Pathology Flashcards
What is the normal volume of CSF
120-150ml at one time
500ml is produced per day so lots of turnover
What does CSF usually contain
Should be clear with some protein and glucose
No RBC, neutrophils and only a small number of lymphocytes
What suggests an infection in the CSF
Increase in the number of neutrophils or lymphocytes
What causes hydrocephalus
Obstruction to flow of CSF - tumour, pus etc
Decreased reabsorption of CSF - post SAH or meningitis
Overproduction of CSF - tumour in the choroid plexus (rare)
What is hydrocephalus
Accumulation of excessive CSF within the ventricular system of the brain
what is the difference between communicating and non-communicating hydrocephalus
Non-com - obstruction to CSF is within the ventricular system
Com - obstruction to flow is outside of ventricle (e.g. in the subarachnoid space)
- all of the ventricles will dilate
How can hydrocephalus present in very young children
If hydrocephalus occurs before the sutures close, then the head enlarges
What is hydrocephalus ex vacuo
When the ventricles dilate due to loss of brain parenchyma and there is a compensatory increase in CSF volume
Seen in Alzheimer’s
What can lead to raised ICP
Hydrocephalus - increase in CSF Space occupying lesion Idiopathic Intracranial Hypertension Oedema Cerebral venous sinus thrombosis Increased venous volume Physiological - hypoxia, hypercapnia and pain
What effects does raised ICP have on the brain
Intracranial shifts and herniation
Pressure on the cranial nerves and vital brain centres
Impaired blood flow
reduced consciousness
How do you work out cerebral perfusion pressure
MAP-ICP
What would a subfalcine herniation cause
Results in weakness and/or sensory loss on the opposite side (particularly in legs)
What would a tentorial herniation cause
Pupil dilation on that side
What would a cerebellar herniation cause
Death = life-threatening as causes brain stem compression
What is a transcalvarial herniation
Swollen brain will herniate through any defect in the dura and skull if there is damage (post-trauma)
What are the early clinical signs of raised ICP
Papilloedema – pressure on the optic nerve
Pupillary dysfunction and vision changes
N and V – due to pressure on the vomiting centre in the brain
Headache – worse when lying down, due to pressure on the dura
Neck stiffness
Decreased consciousness - drowsy
Where do single brain abscesses tend to come from
Local extension - infection in nearby area such as mastoiditis
Direct implantation - due to skull fracture
Where do multiple brain abscesses tend to come from
Haematogenous spread - often from lungs (pneumonia) or heart (endocarditis)
Usually occur at boundary between grey & white matter
What lifestyle factor increases risk of brain abscess
IV drug use
What effect does a brain abscess have
Can cause a mass effect and also leads to oedema
Toxic injury can occur
How does a brain abscess present clinically
Fever
Symptoms of raised ICP
May also have symptoms of the underlying cause
How do you diagnose a brain abscess
CT or MRI
Can aspirate to determine organism and therefore treatment
How do you treat a brain abscess
Weeks of antibiotics
Depends on organism
What is meningitis
Inflammation of the meninges and CSF within the subarachnoid space
What would you see on an LP of someone with meningitis
Abundant polymorphs
Decreased glucose
What features must you ask about in a neuro history
Date of onset Nature of main symptom (e.g. weakness) Associated neurological symptoms Exacerbating / relieving factors Evolution Recurrence
Where can neurological deficits/injury arise from
CNS
PNS
NMJ
or the muscle itself
Which area tends to be affected by a CNS issue
Often whole limb - larger area
Hemi or paraplegia
Which area tends to be affected by a PNS issue
Usually causes distal/peripheral problems
Often localised
Can affect whole limb though
Which area tends to be affected by a NMJ issue
Ocular - vision
Bulbar - speech and swallow
Proximal limb
Which area tends to be affected by a muscle issue
Proximal muscles
usually symmetrical
How does weakness present in a CNS issue
Feeling of heaviness
Due to a combination of numbness and weakness
Pyramidal pattern: arms have weaker extensors and legs the flexors are weaker
Therefore have flexed arms and hyperextended legs
Weakness will be contralateral if brain, below level of lesion if spinal
How does weakness present in a PNS issue
Usually positional - e.g. when asleep
Ascending - works its way up from glove and stocking
Affects distal areas - may be some wasting
How does weakness present in a NMJ issue
As fatiguable
Weakness gets worse when you’ve used to muscle - worse at the end of the day or on repeated movement
Pattern is variable
How does weakness present in a muscle issue
May have insidious onset Muscle wasting Symmetrical and in proximal muscles May be accompanied by aching (myalgia) Hard to rise from chair without using arms
Are sensory symptoms seen in CNS issues
Yes
If in brain it is hemisensory and contralateral to the lesion
If in spinal cord the issue will be below the level of the lesion
(spinothalamic on contralateral side and dorsal column on ipsilateral)
Are sensory symptoms seen in PNS issues
Yes
Pain is often prominent
Typically glove and stocking distribution - peripherals
Are sensory symptoms seen in NMJ issues
