Flashcards in Week 232 - Epilepsy Deck (61)
Define an epileptic seizure
A transient event experienced by a subject as a result of synchronous and excessive discharge of cerebral neurones (arising due to variety of pathologic processes)
List some key differential diagnoses for epilepsy
Syncope (vasovagal or cardiogenic); Non-Epilectic Attacks (psychogenic); Sleep disorders (narcolepsy/cataplexy/parasomnias); Migraine; TIA; Hypoglycaemia
List causes of seizure that may be mistaken for epilepsy or cause LOC
Metabolic: low calcium, magnesium, glucose; deranged LFTs
Toxic: tricyclics, MAOIs, Alcohol
Infections/Inflammation: meningitis, abscess, febrile convulsion (paeds)
Vascular / Respiratory: TIA / CVA, hypoxia
What 3 types of epilepsy classification are there?
1) Seizure type
What two seizure types are there?
Generalised or Partial AKA Focal
(Generalised spreads throughout the brain and always results in altered consciousness
Partial affects part of the brain and so causes localised symptoms)
What two forms of partial seizure can occur?
Simple (remain fully conscious) or Complex (altered or lost consciousness)
When classifying epilepsy by location what is meant?
The lobe of the brain being affected (in a partial seizure epilepsy)
What 3 principle aetiologies can all epilepsy be categorised into?
- Idiopathic (no know reason)
- Symptomatic (clearly identifiable cause)
- Cryptogenic (characteristics suggestive of underlying cause but not yet found)
What features of a vasovagal syncopal episode would be suggestive of such?
3Ps: posture, provocation and prodrome
Standing; heat, venesection, micturition; nausea, clammy, tinnitus, blurring or loss of vision, deafness
Rapid orientation with prolonged fatigue as well as a few myoclonic jerks are common; usually last no more than 30s
What are the Red Flags for cardiogenic syncope?
Occur on exercise
FHx sudden death
PMH of IHD
Describe the common features of a generalised tonic-clonic seizure
Sudden onset, tonic stiffening followed by synchronous clonic mvmts
Stertorous breathing (harsh snoring/gasping)
Tongue-biting (lateral) ;incontinence; injuries
Post-ictal period (altered state of conc after), prolonged recovery
Absence seizures are a form of what type of epilepsy, generalised or partial?
In what patient group are absence seizures most common?
Children (uncommon in adults)
They usually grow out of it.
Describe the typical features of an absence seizure including frequency, duration, behaviours and recovery
Can happen several times in a day
Rarely last more than ~20 secs
Individual often stares blankly
Alert immediately after with no knowledge of the seizure
Describe the typical features of a Temporal Lobe (complex partial) seizure including prodrome, frequency, duration, behaviours and recovery
3As > PRODROME Aura (rising epigastric sensation, olfactory and gustatory, déjà vu) BEHAVIOR - Arrest (motor / speech), Automatism (lip-smacking, semi-purposeful actions)
Rarely > couple times a week; up to several mins
Post-ictal period of confusion
List some features of a likely Non-Epileptic Seizure
Awareness retain; gradual onset; prolonged; Frequent; no response it AEDs; Preceded by autonomic arousal; Asynchronous movements; Eyes closed and resist opening; Back arching; Carpet burns; Biting tip of tongue
What is Status Epilepticus?
A medical emergency
When a seizure lasts >5 mins (some say >30 mins but intervention should have occurred well before then as they can lead to brain damage and death)
What clinical signs often present with epileptic seizures?
Increased BP and Tachycardia, cyanosis
Up going plantars
Fall in pO2 and pH
Rise in creatinine kinase levels
What examinations would be sensible to perform with suspected epilepsy?
Neurological examinations (peripheral, cranial nerve)
Lying and standing BP
Check for injuries and neurocutaneous lesions (e.g. From neurofibromatosis)
What investigations should be performed?
ECG (all blackouts)
Imaging (cranial - CT for masses/CVA; MRI
Give 3 reasons for imaging the brain in epilepsy
1) to find the cause
2) for treatment: response to AEDs or surgery
3) important for prognosis
(All new-onset unprovoked seizures need imaging)
Give 3 major causes of epilepsy in infants
What is the major cause / type of epilepsy among children/adolescents?
Idiopathic Generalised Epilepsy
Besides idiopathic generalised epilepsy give 4 possible causes of epilepsy in young adults
head injury, alcohol, vascular malformations, hippocampal sclerosis
What is the major cause of epilepsy in 30-50s?
What is the major cause of epilepsy in >50s?
What is often seen on EEG and brain imaging with IGE?
Imaging is ALWAYS normal
EEG often abnormal, showing generalised 'Spike and Wave'
What type of epilepsy does Juvenile Myoclonic Epilepsy come under and what normally precipitates seizures?
Type of IGE
Waking, alcohol excess and sleep deprivation can precipitate
What are the first line drugs for IGE?
male = sodium valproate
female (of reproductive age) = lamotrigine or levetiracetam
What are the first line AEDs used for partial/focal epilepsy?
Carbemazepine, lamotrigine or levetiracetam
2nd line is one of those above not used 1st line in its place or in addition (though generally aim for mono-therapy )
What is the most common side effect of lamotrigine?
