Neurology Flashcards
What is Horner syndrome? - PAM is Horny
When sympathetic supply to the eye is affected
Sympathetic system can’t perform function of dilating the eye and opening the eye wide.
Ptosis, anhidrosis, miosis
usually underlying problem like stroke, tumour, spinal cord lesion
state and describe headache red flags
Onset - thunderclap, acute, subacute
Meningism - photophobia, phonophobia, stiff neck, vomiting
Systemic symptoms - fever, rash, weight loss
Neurological or focal signs - visual loss, confusion, seizures, hemiparesis, double vision, 3rd nerve palsy, Horner syndrome, papilloedema
Orthostatic-better lying down
Strictly unilateral
state some vascular and circulatory causes of headaches
- subarachoid hemorrhage
- acute intracerebral bleed (fatal hemorrhage due to coning)
- chronic subdural hemorrhage
- carotid and vertebral artery dissections
- temporal arteritis
- central venous thrombosis
what are some symptoms of a subarachnoid hemorrhage?
what are causes?
Thunderclap headache
meningism - stiff neck and photophobia
Usually occipital
Most caused by a ruptured aneurysm
Few caused by arteriovenous malformations, some unexplained
how do you treat and monitor a subarachnoid hemorrhage
Nimodipine (to reduce vasospasm and resulting ischemic infarct). And BP control
Diagnose with CT, Lumbar puncture (bloody or yellow) and MRA, angiogram
Treat aneurysms with platinum coiling
State some symptoms of a carotid and vertebral artery dissection
Headache and neck pain
Mean age 40, carotid > vertebral
Vertebral - occipital headache, Carotid - eye and forehead
How do you diagnose and treat carotid and vertebral dissections?
MRI/MRA, Doppler, Angiogram
Aspirin or anticoagulation
features of chronic subdural hemorrhage?
Bleeding Veins
Dark blood on scan in comparison to white blood on subarachnoid scan. Darkness shows the blood has already begun to decay
Common in old people
what is temporal arteritis?
what are the features?
Inflammation of temporal arteries
More common in females over 55
Constant unilateral headache, scalp tenderness, jaw claudication
25% Polymyalgia Rheumatica- proximal muscle tenderness
Blindness - if involvement of posterior ciliary arteries
how do you diagnose temporal arteritis?
biopsy (shows disruption of the internal elastic lamina and giant cells with nuclei)
what are some causes of central venous thrombosis?
Thrombophilia, pregnancy, dehydration and Behcets are causes
Optic disc swelling due to raised ICP is ___
papilleodema
What are the symptoms of meningitis?
Headache, Fever, Stiff neck, photophobia. Sometimes rash
confusion, alteration of consciousness
Treatment and diagnosis for meningitis?
antibiotics
blood urine culture
lumbar puncture after CT and MRI
Hemorrhagic changes in the temporal lobe can occur after meningitis infection with which virus?
Herpes Simplex
features of sinusitis?
(Malaise, headache, fever)
- Loss of vocal resonance, anosmia, catarrh, local pain and tenderness
- Opacification of paranasal sinus - blocked nasal passages
- Frontal pain 1-2 hours of waking and clears in afternoon
state 2 infective causes of headaches
- meningitis
2. sinusitis
state raised intracranial pressure causes of headaches
- brain tumour -e.g. glioblastoma multiforme
- Idiopathic intracranial hypertension
- chiari malformation
- sleep apnoea
How does IHH appear on imaging.
what are the risk factors for IHH?
cerebral oedema with effacement of ventricles and sulci but no mass lesion.
female sex, obesity
what are the symptoms of IHH
Tinnitus, Headache + various visual symptoms - visual obscurations, diplopia, papilloedema, visual field loss.
Associated with central venous sinus stenosis
treatment for IHH?
Weight loss, diuretics, optic nerve sheath decompression, lumboperitoneal shunt, stenting to treat dural venous sinus stenosis.
Why does sleep apnoea cause a headache?
How do you treat it?
Hypoxia, C02 retention causes vasodilation of brain blood vessels
sleep study, nocturnal NIV
What is the cause of a low pressure headache?
These are caused by low CSF pressure or volume
Spontaneous or provoked (e.g. tear in dura during spinal anaesthesia, after lumbar puncture)
How do you diagnose and treat a low pressure headache?
MRI scan + contrast agent - this will give you characteristic meningeal enhancement
Rehydration, caffeine, blood patch
state 2 facial pain causes of headaches
trigeminal nerve neuralgia
atypical facial pain
what is trigeminal nerve neuralgia?
how do you treat it?
Electric shock like pain in the distribution of a sensory nerve. can be a symptom of MS
carbamazepine, posterior fossa decompression
What are the features of atypical facial pain?
how do you treat it?
