Seizure
Clinical manifestation of an abnormal, excessive excitation/synchronization of a population of cortical neurons
Epilepsy
Disease of brain defined by any following conditions:
- Two unprovoked seizures occurring >24 hours apart
- One unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures occurring over next 10 years
- Diagnosis of an epilepsy syndrome
Seizure Epidemiology
- Approximately 10% of Americans will have 1+ seizures in their lifetime
- 6mo-6 years: febrile seizure (4%)
- Other: acute symptomatic seizure (3.6%)
- Most prevalent among women at childbearing age and among Navajo
Seizure Pathophysiology
Major Neurotransmitters/modulators:
- Excitatory NT: Glutamate
- Inhibitory NT: GABA
- Neuromodulators: ACh, DA, 5HT, histamine
Excitatory and Inhibitory Synapses
Inhibition
- Increase Cl- current inward
- Neurotransmitter: GABA
Excitation
- Increase Na+, Ca++ current inward
- Neurotransmitter: Glutamate
Hyperexcitability causes seizure
Seizure Causes
- Idiopathic/genetic
- Cryptogenic - unknown cause
- Neurodegenerative disorders: Alzheimer
- Electrolytes abnormality
- Traumatic brain injury
- Brain tumor
- Brain surgery
Seizure Triggers
- Medications: stimulants, GABA inhibitors, antibiotics
- Menstrual cycles
- Anxiety
- Sleep deprivation
Epilepsy Diagnosis
- Patient history: onset, family history, etiology, precipitating factors
- Signs/symptoms: frequency, duration, description, post-ictal symptom (HA, fatigue, etc.)
- Genetic Tests: gene mutation
- Medication history: medications tried, worked/didn’t work, AE
- Utilization of EEG and radiology for structural abnormalities
Partial Seizure
- Onset in one part of brain
- Localization-related or focal seizures
- May last few minutes
- With or without impairment of consciousness/awareness
Secondary Generalized Seizures
- Followed by a focal seizure
- Involves both cerebral hemispheres
- With or without motor symptoms
Generalized Seizures
Occurs in both cerebral hemispheres
Absence Seizures
- Type of generalized seizure
- Brief staring spells (3-20 sec)
- Sudden onset and resolution
Myoclonic Seizure
- Type of generalized seizure
- Brief, shock-like jerk of a muscle/muscle group
Atonic Seizure
- Type of generalized seizure
- Sudden loss of postural tone
Tonic Seizures
- Type of generalized seizure
- Symmetric, tonic muscle contraction of extremities with tonic flexion of waist and neck
Tonic-Clonic Seizures
- Type of generalized seizure
- Tonic and clonic phases
- Tonic: stiffening and fall
- Clonic: rhythmic extremity jerking
Epilepsy Syndromes
Group patients that have similar:
- Seizure type
- Age of onset
- Natural history/prognosis
- EEG patterns
- Genetics
- Response to treatment
Antiepileptic Drug Goal
- Target organ: Brain
- Wanted effects: Seizure control
- Unwanted effects: Toxicity and adverse reactions
Treatment Goals
- Ultimate: Seizure-free (life-long)
- Preferable: well-controlled seizure status with minimal AE
- Medications: AEDs
- Devices: VNS, DBS, etc.
AEDs + Pregnancy
- All pregnancy category C or D
- Birth defects are possible if taking while pregnant
- May possibly effect IQ
- Need special care before, during, and after pregnancy
Contraception + Epilepsy
- Use low-estrogen OC (<50 mcg), seizure trigger
- Use back up contraception since CYP inducing AEDs may reduce OC effectiveness
Pregnancy + Folate
- Folic supplementation recommended before and during pregnancy
- Try to avoid valproic acid
- Can use if other medications are not effective or are unacceptable to treat (NOT CI)
Catamenial Epilepsy
- Cyclical increase in seizure around time of menses or certain phases of menstrual cycle
- Estrogen: Pro-convulsant
- Progesterone: Anti-convulsant
- Treatment agents: Progesterone, topiramate, zonisamide, acetazoramide, clobazam
Seizure Nonpharm
- Surgery
- Implant devices: VNS, DBS, RNS (monitor and treats seizures)
- Diet: ketogenic diet (high fat) recommended when multiple drugs haven’t worked, Atkins Diet
