Epilepsy

Question 1

Define epilepsy

Define status epilepticus

Answer 1

**Epilepsy: **Recurrent tendency (minimum 2 episodes) to spontanous, intermittent, abnormal electrical activity in part of the brain, manifesting as seizures

Status epilepticus: State of seizure activity lasting for 30 min with no return to consciousness

Question 2

Define convulsions

Answer 2

Motor signs of electrical discharges

Question 3

Outline a typical seizure

Answer 3

1. Prodrome - hours/ days previous a ‘change’ is noticed
   
   • Aura - patient notices change
     
     • Strange feeling in the gut, deja vu, strange smells, flashing lights
     • Implies focal seizure from temporal lobe (normally)
2. Seizure occurs
3. Post-ictally
   
   • Headache, confusion, myalgia, sore tongue
   • Todd’s palsy - motor cortex seizure causing temp. weakness
   • Expressive dysphasia (frontal)/ Receptive aphasia (temporal)

Question 4

Outline the different seizure classifications

Answer 4

Partial seizures - focal onset

• Simple - awareness unimpaired, no post-ictal symptoms
• Complex - awareness impaired, aura & post-ictal symptoms common
• 2^ndary generalization - starts focal & spreads causing 2^ndary generalised seizure

**Generalized seizure **- throughout cortex, no localising features

• Absence (petit mal)- brief (<30s) pauses, then continues
• Tonic-clonic (grand mal)- loss of consciousness, limbs stiffen (tonic), then jerk (clonic), post-ictal confusion
• Myoclonic - sudden jerk of limb, face or trunk
• Atonic (akinetic) - sudden loss of muscle tone (no LOC)
• Infantile spasms

Question 5

What are the causes of epilepsy & seizures?

What are precipitating factors?

Answer 5

• Idiopathic (2/3, familial)
• **Structural **(1/3)
  
  • CVA
  • Space-occypying lesion
  • Head injury (particularly when LOC >30min + structural findings)

Others causes of seizures;

• Alcohol/ benzodiazepine **withdrawal **(& binging)
• Meningitis/ Encephalitis
• Drugs: phenothiazines, isoniazid, tricyclic antiDs
• Metabolic:
  
  • Hypoxia - O2 sats
  • ↑↓Na⁺- electrolytes
  • ​↑↓**Glucose **- blood glucose
  • ↓Ca²⁺ - blood calcium
  • Ureaemia - urine biochemistry
  • Liver/ kidney disease - LFTs/ U&Es

Precipitating factors;

• Sleep deprivation, alcohol & medications lower threshold
• Peak during ovulation/ 2nd half of cycle

Question 6

How do you investigate & diagnose epilepsy?

Answer 6

• Electroencephalograph (EEG)
  
  • When Hx suggests seizure is epileptic in origin
• Neuroimaging: MRI > CT
  
  • ​Structural abnormalities
    
    • Focal? Medication failure?
• Bloods
  
  • Hypoxia - O2 sats
  • ↑↓Na⁺ - electrolytes
  • ​↑↓Glucose - blood glucose
  • ↓Ca²⁺ - blood calcium
  • Ureaemia - urine biochemistry
  • Liver/ kidney disease - LFTs/ U&Es
• 12-lead ECG

Question 7

How would you localise a partial (focal) seizure?

Answer 7

• Temporal - bizzare
  
  • Automatisms - complex motor phenomena
  • Emotion - hippocampal areas
  • Smell/ tast - uncal areas
  • Receptive aphasia - Wernicke’s area
  • Delusional behaviour
• Frontal
  
  • Motor
  • ​Jasksonian march [distal limb to ipsilateral face]
  • Expressive Dysphasia - Broca’s area
  • Post-ictal Todd’s palsy
• Parietal
  
  • ​Sensory
• Occipital
  
  • ​Visual

Question 8

Outline the long term management of epilepsy?

Answer 8

Anti-Epileptic Drugs (AED)

• Absence - Sodium valproate (SV) (or Ethosuximide ⇒Lamotrigine)
• Generalized tonic-clinic - SV (⇒Lamotrigine)
• Myoclonic - SV (⇒Levetiracetam)
• Atonic - **SV **(⇒ Lamotrigine)
• Partial - Carbamazepine (⇒ sodium valproate or lamotrigine)
• Drug resistant: Levetiracetam, topiramate, zonisamide

+ supplementary Psychological interventions

Surgery…

Question 9

Outline the mechanism of action of Sodium Valproate

Answer 9

Anticonvulsant;

1. Blocks Na+ channels (weakly)
2. Inhibits GABA deactivators
3. Promotes GABA synthesis?

Question 10

Outline the mechanism of action of Lorazepam

Answer 10

Benzodiazepine

1. Increases GABA effect’s by binding to allosteric site of GABA receptor

Question 11

Outline the acute management of an epileptic seizure & status epilepticus

Answer 11

• 0-5min
  
  • Airway - protect, insert airway if possible
  • Breathing - high flow mask 10L/min
  • Circulation - IV access, 02 stats
    
    • Bloods
    • Lorazepam 4mg IV bolus (diluted 1:1 with sodium chloride/ water) (⇒ Diazepam 10mg IV/ 2min) - monitor O2 sats
  • Poor nutrition/ alcoholism
    
    • Parenteral thiamine as Pabrinex IV 100mL/ 30min/ 8hrly
• 5-10min
  
  • Repeat Lorazepam [max. 8mg]/ Diazepam [max. 30mg]
• 10-40min
  
  • Phenytoin IV with cardiac monitoring
  • Contact Neurology Registrar
• >40min
  
  • Contact consultant
  • MIU/ critical care
• Arrange other investigations (ie EEG)

Question 12

What are the differential diagnoses for seizures?

