Seizure Disorders Flashcards
What do you want to ask in the LOC history?
- Ask if they were well up until the event i.e. infection, dehydration, sleep deprivation, drug us (overtiredness can trigger seizures in those suspectible)
- What were they doing at the time? Sitting/standing/lying/on assuming upright posture? Postural change - vasovagal syncope
- Any warning prior to event e.g. lightheadedness, nausea, sweating indicate pre-syncope. Unexplained smell, deja-vu, focal muscle jerking/twitching could indicate seizure
- First memory on recovery - after syncope recover quick, after epileptic seizures may remember nothing until admission
- Pain, injuries, tongue biting, urinary/faecal incontinence (bilateral tongue biting common in epilepsy)
- Any previous similar events - find out if this is first attack
- Any neurological symptoms in past
What questions do you want to ask the eyewitness in a history of LOC?
- Any warning - focal twitching, forced head turn, eye deviation or blank staring prior to blackout - syncope would be person who looks pale/sweaty, complain of feeling nauseated/lightheaded before
- Did they fall stiffly or floppily - generalised seizures have a tonic phase usually
- Was there any shaking, what did it look like? - tonic clonic seizures gradually reduce in frequency and amplitude. Syncope causes myoclonic jerks
- Cyanosis - in GTCS, due to involuntary muscle contraction, normal breathing is impossible so cyanosis is common
- Duration of LOC - syncope <1 min, GTCS 1-5mins
- Duration of an shaking - generalised seizures <5 mins, longer could mean status epilepticus or NEAD
- Condition on recovery/speed of recovery - after faint rapid recovery, after seizure may appear drowsy >/=15 mins, prolonged unresponsiveness in NEAD
What are other questions to cover in history suspecting epilepsy?
- Birth hx: prematurity, difficult delivery (forceps), postnatal difficulties (e.g. hypoxia, jaundice)
- Childhood milestones or developmental delay
- Seizures in childhood/infancy
- Significant head injuries
- Any hx of CNS infection: meningitis, encephalitis, abscess etc
- FH of epilepsy
- Medications (some can lower seizure thresholds)
- Recreational drugs/alcohol
What investigations should be done for a GTCS?
- Vital signs, O2, BM
- ECG
- Neurological exam
- Bloods - hyponatraemia, hypocalcaemia
- Will need CT scan eventually to exclude acute pathology
- EEG - rarely helpful immediately
What is a partial (focal) seizure?
When abnormal uncoordinated electrical discharges which constitute a seizure are confined to one area of the brain.
What is a complex seizure?
Awareness impaired during event (though patient may not lose consciousness completely and may have partial recollection of event after).
What is a simple partial seizure?
Could be uncontrollable twitching of face and arm but patient is fully aware and may be able to communicate normally throughout event. Partial seizures can then spread to develop into secondary GTCS (patient loses consciousness completely and displays features of GTCS).
What is the function of the temporal lobe?
- Primary auditory cortex
- Memory
- Limbic system (affective/emotional parts)
What are the symptoms of temporal lobe seizures?
- Memory disturbances like deja vu or Jamais vu
- Olfactory and auditory hallucinations
- Feeling of rising epigastric sensation
- Emotional disturbance e.g. sudden terror, panic, anger or elation and derealisation, feeling of impending doom
- Dysphasia
- Bizarre associations/delusional behaviour
- Automatism - phenomenon of doing an act whilst unconscious or grossly impaired conscious e.g. plucking at ones clothes
- Automatisms: primitive oral (lip smacking, chewing, swallowing) or manual movements (fumbling, fiddling, grabbing) to complex actions, repetitively mumbling or repetition of a stereotypical phase, more complex automatisms include getting undressed, with no or only partial awareness/recollection subsequently
- Slight turn of head to side of lesion
What are the differences in symptoms of stress/anxiety and seizures?
- Seizures are paroxysmal, distinct attacks with beginning and end
- Seizures tend to follow the same pattern
- Seizures are much less affected by anxiety related circumstances
- Seizures often tend to cluster, happening several times over a relatively short period and then going into remission for days/weeks
- Seizures can arise from sleep
What is the link between febrile convulsions and epilepsy?
- Proportion of children who had febrile convulsions (typically at 18 months) go on to have epilepsy in later life
- Typically, this type of epilepsy takes the form of seizures originating in 1 of the temporal lobes - associated with atrophy and scarring (gliosis) visible in this area on MRI (hippocampus, bottom near brainstem, coronal view) - termed mesial temporal sclerosis (MTS)
What are the risk factors for children with febrile convulsions developing MTS and epilepsy?
- Prolonged and severe febrile convulsions
- Multiple attacks
- Additional features such as transient hemiparesis
- Atypical age at febrile convulsion
- Minor pyrexia at time
- FH of epilepsy
When do you measure anticonvulsant serum levels?
- Concerns about drug toxicity or overdose
- Questions about concordance or poor absorption of drug being responsible for poor seizure control
- Drug interaction causing drop in anticonvulsant levels
- To guide dosing of non-linear pharmacokinetics e.g. phenytoin
- Desired clinical outcome attained - pharmacokinetic change anticipated e.g. pregnancy, interacting drug or increased pharmacokinetic variability e.g. drug formulation changes
Why are syncopal attacks similar to epileptic attacks?
- Myoclonic jerks can look similar
- Incontinence of urine is common in women
What are the reasons to change from sodium valproate to another anticonvulsant?
- Future teratogenic risk
- Neural tube defects - spina bifida anencephaly
- Syndrome of dysmorphia, developmental delay and cognitive impairment (foetal valproate syndrome)
- Ideally avoid this drug in women of childbearing age
- It is not as effective in treating epilepsy that is localised to 1 part of brain but then spreads to normal brain in secondary generalised convulsion
When could a patient come off anticonvulsants?
- If they have been seizure free for several years - generally applies to children or adults who developed certain forms of epilepsy in childhood. Some of them have good prognosis for spontaneous resolution as the brain matures.
- If they have gliosis of the brain it’s unlikely they can stop.
What are the issues when switching anticonvulsants?
- Avoiding breakthrough seizures
To avoid this current dose needs to be reduced whilst simultaneously increasing dose of new anticonvulsant - Tolerability of new drug - side effects
- Potential interaction between the 2 anticonvulsant drugs during changeover period and interactions between new drug and other medications taken e.g. OCP - many anticonvulsants are enzyme inducing so cause failure of OCP
- Implications for driving
If they experience breakthrough seizure must inform DVLA and stop driving (withhold license for 6 months). They recommend stop driving for 6 months in changeover period and 6 months after.
What is the safety information in changeover of anticonvulsants?
Avoid situations where they could be in serious danger if they lost consciousness:
- Working at height, cycling in traffic, working with dangerous machinery, being alone beside deep water
- Always worth mentioning shower over bath, can bathe with door open and someone near
- Swim in life-guard supervised pools
What is the interaction between sodium valproate and lamotrigine?
Lamotrigine must be increased at half the standard rate whilst still taking sodium valproate (start off with alternate days instead of daily lamotrigine, could easily give rise to confusion).
At normal rate can cause serious hypersensitivity rash.