Common in middle aged depressed or anxious women
Daily, constant poorly localized deep aching or burning in facial or jaw bones, may extend to neck, ear or throat
No sensory loss
Pathology in teeth, temporomandibular joints, eye, nasopharynx and sinuses must be excluded.
tricyclics
How do you treat post traumatic headache
NSAIDS, tricyclics antidepressants
Narrowing of joint space due to worn disc
Usually bilateral
Occipital pain can radiate forwards to the frontal region
Steady pain, worsened by moving the neck
these are features of what condition?
cervical spondylosis
inflammation of meninges caused by viral or bacterial infection is _____
___ is inflammation of the brain caused by infection or autoimmunity - see wbcs around vessels
___ ___ inflammation of blood vessel walls/angiitis
____ is infection of the spinal cord known as?
meningitis
encephalitis
cerebral vasculitis
myelitis
Symptoms of encephalitis?
Initially flu like symptoms (headache, fever, aches, fatigue) Altered mental status Altered behaviour and personality speech/movement disorders Seizures
What types of infections can cause encephalitis and meningitis?
Mainly viral for encephalitis and bacterial for meningitis
What diagnostic tests can be performed for Encephalitis?
CT scan, MRI scan, lumbar puncture, EEG
Features of Multiple Sclerosis?
autoimmune demyelination of CNS (brain and spinal cord)
MRI shows white periventricular plaques.
Perivascular cuffing - t cells and B cells
Leptomeningeal inflammation
what are the phases of a migraine
Prodrome: Changes in mood, urination, fluid retention, food craving, yawning
Aura: Visual, sensory (numbness/paraesthesia), weakness, speech arrest
Headache: Head and body pain, nausea, photophobia,phonophobia
Resolution: rest and sleep
Recovery: mood disturbed, food intolerance, feeling hungover
4-72 hours
How do you treat an acute migraine attack?
Non-steroidals and paracetamol and metoclopramide (anti-emetic) to prevent nausea
Triptans-tablets (vasoconstrictors) - Synergise with
NSAIDS
A short nap, TMS
What does Migraine prophylaxis for people with chronic migraines (more than 14 a month) involve?
Over-the-counter preparations: feverfew, coenzyme Q10, riboflavin, magnesium, EPO, nicotinamide
Tricyclic antidepressants Beta-blockers Serotonin antagonists Calcium channel blockers Anticonvulsants Greater occipital nerve blocks Botox: crown of thorns Suppress ovulation (progesterone only pill or implant/injection)
what are the 3 forms of migraine attacks?
Pain
Pain and focal symptoms
Focal symptoms
How is Erenumab used in migraine prophylaxis?:
An anti-CGRP Monoclonal antibody
disables calcitonin gene-related peptide or its receptor (CGRP mAbs)
What is a Tension type headache?
treatment?
Tight muscles around head and neck bilaterally
No photophobia, phonophobia or aura
>30 minutes. Constant
Acute - NSAIDs
Prophylaxis - Tricyclic antidepressants - Amitriptyline
Extreme unilateral periorbital pain lasting 15-180 minutes untreated. And repetitive
May present with horner syndrome - “PAM” symptoms
At least one of the following, ipsilaterally:
- Conjunctival redness and/or lacrimation
- Nasal congestion and/or rhinorrhoea
- Eyelid oedema
this describes what type of headache?
cluster
how do you treat a cluster headache
Acute - Inhaled oxygen, S/C or Nasal Sumatriptan
Prophylaxis - verapamil
what are some key features of a migraine?
- pulsatile
- unilateral
- nausea
- sensitivity to light and sound
- prodrome & aura
how do you treat dementia?
- acetylcholinesterase inhibitors - not a cure
what are some reversible causes of dementia?
Depression, alcohol related brain damage, hypothyroidism, B1/B2/B12 deficiency, benign tumors
what tests are carried out for dementia and what are potential findings?
neurological examination(MoCA, ACE) + focused tests
(MMSE)
bloods
MRI (narrower gyri, wider sulci, ventricles enlarged, medial temporal volume loss, hippocampal volume loss and replacement with CSF)
PET (for B-amyloid)
___ dementia can manifest as behaviour variant or primary progressive aphasia
fronto-temporal
____ ____ dementia can manifest as visual haLEWYcinations, fluctuating cognition, REM sleep disorder. cognitive impairment before or within one year of Parkinsonian symptoms
Lewy Body
___ dementia is related to CVD and shows a step-wise deterioration
Vascular dementia
what causes lewy body dementia?
what do tests show?
Caused by aggregation of alpha-synuclein, leading to deposition of lewy bodies
- preserved hippocampal and temporal volume
- DAT scan - decreased availability of dopamine transporter in caudate and putamen
what are the histological/gross findings in Alzheimer’s?
- widespread cortical atrophy especially in hippocampus -> impairment of episodic memory
- Alpha beta amyloid deposits
- phosphorylated tau
- narrowing of gyri, widening of sulci
what are the histological/gross findings in Alzheimer’s?
fronto-temporal lobe degeneration
What are the different types of generalised seizures?