No
Are sensory symptoms seen in muscle issues
No
What are the additional features of a CNS pathology
Spasms or jerks
May have sphincter involvement
What are the additional features of a PNS pathology
Cramp Twitching - e.g. fasciculations Distal wasting Loss of grip Tripping up Unsteady when eyes are closed
What are the additional features of a NMJ pathology
Swallowing and speaking difficulty May struggle with lots of chewing/talking Diplopia and ptosis Opthalmoplegia Orthopnoea Worse later in the day
What are the additional features of a muscle pathology
Myalgia - pain
Cramp
May struggle with specific movement - e.g. getting up from a low chair
What physical signs of CNS pathology might you see on inspection
Abnormal limb posture
Upper limb fixed flexion
Lower limb hyperextension
What physical signs of PNS pathology might you see on inspection
Muscle wasting - distal
Fasciculations
Pes cavus
What physical signs of NMJ pathology might you see on inspection
Ptosis
Ophthalmoplegia
What physical signs of muscle pathology might you see on inspection
Proximal wasting
How is tone affected in CNS pathology
Increased
Spasticity or clonus
How is tone affected in PNS pathology
Decreased
Particularly distally
How is tone affected in NMJ pathology
Either the same or slightly decreased if very long standing
How is tone affected in muscle pathology
Either the same or slightly decreased if very long standing
How are reflexes affected in CNS pathology
Increased
How are reflexes affected in PNS pathology
Decreased or absent
How are reflexes affected in NMJ pathology
Usually the same
May be slightly decreased if very long standing
How are reflexes affected in muscle pathology
Either the same or slightly decreased
Reflexes usually retained until pathology is very advanced or long standing
What is the plantar response like in CNS pathology
Get an extensor response
Toes splay out and extend
What is the plantar response like in PNS pathology
Flexor response - normal
Toes curl down
What is the plantar response like in NMJ pathology
Flexor response - normal
Toes curl down
What is the plantar response like in muscle pathology
Flexor response - normal
Toes curl down
What is clonus
Continued jerking after sharp, fast movement
3 beats is abnormal, 6 is pathological
Pathology in the cervical spinal cord will affect which area of the body
The hands and arms
Pathology in the thoracic spinal cord will affect which area of the body
The legs
What kind of disease pattern is seen in CNS inflammatory conditions
Tend to come and go symptom wise
Relapsing and remitting seen in MS
What kind of disease pattern is seen in CNS vascular conditions
Normally a sudden deficit that slowly gets better
What kind of disease pattern is seen in CNS space occupying lesions
Gradual increase in the deficit
What kind of disease pattern is seen in disc prolapse
Disc prolapse issue can come on and get gradually worse or a sudden event can lead to a more intense deficit that stays at that level
How can you test for a bulbar deficit in NMJ pathology
Ask them to count out loud - may decline as goes on
Say tough phrase at the start and end ‘West Register Street
How can you test for a ocular deficit in NMJ pathology
Get them to fix their gaze on a set horizontal point and ask if they develop diplopia
How do you test for ptosis
Get patient to look up for 30secs and see if their eyes start to droop (ptosis)
Ocular issues in a suspected NMJ problem is suggestive of what
Myasthenia Gravis
What causes myasthenia gravis
Autoimmune disease where there are antibodies against the acetylcholine receptors on the post-synaptic membrane
Fewer ACh receptors means transmission becomes inefficient and causes weakness
Loss of action potential leads to lack of muscle contraction
Affects the NMJ
Are you unconscious when asleep
Technically not
It is a state between conscious and unconscious as you can be awoken when stimulated
What is REM sleep
Rapid eye movement
Mostly occurs at the end of the night
EEG will show fast brain activity - similar to being awake
Muscles will be atonic (except diaphragm and eye muscles)
What is Non-REM sleep
Occurs at the start of the night
EEG activity is synchronised and rhythmic
Heart rate, BP and cerebral blood flow are reduced
There is partial relaxation of the muscles
What are the differences between dreams in REM and non-REM sleep
REM dreams – act out a story that you remember (narrative dreaming)
A non-REM dream you will not remember but may feel a strong emotion upon waking
What is the function of deep sleep (non-REM)
This is essential sleep
Allows the cortex to recover after a busy day
What is the function of REM sleep
Mainly for early brain development - important for kids
Adults can cope without
Consolidates memory and possibly deletes unnecessary memory
What role does emotion play in sleep
Brain has to feel ready to go to sleep
States of anxiety will make it feel like you haven’t slept as the brain isn’t rested
Describe the circadian rhythm
This is our ‘body clock’
Has 2 peaks at 4am and 2pm = most tired at these points
Lasts 25 hours
Also controls appetite, hormone secretion, temperature
Varies with age - kids and elderly wake/sleep early whilst teenagers sleep late
What is suspected to reset the circadian rhythm
