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Flashcards in Seizures and Epilepsy Deck (41)
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Tonic vs clonic

Tonic - stiffening

Clonic - movement

Tonic-Clonic (grand mal) - alternating stiffening and movement

Myoclonus - quick, repetitive movements


Atonic vs Absence

Abscence (petit mal) - 3Hz, no postictal confusion, blank stare

Atonic - drop seizures (falls to floor) - commonly mistaken for fainting


Seizure vs epilepsy

Seizure is paroxysmal event caused by abnormal, excessive electrical discharge from an aggregate of CNS neurons

Epilepsy is when there is a syndrome of recurrent seizures. Use term with caution and don't apply to patients who have periodic seizures provoked by secondary causes like diabetics with hypoglycemic episodes

HOWEVER, consider a patient with a brain tumor and recurrent seizures. This IS epilepsy. You can't explain why patient had seizure on Tuesday but not on Wednesday.


Generalized vs partial seizures

If abnormal activity arises from both hemispheres at once (generalized - always with LOC) or from a focal area of cortez (partial).

Partial seizures can occasionally spread to involve the whole cerebral cortex - secondary generalization. It's important to get good history to know if something started out as partial since partial and generalized have different differentials.


Generalized seizures

Cortical discharge - entire cortex

Consciousness - Lost

Common causes - metabolic**, fever, genetic epilepsy syndromes, sleep deprivation, idiopathic

Initial work up - systemic labs, EEG and MRI

Examples - Generalized tonic-clonic, absence, tonic, myoclonic


Partial seizures

Cortical discharge - regional

Consciousness - preserved (simple) or altered (complex)

Common causes - stroke, neoplasm, head trauma, infection, mesial temporal sclerosis

Initial workup - Neuroimaging

Examples: Simple - motor (classical Jacksonian march), sensory, psychic (deja-vu), autonomic (rising epigastric sensation). Complex - temporal lobe seizures, frontal lobe seizures


Clean MRI and EEG following first generalized tonic clonic seizure

Risk of seizure in next year is very low so no need for AEDs

No driving for 6m

Don't operate alone

If EEG or MRI are abnormal then you get AEDs


Systemic abnormalities associated with seizures (6)

1) Electrolytes - hypoNa, hypoCa, hypoMg

2) Blood glucose - hypoglycemia

3) Organ failure - uremia, hepatic failure, TTP, sepsis

4) Drug intox - Penicillins, local anesthetics, TCAs, Li, theophylline, amphetamine, cocaine, phenycyclidine, wellbutrin

5) Drug withdrawal - alcohol, benzos, barbs

6) Endocrinopathies - hypoparathyroidism


Absence seizures

Duration - seconds

Automatisms (motor) - Rare

Post-ictal state - None

EEG pattern - 3 cycles/second in all leads (generalized)


Complex partial seizures

Duration - minutes

Automatisms (motor activity) - Frequent (lip smacking)

Post-ictal state - Frequent

EEG pattern - Focal area of abnormal spikes and waves


GTC vs Syncope

1) Precipitating factor - None (seizure) vs emotional stress, valsalva (syncope)

2) Premonitory symptoms - None or vague (seizure) vs tunneling vision, lethargy, nausea, diaphoresis (syncope)

3) Posture at onset - Any posture (seizure) vs generally standing (syncope)

4) Transition to unconsciousness - immediate (seizure) vs gradual over seconds in vasodepressor form (syncope)

5) Duration of tonic and/or clonic movements - 30-60s (seizures) vs always less than 15s if present (syncope)

6) Facial appearance - cyanotic (seizure) vs pallid (syncope)

7) Post-event confusion/lethargy - minutes to hours (seizure) vs less than 5 minutes if present (syncope)

8) tongue biting - occasionally (seizure) vs rarely (syncope)

9) Incontinence - occasionally (seizure) vs sometimes (syncope)

10) Elevated CPK, myalgias - frequent (seizures) vs sometimes (syncope)


Phenytoin kinetics

zero order - rate is independent of reactant concentrations. Rate is constant in rate vs time graph


Phenytoin half life

24h, but this is dose-dependent

Effective level 10-20 mcg/ml


Phenytoin uses

1) GTC*

2) Partial


Phenytoin mechanism

Increasing Na channel inactivation


Phenytoin side effects

Ataxia, confusion, cerebellar degeneration, gum hyperplasia, LAD, osteomalacia, rash, SJS, SLE-like syndrome, induction of P450


Carbamazepine uses, mechanism and half life

1) Partial*

2) GTC*

3) Trigeminal neuralgia*

Mechanism - Increased Na channel inactivation

Thalf- 15h

Level 4-12


Carbamazepine side effects


Ataxia, vertigo, aplastic anemia, leukopenia, hepatotoxic, GI upset, SIADH, SJS

Heme stuff! Check CBC


Valproic Acid uses, mechanism, and half life

1) GTC

2) Partial

3) Myoclonic*

4) Atonic*

5) Bipolar

Mech - Increased Na channel inactivation and increased GABA concentration by blocking GABA transaminase

Half - 15h

Level 50-100


Valproic acid side effects

Ataxia, tremor, lethargy, hepatotoxic, thrombocytopenia, alopecia, weight gain, PCOS



Phenobarbital uses, mech, half life

1) GTC

2) Partial onset

Mech - Increased GABA A action

Half - 90h

Level 10-40

1st line in neonates!


Phenobarbital side effects

Sedation, depression, confusion, ataxia, induces P450

Toxicity is CNS depressant and too much inhibition of neurons


Ethosuxamide uses, mech, half life

1) Absence***

Mech - Blocks thalamic T type Ca channels

Half - 60h

Level 40-100


Ethosuxamide side effects


Ethosuxamide causes
GI distress
Itching and

Cytopenias, ataxia, lethargy


Gabapentin uses, mech, half

1) Partial

2) Peripheral neuropathy

3) Postherpetic neuralgia

Mech - Mainly inhibits high voltage activated Ca channels designed as GABA analog

half - 5-9h


Gabapentin side effects

Sedation, ataxia, GI



1) Partial
2) GTC

Blocks voltage gated Na channels

Side effects - SJS** (titrate slow - watch for it with initiation and with every adjustment), sedation, ataxia

Half is 25h (60h with valproate)



1) Partial
2) GTC
3) migraine prevention

Blocks Na channels, increases GABA action

Side effects - weight loss, sedation, metabolic acidosis, word finding issues, kidney stones



1) Partial
2) GTC

Acts at synaptic vesicle proteins

Side effects - behavioral disturbances. sedation


Etiologies of first time seizure


Vascular (stroke)
Infection (meningitis, encephalitis)
Trauma (TBIs, brain bleeds)
Autoimmune (cerebritis, Lupus)
Metabolic (glucose, shock, Ca, Na)
Ingestion/withdrawal (benzo, alcohol withdrawal)
Sych (pseudoseizure)