Absence - blank stare
Myoclonic - quick, repetitive jerks
Tonic-clonic - patient contracts muscles (stiffening), followed by rhythmic jerking. Urinary incontinence, tongue biting may occur. post-ictal confusion. classic seizure.
Tonic - muscle stiffening, fall - usually backwards
Atonic - muscle relaxation. Drop seizures. fall- usually forwards
What are the different types of Partial (focal) Seizures?
Simple partial(consciousness intact) - motor, sensory, autonomic, psychic
Complex partial(impaired consciousness)
What type of seizure is characterised by motor or sensory abnormalities in 1 muscle group?
partial seizure
Most Epilepsy drugs are sodium channel ___ or GABA receptor ___
Blockers
Agonists
What is the mechanism of Lamotrigine? Name a serious side effect
blocks voltage gated Na+ channels
SJS
What is the mechanism of Sodium Valproate? Name two serious side effects
blocks sodium channels
Inhibits GABA transaminase so increases GABA
Hepatotoxicity. Neural tube defects.
What is the mechanism of Levetiracetam?
SV2A receptor blocker - prevents vesicle exocytosis and glutamate release
What is the mechanism of Benzodiazepines
increases GABA action
Diazepam increased frequency of Cl- channel opening - increased chloride ion influx
which drug can decrease the concentration on lamotrigine and therefore decrease seizure control?
OCP
Essie, who takes lamotrigine, noted that she had more seizures during the second and third week of the 4-week contraceptive cycle. Why?
how do you solve this problem?
4th week = placebo
earlier weeks = active pill
increase dose of lamotrigine in weeks 2-3
what is status epilepticus?
what is the 1st line treatment?
seizures for >5min or recurring seizures
benzodiazepines.
1st line = IV Lorazepam
2nd line = IV diazepam or buccal midazolam
Effect of oestrogen and progesterone on seizures?
Oestrogens are seizure promoting and progesterone is seizure inhibiting.
Many women have an increased frequency of seizures during days 10-13 (periovulatory estrogen peak)
when a patient is on lamotrigine, what is an alternative to OCP?
progesterone implant
Effect of pregnancy on seizures?
Increasing seizure frequency - changes in liver metabolism of lamotrigine
What are saccadic eye movements? State the different types
short fast burst,
•Reflexive saccade to external stimuli
•Scanning saccade
•Predictive saccade to track objects, Memory-guided saccade
What are Smooth Pursuit eye movements? What causes this?
Slow movement – up to 60°/s - Driven by motion of a moving target across the retina.
What are the major actions of the eye muscles?
Lateral rectus - lateral movement
Medial rectus - medial movement
Superior rectus - elevation
Inferior rectus - depression
Superior oblique - depresses and intorts the eye
Inferior oblique - elevates and extorts the eye
Describe the innervation of the muscles of the eye
LR6SO4R3
Lateral rectus - abducens
Superior oblique - trochlear
Rest - oculomotor nerve - nerve also raises eyelid and constricts pupil
What are the findings in a 3rd nerve palsy?
Down and out eye
Ptosis
Pupillary may be dilated:
- Dilation shows parasympathetic nerves running on outside of CN3 have been damaged. E.g compression by mass like PComm Aneurysm (headache present)
- Absence of dilation suggest ischemia as cause (common in diabetics)
What happens in a 6th nerve palsy?
Eye displaced medially
Double vision worsens on gazing to the affected side
Function of optokinetic nystagmus reflex test?
useful in testing visual acuity in pre-verbal children
In the eye, Crossed Fibres originate from __ __ and are responsible for ___ visual field
Nasal retina
Temporal
In the eye, uncrossed Fibres originate from ____ ____ and are responsible for __ visual field
Temporal retina
Nasal
What does a lesion to the optic nerve or retina result in?
Anopia in that eye
What is the effect of lesion to the RIGHT optic tract or RIGHT occipital lobe?
LEFT homonymous hemianopia
What is the main cause of a homonymous hemianopia?
stroke
Main cause of horizontal vs vertical field defect?
Vertical - neurological
Horizontal - eye condition
when would you get a right nasal hemianopia?
Only right eye affected
When only the uncrossed fibres in the optic tract are affected.
___ causes constriction of the pupil and innervation is parasympathetic
miosis
__ causes Dilation of the pupil and innervation is sympathetic
myDriasis
Describe the pupillary reaction to light/ miosis
1st neuron = Edinger-Westphal nucleus -> ciliary ganglion via CN III
2nd neuron = short ciliary nerves -> pupillary sphincter
Describe the pupillary reaction to light/ miosis
1st neuron = Edinger-Westphal nucleus -> ciliary ganglion via CN III
2nd neuron = short ciliary nerves -> pupillary sphincter
Describe the pupillary reaction to darkness/ mydriasis
Sympathetic stimulation causes radial muscles to contract
What happens when you shine light in one eye?
pupils constrict bilaterally
What causes holmes adies pupil? What are the key findings?
Blocked parasympathetic innervation due to damage to damage to ciliary ganglion
Dilated pupil unresponsive to light.