Light - specifically blue light which is picked up by retinal cells
This is why its harder to wake up in winter when its dark
What are the risks of chronic sleep deprivation
Loss of inhibition and sense of danger
Leads to poor judgement and decision making
Can cause irritability, suspiciousness and even visual illusions
Will end up having lapses in concentration and microsleeps
Missing out on which type of sleep will cause sleep deprivation
Non-REM (deep) sleep
Can get by without REM
Which area of the brain is most effected by lack of sleep
The cortex
It can only rest during sleep
Therefore a lot of the symptoms of sleep deprivation are pre-frontal
How can sleep deprivation kill you
No cases of dying just due to lack of sleep but it would probably kill you
Most common cause is RTA - spikes early hours of the morning
How much sleep do we need
Around 7-7.5 hours a night minimum
Can you catch up on sleep
Nope
Long lie at weekend will not make up for sleep deprivation in the week
What is a REM sleep disorder
People will act out dreams (e.g. kick, running)
Will shout out in sleep
Only an issue if it occurs regularly
Seen in Parkinson’s
List some common parasomnias
REM or non-REM Sleep walking Restless legs Sleep terrors Sleep paralysis
How does narcolepsy present
Daytime sleepiness - may fall asleep during conversations/meals
Cataplexy - sudden loss of muscle tone triggered by strong emotion
If people get very angry or laugh a lot they can suddenly slump to the ground
Hallucinations occurring at sleep onset - hypnagogic
How would you investigate narcolepsy
Overnight polysomnography
Multiple sleep latency test - assess how quickly someone falls asleep
narcoleptics will fall asleep almost immediately and go straight into REM sleep
LP will show low CSF hypocretin
What are the complications of narcolepsy
Job impairment - struggle to stay awake
Increased risk of death in car accidents - shouldn’t drive if not controlled
How does decorticate rigidity present
Upper limb flexed
Lower limb extended and internally rotated
How does decerebrate rigidity present
Arms are extended and pronated
Wrists flexed
Plantars flexed
How does a central cord syndrome present
Affects the medial corticospinal fibres
Get a cape like loss of sensation
What commonly causes a central cord syndrome
Common in the elderly who have cervical injuries or overextension
How does an anterior cord syndrome present
DCML is intact but other tracts affected
Bilateral loss of spinothalamic sensation
What commonly causes an anterior cord syndrome
Usually due to interruption of blood supply in the anterior artery
Can present as spinal shock
How does brown-sequard syndrome present
Ipisilateral loss of motor below the level of the lesion
Loss of sensation on opposite side
What is a common cause of brown-sequard syndrome
Penetrating injury to the back or neck
Stab wound is buzzword
Syringomyelia is a type of what cord syndrome
Central cord syndrome
Due to increased CSF pressure around the cord
What investigation would give you a definitive diagnosis in suspected brain cancer
Biopsy
What investigation would give you a definitive diagnosis in suspected extradural haemorrhage
CT scan
What investigation would give you a definitive diagnosis in suspected SAH
CT angiography
What are the symptoms of cerebral herniation
Cause by raised ICP
Extensor responses - upgoing plantars
Cushing’s triad - hypertension, bradycardia and irregular breathing
Unreactive pupil
What type of herniation is most likely to cause unresponsive pupil
Uncal
What type of back pain gets better when walking uphill
That caused by lumbar stenosis
The lean forward opens up the canal
What type of back pain gets worse with sitting or turning over
Mechanical
How does an anterior circulation stroke present
Higher cerebral dysfunction (e.g. dysphasia).
Homonymous visual field defect
Contralateral motor and/or sensory deficit
How does a posterior circulation stroke present
Cerebellar dysfunction
Isolated homonymous visual field defect
Cranial nerve dysfunction
How does a lacunar stroke present
Purely motor or sensory symptoms
What are sunset eyes a sign of
Hydrocephalus
Upward gaze will be impaired
What are the symptoms of normal pressure hydrocephalus
Ataxia - shuffling gait like Parkinson’s but no stopping issues
Incontinence
Dementia
Disorders of the pyramidal tracts present with what symptoms
Pyramidal weakness
Spasticity
Disorders of the basal ganglia present with what symptoms
Can be hyperkinetic: dystonia, tics, myoclonus, chorea
Or Hypokinetic = rigidity, bradykinesia
What is the Babinski reflex
When you drag a pointer up the sole of the foot the plantar reflex is increased
Toes splay outward
Describe the pattern of upper motor neuron disease
Increased tone - stiffness and spasticity
Minimal muscle wasting
No fasciculations
Clonus present
Brisk reflexes
Extensor plantar reflex - Babinski present
Pyramidal/ corticospinal pattern of weakness (= weak extensors in the arm, weak flexors in the legs)
Central pattern of sensory loss
Describe the pattern of lower motor neuron disease
Muscle wasting - early atrophy Fasciculations Decreased power Decreased tone - flaccid Decreased or absent reflexes No clonus Flexor plantar reflex - normal (no Babinski)
Describe the neurological pattern of functional disorders
No wasting
Normal tone and reflexes
