Epilepsy Flashcards
What is a seizure?
An abnormal discharge of electrical activity in the brain
What is epilepsy?
A tendency to recurrent, usually spontaneous, epileptic seizures
What are some factors that can contribute to epilepsy?
Genetic factors
Acquired brain conditions
Metabolic factors
Toxic factors
Environmental factors
Describe the aetiology of generalised epilepsy
Childhood - Adolescence
Usually have a genetic predisposition
What is an epileptic seizure?
An abnormal synchronisation of neuronal activity, usually excitatory with high frequency action potentials but can sometimes be predominantly inhibitory
What are some changes that occur in seizure?
- Cell numbers/types
- Connectivity
- Synaptic function
- Voltage-gated ion channel function
What us the usual length of a seizure?
Seconds to minutes
What are some ways in which seizures can be classified?
Location of onset
Awareness of seizure
Symptoms of seizure
How are seizures classified by location of onset?
Focal
Generalised
How are seizures classified by awareness?
Aware
Impaired
How are seizures classified by symptoms?
Motor
Sensory
Psychic
Describe the pathophysiology of focal seizure
1 area of the brain is structurally normal
This causes production of a seizure which stays in this area
How can a focal seizure generalise
The area of electrical activity may pass onto a pathway that runs throughout the brain, causing spread to other parts of the brain
What are the 3 main forms of focal seizure
Motor
Sensory
Psychic
What are the 5 main types of generalised seizure?
Absence
Myoclonic
Atonic
Tonic
Tonic-Clonic
Describe the pathophysiology of a generalised seizure
An abnormality occurs of a pathway that runs through the brain (Not an abnormality that spreads through the pathway), causing problems in many regions of the brain
Presentation - Absence seizure
Goes blank and unresponsive for a few seconds
Presentation - Myoclonic seizure
Sudden muscle jerks
Presentation - Atonic
Muscles suddenly relax and the person will fall over
Presentation - Tonic
Muscles go stiff and the person will fall
Presentation - tonic-clonic
Muscles stuffed and tighten rhythmically
What type of epilepsy is associated with hippocampal sclerosis
Temporal lobe epilepsy
What are some risk factors for juvenile myoclonic epilepsy?
Sleep deprivation
Flashing lights
How will juvenile myoclonic epilepsy present?
Early morning jerks
Generalised myoclonic (rhythmic muscle jerks) seizures
What are some symptoms of motor focal epilepsy?
Rhythmic jerking, posturing, head and eye deviation, other movements (eg cycling), automatisms (eg plucking), vocalisation
What are some symptoms of sensory focal epilepsy?
Somatosensory, olfactory, gustatory, visual, auditory dysfunction
What are some symptoms of psychic focal epilepsy?
Memories, déjà vu, jamais vu, depersonalisation, aphasia, complex visual hallucinations etc
What are some important history points in epilepsy?
What were they doing before, during and after the event, what did they look like (Ask witnesses), what type of movements were there
What test is always performed in suspected seizure?
ECG - Rule of prolonged QT syndrome
What are the uses of EEG in epilepsy?
Distinguish between non-convulsive status and encephalopathy
Otherwise very unreliable
What are some uses of CTb or MRIb in epilepsy?
Indicated in acute cases to rule out skull fracture, in cases of deteriorating GCS or head injury
What anti-E drugs are good for most seizure types?
Lamotrigine
Levetiracetam
Valproate
What are some anti-E medications used in focal seizures?
Carbamazepine
Gabapentin
Phenytoin
What anti-E drug may worsen myoclonic seizures
Carbamazepine
Drug - Absence seizures
Ethosuxamide
Sodium valproate
Drug - Myoclonic seizures
- Sodium valproate
- Levetiracetam
- Clonazepam
Drug - Tonic, atonic, generalised tonic-clonic
- Sodium valproate (1st line)
- Levetiracitam
- Lamotrigine
Describe the car driving rules for seizures (Non-epilepsy)
1st seizure = 6 months no car-driving
Describe the HGV driving rules for seizures (Non-epilepsy)
1st seizure = 5 years no HGV-driving
Describe the car driving rules for epilepsy
1 year no car-driving following last seizure
Describe the HVG driving rules for epilepsy?
10 years no HGV-driving following last seizure and no medication
What are some of the pre-synaptic targets for anti-epileptic drugs?
Voltage-gated Na+ channels (drives APs)
Voltage-gated K+ channels (Lowers neuronal excitation)
SV2A (Neurotransmitter release)
Voltage-gated Ca2+ channels (influx drives neurotransmitter release)
What anti-E medications target voltage-gated Na+ channels to reduce APs in the pre-synaptic neurones
Carbamazepine
Lamotrigine
Phenytoin
What anti-E medication targets voltage-gated K+ channels to reduce pre-synaptic neuronal excitation?
Retigabine
What anti-E medications target SV2A channels to reduce neurotransmitter release?
Levetiracetam
What anti-E medications target voltage-gated Ca2+ channels to reduce neurotransmitter release?
Pregabalin
Gabapentin
Ethosuxamide
What are some targets for anti-E medication in the GABA system?
GABA synthesis
GABA transporter (Removes GABA from synapse)
GABA transaminase (Degrades GABA)
GABA receptor (Reduces neuronal excitability)
What anti-E medication increases GABA synthesis?
Sodium valproate
What anti-E medication inhibits the GABA transporter?
Tiagabine
What anti-E medications inhibit GABA transaminase?
Vigabatrin
What anti-E medications increase GABA receptor presentation?
Benzodiazepines
Barbituates
Falbamate
Topiramate
Side effects of phenytoin
Gum hyperplasia
Hair growth
Side effects of sodium valproate
Weight gain
!!!!!!!!!!!!!!! Teratogenic !!!!!!!!!!!!!!!!!!!!!!!
Hair loss
Fatigue
Side effects of levetiracetam
Mood swings
Side effects of topiramate
Sedation
Dysphasia
Weight loss
What anti-E medications can alter the efficacy of morning-after pill
- Carbamazepine
- Oxycarbazepine
- Phenobarbitol
- Phenytoin
- Primidone
- Topiramate
