TLOC, Epilepsy and EEG Flashcards
(124 cards)
Seizure definition?
the clinical manifestation during abnormal excessive excitation and synchronisation of a population of cortical neurons
Epilepsy definition?
a tendency to recurrent seizures >24hrs apart which are not provoked by systemic or acute neurologic insults
Describe what an EEG is
records cortical electrical activity, usually from the scalp, most important neurophysiological study for diagnosis, prognosis and treatment of epilepsy, electrodes are attached in in the 10/20 system
Which side of EEG is odd numbers and which even?
Left - Odd
Right - Even
Describe the 1981 classification of seizures
Partial: Simple, complex and secondary generalised
Generalised: absence, myoclonic, atonia, tonic, tonic-clonic
Describe absence seizures
- Brief staring spells with impaired awareness
- Hypoventilation is a provoking method
- 3-20 seconds
- Sudden onset and sudden resolution,
- Typically in children, normal development and intelligence
- Typically resolved by 18 years
- Generalised 3 Hz spike waves discharge
Describe myoclonic seizures
- Brief shock-like jerk of muscles or group of muscles,
- Not all myoclonus is epileptic e.g. when falling asleep
- 4-6Hz polycyclic waves (more than one spike)
- Can be subtle or dramatic
Describe tonic seizures
- Symmetric tonic muscle contraction of extremities with tonic flexion of waist and neck
- Distinct to tonic-clonic,
- 2-20 seconds
- EEG – slow wave, attenuation (stopping) and then rapid waves
Describe atonic seizures
- Sudden loss of muscle tone,
- Floppy and fall on floor,
- Milder version just head,
- Similar EEG to tonic seizures
Describe tonic-clonic seizures
- Association with loss of consciousness and post ictal confusion/lethargy,
- Stiffening of all muscles (also larynx so can scream), followed by fast low amplitude jerking and then slow high amplitude jerking
- 30-120 seconds
- Afterwards patients very confused and not aware of where they are
- EEG- sharp activity everywhere, a lot of muscle interference
Describe a focal without impaired awareness seizure
- Aura
- Patient is aware
- Diverse range as due to where in the brain the seizure is, if in the visual cortex you can get visual aura often large coloured circles, motor = jerking, can be more subtle e.g. temporal = dream like experience
- The aura will always be the same for the patient
Desribe a focal with impaired awareness seizure
- Arise from one part of brain but patient loses awareness,
- Manifestations depend on the area affected
- Autonomisms – semi-purposeful movements
Describe a focal evolving to bilarteral tonic-clonic seizure
- Start in one place e.g. aura etc. and then spread to the whole brain
- Generalised tonic-clonic phase looks the same as primary tonic-clonic phase
- Typically 1-3 mins
- Can have Todd’s paresis – weakness on the opposite side of brain to where the seizure started
What sort of factors can be used to group epilepsy patients into syndromes
- Seizure type
- Age of onset
- Natural history/prognosis
- EEG patterns
- Aetiology/genetics
- Response to treatment
Describe temporal lobe epilepsy syndrome
- Onset at any age
- EEG shows temporal lobe epileptiform discharges
- Simple partial, complex partial and secondary generalised tonic clonic seizures can all be had
- May be symptomatic or cryptogenic
- Inter-ictal EEG shows sharp and slow waves that are abnormal
- 2 sharp waves pointing to each other – point to focus
- Can be due to hippocampal sclerosis
Describe juvenile myoclonic epilepsy syndrome
- Juvenile onset
- Myoclonic seizures, GTCS, and absences
- Seizures have morning predominance, exacerbated by sleep deprivation and alcohol
- Idiopathic
- EEG shows generalised spike or polyspike/wave discharges
- Often photosensitive (30-40%)
Describe West epilepsy syndrome
- Paediatric syndrome
- Can be symptomatic or cryptogenic
- Infantile onset
- Spasms
- Hypsarrythmic EEG – sharp waves and slow waves everywhere which are chaotic, followed by attenuation of EEG (flexion of the body and extension of limbs)
What did the 2010 classicifcation of epilepsy seizures introduce?
Introduces idea of networks:
Focalised – started somewhere in the brain which triggered one localised hemisphere network
Generalised – starts somewhere but rapidly involves bilateral network in both hemispheres
What is the criteria for mild TBI?
- Loss of consciousness <30 min
- No skull fracture
- PTA (Post trauma amnesia) <1 day
What is the criteria for moderate TBI?
- LOC >30mins and <24 hours
- With or without skull fracture
- PTA >1 <7 days
What are the criteria for severe TBI?
- LOC > 24 hours
- With contusion, hematoma, or skull
- PTA > 7 days
What is the classification for immediate seizures following TBI
within 24 hrs
What is the classification for early seziures following a TBI?
seizure within a week, skull fractures or intracranial bleed increases chance of early seizures, early seizures are an indicator for PTE
What is the classification for late seizures following TBI?
afer a week post trauma, diagnosis for PTE