Neurology: Epilepsy Flashcards
What is Epilepsy?
- Common neurological condition characterised by recurrent seizures due to abnormal excessive or synchronous neuronal activity in the brain
- Epilepsy most commonly occurs in isolation although certain conditions have an association with epilepsy
- Cerebral palsy: 30% have epilepsy
- Tuberous sclerosis
- Mitochondrial disease
- 2/3rds of those afflicted achieve control through antiepileptic medication
What are common causes of Epilepsy?
- Childhood: Genetic, Febrile, Syndromes, Congenital brain disorders.
- Adolescence: Genetic, metabolic, toxins, trauma
- Adulthood: Brain lesions, Alcohol, Drugs.
- Elderly: Vascular, Degenerative disorders.
What are some differentials for Seizures?
- Febrile Convulsions
- Alcohol Withdrawals
- Psychogenic non-epileptic seizures
- Complex faints with cerebral hypoxia
- Hypoglycaemia
- Migraine
- Cerebrovascular episodes
- Transient Global Amnesia
- Other causes of nocturnal incontinence
What are some provoking factors for seizures?
- Photosensitivity -flashing lights
- Hyperventilation
- Sleep deprivation.
- Alcohol
- Menstruation - catamenial.
How are seizures classified?
Classify
- CAUSATION of discharge
- Idiopathic – usually genetic
- Symptomatic – usually brain lesion/metabolic
- Cryptogenic – presumed lesion
- LEVEL OF AWARENESS during a seizure (may affect safety during seizure)
- OTHER features
What are some types of seizures?
- Focal seizures
- Generalised Seizures
- Focal to bilateral seizure (previously termed secondary generalized seizures)
- Unknown onset
What are different variations of generalised seizures?
- Tonic-clonic (grand mal)
- Tonic
- Clonic
- Typical absence (petit mal)
- Myoclonic: brief, rapid muscle jerks
- Atonic
What are features of Focal Seizures?
- Focal seizures start in a specific area on one side of the brain and can be Simple or Complex.
- They can be further classfied by their level of awareness
- Focal aware (previously termed ‘simple partial’)
- Focal impaired awareness
- Awareness unknown
- Focal seizures can also be classified as being motor (e.g. Jacksonian march), non-motor (e.g. déjà vu, jamais vu;) or having other features such as aura
What are generalised seizures?
- Generalised Seizures engage or involve networks on both sides of the brain at the onset. Consciousness lost immediately.
What are symptoms and signs of generalised seizures?
- Biting of the tongue
- Experience of incontinence of urine
- Blackout and collapse
- Postictal phase of drowsiness and tiredness for around 15 minutes following the seizure.
What is focal to bilateral seizures/secondary generalized seizures?
Starts on specific area of one side of the brain before spreading to both lobes
What are some special forms of epilepsy in children?
- Infantile spasms (West’s syndrome)
- Lennox-Gastaut syndrome
- Benign Rolandic Epilepsy
- Juvenile myoclonic epilepsy (Janz syndrome)
- Typical absence seizures (petit mal)
- Neonatal period seizures
What are features of West’s syndrome?
Symptoms and Signs
- Brief spasms beginning the first few months of life
- Flexion of head, trunk, limbs leading to extension of arms (Salaam attack). Last 1-2 secs and repeat up to 50 times
- Progressive mental handicap
- EEG shows hypsarrhythmia
- Usually secondary to serious neurological abnormality (e.g. birth asphyxia, encephalitis, tuberous sclerosis) or may be cryptogenic
Management: Vigabatrin/Steroids
- Poor prognosis
What are the characteristics of Lennox-Gastaut syndrome?
May be extension of infantile spasms (50% have history) with onset typically at 1-5 years.
- Symptoms/Signs: Atypical absences, falls and jerks, 90% moderate-severe handicap
- EEG: slow spike
- Management: Ketogenic diet may help
What is Benign Rolandic Epilepsy?
- Paraesthesia usually on waking up
- Most common in childhood and occur more in males
What are Juvenile Myoclonic Epilepsy?
- Typical onset in teens commonly girls
- Infrequent generalized seizure often in morning
- Daytime absences
- Sudden, shock like myoclonic seizure
- Usually a good response to sodium valproate
What are characteristics and investigations of abscence seizures?
- Characteristics: Onset 4-8 yrs and has a good prognosis. 90-95% become seizure free in adolescence
- Investigations: EEG show 3Hz symmetrical generalized waves
How can neonatal period seizures be managed?
-
Neonatal period seizures types
- Pyridoxine dependency (AR, IV B6)
- Benign familial neonatal seizures (AD)
- Benign neonatal convulsions (5th day)
-
Causes
- Hypoglycaemia
- Meningitis
- Head trauma
- Management: Try vitamin B6
What are features of tonic-clonic seizures?
Tonic phase → Clonic phase → Post Ictal phase
- Aura
- Cry
- Tongue biting
- Incontinence
- Unwell after with Headaches, Confusion and Muscles aches
What are symptoms of Complex Partial Seizures?
