Neuro Flashcards
What information do the ascending tracts carry?
Is the input from the body contralateral or ipsilateral to the side of the brain that receives it?
sensory info to the CONTRALATERAL cerebral cortex
How many neurons are the ascending tracts made up of? Where are these neurons found?
4
1st order: in dorsal root ganglions
2nd order: spinal cord or brainstem
3rd order: thalamus
4th order: cerebral cortex
What are the 3 key ascending tracts?
- Dorsal column-medial lemniscus
- Spinothalamic
- Spinocerebellar
What information does the DCML tract carry?
vibration, conscious proprioception, 2-point discrimination, fine touch
There are 2 fascicles that make up the DCML: what are they, where in the spinal column are they found and where do they carry information from?
- gracilis fascicle > sensation form lower body (medial part of column)
- cuneate fascicle > sensation from upper body (lateral part of column)
Where does the DCML tract decussate?
dorsal column decussates in the medulla to form the medial lemniscus
What information does the spinothalamic tract carry?
crude touch, pain, pressure, temperature
What happens when the spinothalamic tract enters the spinal cord?
enters ipsilateral spinal cord > ascends 1-2 segments > decussates at this level to form the anterior and lateral spinothalamic tracts
What information does the anterior spinothalamic tract carry vs the lateral spinothalamic tract?
anterior: crude touch and pressure
lateral: pain and temperature
Which receptors detect:
touch/pressure
proprioception
pain
temperature
touch/pressure: mechanoreceptors
proprioception: muscle spindles/golgi tendon organs
pain: nociceptors
temperature: thermoreceptors
What information does the spinocerebellar tract carry?
unconscious proprioception e.g. stance, flexion of joints
= helps to coordinate movements of muscle in the trunk and limbs
What information do the descending pathways carry?
motor information from the brain to the body
What 2 neurons are the descending tracts made up of? Where are they found?
UMNs: in cerebral cortex
LMNs: anterior horns of spinal cord > leave spinal cord as peripheral nerves and innervate muscles
What is the difference between direct/pyramidal and indirect/extra-pyramidal descending tracts?
pyramidal: control fine, VOLUNTARY muscle movements + originate in the primary motor cortex
extra-pyramidal: innervate larger muscles of balance, posture, muscle tone, coordination + originate in the deep nuclei of the brainstem
What are the 3 key pyramidal descending tracts?
- Anterior corticospinal tract
- Lateral corticospinal tract
- Corticobulbar
Which muscles does the anterior corticospinal tract control?
controls muscles of the trunk
Where does the anterior corticospinal tract decussate?
At desired spinal segment
Which muscles does the lateral corticospinal tract control?
controls muscles of the extremities
Where does the lateral corticospinal tract decussate?
At the decussation of pyramids in the medulla
Some UMNs of the corticobulbar tract branch into 2 fibres and synapse with the ipsilateral and contralateral CN nuclei. Which CN nuclei receive dual supply?
V, XI and part of VII - muscles in upper half of face only
Some UMNs of the corticobulbar tract branch into 2 fibres and synapse with the ipsilateral and contralateral CN nuclei. Why is this important in UMN lesions of the CN VII?
Upper half of face receives dual supply from ipsilateral and contralateral UMNS of the corticobulbar tract.
Lower half of the face just receives contralateral supply.
= UMN lesion > forehead sparing
What are the 4 main extra-pyramidal descending tracts?
- lateral vestibulospinal
- reticulospinal
- tectospinal
- rubrospinal
What 3 parts make up the brainstem?
- midbrain (incl. red nucleus, crus cerebra)
- pons
- medulla oblongata
What are UMN lesions caused by?
damage to the brain e.g. stroke, infection, tumour
or brainstem, cerebellum, spinal cord
ie above anterior horn level
What are LMN lesions caused by?
damage to peripheral nerves, nerve root, anterior horn of spinal cord e.g. poliomyelitis
What signs indicate a UMN lesion?
hypertonia
pyramidal weakness (in UL, flexors stronger than extensors and vice versa in LL)
hyperreflexia, +ve Babinski’s
+ve ankle clonus
spastic paralysis
What signs indicate an LMN lesion?
hypotonia
weakness
absent/dimished reflexes, -ve Babinski’s
flaccid paralysis
fasciculations
muscle atrophy
What does CN I control?
olfactory nerve
sensory info about smell
What may be some causes of anosmia?
