Epilepsy Flashcards
Define epileptic seizure
A transient event experienced by a subject as a result of a synchronous and excessive discharge of cerebral neurones
Define epilepsy
The continuous tendency to have epileptic seizures
- arises secondary to pathological process
Define prodrome
A change in behaviour noticed by patient or others which may precede the seizure
- not part of seizure itself
- may last hours/days
Define Aura
A strange feeling in the gut, an experience of deja-vu or strange smells/flashing lights
- patient is aware
- may precede other manifestations
- implies a partial seizure quite often
Define post-ictal period?
Period following seizure where symptoms may occur
Describe post-ictal Sx that may occur
Headache, confusion, myalgia, sore tongue
Temporary weakness after focal seziure in motor cortex
Dysphasia - following temporal lobe focal seizure
Name two features in the history that a typical of epileptic seizures
Tongue biting
Slow recovery
Describe the two general classification categories of epileptic seizures
Generalised seizures
Partial seizures (focal seizures)
Name six types of generalised seizure
Absence seizures
Tonic-clonic seizures
Myoclonic
Tonic seizures
Atonic seizures (akinetic seizures)
Infantile spasms
At what stage of life do absence seizures usually develop?
Childhood
Describe an absence seizure
Loss of awareness and vacant expression for less than 10 seconds before returning abruptly to normal, continuing as if nothing has happened
Describe a tonic-clonic seizure
Often no prodrome but may have aura if secondary generalised
Tonic clonic phase
- initial tonic stiffening followed by clonic phase with synchrounous jerking of the limbs which reduce in freq over about 2 mins until convulsion stops
- eyes remain open, often tongue biten
- may be incontinence of urine or faeces
Post-ictal phase
- Period of flaccid unresponsiveness -> gradual return of awareness
- confusion and drowsiness lasting a while
- headache
Describe myoclonic seizures
Take the form of momentary brief contractions of a muscle or muscle groups
- sudden involuntary twitch of a finger or hand
Describe atonic seizures
Sudden loss of muscle tone causing a fall (no LoC)
What is commonly associated with infantile spasms?
Tuberous sclerosis
- genetic disease that causes beningn tumours to grown in the brain and other vital organs
What is a primary generalised seizure?
Simultaneous involvement of both hemispheres - always associated with LoC and LoA
What is partial seizure?
Electrical discharge constricted to a limited part of cortex of one cerebral hemisphere
Describe a simple partial seizure
Partial seizure without loss of awareness
- e.g. one limb jerking
Originates in motor cortex, can spread to involve the entire hemisphere
Describe a complex partial seizure
Partial seizure with loss of awareness
- usually arise from temporal lobe (60%) or frontal lobe
Post-ictal confusion is common with temporal lobe seizures
- rapid recovery in frontal lobe
What is a secondary generalisation seizure?
Electrical disturbance from partial seizures spreads widely causing a generalised seizure
- typically convulsive
What are the features of temporal lobe seizures?
Automatisms - complex motor phenomena with impaired awareness and no afterward recollection
Abdominal rising sensation or pain
Dysphasia
Memory phenomena
Emotional disturbance - due to hippocampal involvement
Uncal involvement - hallucinations of taste or smell
Delusional behaviours
Give an example of automatisms involved in temporal lobe epilepsy
Primitive oral - lip-smacking, chewing
Manual movements - fumbling, fidling, grabbing
Complex actions - singing, kissing,…
What are the features of frontal lobe seizures?
Motor features - posturing, versive movements of head and eyes
Jacksonian march
Motor arrest
Subtle behavioural disturbance
Dysphasia or speech arrest
Post-ictal Todd’s palsy (motor weakness)
What are the features of occipital lobe seizures?
Visual phenomena - spots, lines, flashes
What are the features of parietal lobe seizures?
Sensory disturbance - tingling, numbness, pain (rare)
Motor Sx - due to spread to the pre central gyrus
What are the differential diagnosis of epilepsy?
Syncope Non-epileptic attacks Panic attacks Sleep disorders - prasomnias or narcolepsy Migraine TIA Hypoglycaemia
What is the main aetiology of seizures?