Absent reflex and impaired sweating may occur if there is damage to dorsal root ganglion in spinal cord
No findings consistent with CN3 palsy
Pilocarpine is a drug that acts on ___ receptors in iris sphincter muscle and brings about ____
muscarinic
miosis
What is light near dissociation? Name a condition that can cause it.
More meiosis due to accommodation than due to light
Adies pupil - damage to ciliary ganglion
Anisocoria (difference in pupil size) can be seen in what 3 conditions?
Horner - small
Adies pupil and CN3 palsy - larger
What happens if there is a Right Afferent Defect? E.g. damage to optic nerve
No pupil constriction in both eyes when right eye is stimulated with light
Normal pupil constriction in both eyes when left eye is stimulated with light
What happens if there is a Right Efferent Defect? e.g. damage to right 3rd nerve
No pupil constriction in the right eye when the right eye is stimulated. Pupil constriction in left
Pupil constriction in left eye when stimulated. No pupil constriction in right
Causes include CN 3 palsy with pupil involvement, holmes adie pupil
Describe the two types of lens
Convex - takes light rays and bring to a point - e.g. eyes and camera
ConCave - takes light and spreads them out
What is emmetropia?
Adequate correlation between axial length and refractive power
Parallel light rays fall on retina - no need for accommodation
What is ametropia?
Give examples of conditions with ametropia
Miss-match between axial length and refractive power
Parallel rays don’t fall on the retina
- near-sightedness (Myopia)
- Hyperopia Farsightedness
- Astigmatism
- Presbyopia
What happens in myopia? How do you treat it?
Eye too long for refractive power of cornea and lens - axial myopia
OR excessive refractive power - refractive myopia
Light focused in front of the retina
Correct with concave lens
Need Medical Doctors - Near Sightedness is the same as Myopia and requires a Diverging lens
What happens in hyperopia? How do you treat it?
Eye too short for refractive power of cornea and lens - axial hyperopia
Or insufficient refractive bower - refractive hyperopia
Light focused behind retina
Correct with convex lens
symptoms of Hyperopia?
Blurring close up , Eye pain, headache in frontal region, burning sensation in eyes, blepharoconjuctivitis
ambylopia
___ is uncorrected hyperopia in one eye
What happens in astigmatism? How do you treat it?
Abnormal curvature of the cornea - different refractive power at different axes. -
Parallel rays focus in 2 focal lines
“circle of least confusion”- least loss of image definition
Cylindrical lens
symptoms of astigmatism
Headache, eye pain
Blurred vision,
distortion of vision,
head tilting and turning
What happens in presbyopia and how do you correct it?
Aging-related impaired accommodation (focusing on near objects)
Due to decrease in lens elasticity, changes in lens curvature, decrease in strength of ciliary muscle
Reading glasses.
state and describe the near response triad
- Accommodation - circular ciliary muscle contract, relaxation of zonules and increased refractive power. Lens thicken, increase curvature
- Convergence
- Pupillary miosis
Describe the innervation of the lacrimal system
Afferent - cornea, V1 cranial nerve
Efferent - parasympathetic (acetylcholine)
Describe the production and drainage of tears
Produced by lacrimal gland
Drain through two puncta into superior and inferior canaliculi
Gather in tear sac and exit through tear duct into nasal cavity
what are the functions of the tear film?
Oxygen supply to the cornea,
Removal of debris,
Bactericide,
Maintains smooth cornea air surface
State the layers of the tear film and their functions
Mucus layer - maintains surface wetting
Middle water layer
Upper lipid layer - reduces tear film evaporation
___ is the white of your eye
sclera
___ is the clear dome that covers the iris
cornea
___ is the thin transparent tissue that covers the entire front of your eye (except for the cornea) and lines the inside of the eyelids.
conjuctiva
on an image of the eye, label:
- iris
- pupil
- cornea
- lens
- ciliary body
- suspensory ligament
- fovea
- sclera, choroid, retina (3 layers of the eye)
image in notes
function of the cornea?
refraction. focusing of light (2/3)
what happens if you hydrate the cornea?
it becomes white
State the 3 parts of the uvea.
Where does it lie?
Iris, Ciliary body, Choroid - highly vascular and lies between sclera and retina
function of the lens?
1/3 of focusing power
the visible part of the optic nerve is known as the ___ ___
optic disc/blind spot
___ is located in the centre of the retina and is responsible for detailed central vision
macula
___ is located in the centre of the ____. it has a high concentration of ___ and low concentration of ____
fovea
macula
cones
rods
what is the role of your central vision?