mucous blockage of nose
head trauma (shearing of CN I)
parkinson’s
What does CN II control?
optic nerve
sensory visual info from retina to brain
no motor
What are some key causes of decreased visual acuity?
refractive errors
amblyopia (lazy eye)
cataract, corneal scarring
age-related macular degeneration
CN II pathology e.g. optic neuritis
Does papilloedema affect visual acuity?
due to optic disc swelling from raised ICP
doesn’t usually affect acuity until late stage
What does CN III, IV and VI control?
motor information to extra ocular muscles to control eye movement and eyelid function
+ parasympathetic fibres for pupillary constriction
oculomotor: all extraocular muscles except:
trochlear: superior oblique
abducens: lateral rectus
How does 3rd nerve palsy present?
affected eye is down and out (due to unopposed action of LR + SO)
+ ptosis and mydriasis
How does 4th nerve palsy present?
up + out position
vertical diplopia when looking down (due to loss of SO pulling eye down) eg walking downstairs
often compensate by tilting head forward and tucking chin in
affected eye elevates more when moved medially
affected iris may be higher than other eye
How does 6th nerve palsy present?
convergent squint (due to unopposed adduction of eye)
horizontal diplopia worsened when looking to affected side
What is the action of the superior rectus?
elevation
What is the action of the inferior rectus?
depression
What is the action of the medial rectus?
adduction
What is the action of the lateral rectus?
abduction
What is the action of the superior oblique?
depresses, abducts and medially rotates
What is the action of the inferior oblique?
elevates, abducts and laterally rotates
What does CN V control?
trigeminal nerve
sensory info about facial sensation
motor info to muscles of mastication
What are the 3 branches of the trigeminal nerve? What do each of them innervate?
V1: ophthalmic > sensation to scalp, forehead, NOSE, cornea of eye
V2: maxillary > sensation to lower eyelid, cheeks, upper lip/teeth/gums
V3: mandibular > sensation to chin, jaw, lower lip/teeth/gums, mouth + motor info to muscles of mastication - masseter, temporalis, pterygoids
What does CN VII control?
facial nerve
motor info to the muscles of facial expression and stapedius muscle (regulates hearing)
+ sensation to anterior 2/3rds of tongue = taste
What muscles are affected in facial nerve palsy caused by a LMN lesion? What is the most common cause of this?
all ipsilateral muscles of facial expression
most commonly caused by Bell’s palsy
What muscles are affected in facial nerve palsy caused by a UMN lesion? What is the most common cause of this?
unilateral facial muscle weakness with forehead sparing (due to bilateral UMN supply)
most commonly caused by stroke
What does CN VIII control?
vestibulocochlear nerve
sensory info about sound and balance from inner ear to brain
no motor
What is conductive hearing loss? What can cause it?
sound unable to effectively transfer at any point between outer ear and middle ear (ossicles)
excess ear wax, otitis externa or media, perforated tympanic membrane
What is sensorineural hearing loss? What can cause it?
dysfunction of the cochlea +/- vestibulocochlear nerve
increasing age, viral infections, excess noise exposure, ototoxic agents e.g. gentamicin
What does CN IX control?
glossopharyngeal
motor info to stylopharyngeus (elevates pharynx during swallowing and speech)
sensory info to posterior 1/3rd tongue for taste
+ visceral sensory fibres mediate afferent limb of gag reflex
What does CN X control?
vagus
motor info to several muscles of mouth involved in the production of speech
+ efferent limb of gag reflex
Does the uvula deviate away or towards the CN X lesion?
away from
What does CN XI control?
accessory
motor info to sternocleidomastoid and trapezius
no sensory
What does CN XII control?
hypoglossal
motor info to extrinsic muscles of the tongue (except for palatoglossus = CN X)
no sensory
How does hypoglossal palsy present?
atrophy of ipsilateral tongue
deviation of tongue towards side of lesion
What are the 3 primary headaches?
migraine
tension headache
cluster headache
Define a migraine
episodic but continuous throbbing headache often preceded by an aura
What are the RFs for a migraine?
FHx
female
age - 1st likely to be in adolescence
What are the common triggers of a migraine?