- Aura – smell, taste, déjà vu
- Absence
- Automatism
- Prolonged
- Nausea
- Headache
- No convulsion
What are symptoms and signs of abscence seizures?
- Seizure duration short duration (few-30 secs)
- Quick recovery
- Occur in children
- Multiple attacks during the day
- Sudden onset w/o aura
- Staring only
- Patient may not be aware
- Speech arrest
- 3p/s spike and wave on EEG
What are investigations for seizures?
- Electroencephalogram (EEG)
- MRI - neuroimaging
- ECG
- Bloods e.g. electrolytes, blood glucose.
How are seizures managed?
Single Seizure
- Confirm diagnosis and establish cause.
- Advise on how to avoid future attacks
- Discuss risk factors: up to 50% risk of recurrence.
Two or more attacks
- Diagnosis now epilepsy and there is a higher risk of more attacks.
- Same consideration of risk factors.
- Most neurologist start anti-epileptics following second epileptic seizure as general rule
When would it be considered appropriate to start antiepileptics following the first seizures?
- The patient has a neurological deficit
- Brain imaging shows a structural abnormality
- The EEG shows unequivocal epileptic activity
- The patient or their family or carers consider the risk of having a further seizure unacceptable
What are general mechanism of actions for antiepileptic drugs?
-
Modulation of Neurotransmitters
- Enhance GABA
- Suppress Glutamate.
-
Effect on Cell Membrane
- Action of Na+ / K+ channels
- Effect on Na/Ca dependent action potentials.
- Direct effect on neuronal firing.
What are other factors need consideration in the management of epilepsy?
- Driving: Patients cannot drive for 6 months following 1st seizure. Patients with established epilepsy, must be seizure/fit free for 12 months to drive
- Other Medications: Antiepileptics can induce/inhibit the P450 system to vary the metabolism of other medications
- Women Wishing To Be Pregnant: Antiepileptics can be teratogenic (e.g. sodium valproate). Women need neurologist’s advice prior to becoming pregnant regarding the most suitable antiepileptic medication. Breastfeeding can be safe (exception of barbiturates).
- Women Taking Contraception: Contraceptives can vary the effect of antiepileptic medications and antiepileptic medications can also vary the effect of contraceptives.
What are typical drugs for Generalised tonic-clonic seizures?
- 1st line: Sodium valproate
- 2nd line: Lamotrigine, carbamazepine
What are typical drugs for abscence seizures?
Sodium Valproate or Ethosuximide
- Sodium valproate particularly effective if co-existent tonic-clonic seizures in primary generalised epilepsy
- Should not prescribe Carbamazepine as may exacerbate absence seizures
What are typical drugs for myoclonic seizures?
1st line: Sodium valproate
2nd line: Clonazepam, Lamotrigine
- Should not prescribe carbamazepine as may exacerbate myoclonic seizures
What are typical drugs for focal seizures?
1st line: Carbamazepine or Lamotrigine
2nd line: Levetiracetam, Oxcarbazepine or Sodium valproate
How are seizures acutely managed?
- Rescue medication if seizures don’t terminate after 5-10 minutes
- Benzodiazepines such as diazepam typically may be administered rectally or intranasally/under the tongue
- If status epilepticus occurs then further benzodiazepines, infusions of antiepileptics or even use of general anaesthetics
What is Status Epilepticus?
Status epilepticus when seizures occur >5mins continuously or 2+ seizures without full recovery in 30 minutes.
Recurrent attacks occur without regaining consciousness.
What are the steps in the management of Status Epilepticus?
- A to E
- Medical Management
What are the features of the A to E management of Status Epilepticus?
- Airway: Crucial in the scenario. Can be difficult to assess and if compromised need arrest call and ITU/Anaesthetist
- Breathing: Can be quite difficult. SATs are quite unreliable and early oxygen suggested
- Circulation: Attempt to obtain an accurate HR/BP. Assessment crucial and needed quickly. ABG needed if possible
- Disability: No GCS is possible, but glucose must be accessed. Hypoglycaemia can cause seizures.
- Everything else: Medications, Other substances, Vomit or soiling
What are the steps for medically managing Status Epilepticus?
-
IV Lorazepam – 4mg
- If no Access
- 10mg IM midazolam or 10mg PR diazepam
- If no Access
- After 10-15 mins another bolus of IV lorazepam 4mg
-
Phenytoin infusion needed if 2 boluses of IV lorazepam do not work
- Dose: 20mg/kg - max rate 50mg/min
- After this, call ITU and rapid sequence induction-thiopental etc
What are the typical pattern seen on ABG in status epilepticus?
ABG – Typical pattern
- Acidotic
- Lactate high
- Glucose okay
- Oxygen low but not quite dangerous
What are bloods taken following Status Epilepticus?
- FBC
- U&E/LFT/Bone profile
- CRP/Culture if suspecting infective cause
- Glucose
- Clotting screen
- Toxicology screen
- Viral PCR
