4 - Common Neurological Disorders 1 Flashcards
What is the definition of epilepsy?
Recurrent tendency to seizures. A seizure is an episode of transient abnormal electrical activity in the brain
Synchronus hyperexcited neuronal activity
Need 2 or more unprovoked seizures for diagnosis
What are some features in a history that might suggest a black out was a seizure?
- Prodrome: change in behaviour/mood days or hours before
- Aura: such as deja vu, strange smells
- Post ictal confusion: may also have headache, confusion
- Tongue biting
- Loss of continence
- Todd’s Palsy: temporary paralysis after
- Dysphasia
What are some of the causes of epilepsy? (6 main categories)
- Idiopathic
- Genetic predisposition
- Structural: cortical scarring from trauma, SOL, congenital cortical dysgenesis
- Metabolic:
- Immune: SLE, sarcoidosis
- Infectious: chronic infection predisposing to seizures (e.g. HIV). Different to seizures associated with an acute infection (e.g. meningitis)
What is the pathophysiology of epilepsy?
- Acquired or inherited imbalance between inhibitory (i.e. gabanergic) and excitatory (i.e. glutamatergic) signals
- High frequency bursts of excitatory action potentials leads to synchronous, hyperexcitable activity
- Transformation within neural networks that promote excitability and development of epilepsy
What are some factors that increase a persons risk of developing epilepsy?
- Cerebrovascular disease
- Head trauma
- Cerebral infections
- Family history: epilepsy or neurological illness
- Premature birth
- Congenital malformations of the brain
What are the three different ways of classifying epilsepy?
- Seizure type
- Epilepsy type (see image)
- Epilepsy syndrome
How do you classify a seizure type using the International League against epilepsy classification?
1. Focal, Generalised or Focal to Bilateral Tonic Clonic (a.k.a Secondary Generalised)
2. Impaired awareness or Normal Awareness (Complex or Partial)
3. Motor or Non Motor: absence, tonic-clonic, myoclonic, atonic, spasms
What is the difference between a focal and generalised seizure?
Focal: Starts in one hemisphere of the brain, can then spread and lead to secondary generalised. Not all leads on the EEG will start at the same time
Generalised: Affects both hemispheres of the brain at the same time, always impaired awareness. All leads on the EEG start at the same time. Preferred neural pathways
What are some examples of epilepsy syndromes and how are they diagnosed?
Diagnosed based on age of onset, seizure types, EEG features, additional clinical or radiological features. Need to know to help guide treatment
- Idiopathic generalised epilepsy: myoclonus, generalised tonic-clonic, absence
- West syndrome: infantile spasms aged 3-12 months, hypsarrhythmia on EEG
- Lennox Gastaut syndrome: tonic and absence seizures usually around 6-7 years old, slow development, treatment resistant
- Juvenile Myoclonic Epilepsy: in teens myoclonic or tonic clonic seizures often on waking, no developmental issues, genetic
What are some triggers of seizures in juvenile myoclonic epilepsy?
- Lack of sleep
- Alcohol
- Flashing lights (photosensitive)
What are the four stages of a seizure?
- Prodromal: change in mood or sensation e.g confusion, irritability, mood disturbances
- Early ictal: Aura, will only get in focal epilepsy, happens few seconds before and could a smell or a vision
- Ictal: depends on type of seizure e.g could be period of stiffness then rhythmic jerking
- Post-Ictal: confusion, drowsiness, memory loss, malaise that can take hours or days to recover from
What criteria needs to be met in order to have a diagnosis of epilepsy and what are some differential diagnoses for epilepsy?
- Syncope and anoxic seizures: LOC to impaired cerebral blood flow
- Pseudoseizures
- Sleep-related conditions
- Paroxysmal movement disorders
- Migraine associated disorders
These seizures appear the same as epileptic seizures but there is no investigational evidence for them e.g no trace on EEG, no raised lactate or prolactin after seizure
How can you tell the difference between a pseudoseizure (non-epileptic attack disorder) and an epileptic seizure?
- No clinical evidence for a pseudoseizure e.g normal CT, MRI and EEG
- Pseduoseizures may close eyes, periods of motionless unresponsiveness, rapid breathing, abrupt termination, lack of post-ictal phase, head side to side
What investigations are done following a first seizure to help aid the clinical diagnosis of epilepsy?