- detail day vision
- colour vision
- reading and facial recognition
- assessed using visual acuity assessment
what is the role of your peripheral vison
- shape, movement, night vision, navigation
- assessed using visual field assessment
what is the role of your peripheral vision
- shape, movement, night vision, navigation
- assessed using visual field assessment
Describe the layers of the retina and cells that make them up
- Outer layer - photoreceptors (rods and cones) - first order neurons
- Middle layer - bipolar cells - regulate sensitivity - second order
- Inner layer - retinal ganglion cells - transmission to brain -third order
distinguish between the functions of rods and cones
Rods - scotopic vision
More sensitive to light than cones, Slow response to light
Responsible for peripheral and night vision and spatial vision
More common
Cones - photopic vision
less sensitive to light, Faster response
Responsible for central and day vision
Recognizes detail and color
How are cones classified? State the different types
By wavelength
S-cones - blue
M-cones - green
L-cones - red
what is dueteranomaly?
Colour blindness where you don’t perceive red
what is achromatopsia?
Full colour blindness where you see the world in black and white
what is the colour blindness test called?
Ishihara test
main function of parietal lobe?
sensation - touch pain
spatial orientation
main function of frontal lobe?
motor function, planning movements
main function of occipital lobe?
visual information
main functions of temporal lobe
auditory information
memories
Amygdala, hippocampus, mammillary body, Cingulate gyrus are all components of what?
limbic system
functions of the limbic system?
Feeding (satiety & hunger)
Forgetting (memory) - Important
Fighting (emotional response)
Family (sexual reproduction and maternal instincts)
Fornicating (sexual arousal)- important
insular cortex function?
Lies deep within lateral fissure
Visceral sensations, autonomic control, interoception, auditory processing, visual-vestibular integration
What are the functions of white matter tracts? Name the different types
Connect cortical areas
- Association fibers - connect areas within the same hemisphere
- Commissural fibers - connect homologous structures in left and right hemispheres
- Projection fibers - connect cortex with lower brain structures e.g. thalamus, brain stem and spinal cord
Identify some association fibres and state their functions
superior Longitudinal Fasciculus - connects frontal and occipital lobes
Arcuate Fasciculus - connects frontal and temporal lobe. Connects brocas and wernickes
Inferior Longitudinal Fasciculus - connects temporal and occipital lobes
Uncinate Fasciculus - connects anterior frontal and temporal lobes
Identify two commissural fibres from an image
Corpus callosum - top red
Anterior commissure - bottom red
Projection fibres radiate as the __ ___. They are also congregated into the __ ___ when passing through the thalamus and basal ganglia
corona radiata
internal capsule
Effect of frontal lobe lesion?
Changes in personality, inappropriate behavior
Effect of frontal lobe lesion?
Changes in personality, inappropriate behaviour
effect of parietal lobe lesion?
A lesion in right hemisphere will cause contralateral neglect
effect of temporal lobe lesion?
agnosia - inability to recognize
anterograde amnesia (damage to hippocampus)
Effect of lesion to Broca’s ?
which region of the brain is it located?
Expressive aphasia - broken speech, stuttering, stopping
Frontal lobe
Effect of lesion to wernickes?
Which region of the brain is it located?
Receptive aphasia - fluent but meaningless speech
Temporal
Effect of lesion in primary visual cortex?
blindness in the corresponding part of the visual field
Effect of lesion in visual association area?
prosopagnosia: inability to recognise familiar faces or learn new faces (face blindness)
State applications of TMS in the medical field
Depression, epilepsy, migraine, tinnitus
State applications of TDCS in the medical field
depression, epilepsy, pain
___ __ is an autoimmune condition. Resulting in the loss of myelin from neurons of the CNS
multiple sclerosis
what are some of the main symptoms of MS?
Blurred vision, fatigue, difficulty walking, numbness/tingling, muscle stiffness and balance
in peripheral nerve stimulation, what is an M wave?
Activation of motor axons causing AP to travel down in nerve to muscle and cause contraction/twitch
Fast response
Recorded on an EMG
in peripheral nerve stimulation, what is an H reflex?
Stimulus activates sensory neurons which then travel to spinal cord & activate lower motor neurons
Twitch but also feeling of response
Reflex activation, takes
longer than M wave
in peripheral nerve stimulation, what is an F wave?
Large electrical stimulation of Motor neuron can cause them to conduct antidromically
goes from motor neuron to spinal cord (wrong way) then back to motor neuron
Contraction/twitch
Not reflex
in peripheral nerve stimulation, what type of waves are activated with varying stimulus?
Low stimulus - sensory nerves only activated - h reflex and absent m wave
Higher stimulus - sensory and motor neuron activation
Very high - can cause an f wave
What does TMS of the motor cortex activate?
Activate upper motor neurons which cause AP to travel to lower motor neurons and cause contraction
Can measure a motor evoked potential (MEP)
Total motor conduction time (TMCT) = time from brain to muscle = MEP latency
How do you calculate peripheral motor conduction time?
It is the time from spinal cord to muscle
Can be calculated using
PMCT = (M latency + F latency -1)/2
-1 = time taken for action potentials arriving at the lower motor neuron to turn around
How do you calculate central motor conduction time? CMCT
Time taken to travel from brain to spinal cord
CMCT = TMCT - PMCT
Describe the effect of Multiple sclerosis on brain stimulation and peripheral nerve stimulation
Brain stimulation - TMCT is delayed - problem can be along upper or lower motor neurons or both.
peripheral nerve stimulation is normal. problem is in the CNS
what blood vessels supply the brain?