Idiopathic = 2/3 of all seizures
Give examples of structural causes of epilepsy
Cortical scarring - head injury years prior to onset
Developmental
- cortical dysgenesis
- dysembryoblastic neuroepithelial tumour
Space-occupying lesions - malignancy
Stroke
Hippocampal sclerosis - after a febrile convulsion
Vascular malformations
Give examples of other epileptic causes of seizures
Tuberous sclerosis
Sarcoidosis
SLE
Polyarteritis nodosa
Give examples of non-epileptic causes of seizures
Trauma
Stroke
Haemorrhage
Raised ICP
Alcohol/Benzodiazepines
Metabolic disturbance
Liver disease
Infections
Raised temperature
Drugs - tricyclics, cocaine, tramadol, theophylline
Pseudoseizures
Ix for epilepsy
ECG - rule out cardiac cause
EEG - useful in context of suspected seizure, may localise seizure
- video EEG =gold standard
Cerebral Imaging
- may find a cause of the epilepsy
- important for treatment and prognosis
What are the most likely epilepsy causes in infants?
Developmental malformations
Perinatal injuries
Infections
What are the most likely epilepsy causes in children/adolescents?
Idiopathic generalised epilepsy
What are the most likely epilepsy causes in young adult onset?
Idiopathic generalised epilepsy
Various - head injury, alcohol, vascular malformations, hippocampal sclerosis
What are the most likely epilepsy causes in 30-50 yrs old?
Brain tumours
What are the most likely epilepsy causes in over 50s?
Cerebrovascular disease
Mass lesions such as neoplasms
Name some specific syndromes related to idiopathic generalised epilepsy
Juvenile Myoclonic Epilepsy
Childhood absence epilepsy
Describe hippocampal sclerosis
Damage and scarring of the hippocampus and surrounding cortex
- main pathological substrate of causing temporal lobe epilepsy
- main cause of localisation-related epilepsy
Usually visible on MRI
One of the most common causes of refractory epilepsy, in which may indicate surgical resection of damaged temporal lobe
What is the main risk factors of developing hippocampal sclerosis?
Childhood febrile convulsions
Give three examples of genetic/developmental brain disorders that cause can epilepsy?
Neuronal migration defects during brain development
Dysplastic areas of cerebral cortex
Hamartomas (benign local malformation resmbling neoplasm)
What is a major cause of seizures in countries India and South American countries?
Neurocyticercosis
- since pork tapeworm is endemic
How can alcohol cause seizures?
Chronic alcohol use
- during heavy dirnking seassion
- period of withdrawal
Which metabolic abnormalities can cause seizures?
Hypoglycaemia
Hypocalcaemia
Hyponatraemia
Acute hypoxia
Uraemia, hepatic encephalopathy
Porphyria (abnormal haemoglobin metabolism)
What is the first line treatment for GTC seizures?
Sodium valproate or Lamotrigine
What is the first line treatment for absence seizures?
Sodium valproate, Lamotrigine or Ethosuximide
What is the first line treatment for GTC seizures?
Sodium valproate or Lamotrigine
- avoid carbamazepine
What is the first line treatment for partial seizures?
Carbamazepine
Define Status epilepticus
Seizure(s) lasting for 30 mins without regaining consciousness in between
What is the mortality of status epilepticus?
20%
Describe the treatment of status epilepticus
Treat if seizure lasting longer than 5 mins
General measure
- A,B,C,D,E
- IV access
- Administer O2
- Check U+Es, Ca, Mg, ABGs, ECG +/- antiepileptic drug levels
- IV glucose +/- thiamine
Specific measures:
If early then - IV Lorazepam 4mg every ten mins (or diazepam, buccal midazolam)
If established then - IV phenytoin 15mg/kg at 50mg/min and monitor obs
If refractory - transfer to ITU, continue same treatment
- look for cause
What does Non-convulsive status epilepticus usally respond well to?
Benzodiazepines
What is SUDEP?
Sudden unexplained death in epilepsy