What is the most common side effect of levetiracetam?
What are the more common / serious side effects of sodium valproate?
Which AEDs are enzyme inducers and what does this mean?
Carbemazepine, Phenytoin, Topiramate
Which means that these drugs can reduce the efficacy of Warfarin and the OCP
After what period of seizure freedom should you consider withdrawing AEDs?
(N.B. Seizure risk DOUBLES upon withdrawal especially if: dual therapy used, symptomatic epilepsy, seizures after pharmacological introduction, frequent seizures, Hx of GTCSs or myoclonic jerks, abnormal EEG)
What is Wernicke-Korsakoff syndrome
A combination of Wernicke's encephalopathy and Korsakoff Syndrome, usually secondary to alcohol abuse. 20% mortality rate, 75% brain damage
Manifestation of Vit B1 (thiamine) deficiency
Sx inc: vision changes, ataxia and impaired memory
What is the general approach to managing someone in Status Epilepticus?
ABC - secure airway
Obtain IV access - glucose, or thiamine (if alcohol suspected)
Bloods: U&Es, Ca, Mg, ABGs, ECG, +/- AED levels
What meds should be used in the Tx of Status Epilepticus?
Early- IV lorazepam (or diazepam, buccal midazolam)
Established - IV phenytoin (or valproate, leve., phenobarbitone)
Refractory - ITU, GA - propofol, thiopental, midazolam
What is catamenial epilepsy?
That which coincides with hormonal changes of menstruation
What considerations should be taken into account in pregancy with AEDs?
Danger of seizure greater risk to mother and baby than AED usually
Sodium Valproate - Teratogenicity!!!
Phenytoin - cleft lip and palate, limb or organ malformation
Valproate; Carbemazepine - neural tube defects
Folate should ALWAYS be taken through pregnancy
What are the rules and legal requirements with regard to driving with epilepsy?
No legal requirement though the GMC state that Drs should strongly advise patients to report to DVLA then if not report it themselves informing pt you're going to.
1yr seizure free can reapply
If only ever occur during sleep ok to drive or seizures not affecting consciousness or ability to control a vehicle
What score on the GCS is suggestive of Coma?
= or less than 8
Want are the 4 over-arching causes of coma?
1) significant structural injury to cerebral hemisphere(s)
2) significant structural injury to brainstem
3) diffuse physiological brain dysfunction
4) metabolic/endocrine dysfunction
List 2 important mimics of coma and state how they differ
1) Locked-in syndrome: de-efferented motor tracts, only blinking and vertical eye movements intact, awareness and arousal retained
2) psychogenic coma - exclude all others!!!
What is the main overarching cause of unilateral hemisphere damage? Give some causes of that outcome
Expanding mass lesion, haemorrhage
large middle cerebral artery infarct can also cause
List causes of bilateral hemisphere brain damage?
Diffuse cerebral oedema
Diffuse brain injury
Give 5 causes for brainstem dysfunction
Bilateral thalamic lesion
What should roving eye movements in a comatose patient indicate?
A intact brainstem (therefore better prognosis)
Give 5 causes of physiological brain dysfunction
Prolonged status epilepticus (cerebral hypoxia)
Toxins (drugs, alcohol, poisoning)
Give 3 metabolic causes of coma
Too much or too little Na or Glucose
Too much calcium
(Renal or hepatic failure can also cause coma)
Describe the initial management for coma?
Improve oxygenation (intubate if necessary)
Correct hypo- or extreme hypertension
Warm up if cold and cool if hot
Glucose / thiamine / naloxone / flumazenil if indicated
Identify underlying cause, gain as much Hx as possible
(Flumazenil reverses benzodiazepine OD)
What factors will make a neurological assessment less reliable?
Sedative drugs in system
What should a neurological assessment involve?
Motor reflexes (?symmetrical. brisk, up going plantar suggests contralateral damage)
Brainstem reflexes (pupil reactivity and eye movements)
Papilloedema/retinal haemorrhage; unilateral UMN signs; meningism (could suggest SAH); pupil responses (opiate, MDMA, ecstasy OD)
What is a single 'blown' pupil a sign of?
Increased ICP "impending doom"!!
Give 4 signs of brainstem integrity
Roving eye movements
Oculocephalic response (turn head briskly side-to-side, eyes stay on you)
Oculovestibular (slow phase of nystagmus to ear irrigated)
What bloods should be done for a patient in a coma?
FBC, U&Es, glucose, LFTs, ABG, cultures, kidney function, thyroid, drug screen
Besides bloods what other investigations should you consider for a coma patient?
LP (unless raised ICP)!
What criteria qualify a persistent vegetative state?
Recovery of arousal but not awareness
-no evidence of awareness -no language or comprehension
-roving eye movements -brainstem reflexes intact
-maintenance of respiration and circulation
(Generally due to diffuse cortical or subcortical damage)
Describe the main features of 'Locked-in syndrome'
Patient has awareness
Little or no motor output below CNIII
Voluntary eye movement in vertical plane and eye opening
What is Locked-in syndrome usually caused by?