- Common carotid artery
- Arises from brachiocephalic artery
- Divides into external carotid which feeds the face and internal carotid artery which goes up to the brain via the carotid canal - Vertebral artery:
- Main branch of subclavian artery
How does venous blood drain in the brain cavity?
label a diagram of the venous system in the brain
Cerebral veins -> venous sinuses in the dura matter -> internal jugular vein
Drains via superior sagittal to the back of the head (confluence of sinuses) then drains laterally down through sigmoid sinus and into internal jugular vein
What are the general symptoms of intracranial hemorrhage?
Headache, loss of consciousness, drowsiness (typical signs due to increased ICP)
How does an extradural hematoma manifest? What are the findings on Head CT
trauma, immediate clinical effects (arterial, high pressure)
Biconvex blood collection, does not cross the suture lines, may cause midline shift due to high ICP. hyperdense blood. Lucid interval for patient
How does a Subdural hematoma manifest? What are the findings on CT?
trauma, can be delayed clinical effects (venous, lower pressure).
Blood is between dura and arachnoid space
Crescent shaped, can cross suture lines, can cause midline shift
Acute = hyperdense CT, chronic = hypodense
How does a subarachnoid hemorrhage manifest? What are findings on CT?
ruptured aneurysms
White areas in the middle of the brain brain between lobes
What is the main cause of intraparenchymal hemorrhage?
Hypertension - hemorrhages due to hypertension occur in regions like Putamen, cerebellum
What are the risk factors for stroke?
Age, Hypertension, Cardiac disease, Smoking, Diabetes mellitus
symptoms of a stroke?
F - ace
A - rm
S - peech
T
visual field defects
loss of consciousness
What are anterior cerebral artery stroke symptoms?
Paralysis of contralateral structures (leg > arm, face). Supplies the lower limbs more
Disturbance of intellect, executive function and judgement (abulia) as artery is in frontal lobe
Loss of appropriate social behaviour
symptoms of a stroke?
F - ace
A - rm (paralysis of limbs)
S - peech
T
visual field defects
loss of consciousness
What are posterior cerebral artery stroke symptoms?
homonymous hemianopia
Visual agnosia
What are the major descending tracts of the spinal cord?
Pyramidal tracts:
- Corticospinal tract - voluntary movement of body
- Corticobulbar tract - voluntary movement of face
Extrapyramidal tracts: (involuntary movements of balance, posture, locomotion)
- Vestibulospinal,
- tectospinal,
- reticulospinal,
- rubrospinal
What are some signs of an Upper Motor neuron lesion?
*generally things go up Hyperreflexia Spasticity (increased muscle tone) Clonus \+ve babinski's sign *disuse atrophy *no fasciculations
What are some signs of a lower motor neuron lesion?
Hyporeflexia
Flaccidity
*denervation atrophy
*fasciculations
State 2 symptoms that can present in both UMN and LMN lesions
weakness
dysphagia
what is Apraxia?
- Result of upper motor neuron lesion
- Lesion of inferior parietal lobe, frontal lobe (premotor cortex, SMA)
- Patients are not paralyzed but have lost information on how to perform skilled movements
- Stroke and dementia most common cause
What is motor neuron disease? MND/ALS
Progressive neurodegenerative disorder of the motor system
Affects both upper and lower motor neurons
A ____ babinski sign occurs in UMN lesions. Toes curl ____ and fan out. This helps differentiate from a LMN lesion.
positive
upwards
The putamen and globus pallidus are collectively known as ____ ___
lentiform nucleus
The putamen and caudate nucleus are collectively known as the ___
striatum
what is the function of the basal ganglia?
- Coordinates voluntary movement
- Receives input from motor cortex -> provides feedback to cortex to stimulate and inhibit motor activity -> complex movement
State 3 movement disorders of the basal ganglia
- Parkinsons disease
- Huntingtons disease
- hemiballism
State 3 movement disorders of the basal ganglia
- Parkinsons disease
- Huntingtons disease
- ballism
what causes Parkinson’s?
Degeneration of dopaminergic neurons of substantia nigra pars compacta
What are some symptoms of Parkinson’s disease?
Parkinson TRAPSS your body
Tremor - pill rolling at rest Rigidity (cogwheel) Akinesia or bradykineia Postural instability Shuffling gait Small handwriting
What causes Huntington’s disease?
Degeneration of GABAergic neurons in the striatum-> atrophy of striatum
Chromosome 4, autosomal dominant.
CAG repeat
what are some symptoms of huntingtons disease?
Chorea
Speech impairment,
Difficulty swallowing
Irritability, depression
Cognitive decline and dementia
what causes ballism?
Lesion in subthalamic nucleus e.g stroke
symptoms of ballism?
