Week 18 - Nervous System Flashcards
What type of motor neuron lesion causes hyperreflexia?
Upper motor neuron lesion
What is Parkinson’s disease?
Progressive reduction in dopamine in the basal ganglia leading to disorders of movement
What is the typical patient of Parkinson’s?
Man around aged 70
Gradual onset of symptoms
What is the classic triad of symptoms for Parkinson’s?
Resting tremor
Rigidity
Bradykinesia
What is myasthenia gravis?
Autoimmune condition affecting NMJ
Causes muscle weakness that gets progressively worse with activity and improves with rest
How do you elicit fatigability of muscles?
Repeated blinking -> ptosis
Prolonged upward gazing -> exacerbate diplopia
Repeated abduction of 1 arm -> unilateral weakness
What is the typical patient of motor neuron disease?
60 year old man with an affected relative
What are 4 common signs of lower motor neuron disease?
Muscle wasting
Reduced tone
Fasciculations
Reduced reflexes
What are 3 common signs of upper motor neuron disease?
Increased tone/spasticity
Brisk reflexes
Upgoing plantar reflexes
What drug can extend survival and slow progression of MND?
Riluzole
What are the common causes of death in MND?
Respiratory failure
Pneumonia
What is multiple sclerosis?
Autoimmune condition involving demyelination in central nervous system
What is a typical patient of MS?
Young adult
More likely women
What are key features of optic neuritis?
Enlarged central blind spot (central scotoma)
Pain with eye movement
Impaired colour vision
Relative afferent pupillary defect
When is optic neuritis seen?
Multiple sclerosis
What is ataxia?
Problem with coordinated movement
What is sensory ataxia and in what test is it positive?
Loss of proprioception
Results in a positive Rombergs test = lose balance when standing with eyes closed
What lesion causes sensory ataxia?
Lesion in the dorsal columns of the spine
Which parts of the visual field do not cross at the optic chiasm and which do?
Lateral aspects of vision don’t cross
Medial aspects of vision do cross
Which tract transports information about vibration, proprioception and fine touch?
Dorsal column
What information is carried in the dorsal column?
Sensory
- Proprioception
- fine touch
- vibration
What are the 2 regions of the dorsal column and where do they carry information from?
Fasciculus gracilis = more medial, info from below T6-T8
Fasciculus cuneatus = more lateral, info from above T6-T8 but below the head
What information is carried by the spinothalamic tract?
Sensory
- crude touch
- pressure
- pain
- temperature
What tract transmits info on pain, temperature, crude touch and pressure?
Spinothalamic
At what level do nerve fibres cross over in the spinothalamic tract?
At the level the spinal nerve enters
What type of tract is the corticospinal tract?
Motor - pyramidal
What is the function of a pyramidal tract?
Conscious control of muscles from the cerebral cortex to the muscles of the body and the face
What is the function of extrapyramidal tracts?
Unconscious, reflexive or responsive control of muscles from various brain stem structures
What 3 major cortical areas does the corticospinal tract communicate with?
Primary motor cortex
Premotor cortex
Supplementary motor cortex
Where do nerves of the corticospinal tract converge after leaving the cortical areas?
Internal capsule
At what point does the lateral corticospinal tract cross over?
Medulla
At what point do neurons of the anterior corticospinal tract cross over?
At the level the spinal nerve root enters
This will be in cervical or upper thoracic spinal cord
Where do UMNs of the corticospinal tract synapse with LMNs?
Ventral horn of the spinal cord
What is the main management of an acute attack of MS?
High dose steroid therapy
500mg methylprednisolone oral for 5 days
Or
1g methylprednisolon oral for 3-5 days
What is the long term management of MS?
Disease modifying agents - manage demyelination process
Injectable = beta interferon
Oral = dimethyl fumarate
Monoclonal antibodies = alemtuzumab
What happens to visual evoked potentials in demyelination?
Decreased amplitude and prolonged latency
What drugs can help control spasticity in MS?
Baclofen and gabapentin
What drugs can help neuropathic pain in MS?
Amytriptyline
Gabapentin
What are normal levels for WBCs, RBCs, protein, glucose and pressure in a lumbar puncture?
WBC = 0-5 cells/uL
RBCs = 0-5 /uL
Protein = 0.15-0.45 g/L (<1% of serum conc)
Glucose = 2.8-4.2 mmol/L (>60% serum conc)
Pressure = 10-20 cm H2O
What is clinically isolated syndrome?
Unexplained episode of neurological dysfunction
Features are suggestive of MS but do not meet diagnostic criteria
More likely to get MS in next 5 years
What is relapsing-remitting MS?
No progression between attacks
Unpredictable attacks of neurological dysfunction (>24hrs) followed by recovery
What is secondary progressive MS?
