Neurology Flashcards
What is epilepsy?
Epilepsy is a recurrent tendency to:
- Spontaneous
- Intermittent
- Abnormal electrical activity
- … in part of the brain.
- This is a siezure.
Convulsions = motor signs of electrical discharges.
- Patients must’ve had at least 2 seizures in the last 5 years
What is a focal seizure?
- Focal (partial) seizures
- electrical and clinical seizure manifesting from one portion of the brain e.g. one hemisphere or lobe.
- Often seen with underlying structural disease
- local discharge over the area of onset seen on EEG
- Focal aware seizure = preserved consciousness in a focal seizures
- there are still focal motor, sensory, autonomic or psychic symptoms
- no post-ictal symptoms
- Focal impaired awareness seizure = may include memory loss for the duration of the clinical event or loss of consciousness.
- Common from the temporal lobe where post-ictal confusion is a feature
- In 2/3rds of patients focal –> 2” generalised seizure the electrical disturbance in their partial seizure spreads widely –> generalised (bilateral) seizure = typically convulsive
What is a generalised seizure?
Generalised seizures
Starting within then spreating to bilaterally distributed networks which gives simuntaneous onset of widespread electrical discharge with no localising features referable to a single hemisphere.
Subtypes
Absence seizures:
- These are brief e.g. <10s, can be several X day
- no aura/postictal state
- E.g. Stops talking then carries on without realising, eyelid blinking, walking/circling behaviour
- Childhood presentation; Atypical absence seizures tend to be medically refractory and associated with mental retardation; typical absence seizures are medically responsive, and childhood absence epilepsy (CAE) even tends to remit by adulthood.
- EEG is definitive test
Tonic-Clonic Seizures [GTCS]:
- Classically involve loss of consciousness and a phasic tonic stiffening of the limbs, followed by repetitive clonic jerking.
- Can have one without the other.
- Post-ictal confusion and drowsiness.
- Most GTCS are self-limited without intervention.
- bisynchronous epileptiform activity in both cerebral hemispheres on EEG
Myocolonic seizures:
- Sudden jerk of a limb face or trunk
- patient maybe thrown suddenly to the ground, or have a violently disobedient limb
Atonic/akinetic seizures:
- Sudden loss of muscle tone causing a fall, no LOC
Infantile spasms: Commonly associated with tuberous sclerosis.
What elements may a patient experience in a seizure?
Before: a prodrome.
- ~hours or days.
- Maybe a change in mood or behaviour.
- aura implies a focal seizure - which are most common from the temporal lobe.
- Strange feeeling in gut, experience e.g. deja vu, strange smells or flashing lights
Post-ictally:
- Headache, confusion and myalgia
- or temporary weakness/paresis after a focal seizure in the motor cortex (Todds Palsy, lasts 30 mins-36hrs)
- or dysphagia following focal seizure in temporal lobe
What are the causes of seizures?
- 2/3rds of seizures are idiopathic
- Structural
- cortical scarring e.g. head injury years before onset
- developmental
- e.g. dysembryoplastic neuroepithelial tumour or cortical dysgenesis
- space occupying lesion
- stroke
- hippocampal sclerosis e.g. after febrile convulsion
- Others:
- Tuberous Sclerosis
- Sarcoidosis
- SLE
- PAN - Polyarteritis nodosa, rare disease from vasculitis
- Antibodies to voltage gated potassium channels
How do you diagnose epilepsy?
All patients with seizure = specialist assessment and investigations referral in <2wks
- History is important - and from witness;
- tongue biting and slow recovery. In 1st seizures ?funny turns/odd behaviour
- ?auras including deja vu, odd episodic feelings of fear
- triggers e.g. alcohol, stress, flickering lights/tv - if triggered episode they tend to reccur
- Establishment of seizure type:
- focal vs generalised feeatures
- also consider non-epileptic attack disorder [stress +/ PMH major emotional trauma is a trigger]
- gradual onset and prolonged duration
- closed eyes and resistance to eye opening, rapid breathing, fluctuating motor activity and episodes of motionless unresponsivness
- CNS, CT, MRI and EEG are normal
- May co-exist with true epilepsy though
- Rule out provoking causes
- unprovoked seizures have a recurrence rate of 30-50%
- only 3-10% of provoked seizures recur
- generally when provocation is irreversible
- most people would have a seizure given a sufficient provocation e.g. reflex anoxic seizures in faints
- causes include:
- trauma
- stroke
- haemorrhage
- raised ICP
- alcohol or benzo withdrawal
- metabolic disturbance
- hypoxia, low Ca2+
- high/low glucose or sodium,
- uraemia
- liver disease
- infection
- meningitis, encephalitis
- increased temp
- drugs (tricyclics and cocaine)
What investigations are necessary in epilepsey?
