactory, and/or gustatory phenomena, without change in awareness
Illusory Aura
A motor feature involves motor activity and may consist of
Motor features may be?
an increase (positive) or decrease (negative) in muscle contraction
elementary or complex