Initially presents as relapsing remitting
Then gets progression
With or without attacks
What is primary progressive MS?
Steady progression of disease from onset
No attacks
What are the causes of MS?
Low vit D
EBV
Smoking
Obesity
What types of plaques are seen in relapsing remitting MS?
Acute active plaques
Many macrophages
What types of plaques are seen in progressive MS?
Chronic
What are the 3 most common symptoms on presentation of MS?
Limb numbness / tingling
Limb weakness
Cerebrellar symptoms
What is Uhtoffs phenomenon? When is it seen?
Worsening of symptoms on exercise or in warm environments
MS
What is Lhermittes phenomenon? When is it seen?
Lightening shock pain down spine on flexion of the neck secondary to cervical cord plaque formation
MS
How can you characterise a previous episode of optic neuritis on a Fundoscopy?
Optic disc pallor
Blurring of optic disc
What happens with the relative afferent pupillary defect when light is shone in eye affected by optic neuritis?
Pupil of healthy eye will constrict when light is shone in it as will contra lateral pupil
In effected eye when light is shone it will not constrict
Which cranial nerve is optic neuritis affecting?
Optic nerve (II)
What is seen in MS when lesions affect cranial nerves III, IV, VI)?
Double vision (diplopia)
Nystagmus
What is nystagmus?
Repeated involuntary movement of the eye
What do lesions in MS affecting CN V do?
Cause facial Parasthesia and or weakness in muscles of mastication
What can lesions in MS affecting CN VII do?
Weakness of facial muscles
Mimics stroke (can still move eyebrows as just UMN)
What do lesions in MS affecting CN VIII do?
Loss of balance and sensorineural deafness
What do lesions in MS affecting CN IX, X and XII do?
Loss of motor function to tongue and pharynx causing speech and swallowing problems
What do lesions in MS affecting CN XI do?
Loss of motor function to sternocleidomastoid and trapezius resulting in neck weakness and hypertonic
What are the results of an LP in bacterial meningitis?
Cloudy
WBCs = elevated (>100/uL)
Protein = elevated (>0.5g/L)
Glucose = low (<40% serum)
Pressure = elevated [>25)
What do these LP results show?
Cloudy
WBCs = elevated (>100/uL)
Protein = elevated (>0.5g/L)
Glucose = low (<40% serum)
Pressure = elevated [>25)
Bacterial meningitis
What LP results are seen for viral meningitis?
Clear
WBCs = elevated (>100/uL)
Protein = elevated (>0.5g/L)
Glucose = normal (>60% serum)
Pressure = normal or elevated
What does this LP result show?
Clear
WBCs = elevated (>100/uL)
Protein = elevated (>0.5g/L)
Glucose = normal (>60% serum)
Pressure = normal or elevated
Viral meningitis
What LP results are seen in tuberculosis meningitis?
Opaque, forms a fibrin web when settled
WBCs = elevated
Protein = elevated (1-5g/L)
Glucose = low
Pressure = elevated
What do these LP results show?
Opaque, forms a fibrin web when settled
WBCs = elevated
Protein = elevated (1-5g/L)
Glucose = low
Pressure = elevated
Tuberculosis meningitis
What LP results are seen in fungal meningitis?
Clear/cloudy
WBCs = elevated
Proteins = elevated
Glucose = low
Pressure = elevated
What do these LP results show?
Clear/cloudy
WBCs = elevated
Proteins = elevated
Glucose = low
Pressure = elevated
Fungal meningitis
What LP results are seen in subarachnoid haemorrhage?
Blood stained initially, with xanthochromia (yellowish) >12 hours later
WBCs = elevated (WBC:RBC 1:1000)
Proteins = elevated
Glucose = normal
Pressure = elevated
What does this LP show?
Blood stained initially, with xanthochromia (yellowish) >12 hours later
WBCs = elevated (WBC:RBC 1:1000)
Proteins = elevated
Glucose = normal
Pressure = elevated
Subarachnoid haemorrhage
What LP results are seen in MS?
Clear
WBCs = 0-20 cells/uL
Protein = mildly elevated (0.45-0.75g/l)
Glucose = normal
Pressure = normal
Electrophoresis = oligoclonal bands present
What do these LP results show?
Clear
WBCs = 0-20 cells/uL
Protein = mildly elevated (0.45-0.75g/l)
Glucose = normal
Pressure = normal
Electrophoresis = oligoclonal bands present
Multiple sclerosis
What LP results are seen in Guillain-Barré syndrome?
Clear
WBCs = normal
Protein = mildly elevated (>5.5g/L)
Glucose = normal
Pressure = normal
What do these LP results show?
Clear
WBCs = normal
Protein = mildly elevated (>5.5g/L)
Glucose = normal
Pressure = normal
Guillain-Barré syndrome