Look for provoking causes
- ?EEG
- But EEGs cannot exclude epilepsey and can be falsely +ve so DON’T do if likely to be simple syncope
- Emergency EEG only done if non-convulsive status epilepticus is the problem
- MRI
- Structural lesions
- Drug levels
- if on anti-epileptics –> check patient adherence
- Drugs screen
- Lumbar puncture
- if infection is suspected
Why is counselling important after seizures?
Counsel on:
- Advice about any future dangers
- swimming, driving, (not for 1 year after a seizure, pt to contact DVLA), heights
- until the diagnosis is known
- swimming, driving, (not for 1 year after a seizure, pt to contact DVLA), heights
- then individualised counselling can be given on employment, sport, insurance and conception
- epilepsy and anti-epileptics often have drug side effects
What localising features of temporal lobe focal seizures are there?
- Automatisms
- complex motor phenomena with impaired arareness
- primitive oral
- lip smacking, chewing, swallowing
- or manual movements
- fumbling, fiddling grabbing
- or compex actions
- dysphasia
- Deja Vu
- or Jamais Vu (things seem strangely unfamiliar)
- emotional disturbance
- suddent terror, panic, anger or elation and deralisation (out of body experiences)
- Hallucinations of smell, taste or sound
- Delusional behaviour
- Bizarre associations
What are loclising features of a Frontal lobe focal seizure?
- Motor features such as posturing or peddling movements of the legs
- jacksonian march
- spreading focal motor seizure with retained awareness- often starting with the face or a thumb
- Motor arrest
- Subtle behavioural disturbances
- these are often diagnosed as psychogenic
- Dysphasia or speech arrest
- Post-ictal Todds Palsy (transient paresis after a seizure e.g. face, arm, leg, aphasia or gaze)
What are the localising features of focal seizures in the parietal lobe?
- sensory disturbances
- tingling, numbness or rarely pain
- Motor symptoms
- due to spread to the pre-central gyrus
What are the localising features of focal seizures in the occipital lobe?
- visual phenomena e.g. spots, lines and flashes
What anti-epileptic drugs are used in different seizure types?
AEDs are only started by a specialist after confirmed epilepsy - e.g. 2 or more seizures, unless recurrence risk is high e.g. structual brain lesions, focal CNS deficit or unequivocal epileptiform EEG.
There should also be detailed discussion of treatment options with patient. The AED choice depends on seizure type and epilepsy syndrome, comorbidities, lifestyle and patient preference.
- Focal (partial) seizures = carbamazapine [blocks pre-synaptic Na+ channels and TF glutamate] or lamotrigine
- Generalised tonic-clonic seizures = sodium valporate or lamotrigine [blocks Na+ and Ca2+ channels TF stops glutamate]
- Absence seizures = sodium valporate or ethosuximide [blocks Ca2+ channels, pre-synaptic depolarisation prevent]
- Myoclonic seizures = sodium valporate
- [block voltage-gated sodium channels (glutamate) and increased brain levels of gamma-aminobutyric acid (GABA - allows Cl- into post synaptic membrane to stop depolarisation)]
- NO carbamazepine or oxcarbazepine - may worsen seizures
- [block voltage-gated sodium channels (glutamate) and increased brain levels of gamma-aminobutyric acid (GABA - allows Cl- into post synaptic membrane to stop depolarisation)]
- Tonic or atonic seizures= sodium valporate or lamotrigine
What side effects are there with common AED drugs?
Carbamazepine side effects = leucopenia, diplopia, blurred vision, impaired balance, drowsiness, mild generalise erythematous rash, (rarely) SIADH
Lamotrigine side effects = maculopapular rash (1/10 & in 1st 8 weeks); 1/1000 can develop Stevens-Johnson syndrome esp if on valoprate so warn Pt to see Dr if get rash/flu symptoms. Diplopia, blurred vison, photosensitivity, temor, agitation, vomiting, aplastic anaemia
Sodium valporate side effects: teratogenic. Nausea (common, so eat w/food). Liver failure (LFTs for 1st 6 months), pancreatitis, hair loss (grows back curly), oedema, ataxia, tremor, thrombocytopenia, encephalopathy (from hyperammonaemia)
What should be considered when taking/removing anti-epileptic drugs?
- All pts should be treated with one drug and one doctor in charge only
- doses slowly built up over 2-3 months until seizures are controlled or max dose is reached
- if ineffective/not tolerated change to next appropriate drug
- introduce the new drug slowly when switching and only withdraw 1st drug once 2nd is established
- <10% patients need dual therapy - consider in cases of all appripriate drugs been tried singly at the optimum dose
- Consider stopping AEDs if patient has been sizure free for >2years - under specialist supervision only. Decrease dose slowly over 2-3 months or if on benzodiazepines (stim GABA-A receptors) or barbiturates >6months.