Uncontrolled flinging of extremities
Contralateral symptoms
What is the function of the vestibulocerebellum?
GAIT, POSTURE, equilibrium
Coordination of head movements with eye movements
A lesion to ___ can result in gait ataxia and tendency to fall even when sitting and eyes open. It is similar to vestibular disease.
vestibulocerebellum
Damage to _____ mainly affects legs (LIMB movement) it results in a wide-based gait and is associated with chronic alcoholism
spinocerebellum
Damage to ___manily affects arms. It affects SKILLED movements (tremor) and speech.
cerebrocerebellum
what are the main signs of cerebellar dysfunction?
Ataxia - impairment of coordination- disturbance of posture or gait
Dysmetria
Intention tremor
Dysdiadochokinesia - inability to perform rapidly alternating movements
Scanning Speech - staccato
What are alpha motor neurons? What is their function?
Lower motor neurons of the brainstem and spinal cord
Occupy the ventral horn
Innervate the extrafusal muscle fibers - activation causes contraction
what is the motor neuron pool?
All the alpha motor neurons that innervate a single muscle
describe some properties of a slow/Type 1 motor unit
smallest diameter cell bodies
Small dendritic trees
Thinnest axons thus slow conduction velocity
Describe the 2 ways in which the Brain regulates muscle force
Recruitment - slow fibres first
Rate coding
describe how muscle fibres can change
IIB to IIA most common after training
I to II possible In severe deconditioning, spinal cord injury, microgravity
Aging causes loss of type I and II fibres but preferentially II
state 2 pieces of evidence for inhibitory control dominating and preventing reflexes
- decerebration
2. jendrassik manoeuvre
in the control of reflexes, what neurons innervate and alter the sensitivity of sensory neurones?
gamma motor neurones
What makes up the outer ear? Function?
Pinna, auditory canal and tympanic membrane
Transfers sound waves via vibration of tympanic membrane
What makes up the Middle ear? Function?
3 bones/ossicles: malleus, incus, stapes
Amplification of sound from tympanic membrane to inner ear - Focusing vibrations from tympanic membrane to oval window
What makes up the Inner ear? Function
Cochlea
Cochlea transducers vibration into nerve impulses.
Basilar membrane vibrates -> vibration transduced by specialised hair cells -> auditory nerve signalling -> brain stem
State and describe the compartments of the cochlea
Scalia vestibuli - bone structure - contains perilymph (high in Na+)
Scala Tympani - bone structure - contains perilymph
Scala Media - membranous - endolymph (high in K+) - contains the hearing organ/organ of Corti
Where does the organ of corti lie?
basilar membrane
In the basilar membrane, high frequency is heard best at the ___ which is ___ and low frequency is heard best at the ____ which is ___ .
Base
Thin and rigid
Apex
Wide and flexible
What is the function of the tectorial membrane?
Cause Hair deflection which depolarises the cell
In contact with OHCS which then contact IHCs
What is the function of the tectorial membrane?
Cause Hair deflection which depolarises the cell
What is the function of the outer hair cells
Modulation of the sensitivity of response -amplifier
Carry 95% of EFFERENT info
If OHC brings tectorial membrane closer to inner hair cell, __ of sound occurs and vice versa
transmission
Describe how the hair cells bring about transduction
- Deflection of steriocillia towards the longest cilium will open K+ channels
- Depolarization and neurotransmitter release
- Higher amplitudes = greater deflection of stereocilia and K+ channel opening
Describe how the hair cells bring about transduction
- Deflection of steriocillia towards the longest cilium will open K+ channels
- Depolarization and neurotransmitter release
- Higher amplitudes = greater deflection of stereocilia and K+ channel opening
What happens to sound that enters the cochlea?
Enters as a result of vibration of tympanic membrane and ossicles and focusing onto oval window - Goes in through the oval window - vibration of the perilymph which goes around the cochlea - vibration of the basilar membrane - organ of corti lies on this - deflection of stereocilia brought about by tectorial membrane contacting hair cells - opening of K+ channels
what happens if sound is too soft?
Outer hair cells will contract - shorten its length to make tectorial membrane come closer to cillia of inner hair cells
and vice versa
the downward phase of movement of the tectorial membrane and hair cells causes ____.
The upward phase causes ____
hyperpolarisation
depolarisation
Describe the auditory pathway following sound transduction
Label a diagram as well
Cochlea -> cochlea nerve -> cochlea nucleus (impulse crosses and is transduced bilaterally) -> superior olive -> inferior colliculus -> medial geniculate body (in thalamus) -> primary auditory cortex
In the auditory cortex, going from front to back, the frequency of sound _____
increases
what is the human range of hearing?
20-20,000Hz
0dB to 120 dB
what is most commonly damaged in hearing loss?
OUTER hair cells
___ is aging-related bilateral hearing loss often of ____ frequencies due to destruction of hair cells at the cochlea ____
presbycusis
high
base
What 4 procedures can be carried out during hearing assessment?