Erratic changes in muscle power - e.g. able to walk but power on the couch is much lower
Migrating and fluctuating sensory patterns
What causes upper motor neuron lesions
Strokes
Space occupying lesions
Spinal cord problems
What causes lower motor neuron lesions
Motor neuron disease
Spinal muscular atrophy
Peripheral nerve issues - diabetes, toxic or metabolic insult
Nerve compression - carpal tunnel etc
What causes neuromuscular junction disorders
Myasthenia gravis - ACh receptor antibodies
Lambert-Easton paraneoplastic syndrome - interferes with calcium channels
What nerve roots are responsible for the ankle jerk reflex
S1 and S2
What nerve roots are responsible for the knee reflex
L3 and L4
What nerve roots are responsible for the biceps reflex
C5 and C6
What nerve roots are responsible for the triceps reflex
C7 and C8
What does a glove and stocking distribution of sensory loss suggest
Length dependant neuropathy
Can range from mild to severe
What does a sensory level distribution of sensory loss suggest
Spinal cord lesion
What does loss of temp/pain sensation but preserved light touch suggest
Hemicord damage
What does the cerebellar gait look like
Broad based
Unsteady
Cannot walk heel to toe (tightrope) - very unsteady
What is dysdiadochokinesis
Clumsy when attempting fast, alternating movements
What are signs of cerebellar disorders
Dysdiadochokinesis Ataxia - cerebellar gait Nystagmus Intention tremor Speech issue - dysarthria Hypotonia
List the key extra-pyramidal symptoms seen in Parkinsonism
Bradykinesia Rigidity Resting tremor Impaired gait and posture - stooped and small steps Impaired postural reflexes Reduced arm swing Hypophonia - slow speech
Are motor symptoms in Parkinson’s disease symmetrical
Nope
They are asymmetrical in Parkinson’s
Symmetry suggests drug induced or atypical parkinsonism
What are the symptoms of large motor fibre damage
weakness, unsteadiness and muscle wasting
Reduced power
Absent reflexes
What are the symptoms of large motor fibre damage
Numbness, paraesthesia, unsteadiness
Reduced vibration sensation
Absent reflexes
What is a high stepping gait suggestive of
Peroneal nerve palsy - causes a foot drop
Often due to an L5 issue - e.g. prolapse
They have to lift their feet up high due to foot drop
Front of shoe may be scuffed
What is mononeuritis multiplex
Neurological issue affecting one side of the body
Can be due to an underlying inflammatory disorder
Lose function quickly
Patchy sensory loss
Can present with wrist or foot drop
What is a radiculopathy
When the nerve root is damaged
Can be due to a disc prolapse or inflammation
What is a plexopathy
Affects a nerve plexus
Traction injuries common cause (especially in kids)
Causes a lot of pain
What is the most common cause of peripheral nerve demyelination?
Guillain-Barre syndrome
How can nerves be damaged (underlying process)
Axonal loss
Demyelination
Trauma
How does demyelination present on nerve conduction studies
Slow conduction
Amplitude is preserved
How does axonal loss present on nerve conduction studies
Loss of amplitude
Can also determine severity
What can cause demyelinating neuropathy
Acute - Guillain-Barre syndrome
Chronic - CIDP or hereditary sensory motor neuropathy
How does Guillain-Barre Syndrome present
Progressive paraplegia over days up to 4 weeks.
Will quickly go ‘off legs’ and lose reflexes
Associated sensory symptoms proceed weakness - tingling or numbness
Peripheral glove and stocking pattern mainly
Severe pain is common
Can lead to breathing difficulty
Describe how Guillain-Barre syndrome progresses
Usually preceeded by some form of infection - e.g. food poisoning
Progressive symptoms over days to weeks
Peak symptoms are usually 10-14 days of onset
Sensory symptoms usually precede weakness
Can lead to breathing problems and death
How can Guillain-Barre syndrome cause death
Through cardiac arrhythmia as the autonomic nerves also become demyelinated
The breathing problems can kill if not dealt with - muscle weakness affects the respiratory muscles too
DONT miss this presentation
How do you treat Guillian-Barre syndrome
Immunoglobulin infusion
or
Plasma exchange
Mechanical ventilation if breathing affected
How do hereditary neuropathies present
Pure motor, sensory, sensorimotor, small fibre and autonomic variants
May get orthopaedic complications - HMSN type 1
Can be axonal loss or demyelinating
Hundreds of possible mutations
Genetic testing is available for the most common types
What can cause axonal neuropathies
Idiopathic - age related Vasculitic - RA or ANCA Paraneoplastic Infections - HIV, syphilis, HB/C Drugs and toxins - alcohol included Metabolic - diabetes, b12, porphyria
Which neuropathies can affect the autonomic nerves
Acute - GBS or porphyria
Chronic - Diabetes, amyloidosis or hereditary
How do you treat axonal neuropathies
Treat underlying cause
Symptomatic - physio, orthotics, pain relief
How do you treat neuropathies caused by vasculitis conditions
Pulsed IV methylprednisolone + cyclophosphamide
What is Lambert Eaton Myasthenic Syndrome
Condition where there are antibodies to presynaptic calcium channels which cause less vesicle release
Associated with small cell carcinoma
May present like myasthenia but need to look for underlying cancer
How do you treat Lambert Eaton Myasthenic Syndrome
3- 4 diaminopyridine.