Answer 12

• Syncope!
  
  • Vasovagal
    
    • Reflexive anoxic seizures (asystole due to trigger [pain, fear])
    • Carotid sinus hypersensitivity
  • **Cardiac **- arrythmias & mechanical valves
  • Electrolyte abnormalities
    
    • ↑↓Na⁺
    • ​↑↓Glucose
    • ↓Ca²⁺
    • Ureaemia
  • Orthostatic hypotension
• Hyperventilation

Question 13

What implications does epilepsy have on driving?
What are the laws regarding it?

Answer 13

• Following a seizure you must stop driving, inform DVLA & motor insurance company
• Group 1 (car/ motorcycle)
  
  • Epileptic attack
    
    • Stop driving for 1 year after attack
    • If attack while sleeping must stop for 1 year also (unless for the past 3 years youve only had an attack while asleep)
    • Must comply with treatment & check-ups
  • First unprovoked seizure
    
    • 6 months off unless evidence suggests risk
• Group 2 (large goods)
  
  • For epileptics
    
    • 10 years preceeding license issue must have NO epileptic attacks & be on no medication
  • First unprovoked seizure
    
    • 5 years off driving unless evidence suggests risk

Question 14

What are complications of epilepsy?

Answer 14

• SUDEP
  
  • Sudden unexpected death in epilepsy (no identifiable cause)
  • 500 deaths each year
  • Risk increases with inc. freq. & severity of seizures
• Accidents (obviously)
• Depression & anxiety more prevalent
• Women with epilepsy: osteoporosis, osteomalacia, fractures

Question 15

Outline typical petit mal seizure

• Presentation
• Provocation
• Prognosis

Answer 15

Absence seizure;

• Child stops what they are doing, stares, then continues
• Provoked by hyperventilation
• 90% resolve by teens
  
  • ⇒ Grand mal (tonic-clonic) & Juvenile myoclonic epilepsy

Question 16

Outline Juvenile myoclonic epilepsy

• Age
• Typical presentation
• Prognosis
• Aetiology

Answer 16

Juvenile myoclonic epilepsy;

• Teen years
• Early morning sudden myoclonic jerks, esp. arms & shoulders
  
  • ⇒ Often later developing generalised tonic-clonic seizures
• May be inherited as autosomal dominant

Question 17

Outline Benign Rolandic epilepsy with centrotemporal spikes

• Other names
• Meaning of Rolandic
• Age & sex
• Typical presentation
• Prognosis
• EEG findings

Answer 17

Benign Rolandic epilepsy with centrotemporal spikes

• Benign Partial/ Childhood Epilepsy with centrotemporal spikes
• Seizure starts around Rolandic fissue (aka Central sulcus)
• 4-10yrs, boys>
• Nocturnal seizures with facial twitching & aphasia
  
  • +/- generalised tonic-clonic seizures
• Infrequent & outgrown.
• Centrotemporal spikes
  
  • Inter-ictal EEG characterised by large spikes over Rolandic area **of one hemisphere **(aka Central sulcus)

Question 18

Outline typical infantile spasms

• Age
• Typical presentation

Answer 18

Infantile spasms;

• Infants aged 4-8 months
• Clusters of myoclonic spasms when waking up

Question 19

Outline Dravet’s syndrome

• Typical presentation (definition)
• Onset
• Comorbitities
• Prognosis

Answer 19

Dravet’s syndrome;

1. Severe myoclonic epilepsy of infancy +
2. Recurrent a/febrile hemiclonic/generalised seizures, or status epilepticus

• Onset <15 months
• Developmental arrest/ regression
• Motality up to 15% by 20yrs

Question 20

Outline Lennox-Gastaut syndrome

• Typical presentation & definition
• Onset age
• Classifications

Answer 20

Lennox-Gestaut syndrome;

1. Mutliple types of epileptic seizures
   
   • Most commonly tonic-axial, atonic & absence
   • Drop attacks frequent & most dangerous
   • Often resistant to treatment
2. Slow spike-and-wave EEG
3. Psychomotor delay
4. Behavioural disorders
   
   • ​​Hyperactivity, aggressiveness, autistic ⇒ psychosis

• Onset <8yrs (peak 3-5)
  
  • 20% have infantile spasms with hypsarrhythmia
• Classification
  
  • Idiopathic (25%)
    
    • Normal psychomotor development prior to symptoms
    • No neuro-logical/radiological abnormalities found
  • Symptomatic (75%)
    
    • Due to diverse cerebral conditions usually generalised involving grey matter
    • ie Encephalitis, meningitis, tuberous sclerosis, malformations, lesions, injury & trauma

Question 21

Outline Panayiotopoulos syndrome

• Definition & typical presentation
• Age onset & prevelence
• EEG findings
• Common differentials

Answer 21

Panayiotopoulos syndrome;

• Multifocal autonomic childhood epileptic disorder
  
  • Prolonged seizures with autonomic symptoms & ictal vomiting
• Onset 3-6yrs, Common.
• EEG: shifting/ multiple foci + occipital dominance
• Often confused with occipital epilepsy & acute non-epileptic disorders