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Flashcards in Seizures - Neuro Deck (18):
1

Seizure

episode of abnormal neurologic function caused by abnormal electrical discharge of brain neurons

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Epilepsy

condition of recurrent seizures, usually due to fixed condition

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Mechanism

-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

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Etiology

-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

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Generalized Seizures

-Near-simultaneous activation of entire cerebral cortex
-Causes abrupt LOC
-Grand Mal
-Petit Mal (Absence)
-Myoclonic

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Grand Mal Seizure

-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

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Petit Mal (Absence) Seizures

-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

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Myoclonic Seizures

LOC associated with isolated extremity jerking

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Partial (Focal) Seizures

-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

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Simple Partial Seizures

-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

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Complex Partial Seizures

-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)

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History

-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

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Psychogenic Seizures

-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

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Physical Exam

-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.

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Treatment of the Acute Seizure

-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

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Status Epilepticus

-Continuous seizure activity lasting >30 min.
or
-Two or more seizures without return of consciousness in between
-Seizures are usually tonic-clonic, but may also be simple partial, complex partial, absence
-50% have no prior sz. history
-Demands urgent treatment
-Hypoxia > 30-60 min. leads to permanent neuro injury
-10% mortality

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Causes of Status Epilepticus

-CNS infection
-Trauma
-Anoxia
-Noncompliance or change in anticonvulsant meds
-Stroke
-Metabolic derangements

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Status Epilepticus: Treatment

-ABC’s
-O2 by facemask, consider intubation
-Large-bore IV
-Check stat glucose! Administer D50 if hypoglycemic
-Anticonvulsant therapy
-First-line: benzo’s (diazepam, lorazepam)
-Second-line: phenytoin/phosphenytoin
-Third-line: phenobarbital
-Fourth-line: lidocaine, midazolam, paraldehyde, general anesthesia (pentobarbital)
-Always search for underlying cause
-Look for injuries resulting from sz.
-Labs: Glucose, Lytes, BUN/Cr, Tox. screen, Anticonvulsant levels, Serum CK for rhabdomyolysis
-CT head after seizures controlled
-IV antibiotics if meningitis suspected