- Tuning fork - Rinne test, Weber Test
- Audiometry/PTA
- Central processing assessment - sound localization, filtered speech, speech in noise
- Tympanometry - creates variations of air pressure in the air canal - used to test the condition of the middle ear and mobility of the eardrum
What is the implication of these graphs on a tympanogram:
- A ?
- B ?
- C ?
INSERT PICTURE***
A:
- normal
- peak compliance occurs at near atmospheric pressure indicating normal pressure within the middle ear
B:
- no sharp peak little to no variation with pressure
- middle ear effusion, tympanic membrane perforation, occluded ear canal, eustachian tube dysfunction
C:
- negative middle ear pressure
What are the 3 different types of hearing loss?
- conductive
- sensorineural
- mixed
what happens in conductive hearing loss?
give examples of conditions that cause this
- problem in outer or middle ear problem with conduction or amplification of sound
causes:
- wax
- otitis or otosclerosis in middle ear
what happens in sensorineural hearing loss?
give examples of conditions that cause this
- problem in inner ear or the auditory nerve. Transduction problem
causes:
- presbycusis
- ototoxicity in inner ear
- VIII nerve tumor in nerve
In conductive hearing loss, bone conduction is ____
Normal
bone conduction bypasses outer and middle ear and stimulates cochlea
In sensorineural hearing loss air conduction and bone conduction are ___ affected
both
How do you treat hearing loss?
Treat underlying cause like wax
Hearing aids, Cochlear implants, Brainstem implants
How do cochlear implants function?
- Replaces the function of the hair cells
- Receives sounds and sends an electrical impulse directly to auditory/cochlea nerve
- So requires functioning auditory nerve
What treatment can be given for hearing loss due to auditory nerve damage?
brainstem implant
What are the 3 main inputs of the vestibular system
Visual
Proprioceptive
Vestibular information
What are the main outputs of the vestibular system?
ocular reflex
postural control
where is the vestibular organ?
In the posterior area of the inner ear
Inner ear contains hair cells for balance as well as hearing
State the structures that make up the vestibular organ
Label them on a diagram
otoliths organs - utricle and saccule
3 semi-circular canals - anterior, lateral, posterior
what movement do semicircular canals respond to?
angular
What is the function of hair cells in the vestibular organs during head movement?
Allows the cells to depolarize with movement of endolymph generated by movement of head.
How are hair cells arranged in the otolith organs?
located on maculae in the otoliths organs.
placed horizontally in the utricle
placed vertically in the saccule
Why are utricle and saccule called otoliths organs?
Have otoliths/crystals on top of the hair cells that help with hair cell movement
state 3 substances contained in the maculae
Hair cells
Gelatinous matrix
Otoliths/crystals on top
Where are hair cells located in the semicircular canal?
In the ampulla - Crista ampullaris
What brings about movement of hairs in the semicircular canal?
Head movement - endolymph flow - Cupula displacement closes the ampulla - helping deflection of the cilia
The vestibular nerve transmits impulses from the vestibular organ to the vestibular nucleus in the brain stem. Where do the vestibular nuclei project to?
look at diagram of the vestibular pathway to aid understanding
DOWN, BACK, UP AND VERY UP
- Down = SPINAL CORD (vestibulospinal tract) -> ends at muscles -> postural changes. lateral tract to limbs, medial to neck and back
- Back = CEREBELLUM -> vestibulocerebellum
- Up = CNVI, CN IV, CN III nuclei/ nuclei of extraocular muscles via medial longitudinal fasiculi -> Vestibulo-ocular reflex (VOR) which keeps image fixed on retina
- Very Up -> ventroposterior nucleus in thalamus -> vestibular cortex (awareness of sensations)
Where is the vestibular cortex thought to be located?
Parieto-Insular Vestibular Cortex (PIVC). This is in the parietal lobe
Functions of the vestibular system?
Postural control
Detect and inform about head movements
Keep images fixed in retina during head movement
What type of stimulation do Otoliths organs respond to?
linear acceleration and tilt
Utricle - Horizontal plane movement
Saccule - Vertical
What happens during the Vestibulo-ocular reflex?
Eye turns in opposite direction to head
How do you assess the vestibular system?
Anamnesis , Posture and gait , Cerebellar function, Eye movements
Vestibular tests: vHIT, VEMP etc
Imaging
Symptoms and impact assessment
What are the main symptoms of a balance disorder?
dizziness
vertigo
what are peripheral vestibular disorders?
Give examples of causes
- vestibular disorders of labyrinth or VIII nerve (inner ear)
- vestibular neuritis
- BPPV (abnormal presence of crystals in the scc canals)
- Ménière’s disease
- unilateral and bilateral vestibular hypofunction
what are central vestibular disorders?
Give examples of causes
stroke, MS, tumour
Distinguish balance disorders using evolution
Acute - vestibular neuritis, stroke
Intermittent - BPPV
Recurrent - Meniere’s Disease, Migraine
Progressive - tumour, MS
