Neuro Flashcards
What is the pathophysiology of multiple sclerosis
acquired chronic immune mediated inflammatory condition of the CNS.
autoimmune destruction of oligodendrocytes by T cells
demylination
gliosis - scarring
neuronal damage leading to cell loss
What are the different types of MS
relapsing remitting
secondary progressive
primary progressive
Describe the course of relapsing remitting MS
symptoms come and go. Periods of good health or remission are followed by sudden symptoms or relapses
Describe the course of secondary progressive MS
the onset of MS is of the RRMS pattern. But, at some point later, the disease course changes and neurological function gradually worsens, with or without continued relapses.
Describe the course of primary progressive MS
from the beginning, symptoms gradually develop and worsen over time
Define a relapse in MS
onset of new or worsening of current symptoms
attributable to demyelinating disease
>24hr onset
absence of infection, fever, metabolic disturbance
What are the most common presentations of MS
optic neuritis - partial or total unilateral visual loss, pain on movement, dereased visual acuity, decreased colour sensitivity
transverse myelitis - paresthesia or weakness below level of inflammation
cerebellar problems - ataxia, vertigo, clumsiness, dysmetria
brain stem problems - ataxia, abnormal eye movements, dysphagia
What is Lhermitte’s phenomena
shock like sensation radiating down the spine induced by neck flexion
Give some differentials for MS
neuromyelitis optica low vit B12 Lyme disease tertiary syphilis HIV SLE sarcoidosis brain neoplasm
What is the key diagnostic investigation in MS
MRI head - periventricular lesions and discrete white matter abnormalities
What is the treatment for a relapse of MS
IV or oral steroids - metyhlprednisolone for 5 days
What is the treatment long term for MS
DMARDs - eg. interferon beta
management of long term problems of fatigue, pain etc
What causes a seizure
neurons synchronously depolarising due to increased excitation or decreased inhibition
What are the main excitatory and inhibitory neurotransmitters in the brain
excitatory: NMDA
inhibitory: GABA
Define seizure
transient occurrence of signs and symptoms due to abnormal electrical activity in the brain
What is the difference between a partial seizure and a generalised seizure
partial - only part of the brain is affected
generalised - both hemispheres affected
What is the difference between a simple partial seizure and a complex partial seizure
partial - no loss of consciousness, remember what happened
complex - partial or complete loss of consciousness, may not remember it
What is a secondary generalised seizure
started as partial, becomes generalised
What happens in a tonic seizure
become stiff, flexed. fall backwards
What happens in an atonic seizure
become relaxed, complete loss of tone, fall forwards
What happens in a clonic seizure
convulsions
What happens in a tonic-clonic seizure
increased tone and convulsions
What happens in a myoclonic seizure
short muscle twitches
What happens in an absence seizure
lose and regain consciousness, zones out
What is a Jacksonian march
seizure starts in small area eg hand, then spread to larger eg arm. Can become generalized
What are some of the signs or symptoms of post-ictal period
Drowsiness or amnesia.
Injury, including bites to the sides of the tongue.
Aching limbs or headache.
Focal neurological deficit, that slowly recovers.
What is Todd’s paralysis
a focal neurological deficit, most commonly weakness, that occurs after a seizure
fully recovers after 48 hours
How is epilepsy defined
At least two unprovoked seizures occurring more than 24 hours apart.
One unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures, occurring over the next 10 years.
Diagnosis of an epilepsy syndrome — there are at least 30 different epilepsy syndromes distinguished by their seizure type, age of onset, family history, neurological findings, cerebral imaging (such as CT or MRI scan), electroencephalogram (EEG) pattern, and underlying cause.
What are the causes of epilepsy
idiopathic cerebrovascular disease cerebral tumour post traumatic fetal hypoxia or trauma cortical or vascular malformation cerebral abscess epilepsy syndromes
What are the differential diagnoses for a seizure
What would help you rule these in/out
syncope - postural change, pale. Feel faint/lightheaded beforehand, blurred vision, ringing ears
arrhythmia - prev IHD/SHD, palpitation, breathless, CP
hyperventilation of anxiety - fear, breathless, paresthesia
febrile convulsions - temp >37.8, 6m-5y
alcohol withdrawal - known alcoholic, around 36 hours following cessation of drinking
infantile spasms - flexion of head, trunk and limbs, extension of arms
Psychogenic non-epileptic seizures - history of mental health problems or a personality disorder
What investigations need to be done in a patient presenting with a seizure
obs, LSBP, ECG
glucose, U+E
EEG, MRI
What is the definition of status epilepticus
continuous seizure for 30 minutes or longer,
or recurrent seizures without regaining consciousness lasting 30 minutes or longer.
What is the emergency treatment for a seizure
<5mins
Protect them from injury by:
Cushioning their head with your hands or soft material.
Removing harmful objects from nearby
Do not restrain them or put anything in their mouth.
When the seizure stops, check their airway and place them in the recovery position.
Observe them until they have recovered.
Examine for, and manage, any injuries.
Arrange emergency admission if it is their first seizure.
> 5mins or more than 3 in 1hr
Buccal midazolam as first-line treatment or rectal diazepam
Intravenous lorazepam if intravenous access is already established and resuscitation facilities are available.
Phenytoin after 20 mins
When should an ambulance be called for someone having a seizure
if seizures do not respond promptly to treatment.
Seizures were prolonged or recurrent before treatment was given, particularly if seizures had developed into status epilepticus.
There is a high risk of recurrence, such as a history of repeated seizures or status epilepticus.
There are difficulties monitoring the person’s condition.
This is their first seizure.
What is the first line management of generalised seizures
sodium valproate
or ethosuximide in absence
What is the second line management for generalised seizures?
lamotrigine
myoclonic: levetiracetam or topiramate
tonic/atonic: lamotrigine as adjunctive
What is the first line management of partial seizures
lamotrigine or carbemazepine
What is the second line management of partial seizures
levetiracetam, carbemazepine or sodium valproate
When can one consider stopping antiepileptic drugs?
if seizure free for >2 years
stop gradually over 2-3 months
What are the key side effects of lamotrigine
Stevens-Johnson syndrome
What are the indiations for starting AEDs
second seizure
the patient has a neurological deficit
brain imaging shows a structural abnormality
the EEG shows unequivocal epileptic activity
the patient or their family or carers consider the risk of having a further seizure unacceptable
What is the pathophysiology behind alcohol withdrawal seizures
chronic alcohol consumption enhances GABA mediated inhibition in the CNS (similar to benzodiazepines) and inhibits NMDA-type glutamate receptors.
Alcohol withdrawal is thought to be lead to the opposite (decreased inhibitory GABA and increased NMDA glutamate transmission), therefore leading to over excitation
What are the key side effects of sodium valproate
increased appetite and weight gain alopecia: regrowth may be curly P450 enzyme inhibitor ataxia tremor hepatitis pancreatitis thrombocytopaenia teratogenic (neural tube defects)
What are the key side effects of carbemazepine
P450 enzyme inducer - decreases effectiveness of contraceptives
dizziness and ataxia
drowsiness
leucopenia and agranulocytosis
SIADH
visual disturbances (especially diplopia)
Which contraceptives are recommended to take whilst on carbemazepine?
Why is this?
copper IUD
mirena
depo-provera injection
not metabolised by P-450
What advice is given to patients with epilepsy during pregnancy
risks of uncontrolled epilepsy during pregnancy generally outweigh the risks of medication to the fetus.
All women thinking about becoming pregnant should be advised to take folic acid 5mg per day well before pregnancy to minimise the risk of neural tube defects.
lamotrigine
decreased risk of teratogenicity