Which part of the nerve pathway is affected in myasthenia gravis
It is a post-synaptic disorder
Name 2 pre-synaptic NMJ disorders
Botulinum toxicity
Lambert Eaton Myasthenic Syndrome (LEMS)
How does myasthenia gravis present
Muscle weakness and FATIGUE - worse at end of day
Weakness is extraocular (ptosis), facial and bulbar
Limb weakness is typically proximal
Can have rapid onset respiratory issues
Bilateral facial weakness makes it hard to smile
How is the thymus related to myasthenia gravis
75% of patients will have either thymus hyperplasia or a thymoma
Therefore always get a CT chest to look for thymoma if MG is suspected
Who gets myasthenia gravis
2 peaks - Females in 3rd decade and Males in 6/7th decade
Slightly more common in women
Lots of patients will have another autoimmune condition
How do you treat myasthenia gravis
Acetylcholinesterase inhibitor – pyridostigmine (prevents ACh breakdown)
Steroids or steroid sparing agents - slow intro to avoid side effects
Intravenous immunoglobulin - given IV short term
Thymectomy
What drug should you avoid in people with myasthenia
Gentamicin
Precipitates myasthenia crisis in many people – go into respiratory failure
What are fasciculations
Visible, fast, fine , spontaneous twitch
May be seen in normal muscle after stress, caffeine or in fatigue
Occurs in denervated muscles - has become hyper excitable
Usually a sign of disease in the motor neurone
What is myotonia
Failure of muscle relaxation after use
Will look very stiff
e.g. they will shake your hand but be unable to let go as muscle wont relax
What causes myotonia
An issue with the chloride channels
Usually hereditary
Give examples of some immune mediated muscle disorders
Polymyositis - symmetrical and progressive proximal weakness
Dermatomyositis - similar but with skin lesions
How do you grade muscle power
0 – no movement at all
1 - flicker of movement when attempting to contract muscle
2 – some muscle movement if gravity removed but none against gravity
3 - movement against gravity but not against resistance
4 – movement against resistance but not full strength
5 – normal strength
What is myotonic dystrophy
Commonest muscular dystrophy
Autosomal dominant - inherited muscle disorder
Multisystem involvement
Myotonia, weakness, cataracts, ptosis, frontal balding, cardiac defects
Trinucleotide repeat disorder with anticipation
Why must you screen family members if someone presents with myotonic dystrophy
Some other members may only have the heart defects which need to be found before they cause a real issue
Which common drug class is a major cause of myopathy
Statins
lots get myalgia and some get myopathy
What is rhabdomyolysis and how does it present
Breakdown or dissolution of skeletal muscle
Triad of myalgia, muscle weakness and myoglobinuria
Complications of acute renal failure and DIC
What can cause rhabdomyolysis
Damage to skeletal muscle causes leakage of large quantities of toxic intracellular contents into plasma.
This can occur due to crush injuries, toxins, post-convulsions or after extreme exercise - marathons
Is chronic pain considered a disease
Yes it is officially recognised
This hopes to improve coordination and management
What is the definition of pain
An unpleasant sensory and emotional experience, associated with actual tissue damage, or described in terms of such damage
How is pain received
Painful stimulus is recognised
A-delta and C fibres carry it from receptor to spinal cord
This is then sent up to the thalamus which passes them on to the somatosensory cortex
This is the sensory path
The emotional response is cause by the impulse also being sent to the amygdala and hypothalamus
This brings it to attention
What is peripheral sensitisation
Change that occurs in the nervous system after tissue injury
There is a reduction in the threshold of peripheral afferent nociceptors
What is central sensitisation
Change that occurs in the nervous system after tissue injury
There is increased excitability of spinal neurons
Rewiring in the spinal cord and changes in the brain
May be that more pain signals are able to be received
What are the signs of chronic regional pain syndrome
Allodynia - pain caused by a non-painful stimulus Hyperalgesia - increased pain response Swelling Hair and nail changes Osteopenia
What is allodynia
Pain caused by a non-painful stimulus such as being touched by cotton wool
What is nociceptive pain
Pain from injury relayed through a normal nervous system
What is neuropathic pain
Pain generated within the nervous system
How does neuropathic pain present
Burning, shooting, tingling and increased sensitivity
Allodynia and hyperalgesia
What can cause neuropathic pain
Shingles or post-herpetic neuralgia
Surgery
Trauma
Diabetic neuropathy
What medication can be used to treat neuropathic pain
Tricyclic antidepressants - amitriptyline (most common) Anticonvulsant - gabapentin Opioids NMDA antagonists - ketamine Na channel blockers such as lignocaine Capsaicin GABA agonists
What can cause chronic pain in cancer survivors