First seizure needs urgent referral to first fit clinic within 2 weeks.
Investigations done to rule out any precipitating cause of seizure
- EEG: see if focal cause, cannot be used to exclude epilepsy
- MRI: structural lesions that could be causing epilepsy, do CT if MRI not available
- ECG
- Bloods: FBC, U&E, LFT, Glucose, Bone profile
- Drug screen
- LP: if suspect infection
What are the aspects of management in epilepsy?
- Education and safetynetting
- Acute control of seizures
- Long term prevention of seizures (aiming for no seizures and no/few side effects)
What counselling do you need to give a patient after any fit?
- Need to stop driving and inform DVLA (if first seizure no driving for 6/12, if epilepsy need to be seizure free for a year)
- Watersafety: take showers not baths, buddy system, leave door unlocked, avoid swimming
- Environment: avoid heights, avoid flames, avoid dangerous activities
What happens at a first fit clinic?
- History, Exam, MRI, EEG
- All done to decide whether seizure is likely to represent epilepsy
- Patient education and advice
- If 2 or more seizures or 1 seizure and high risk of another, AEDs started
What are the features of the following seizures and what AEDs are used to treat them?
- Focal
- Generalised tonic clonic
- Absence
- Myoclonic
- Tonic
- Atonic
- Juvenile myoclonic epilepsy:
Focal:
1st line - Levetiracetam or lamotrigine
2nd line - Carbamazepine
Generalised tonic clonic:
1st line - sodium valproate or lamotrigine
2nd line - clobazam, lamotrigine, levetiracetam or topiramate
Absence
1st line - ethosuximide or sodium valproate
2nd line - lamotrigine
Myoclonic
1st line - sodium valoproate
2nd line - levetiracetam or topiramate
Tonic
Sodium valproate or Lamotrigine
Atonic
Sodium valproate or Lamotrigine
Juvenile myoclonic epilepsy
1st line - sodium valproate
2nd line - lamotrigine , levetiracetam or topiramate
What antiepileptics are safest to use in pregnancy?
- Lamotrigine
- Levetiracetam
What are the complications of epilepsy?
- Trauma, drowning, RTAs from actual seizure
- Status epilepticus
- Sudden unexpected death in epilepsy (SUDEP)
How are AEDs started, stopped and switched?
Start: treat with one drug and one doctor only and slowly build up until seizures controlled or maximum dose reached
Switch: Titrate new drug up and titrate old drug down
Stop: Can trial under specialist supeervision if seizure free >2 years after weighing up risks and benefits. Must decreased dose over at least 2-3 months
What advice do you need to give a woman with epilepsy on pregnancy?
- Advise all women of child-bearing age to take folic acid daily
- Avoid sodium valproate and polytherapy completely
- Most AEDs in breast milk apart from carbamazepine, valproate. Lamotrigine is in milk but not harmful
- Enzyme inducing AEDs make POP unreliable. Oestrogen containing contraceptives lower lamotrigine levels
Apart from AEDs, what other interventions can be used in epilepsy?
Psychological: relaxation, CBT may benefit some
Surgical:
- Neurosurgical resection: if single epileptogenic focus e.g tumour but risk of neurological deficits
- Vagal nerve stimulation
- Deep brain stimulation
How can you localise a focal seizure?
Temporal Lobe
- Automatisms (lip smacking, chewing, fiddling, grabbing)
- Dysphasia
- Deja-vu
- Emotional disturbance
- Hallucinations of smell, taste, sound
Frontal Lobe
- Motor features like Jacksonian March
- Subtle behavioural disturbances
- Speech arrest
Parietal Lobe
- Sensory disturbances e.g numbness, pain
Occipital Lobe
- Visual phenomena like spots, lines, flashes
What is the mechanism of action of the following AEDs and what are some side effects are each of them?
- Sodium Valproate
- Carbamazepine
- Lamotrigine
- Levetiracetam
- Phenytoin
- Phenobarbitone
- Topiramate
NEED TO MONITOR FOR DEPRESSION AND SUICIDAL THOUGHTS ON ALL AEDs
What are some symptoms of phenytoin toxicity?
- Nystagmus
- Diplopia
- Tremor
- Dysarthria
- Ataxia
What is Idiopathic Parkinson’s disease?
