Seizures Flashcards
What are febrile convulsions (pathophysiology and aetiology)?
Seizures associated with fever >37.8’C and not due to other underlying pathology such as epilepsy.
children 6 months to 5 years
relatively common
common causes- respiratory tract infection otitis media UTI influenza HHV-6 (sixth disease/roseola infantum) post-immunisation (rare) 1-2 weeks after recieving the vaccine.
Clinical features of febrile seizures
Generalised tonic-clonic seizure
Muscle stiffness and jerking
Shaking of the limbs without focal features
breathing difficulties pallor cyanosis LOC post-ictal drowsiness and confusion
rarely last longer than 10 mins
occur once in 24 hours
What is a complex febril convuslion?
Similar but more focal features e.g movement is limited to one side of the body
15 mins and recur within 24 hrs
Febrile status epilepticus
Seizure lasts longer than 30 mins
Occurs in first 24 hours of febrile illness
Febrile convulsion investigation
check temp following seizure
focal neurological deficits
bloods- FBC, U+E, ESR, coagulation, glucose
urine: <18M
lumbar puncutre if suspected meningitis
EEG
brain MRI
Management of febrile convulsion
Typically self-resolves
Antipyretics- ibuprofen, paracetemol
>5 min or recur= ambulance
Buccal midazolam
Rectal diazepam
repeat if does not abate in 10 mins
Urgent referral for febrile convulsion
If alternative cause is suspected (epilpesy)
first presentation
diagnostic uncertainty
aged <18M
abx have recently been taken
What are some complications that can follow a febrile seizure?
Todd’s paresis- transient hemiparesis. potential short term complications, usually subside in 48hrs
Non febrile siezure / epilepsy
Febrile status epilepticus.
Absence seizure clinical features
“Petit mal”
age of onset 3-10 years old
pically happen in children. The patient becomes blank, stares into space and then abruptly returns to normal. During the episode they are unaware of their surroundings and won’t respond. These typically only lasts 10-20 seconds. Most patients (> 90%) stop having absence seizures as they get older. Management is:
absences last a few seconds
quick recovery
hyperventilation/stress can provoke a seizure
the child is usually unaware of the seizure
can occur many times in the day
EEG: bilateral, symmetrical 3Hz spike and wave pattern
Absence seizure management
1st line- sodium valporate, ethosuximide
Focal seizures (partial seizures)
The seizures start in a specific area on one side of the brain.
Focal seizures start in temporal lobes. They affect hearing, speech, memory and emotions. There are various ways that focal seizures can present:
Hallucinations Memory flashbacks Déjà vu Doing strange things on autopilot Motor (Jacksonian March) clonic, tonic, atonic, myoclonus automatisms (repeat automatic movements like clapping or rubbing of hands, lipsmacking, chewing or running
Non Motor (aura) change in sensation, emotion, thinking, cognition, GI, waves of hot or cold, goosebumps, heart racing.
Generalised seizures
Involves the networks on both sides of the brain
LOC immediately
- motor
- tonic-clonic (grand mal)
- tonic (tense/rigid)
- clonic (jerking)
- myoclonic (brief, rapid muscle jerks) (muscle twitching)
- atonic (muscles are weak/limp) - non-motor
- absence
Focal to bilateral seizure
the seizure starts on one side of the brain and then spreads to both lobes
2’ generalised seizures.
Psychogenic non-epileptic seizures
Pseudoseizures
Patients who present with epileptic-like seizures but no EEG changes
history of mental health/personality problems
*e.g. keep their eyes close
Infantile spasms (West’s syndrome)
This is also known as West syndrome. It is a rare (1 in 4000) disorder starting in infancy at around 6 months of age. It is characterised by clusters of full body spasms. There is a poor prognosis: 1/3 die by age 25, however 1/3 are seizure free. It can be difficult to treat but first line treatments are:
Prednisolone
Vigabatrin
Juvenile myoclonic epilepsy
Infrequent generalised seizures often in the morning
Daytime absences
Sudden shock-like a myoclonic seizure
good response to sodium valproate.