CHOCOLATE:
Chocolate/cheese
Hangover
OCP
Caffeine
orgasm
lie in
alcohOL
Travel/tumult
Exercise
+ smoking, periods, hunger, sensory
What is the usual pattern of onset of a migraine?
long duration (>4hrs) with recurrent acute attacks
What is the usual severity of a migraine?
moderate-severe, increase in severity more rapidly than a tension headache
POUND describes the main sx of a migraine - what does it stand for?
Pulsating
Onset 4-72hrs
Unilateral
Nausea
Disabling
What are the key sx of a migraine?
unilateral and frontal pulsating headache
worse on head movements/physical activity
N&V
photo/phonophobia
with or without an aura
How does a migraine with aura present?
Aura precedes attack by minutes
Usually visual > flashes, lines/dots/zigzags (fortification spectra), scotoma, hemianopia
May get pins and needles spreading from fingers to phase, dysphasia
How is a suspected primary headache investigated?
mainly clinical diagnosis
exclude other causes e.g. ESR/CRP, BP, papilloedema, examine head/neck
CT/MRI + LP later may be indicated if e.g. thunderclap headache, abnormal neuro exam
What is the acute management of a migraine?
triptans e.g. sumatriptan + NSAIDs
+/- anti-emetic
Do not offer ergots or opioids
What is the prophylactic management of a migraine?
reduce triggers e.g. dietary factors
stop COCP if have aura
1st line = propanolol
2nd line = topiramate (anticonvulsant) = CI in pregnancy/child-bearing age women
3rd line = amitriptyline
A migraine with aura whilst a pt is on the COCP is a RF for what?
ischaemic stroke
What is there a risk of causing when treating migraines?
medication overuse headache
Define a tension headache
bilateral tight band around head
What are the common triggers of a tension headache?
stress, anxiety
sleep deprivation
eyestrain
noise
How long do tension headaches last?
Usually long duration - can last from 30 mins to 7 days
Fluctuating severity
What is the severity of a tension headache?
mild-mod
What are the key sx of a tension headache?
bilateral
pressing/tight band-like sensation, non-pulsatile
+/- scalp tenderness, pressure behind eyes, photo/phonophobia
What sx differentiate a tension headache from a migraine?
does not worsen with physical activity/head movement
no N&V
bilateral
non-pulsatile
What is the management of a tension headache?
Reassurance + lifestyle advice e.g. regular exercise
Avoidance of triggers+ stress relief e.g. acupuncture, ADs
Symptomatic treatment - aspirin, NSAIDs, paracetamol
Limit to no more than 6 days/mo
Which analgesics increase the risk of a medication overuse headache?
opioids
mixed analgesics e.g. paracetamol + codeine
Define a cluster headache
Excruciating unilateral episodic headaches with autonomic symptoms
What are the RFs for a cluster headache?
smoking
male
genetics - AD gene
What can trigger a cluster headache?
alcohol
What is the pattern of onset of a cluster headache?
usually short duration (<4hrs), lasts 15-60mins once/twice per day
usually at the same time, often nocturnal/early morning and wakes from sleep
episodic: clusters of a few weeks and then pain-free periods of months-yrs
or can be chronic
How severe are cluster headaches?
severe-very severe
What are the key sx of a cluster headache?
rapid abrupt onset of excruciating UNILATERAL pain around eye/temple/forehead, usually affects same side
with ipsilateral autonomic features - bloodshot eye with lid swelling, miosis, ptosis, lacrimation, facial flushing, rhinorrhea
What is the acute management of a cluster headache?
100% oxygen for 15 mins via non-rebreathable mask
+ SC sumatriptan
analgesics unhelpful
What is the preventative management for cluster headaches?
Ca2+ channel blocker - verapamil = 1st line
Avoid alcohol
Corticosteroids eg prednisone may help during
How does trigeminal neuralgia typically present?
paroxysmal sharp severe stabbing pain
lasts seconds - 2 mins
unilateral in distribution of trigeminal nerve branches, face screws up with pain
triggered by cutaneous stimuli e.g. light, touch, shaving, washing area, eating, talking
What is the most common cause of trigeminal neuralgia?
compression of CN V by loop of vein/artery
can be 2ndary due to aneurysm/tumour
How is trigeminal neuralgia managed?
anticonvulsants - carbamazepine
surgical options available
analgesics/opioids do not work
What are the most common causes of acute headaches?
infection: meningitis, encephalitis
brain haemorrhage
sinusitis headache
venous sinus thrombosis
post-dural puncture headache after LP/epidural
acute glaucoma
hydrocephalus
What are the most common causes of a chronic headache?
raised ICP e.g. SOL, idiopathic intracranial HTN
medication overuse headache
primary headaches
GCA
trigeminal neuralgia
Define epilepsy.