Chronic progressive neurodegenerative disease that occurs due to a loss of dopaminergic neurones in the substantia nigra
Most common cause of Parkinsonism (see image)
Starts unilateral then as it progresses becomes bilateral. Has non-motor symptoms too e.g depression, sleep disturbance, autonomic dysfunction
What is Parkinsonism?
Bradykinesia plus of one:
- Resting tremor
- Postural instability
- Rigidity
What is the pathophysiology of Idiopathic Parkinson’s disease?
Loss of dopaminergic neurones in the substantia nigra so less dopamine in the direct and indirect pathway.
Basal ganglia functions:
- Inhibition of muscle tone
- Coordinated, slow, sustained movement
- Suppression of useless patterns of movement
- Initiation of movement
What are the clinical features of IPD?
- Bradykinesia (slowing of voluntary movements, loss of arm swing)
- Resting ‘pill-rolling’ tremor of 4-6Hz
- Cog Wheel rigidity
- Shuffling gait
- Micrographia
- Parkinsonian mask
- Non motor: sleep disorder, bowel/bladder symptoms, sexual dysfunction, glabellar tap, depression, psychotic symptoms, anosmia
How is a diagnosis of IPD made?
UK Parkinson’s Disease Society (PDS) Brain Bank Clinical Diagnosis Criteria
Step 1
Bradykinesia plus one of: resting tremor, postural instability, muscle rigidity
Step 2
Exclusion of other causes of Parkinsonism e.g review drug chart
Step 3
3 or more supportive criteria:
- Unilateral onset
- Rest tremor present
- Progressive
- Persistent asymmetry
- Excellent response to levodopa
- Levodopa induce chorea
- Levodopa response for 5 years or more
- Clinical course of 10 years or more
What are some exclusion criteria for IPD?
- Repeated strokes and stepwise progression
- History of head trauma
- > 1 relative affected
- Sustained remission
- Unilateral features after 3 years
- Antipsychotic or dopamine-depleting drugs
- Negative response to levodopa
- Oculogyric crisis
- Exposure to neurotoxin
- Cerebral tumour or hydrocephalus
What is the MDS (movement disorder society) criteria for diagnosing IPD?
- Confirmation of Parkinsonism: bradykinesia + tremor or rigidity
- No absolute exclusion criteria present
- ≥2 supportive criteria
- Absence of red flags: rapid development gait impairment, early bulbar dysfunction, non-progressive motor symptoms ≥ 5 years while not on treatment, respiratory dysfunction, early severe autonomic dysfunction
What are some causes of Parkinsonism?
- IPD
- Multisystem Atrophy
- Progressive Supranuclear Palsy
- Dementia with Lewy Body
- Corticobasal degeneration
- Vascular
- Drug induced
- Post encephalitis
- Neurosyphillis
How do the following Parkinson’s plus syndromes present?
- MSA
- PSP
- DLB
- CBD
MSA
- Adult-onset rapidly progressive disease with profound autonomic dysfunction leading to severe postural hypotension, urogenital dysfunction, cerebellar and corticospinal features
- Poor response to treatment
PSP
- Begins at age 50-60 years with vertical gaze dysfunction, dysarthria and cognitive decline
- Tremor is rare
DLB
- Early onset dementia (< 1 year) with features of parkinsonism
- Dementia prior to motor symptoms and has visual hallucination and fluctuating consciousness
- REM sleep disorder
CBD
- Progressive dementia, parkinsonism and limb apraxia
- Alien limb syndrome
What are some drugs that can induce Parkinsonism?
- Neuroleptics e.g Risperidone, Olanzapine, Clozapine
- Metoclopramide
- Prochlorperazine
- Manganese
What investigations can be done when a patient has Parkinsonism to find if it is IPD or there is an underlying cause?
- CT/ MRI: can look for secondary cause
- PET with Fluorodopa: to localise dopamine deficiency in basal ganglia
- DaTscan: differentiate Parkinsonism from essential tremor
- Always review drug chart
How can you distinguish between a Parkinson’s tremor and a Benign Essential tremor?
How can you make a resting tremor more visible in IPD?
Unilateral so distract their other hand by asking them to mime painting a fence or something
What are the principles of management in Parkinson’s disease?
- Initial Therapy
- Adjuvant Therapy
- Surgery
- Non motor symptoms: e.g laxatives for constipation, catheter for bladder dysfunction, modafinil for excessive tiredness