Post surgical pain Chemotherapy induced painful peripheral neuropathies Chronic graft vs host disease Radiation induced pain syndromes Hormonal therapy and arthralgias
Does the NICU increase risk of chronic pain
YES
If we keep injuring the nervous system (through procedures etc) then they are more likely to have chronic pain
The nervous system develops differently than a term baby
Is chronic pain genetic
Some twin studies suggest a genetic influence but very complex
Which type of ion channels have an effect on pain reception
Voltage gated sodium channels
Many channelopathies that lead to pain disorders
Can cause people to be unable to express pain or leads to extreme pathological pain
What type of amputation leads to more chance of chronic pain
If there is prolonged damage to the limb and a delay to amputation there is more chance of chronic pain
Describe sensory remapping
Common after amputation
Sometimes sensation can be remapped so that areas of the brain responsible for sensation the hand (for example) will redirect and instead when stimulated they feel it in another area (as well as the phantom area)
What is the risk with prescribing opioids for chronic pain
Addiction and potential for overdose
Commonly only used for malignancy pain
Give examples of degenerative diseases of the cerebral cortex
Alzheimer’s
Pick Disease
CJD
Give examples of degenerative diseases of the basal ganglia and brain stem
Parkinson Disease
Progressive Supranuclear Palsy
Huntington Disease
Give examples of degenerative diseases of the motor neuron disease
Motor Neuron disease
Which cancers are most likely to metastasise to the brain
Breast, bronchus, kidney, melanoma, colon
What can lead to central herniation through the foramen magnum
SOL
Haemorrhage
What is the most common posterior fossa tumour in children
Medulloblastoma
Can lead to hydrocephalus by compressing the ventricular system and causing CSF to build up
What cellular processes occur after brain tissue is damaged
Macrophages come in and clear up the dead cells (this leads to liquefaction)
After this all that is left is a space
What takes up the majority of the space in the skull
The brain - 80%
CSF and blood make up the rest
Describe the Monroe-Kellie principle
There are 3 intracranial components (brain, blood and CSF) if one of them increases in volume or you add a 4th (tumour, abscess) then the ICP must rise
What can cause a physiological rise in ICP
Coughing
Bending forward
Straining
Can ICP ever be negative
Yes
Seen in new-borns, sedated patients or when standing vertically
What is the immediate compensation for raised ICP
CSF is pushed out of the foramen magnum into the spinal canal
Sinuses can become squeezed to reduce blood volume
How do you calculate the cerebral perfusion pressure
MAP-ICP
What will obstruction to CSF flow lead to
Hydrocephalus
What cerebral perfusion pressure will lead to a loss of consciousness
Below 20
Patient will become comatose
What is the effect of high CO2 in the blood
CO2 is a potent dilator – high CO2 in blood will cause vasodilation
What can affect the blood flow to the brain
pressure changes, metabolic changes, stretch response or CO2 levels
Cerebral flow is autoregulated
What is chiari syndrome
Cerebellar tonsils protrude into the foramen magnum and block CSF flow
Leads to obstructive hydrocephalus
What type of brain tumour can produce CSF
Choroid plexus papilloma
Usually only seen in children
What is the normal ICP in adults
7-15mmHg
What are the late clinical signs of raised ICP
Coma Fixed, dilated pupils Can have hemiplegia Bradycardia (Cushing’s triad) Hyperthermia Increased urinary output (BP trying to compensate)
How do you manage raised ICP or hydrocephalus
Maintain CPP and prevent ischaemia
Maintain head in the midline to facilitate blood flow
Loosen jewellery, collars etc
Set the head of the bed to 30-45 degrees
Avoid anything that could lead them to raise ICP – coughing, gagging etc
Decrease environmental stimuli
Treat the hyperthermia
Maintain the fluid balance and normalise electrolytes Keep CO2 at normal level
What medications can be used in the treatment of raised ICP
Use diuretics (mannitol, furosemide etc) Anti-epileptics Barbiturate coma (reduces brain function to a minimum)
What surgery can be used in the treatment of raised ICP
Surgical decompression - remove part of the skull to allow pressure to escape
Remove any mass lesions and drain abscesses
CSF shunts - from ventricles to peritoneal space
What is the risk of craniotomy
Leads to disfigurement and the cranioplasty to repair carries a large risk
What can cause communicating hydrocephalus
Meningitis
Trauma
SAH
What can cause non-communicating hydrocephalus
Colloid cyst
Tumours
Chiari syndrome
What are the physical signs of hydrocephalus
Sunset eyes – unable to look up due to midbrain pressure
Broad, flat face is a sign in kids
Enlarged head in very young children
How does normal pressure hydrocephalus present
Abnormal gait - wide based and shuffling
Urinary incontinence