The recurrent tendency to have spontaneous, abnormal electrical activity in part of the brain, causing sudden attacks of altered behaviour, consciousness, sensation or autonomic function, manifesting in seizures.
What are the RFs for the development of epilepsy?
FHx
lesions/scarring of the brain e.g. stroke, tumour, infection, trauma > focal seizures
in children: premature, prenatal injury, febrile seizures
developmental disorders e.g. autism
alzheimer’s
What are the common triggers for seizures in a pt with epilepsy?
flashing lights
recreational drugs, alcohol, alcohol withdrawal
sleep deprivation
What is the most common cause for epilepsy?
2/3rds idiopathic - can be brain injury, SOL, infection, alcohol etc
often familial
Using the following headings, how is syncope differentiated from a seizure?
timing
prodrome
duration
tonic-clonic movement?
colour change
injury
incontinence
recovery
timing:
seizure: anytime, commonly during activity
syncope: day, usually standing, often after prolonged standing
prodrome:
seizure: brief - twitching, hallucinations
syncope: longer, light-headed, dizzy, confusion, tunnel vision, vertigo, n&v, headache, palpitations
duration:
seizure: variable
syncope: <5mins
tonic-clonic movement:
seizure: common with tongue biting, head turning
syncope: none
colour change
seizure: may be cyanosed
syncope: pallor
injury:
seizure: common
syncope: rare
incontinence:
seizure: common
syncope: rare
recovery:
seizure: post-octal sx - drowsiness, confusion, headache, myalgia, sore tongue
syncope: quick
How does a non-epileptic attack present?
normal colour
eyes closed with active resistance to opening
retained consciousness, combative
pelvic thrust, arching back, erratic movements
What factors should make you think a seizure is due to NEAD not epilepsy?
lots of other unexplained medical/psych problems
no known epilepsy
things that won’t happen in epilepsy:
pt may be able respond to you
may have continuous convulsions
more likely to have normal vital signs
won’t respond to medications
When can NEAD be fatal?
if mistreated with excess medication, can cause respiratory depression
How is an NEAD seizure managed?
correct diagnosis vital - don’t give epileptic medication
reassure pt, wait for it to pass, no medication needed - just time needed to feel better
What are the key differential diagnoses of epilepsy?
cardiac syncope, postural hypotension, vertigo
NEAD
TIA
migraine
hypoglycaemia
dystonia
What are the 4 elements of a seizure?
- prodrome - changes of mood/behaviours, precedes seizure
- aura - part of seizure where pt is aware, manifestations like deja vu, lights, strange feeling in gut (implies focal)
- ictus - attack itself, +ve sx e.g. jerking
- post-ictal - after seizure, -ve sx e.g. weakness, drowsy, headache, confusion, myalgia, sore tongue
What are the 2 categories of epileptic seizure? What is the difference between their presentations?
- primary generalised
- onset of electrical discharge throughout the whole cortex, no localising features
- bilateral symmetrical motor manifestations
- always associated with loss of consciousness - partial/focal
- features restricted to limited part of cortex of one hemisphere
- often have hx of cerebral injury e.g. stroke
- may remain conscious
A partial/focal seizure may later become generalised, what is this called?
secondary generalised seizure
How long does an epileptic seizure usually last?
30 secs - 2 mins
What are the 4 key types of primary generalised seizure?
- generalised tonic-clonic (grand mal)
- absence (petit mal)
- myoclonic
- atonic
Describe a generalised tonic-clonic seizure
epileptic cry at onset
sudden rigid stiff limbs (tonic) followed by bilateral rhythmic muscle jerking
+/- tongue biting, frothing, eyes remain open, incontinence
lose consciousness
postnatal drowsiness and confusion, headache common
often no aura, flashing lights can trigger
Describe an absence seizure
sudden cessation of motor activity/speech > blank stare, blinking, still, pales for few seconds then continue e.g. might stop talking mid sentence then carry on where they left off and not realise
no aura, lasts <30 secs, no post-ictal
may have a few muscle jerks
Who do absence seizures usually affect? What might they develop into?
