Neuro: Epilepsy and its mimics Flashcards
What is epilepsy?
Umbrella term for a condition where there is a tendancy to have seizures
Investigations used to investigate epilepsy?
Electroencephalogram (EEG) - can show typical patterns in different forms of epilepsy and support the diagnosis
MRI brain - can be used to visulaise the structure of the brain -diagnose structural problems that may be associated with seizures and other pathology such as tumours
Other to exclude alt pathology e.g. ECG
FBC, electrolyte panel
Types of seizures?
Generalised Tonic-Clonic Seizures
Focal Seizures
Absence Sezieures
Atonic Seizures
Myoclonic Seizures
Infantile spasms
Features of Generalised Tonic-Clonic Seizures
Clonic tonic myoclonus
Loss of conciousness
Tonic phase - muscle tensing, typically before clonic phase
Clonic phase - muscle jerking episodes
May be associated with tongue biting, incontinence, groaning and irregular breathing
Prolonged post-ictal period follows seizure
What is meant by post-itcal period?
Period of confusion, drowsieness, feelings of irritability or depression, following a seizure
Management of tonic-clonic seizures?
First line: sodium valproate
Second line: Lamotrigine or carbamazepine
Where do focal seizures start?
In the temporal lobes
What do focal seizures effect?
Hearing
Speech
Memory
Emotions
How might a focal seizure present?
Hallucinations
Memory flashbacks
Deja vu
Doing strange things on autopilot
Treatment of focal seizures?
‘Reverse’ of tonic clonic seizures
First line: carbamazepine or lamotrigine
Second line: sodium valproate or levetiracetam
What are absence seizures?
Typically happen in children
Patient becomes blank, stares into space and the abruptly returns to normal
Patients are unaware of their surroundings and won’t respond
These typicall only last 10-20 seconds
Over 90% of patients will see resolution with age
Treatment of absence seizures?
Sodium valproate or ethosuximide
What is an atonic seziure?
'’Drop attacks’’
Brief lapses in muscle tone
Usual under 3 minuites
Typcially begin in childhood
What syndrome may atonic seziures be indicative of?
Lennox-Gastaut syndrome
Management of atonic seizures?
First line: sodium valproate
Second line: lamotrigine
What are myoclonic seizures?
Sudden brief muscle contractions (sudden ‘jump’)
Patient remains awake during the episodes
Occur in various forms of epilepsy but typically happen in children as part of juvenile myoclonic epilepsy
Management of myoclonic seizures
First line: sodium valproate
Other options: lamotrigine, levetiracetam or topiramate
What is West syndrome?
Rare disorder starting in infancy at around 6 months of age
Characterized by clusters of full body spasms
Poor prognosis 1/3 life expectency <25 yrs
1/3 pts seizure free by 25
Also known as Infantile spasms
First line treaments of West syndrome
Prednisolone
Vigabatrin
What is status epilepticus?
Medical emergency
Seizures lasting more than 5 mins OR
2+ seizures without full recovery within 30 mins time frame
How is status epilepticus managed in hospital?
Secure airway
High conc O2
Assess cardiac and respiratory function
Check pupil and GLUCOSE - hypoglycemia can cause seziures - easily corrected
Check CBG
IV access
IV lorazepams 4mg, repat after 10 mins if continues
If seziures persist IV: phenobarbitial or phenytoin
Medical options to treat status epilepticus in the community or when IV access not obtainable?
Buccal midazolam
Rectal diazepam 10mg
IM midazolam 10mg
Focal seizures originating from what part of the brain could cause automatisms?
Temporal lobe
Stages of a seizure
Beginning phase (prodrome)
You may notice mood changes or an ‘aura’ which tells you a seizure is coming soon
Middle phase (ictal)
This is when intense electrical activity happens in the brain and symptoms of seizures occur
Ending phase (postictal)
This is the recovery stage, where you experience the aftereffects of having a seizures, such as tiredness, frustration, sickness and confusion
Exhibitory activity in the brain?
Glutamate + NMDA Receptor
Inhibitory activity in the brain?
GABA and GABAa Receptor
Pathophysiology is seizures
■ A seizure is the clinical manifestation of abnormal and excessive excitation and
synchronisation of a group of neurones within the brain
■ Therefore a loss of inhibitory (GABA mediated) signals
■ Or too strong an excitatory (NMDA/Glutamate) one
■ This imbalance can happen in any point in the brain, and local changes can lead to
generalised effects
What is the pharmacological treatment of status epilepticus?
A-E and if hypoglcemic - glucose infusion - if not
Follow emergency management plan, if unknown or do not have one:
Full dose of benzodiazepine (IV lorazepam 4mg)
Five to ten minutes after initial dose if not responded: 2nd full dose benzodiazepine (IV lorazepam 4mg)
If no response to two full doses of first line: 2nd line anti epileptic phenytoin (20mg/kg max rate 50mg/min), levetiracetam (may be quickest), sodium valproate
If convulsive status epilepticus does not respond to the second-line treatment options tried, consider the following third-line options under expert guidance:
phenobarbital or
general anaesthesia
How do benzodiazepines manage status epilepticus?
GABAa agonists: increase Cl- conductance therefore membrane resting potential is more negative so less likely to fire and stop seizure activity
Benzodiazepine options for status epilepticus?
Intravenous lorazepam
Diazepam rectally
Buccal or intranasal, midazolam
What is status epilepticus?
This condition is a medical emergency. It is defined as a single seizure lasting more than 30 minutes or recurrent without regaining consciousness. The risk of permanent brain damage increases the longer the condition persists. Status can occur in patients with pre-existing epilepsy, but may be the presenting feature of new intracranial pathology.
Which AEDs are suitable for what seizure types?
Lamotrigine, levetiracetam and valproate are good for all seizure types.
Carbamazepine, gabapentin and phenytoin are better for focal (including secondary generalised)
seizures.
Ethosuximide is the drug of choice for absence seizures.
Carbamazepine may worsen myoclonic seizures.
Presentation of complex partial seizure
Clues to the diagnosis include auras of altered smell and a sense of fear, oro-facial automatisms and altered level of awareness.
Where to complex partial seizures typically arise from?
Temporal lobe (rarely frontal lobe)
When is EEG not a useful test in a patient who has suffered a possible seizure?
EEG is not a useful test following a single episode of altered awareness – it lacks specificity and sensitivity (although it is useful for classifying epilepsy and prognosticating single seizure).
What is Juvenile myoclonic epilepsy (JME)?
A form of idiopathic generalized epilepsy.
It is a common syndrome of tonic-clonic seizures and myoclonic jerks, and sometimes absences, which begins in childhood or adolescence and often persists into adulthood. It has a genetic predisposition.
Characterized by morning myoclonus (tremors or ‘jitteriness’)