Dementia - mild
Called Hakim’s triad
Who gets normal pressure hydrocephalus
The elderly
Its idiopathic
How does normal pressure hydrocephalus appear on scans
Large sylvian fissure
Enlarged ventricles
Crowned brain (a lot of brain up at the top of the skull – pushed up by pressure)
Angle between the lateral ventricles is 90’ or less
How do you treat normal pressure hydrocephalus
VP shunt, medium or low-pressure valve
Who gets idiopathic intracranial hypertension
Usually young and common in women of child-bearing age
Some will develop it in pregnancy and get better after birth
Mainly in western civilisations
Usually overweight - biggest risk factor
What are the symptoms of idiopathic intracranial hypertension
Debilitating headaches Double vision and blurriness Reduced visual acuity Tinnitus (often pulsatile) Radicular pain (affects arms) Papilloedema Unsteadiness
What is the main complications of idiopathic intracranial hypertension
Permanent visual loss
Seen in 25% of patients
How does the CT scan appear in idiopathic intracranial hypertension
CT will be normal
These patients never have enlarged ventricles
What causes idiopathic intracranial hypertension
Exact cause is unknown
May be due to CSF imbalance, hormones (oestrogen) or venous pressure
What investigations are done for idiopathic intracranial hypertension
LP
CT/MRI head
CTV - venogram
Fundoscopy
How can you treat idiopathic intracranial hypertension
Reduce pressure with LP and drainage
Weight loss
Carbonic anhydrase inhibitors - acetazolamide, topiramate
Diuretics
CSF diversion - shunt
Interventional radiology - venous stents
ONSF (optic nerve sheath fenestration)
What is mechanical pain
Pain on movement
If a problem presents acutely what are the likely causes
Trauma
Vascular
If a problem presents over days or weeks what are the likely causes
Infection
If a problem presents over weeks to months what are the likely causes
Tumour
Degenerative disease
What is cervical myelopathy
Compression of the upper MN
Leads to hyperreflexia and hypertonia
Will have a spastic gait and positive Hoffman’s test
Which type of haemorrhage has a lucid interval
Extradural
What is pronator drift
Get the patient to hold their arms out with their eyes closed
If one side is weaker it will slowly drop
Seen in upper MN conditions
What are the signs of cerebellar pathology
Dyskinokinesia Ataxia Nystagmus Intention tremor Staccato speech Hypotonia
Spastic gait can be seen in which conditions
Cervical myelopathy - unilateral
Cerebral palsy
Which gait is seen in cerebral palsy
Spastic
Scissoring - legs are so stiff that they almost end up crossing them when swinging forward
Those who have had a stroke can present with which type of gait
Flexed arm - flexors stronger
Stiff and straightened leg - extensors stronger
Will swing leg round in a circular motion to stop foot scraping
How are reflexes affected by UMN lesions and LMN lesions
UMN - hyperreflexia
LMN - hyporeflexia
How can timescale help you diagnose the underlying cause of a neuro issue
Acute - infection or vascular
Days/weeks - infection
Weeks/months - tumour or degenerative
Night pain is a red flag for which cause of back pain
Cancer
Focal tenderness may be elicited over the site of mets
Night sweats are a red flag for which cause of back pain
TB
A trendelenberg gait is seen in which conditon
In someone which weak hip abductors
e.g. osteoarthritis
How does cervical myelopathy present
Spastic gait
Increased tone in hands - struggle with fine motor skills
Clumsiness - dropping things a lot
Legs jump at night - hyperreflexia
Poor balance if they shut eyes - loss of proprioception
How does lumbar claudication present
Commonly in the elderly - degenerative
Bilateral tingling, numbness, heaviness and occasionally pain
Decreased walking distance
Improves on leaning forward - e.g. when walking uphill or leaning on shopping trolley
Why does lumbar claudication improve on leaning forward
It is in part caused by a thickened ligamentum flavum which narrows the spinal canal
When you lean forward this ligament changes shape and gets thinner - opening canal and improving symptoms
What makes the headache caused by raised ICP worse
Worse on waking, lying down, bending forward, coughing, vomiting
What initial test would you do in clinic if you suspect raised ICP
Fundoscopy to exclude papilloedema
List general red flags for neurology
Focal neurology
Change in behaviour
New onset seizure
How does cauda equina present
Saddle paresthesia
Genital numbness
Erectile dysfunction
Painless urinary retention with urinary incontinence.
How does functional weakness present
Variable power with normal bulk, tone & reflexes
May have collapsing weakness - before you put any pressure on them their limb collapses back down
Power may vary depending on how distracted the patient is - i.e. normal on the ‘trick’ tests such as Hoovers
Acute unilateral weakness is usually due to what
Stroke
What conditions can cause acute generalised weakness
Guillain-Barre syndrome,
Myasthenia
Myopathy
Cord pathology.