disorder of childhood
tend to develop into generalised tonic-clonic seizures as an adult
Describe a myoclonic seizure
repetitive but brief isolated shock-like symmetrical jerks of a limb/face/trunk
Describe an atonic seizure?
sudden loss of muscle tone > ‘drop attack’
usually conscious
What is the difference between a simple and complex partial seizure?
simple - consciousness preserved, asynchronous tonic or clonic movements, no post-octal sx +/- aura
complex - impaired consciousness at some point, automatisms common after LoC +/- aura, usually from temporal lobe
What is the most common headache?
tension headache
How does a focal seizure from the temporal lobe present?
aura (80%) - deja-vu, auditory hallucinations, smells, fear, vertigo
anxiety/out of body experience
automatisms - lip smacking, chewing, fiddling
post-octal confusion/headache/dysphasia
What is the main cause of temporal lobe epilepsy?
hippocampal sclerosis
How does a focal seizure from the frontal lobe present?
motor features > posturing, peddling movements
Jacksonian march: motor seizure spreads from hand/foot/face to other areas on ipsilateral side
post-ictal Todd’s palsy: paralysis of limbs involved in seizure for several hrs
more rapid recovery as no post-ictal confusion
How does a focal seizure from the parietal lobe present?
sensory disturbances e.g. tingling/numbness, feeling skin crawl, odd noises
How does a focal seizure from the occipital lobe present?
visual phenomena e.g. spots, lines, flashes
How many seizures need to occur for a diagnosis of epilepsy?
at least 2 unprovoked seizures occurring >24hrs apart
What is the investigation process for suspected epilepsy?
- make diagnosis: clinically, eyewitness important, other causes of LoC ruled out
- determine seizure type: EEG - almost always abnormal during a seizure (cortical spike focus, generalised spike activity)
- identify underlying cause (esp if pt has focal signs): MRI for localised lesions e.g. hippocampal sclerosis, tumour, stroke
- bloods: screen for alternative causes - FBC, U&Es, LFTS, glucose
12-lead ECG
How is an epileptic seizure treated in an emergency? When is a seizure an emergency?
3min+ seizure
ABCDEF(fluids)G(glucose) assessment
1st line: rectal/IV diazepam/lorazepam - repeat x2 until it stops
2nd line: IV phenytoin if still fitting
When is long-term management started after an epileptic seizure?
started after 2nd seizure
or after 1st if high risk of recurrence - neurological defect, +ve EEG, structural abnormality
What is the 1st line management for primary generalised seizures?
men: sodium valproate
women: lamotrigine/levetiracetam
What is the 1st line management for partial/focal seizures?
1st line: lamotrigine/levetiracetam
2nd line: carbamazepine
What non-pharmacological advice should be given to epileptic pts?
must inform DVLA - cannot drive until free of daytime seizures for >1yr
avoid swimming/dangerous sports alone
leave door open when taking a bath
What is the aim with pharmacological treatment for epilepsy?
start on 1 anti-epileptic drug, dose increased until seizure control achieved
aim = MONOTHERAPY, try not to use multiple
1/3rd of pts resistant to treatment
What are the surgical options for epilepsy if medication isn’t working?
if cause identified e.g. tumour > surgical resection, hemispherectomy, non-dom lobectomy
vagal nerve stimulation - less effective
What is status epilepticus?
continuous seizures (>30 mins or 2+ seizures without recovery of consciousness)
tend to occur for 2-3 mins > rest period > more convulsions
What can cause status epileptics in pts with known epilepsy?
most common = poor adherence to medication
infections, worsening of primary cause e.g. tumour, alcohol
What can cause status epileptics in pts with SE as a 1st presentation of epilepsy?
most common = alcohol abuse
acute brain problem: stroke, trauma, infection, hypoglycaemia
In status epilepticus, where should the seizure stop and when does brain injury occur?
T0 = when seizure starts
10 mins/T1 = when seizure should stop
30 mins/T2 = when brain injury occurs
How is status epileptics investigated?
EEG
bloods - FBC, LFTs, U&Es, glucose, BCs if pyrexic
How is status epileptics managed?
Benzos - 2 doses
then AEDs e.g. IV valproate or phenytoin
Find an treat underlying cause
- alcohol related > thiamine
- medication not working > think non-epileptic
can be stopped with anaesthetics = very dangerous
What is the prognosis of status epilepticus?
10% mortality
long-term morbidity e.g. if hypoxic brainn injury occurs
risk of cardio resp failure