Seizure investigation and management
EEG
MRI
Management:
1st line for generalised seizure: sodium valporate
1st line for focal seizure: carbamezepine.
DVLA and seizures
Patients cannot drive for 6 months following a seizure
for patients with established epilepsy, they must be fit free for 12 months
Sodium valproate
1st line for generliased seizure
increases GABA activiy
Carbaezepine
1st line for focal seizures
binds to sodium channels increasing their refractory period
Lamotrigine
2nd line for generliased and partial seizures
sodium channel blocker
Phenytoin
no longer used due to side effects
binds to Na+ channel increaseing thier refrctory period.
Acute mx of seizure
if a seizure does not terminate after 5-10 mins, administer meds
Benzodiazpeines (intranasally or under tongue)
Focal seizures (localising features)
Temporal lobe- hallucinations, auditory, gustatory, olfactory. epigastric rising or emotional. automatism lip-smacking, deja vu
(head is temporary)
frontal lobe: head or leg movement, post ictal weakness, Jacksonian march
(motor)
parietal: paraesthesia
(p=p)
occipital: floaters/flashers
(visual)
- Focal onset awareness
2. Focal onset impaired awareness
- person is aware during seizure (simple partial seizure)
2. person is confused / awareness is affected. focal impaired / complex partial seizure.
What is the definitionof status epilepticus
A seizure continuing for longer than 5 minutes or when multiple shorter seizures occur with incomplete recovery between them
Causes of seizures
Known epilepsy Drug overdose (amphetamines, TCAs) drug withdrawal (alchol) CNS injury (traumatic brain injury, acute stroke, SAH, cerebral hypoxia) CNS infection (meningitis, encephalitis, cerebral abscess)
Initial investigation of a seizure
Glucose Venous blood gas (VBG) Full blood count Urea & electrolytes Magnesium Calcium
Guided by the likely cause but may include
CT head
Bloods cultures
Toxicology screen
Lumbar puncture (LP)
12 lead electrocardiogram (ECG)
Look specifically for prolonged PR, QRS and QT interval
Clinical feature of seizure
Witnessed or unwitnessed Collateral history if possible Prodrome Loss of consciousness Convulsions Tongue biting Urinary incontinence Post-ictal period Injuries
Initial management of seizure
Secure the airway
Give high-concentration oxygen
Assess cardiac and respiratory function
Check blood glucose levels
Gain intravenous access (insert a cannula)
IV lorazepam 4mg, repeated after 10 minutes if the seizure continues
If seizures persist: IV phenobarbital or phenytoin
in community:
Buccal midazolam
Rectal diazepam
Atonic seizure
Atonic seizures are also known as “drop attacks”. They are characterised by brief lapses in muscle tone. These don’t usually last more than 3 minutes. They typically begin in childhood. They may be indicative of Lennox-Gastaut syndrome. Management is:
First line: sodium valproate
Second line: lamotrigine
Myoclonic seizure
Myoclonic seizures present as sudden brief muscle contractions, like a sudden “jump”. The patient usually remains awake during the episode. They occur in various forms of epilepsy but typically happen in children as part of juvenile myoclonic epilepsy. Management is:
First line: sodium valproate
Other options: lamotrigine, levetiracetam or topiramate
management
most neurologists start anti-epileptics following a second epileptic seizure.
general rule- sodium valproate is used 1st line with generalised seizures
carbamezapine is used for focal seizures.
sodium valporate
increases GABA activity
1st line for generalised seizures
adverse side effects: weight gain alopecia ataxia tremor *teratogenic*
carbamezapine
binds to Na+ channels increasing their refractory period
first line for focal seizures
adverse:
dizzy, ataxia, drowsy, SIADH
lamotrigine
sodium channel blocker
2n line for generalised seizure
adverse: steven johnson syndrome
phenytoin
binds to Na+ to increase their refractory period
no longer used 1st line as extensive side effect profile