What is the pyramidal pattern of power changes
weak extensors in the arm, flexors in the leg
Glove and stocking sensory loss is common in which condition
Peripheral neuropathy
Starts in toes and works up to knees before hands become involved
What is a resting tremor
A tremor which is no worse with action
Seen in Parkinsons
What is a pill-rolling tremor
A subtype of resting tremor seen in the index and thumb only
Looks like they are rolling something in their fingers
Seen in Parkinson’s
What is a postural tremor
Tremor most obvious in outstretched hands
Comes on with certain positions
What can cause a postural tremor
May be physiological
Increases with anxiety, hyperthyroidism and medication eg
thyroxin, lithium and sympathomimetics
What is an intention tremor
Tremor which is worse during movement, especially when moving towards a target when past-pointing may occur
Intention tremors are seen in which conditions
It is typically
associated with cerebella disorders, although severe forms occur with
ischaemia or demyelination of the red nucleus.
What are the most common causes of peripheral neuropathy
Diabetes
Alcohol - nutrition and toxicity
Idiopathic - generally age related
Are peripheral neuropathies typically asymmetrical or symmetrical
Symmetrical
What is the difference between occular and generalised myasthenia
Ocular myasthenia is purely eye involvement
Generalised will include limbs, neck, bulbar symptoms
How do you diagnose myasthenia gravis
Antibody testing
Electrophysiology test
Always get a CT chest - look for thymoma
How do essential tremors present
Postural
Generally symmetrical
No change in tone
Often have family history
How does a cerebellar tremor present
Action/intention tremor
Can be symmetrical or asymmetrical depending on pathology
May have reduced tone
How might eyes be affected in cerebellar pathology
Nystagmus
Eyes may also goes past the point and have to come back - kinda like an intention tremor
How can you test for fatiguable muscle weakness
Shoulder abduction before and after repetitive movement (flap arm 20x then test again)
How do extra-pyramidal tremors present
Resting tremor
Can be brought out by distracting the patient, may come with cog-wheeling
Asymmetrical
Will have rigidity
What features in a history make a swallowing problem more likely to be neurological
Dysphagia to liquids then solids
Do steroids have a role in the treatment of Guillian-Barre syndrome
No
Unlike many neurological disorders, there is no evidence for steroids in GBS
How do you diagnose Guillian-Barre syndrome
Neurophysiology
- Generally a demyelinating picture (decreased conduction velocity but normal amplitude of AP)
Lumbar puncture
- high protein with no cells
- excludes infective mimics
Antiganglioside antibodies
- Seen in 60% of cases
Those presenting with functional disroders may complain of which symptoms
Migrating and fluctuating sensory patterns
Motor symptoms - lack of control over limbs, heavy limbs, collapsing limbs
Memory problems are usually exaggerated - persistent and more pronounced
Often lots of fluctuation - some days very distressed and cant remember anything, other days are fine
Often have balance issues - not vertigo or lightheadeness, mainly internal feeling
What is a conversion disorder
When a psychological trauma in past is not dealt with and presents as a neurological deficit
Now considered to be different to FND
How do you manage a functional disorder
- Explaining a functional disorder to patients can be usuful - e.g. Hardware vs software issue
Don’t go overboard as it is very confusing
May scan them to look for any underlying issue - usually normal
Neuropsychology can help with cognitive symptoms
How can Hoover’s test be used to find a functional disorder
If you ask them to push their ‘weak’ leg into the bed they will often lack power
However, then tell them you are testing the other side and ask them to lift the ‘unaffected’ leg up
In order to do they you unconsciously press down with the other leg - therefore you know the nerves are intact and power is in fact normal
What is a benign essential tremor
A sporadic and slower subtype of resting tremor
Typically maximal in the upper limbs, head, jaw and tongue
When might an upper motor neurone issue present with flaccidity
When associated with spinal shock
Initial flaccidity
List general causes of somatosensory disturbance
Pathology affecting peripheral nerves, nerve roots, or the CNS sensory
pathways from the spinal cord to the cerebral cortex.
Physiological stimuli affecting a normal nervous system, such as hyperventilation, transient pressure on a nerve, transient ischaemia
or drug treatment
Transient dysfunction of sensory cortex in epilepsy and in migraine
Psychiatric or psychological illnesses
What is parasthesiae
A burning or prickling sensation
Pins and needles
What is hyperpathia
Where the pain threshold of one area is much lower
Painful stimuli are much more painful than usual
How does functional weakness present
Variable power with normal bulk, tone & reflexes
Acute unilateral weakness is typically caused by which pathology
Stroke
What is polyradiculopathy
Diffuse disease of the nerves causing generalised weakness
List UMN causes of weakness in all 4 limbs
Cervical cord lesion
Brainstem lesions
Bilateral cerebral lesions
MND - affects both UMN and LMN
List LMN causes of weakness in all 4 limbs
Polyradiculopathy
Peripheral neruopathy
MND - affects both UMN and LMN
List UMN causes of weakness in both legs
spinal cord lesion
List LMN causes of weakness in both legs
cauda equina lesion
List UMN causes of weakness in one leg
lesion above highest level
List LMN causes of weakness in one leg
single nerve = monotherapy
single root = radiculopathy
List causes of patchy weakness
multiple CNS lesions
polyradiculopathy
multiple single nerves
mononeuritis multiplex
