Seizures - Neuro Flashcards
1
Q
Seizure
A
episode of abnormal neurologic function caused by abnormal electrical discharge of brain neurons
2
Q
Epilepsy
A
condition of recurrent seizures, usually due to fixed condition
3
Q
Mechanism
A
- Increased cell membrane excitability due to failure of normal inhibitory mechanisms (e.g., GABA)
- Leads to intense, prolonged neuronal discharges
- May remain localized, or may spread to involve entire cortex
4
Q
Etiology
A
- Idiopathic
- Degenerative (MS, presenile dementia)
- Infectious (meningitis, abscess, neurosyphilis)
- Metabolic (hypoglycemia, hepatic failure, hyper/hypo-natremia)
- Neoplastic (primary or metastatic tumors)
- Perinatal (infection, metabolic disorders)
- Toxic (theophylline, lidocaine, tricyclic antidepressants, cocaine)
- Head trauma (epidural/subdural hematomas, cerebral contusion)
- Vascular (stroke, AVM, subarachnoid hemorrhage)
- Eclampsia (pregnanacy)
- Alcohol withdrawal
5
Q
Generalized Seizures
A
- Near-simultaneous activation of entire cerebral cortex
- Causes abrupt LOC
- Grand Mal
- Petit Mal (Absence)
- Myoclonic
6
Q
Grand Mal Seizure
A
- Aka, tonic-clonic seizure, “convulsions”
- Begin with abrupt LOC, usually without warning
- Pt. falls to ground with trunk/extremities extended (tonic phase)
- Then, rhythmic jerking of trunk and extremities (clonic phase)
- Often, apnea, cyanosis, tongue-biting, urinary incontinence
- Typically last 60-90 seconds
- Post-ictal phase
- Follows grand mal sz.
- After attack, pt. remains unconscious, flaccid, confused, usually for many minutes, before slowly regaining consciousness
- Todd’s paralysis: May occur after grand mal sz., Transient postictal focal paresis
7
Q
Petit Mal (Absence) Seizures
A
- Typically very brief (few seconds)
- Abrupt LOC
- Blank stare
- Eyelids may twitch
- No response to voice
- No falls, no involuntary movement, no incontinence
- No post-ictal phase, attacks cease abruptly, pt. unaware that anything happened
- May be frequent (>100/day)
- Typically seen in school-aged kids
- True petit mal sz. unusual in adults, who more likely are having partial seizures
- Often resolve as child gets older
8
Q
Myoclonic Seizures
A
LOC associated with isolated extremity jerking
9
Q
Partial (Focal) Seizures
A
-Due to electrical discharges beginning in localized region of brain
-May remain localized or may spread, becoming generalized
-Often due to focal structural brain lesion (e.g., tumor, AVM, scar tissue, CVA, head injury)
Classified as:
-Simple partial
-Complex partial
10
Q
Simple Partial Seizures
A
-No alteration of consciousness
Manifestations may be:
- Motor: Tonic or clonic movements, often unilateral, often limited to one extremity
- Sensory: Paresthesias/numbness, Flashing lights, Olfactory/gustatory hallucinations
11
Q
Complex Partial Seizures
A
- aka, “psychomotor sz.”, “temporal lobe sz.”
- Involves change in LOC or mentation
- Usually bizarre sx. with psychic features
- Visceral sx. (nausea, butterflies in stomach)
- Hallucinations (visual, olfactory, auditory, olfactory)
- Memory disturbances (déjà vu, jamais vu)
- Dream-like states
- Automatisms: repetitive, purposeless movements (lip-smacking, playing with clothes)
- Affective disorders (paranoia, depression, elation)
12
Q
History
A
- Need to rule out seizure mimics
- Syncope: premonitory feeling of “going to black out”, graying of vision, quick recovery of consciousness
- Narcolepsy: brief attacks of uncontrollable daytime sleepiness
- Movement disorders (tics, jerks, tremors): consciousness preserved, movements involuntary, but pt. can usually suppress them
- Hyperventilation syndrome: gradual onset with SOB, anxiety, numbness of mouth/extremities, maybe LOC
- Psychogenic seizures
13
Q
Psychogenic Seizures
A
- Often occur in response to emotional upset
- Often occur only when witnesses present
- Bizarre features, often with variable presentation
- Pts. protect themselves from noxious stimuli
- No incontinence or injury during episode
- No post-ictal confusion
- Normal EEG during attack
14
Q
Physical Exam
A
- Look for systemic illness that may have precipitated attack
- Vital signs
- Detailed neuro and mental status exam
- Look for injuries resulting from seizure
- Fractures, bruises
- Tongue lac, broken teeth
- Aspiration
- Head/neck injury
- Always check a glucose!
- Possibly: lytes, BUN/Cr, Ca, Mg, PO4
- Lumbar puncture if meningitis suspected
- Toxicology screen if ingestion suspected
- Anticonvulsant levels in pt. with known sz. history
- CT head: Appropriate in first-time sz., Looks for structural lesions, head bleed
- MRI head: More sensitive than CT for subtle abnormalities
- EEG: Identifies and locates abnormal electrical findings, Abnormal EEG supports dx. of true sz.
15
Q
Treatment of the Acute Seizure
A
- Protect pt. from injury, prevent falls with gentle restraint
- Place pt. on side to reduce aspiration
- Bite block not necessary; do not force open closed tonic jaw
- Assure airway patency after sz. subsides
- If sz. lasts >5 minutes, consider benzodiazepine (diazepam, lorazepam)
- Treat underlying illness, if present
- If known sz. disorder, check anticonvulsant levels, adjust as appropriate