- Epilepsy itself gives 5% risk of foetal anormalities + some AEDs are teratrogenic –> accurate information counselling needed about contraception, conception, pregnancy and breastfeeding in order to make an informed decision
- women of child bearing age to take 5mg/d folic acid
- voic sodium valporate and polytherapy before coneption and during pregancy - lamotrigine is preferable but needs planning
- of the AEDs, only carbamazepine and valporate are not present in breast milk; while lamotrigine is not thought to be harmful to infants
- Contraception: endyme inducing ARDs - carbamaepine, phenytoin and barbiturates make POP unreliable; while oestrogen containing pills lower levels of lamotrigine so ic dose maybe needed to control seizures
What are the non-drug therapies relevant to epilepsy?
- Psychological therapies:
- Relaxation
- CBT
- these do not improve siezure frequency though so used as ADJUNCT to meds only
- Surgery
- Considered if a single epileptogenic focus can be ifentified e.g. hippocampal sclerosis or small low grade tumour
- neuro-surgery resection gives up to 70% chance of seiure resolution but carries the risk of causing focal neurological deficits
- Vagal nerve stimulation
- deep brain stimulation
What is SUDEP?
Sudden unexpected death in epilepsy:
- More common in epilepsy that is uncontrolled and maybe related to night seizures associate apnoea or asystole.
- Those with epilepsy have 3x increased mortality
- ~>700 epilesy deaths/yr in UK are recprded and 17% are SUDEPs.
What pathologies can cause blackouts?
Blackouts e.g. collapse +/- loss of consciousness can be caused by:
- Vasovagal (neurocardiogenic) syncope
- Situation syncope e.g. cough, effort, micturition syncope
- carotid sinus syncope
- epilepsy
- Stokes-Adams attacks
- Hypoglycaemia
- Tremor, hunger and perspiration herald light-headedness or LOC; rare in non diabetics
- orthostatic hypotension
- unsteadiness or LOC on standing from lying in those with inadequate vasomotor reflexes
- E.g. the elderly; autonomic neuropathy; antihypertensive medication; overdiuresis; multisystem atrophy (e.g. parkinsons)
- unsteadiness or LOC on standing from lying in those with inadequate vasomotor reflexes
- Anxiety
- Hyperventilation, tremor, sweating, tachycardia, paraesthesiae, light headedness, + no LOC (suggests panick attack)
- Drop attacks
- Sudden fall to the ground without LOC
- are mostly benign and due to leg weakness but may also be caused by
- hydrocephalus
- cataplexy (strong emotion or laughter causes drop)
- narcolepsy
- are mostly benign and due to leg weakness but may also be caused by
- Sudden fall to the ground without LOC
- Factitious blackouts
- psuedoseizures
- munchausens
What examinations and investigations need to be done for blackouts?
Examination:
- CVS
- Neuro
- Standing and lying BP
- this shouldnt change (too much) if healthy
- In orthostatic hypotension systolic can change 20mm/HG and dia can be 10mmHG
Investigations
- All recurrent syncope or falls need CVS assessment –> if associated with palpitations, arrhythmias, 3rd degree AV block or prolonged QT interval then its URGENT (not going to get blood round the body)
- use ECG +/- 24h ECG - shows arrhythmias, long QT
- Echocardiogram
- U&E, FBC, Mg2+, Ca2+, glucose
- Tilt table test = ECG and BP monitored from lying/standing on table; if BP drops >30mmHg or there is bradycardia = neurally mediated syncope; consider pacing
- EEG, sleep EEG,
- CT/MRI brain
- ABG if practical (decreased PaCO2 in attacks suggests hyperventilation as the cause)
*while cause is being eludicated, advise against driving
What are the indications that blackouts are due to syncope?
Vasovagal or neurocardiogenic syncope is
- due to reflex bradycardia +/- peripheral vasodilation provoked by emotion, pain or standing too long
- it cannot occur when lying down
- onset: over secs - not instantaneous;
- pre-syncopal symptoms e.g. nausea, pallore, sweating and narrowing of visual fields
- During: ~2 mins lasting. potential brief clonic jerking of limbs (cerebral hypoperfusion) but NO tonic/clonic sequence. Dont normally lose continence or bite tongue.
- After: Rapid recovery
Situation syncope:
- Has vasovagal syncope symptoms but there is clear precipitant e.g. cough (happens after cough), effort syncope (exercise) –> usually a cardiac cause e.g. aortic stenosis, hypertophic cardiac myopathy. Micturition syncope (during or after urination, mostly men, @night)
Carotid sinus syncope: Hypersensitive baroreceptors = excessive reflex bradycardia +/- vasodilation on MINIMAL stimulation
- e.g. head turning, shaving
Syncope VS epilepsy = attacks when asleep or lying down; aura; identifiable triggers e.g. TV; altered breathing; cyanosis; typical tonic-clonic movments; urine incontinence; tongue biting; prolonged post-ictal drowsiness; confusion; amnesia and transient focal paralysis
What is a Stokes-Adams attack?
Where a transient arrhythmia [e.g. bradycardia due to complete heart block (heart only beats on ventricular escape pattern which is max 50bpm)] causes decreased cardiac output and LOC
Pt falls on ground - oft with no warning except palpitations; injuries are common - and is pale with slow or absent pulse
Recovery = seconds:
patient flushes and pulse speeds up and consc is regained.
Like in vasovagal syncope anoxic clonic jerks may happen in prolonged LOC
Attacks may happen several times a day and in any posture [not just lying/sitting to standing]
What is Status epilepticus?
- Means a seizure lasting for >30min or repeated seizures without interveneing consciousness
- Mortality and the risk of permannent brain damage increase with the length of attack
- Aim to terminate seizures lasting more thana few minutes ASAP e.g. <20min
- [evidence for seizures lasting over 5 minutes likely to last 30 mins so treat after 5 pretty much]
- Status Ep usually happens in patients with known epilepsy
- if its 1st presentation and this happens then >50% chance of structural brain lesion (high)
- diagnosis of tonic clonic status is usually clear where non-convulsive status e.g. absence or continuous partial seixures with consciousness preserved maye more difficult
- ?subtle eye or lid movements
- diagnosis of tonic clonic status is usually clear where non-convulsive status e.g. absence or continuous partial seixures with consciousness preserved maye more difficult
- if its 1st presentation and this happens then >50% chance of structural brain lesion (high)
- Also: could the patient be pregnant? (any pelvic mass?) –> yes? –> eclampsia is the likely diagnosis –> check the urine and BP [get obstetrician, immediate delivery maybe needed]
What investigations should be done for status epilepticus?
- Bedside glucose
- begin treatment for status epilepticus
- now the tests that can be done are
- lab glucose
- ABG
- U&E
- Ca2+
- FBC
- ECG
- consider anticonvulsant drug levels (adherence), toxicology screen, lumbar puncture, culture blood and urine, EEG, CT, carbon monoxide level
- pulse oximerty, cardiac monitor
- now the tests that can be done are
What is the management of convulsive status epilepticus?
- Open and secure airway (using adjuncts if necessary, remove false teeth if necessary)
- Oxygen, 100% + suction as required
- IV access and take blood: U&E, LFT, FBC, glucose, Ca2+; if indicated - toxicology screen; anticonvulsant levels
- IV bolus - to stop seizures
- e.g. lorazepam 4mg; give 2nd dose of lorazepam if no response after 10-20min
- Give thiammine if alcoholism or malnourishment suspected
- glucose given IV unless glucose is known to be normal
- treat acidosis if severe (contact ICU)
- due to local muscle hypoxia during seizures, changes in the levels of lactate and pH can seen after generalized epileptic attacks.
- Correct hypotension with fluids
- IV infusion - if seizures continue, start phenytoin; monitor ECG and BP
- General anaesthesia
- continuing seizures after 60-90mins of above therapy need expert help with paralysis e.g. propofol infusion and ventilation with continuous EEG monitoring in ICU
NB: never spend longer than 20 mins on someone with status epilepticus without having help at the bedside from an anaesthetist
What drugs are used in Status epilepticus?
BENZOs:
- Lorazepam - IV.
- Slow bolus into large vein.
- give 2nd dose if no response after 10-20 mins.
- Beware of resp arrest during last part of injection.
- have resucitation facilities to hand for ALL IV benzo use.
- alternative route = rectal if IV acess is difficult.
- Midazolam - Buccal. easy to use if no IV access e.g. in community; put half volume between lower gum and cheek on each side;
- prepare other drugs while waiting for this to work
IF fits continue… move to….
Anticonvulsant
- Phenytoin infusion
- Blocks voltage dependent Na channels in neurons - makes AP more difficult to occur
- Do not use in bradycardia or heart block; beware low BP; needs BP and ECG monitoring
IF fits continue…
- ICU help as paralysis and anaesthesia with propofol is required. Close monitoring esp resp function is vital.
- –> ?pseudoseizures especially if there are odd features e.g. pelvic thrusts, resistance to your attempts to open eyelids and do passsive movements - arms and legs flailing around
Use dexamethasone if vasculitis/cerebral oedema (tumour) possible [corticosteroids; used to supress autoimmune diseases and also reduce tumour associated swelling].
- When siezure is contolled, start oral epilepsy drugs;
- take Hx to find cause
- e.g. hypoglycaemia, pregnancy, alcohol, drugs, CNS lesions or infection, HTN encephalopathy, inadequate anticonvulsant dose/compliance
- take Hx to find cause
