Neuro Flashcards
Ulnar claw
Mild extension at 4th and 5th MCPJ and relative flexion of the fingers
Which muscle differentiates a C8/ T1 lesion from ulnar lesion? Ie not a radiculopathy but an ulnar neuropathy
Abductor policis brevis - median nerve
Hoffmans sign
Hold DIPj and flick the finger
Thumb and index finger flex
Causes of peripheral neuropathy
Metabolic: Diabetes
Hypothyroid
Uraemia
Vitamin B1/ 6/ 12 deficiency
Toxic: chemo, alcohol
Inflammatory: CIDP, sarcoidosis, vasculitis, RA
Paraneoplastic: lung cancer, paraproteinaemia
Predominantly sensory: DM, alcohol, drugs, vit b deficiency
Predominantly motor: GBS and botulism acutely, lead toxicity, porphyria, HSMN ie CMTD
Why do we do nerve conduction studies for peripheral neuropathy?
Determine if it is demyelinating or axonal
Demyelinating = more likely to be inflammatory condition ie CIDP
Why is nerve conduction studies useful in HSMN?
HSMN type 1 is demyelinating
Type 2 is axonal
(HSMN also known as Charcot Marie tooth)
Inheritance of CMTD
Type 1 is autosomal dominant
how to differentiate a posterior stroke from a middle cerebral artery stroke with visual field defects
They both have homonomous hemianopia but a posterior stroke has macular sparing
How to differentiate a middle cerebral stroke from trigeminal neuropathy?
Test sensation on the neck - trigeminal neuropathy will have intact sensation on neck
Corneal reflex will be intact in hemispheric damage
How to differentiate cerebella versus sensory ataxia?
Cerebellar ataxia will have nystagmus and dysarthria
Sensory ataxia will have impaired sensation, particularly proprioception and vibration. They will also have pseudo athetosis in the upper limbs. Removing the visual input exacerbate the ataxia
What causes both central and peripheral sensory ataxia
B12 deficiency
lower motor neuron signs and peri oral fasciculations
Kennedys disease
Bulbar dystrophy
X linked
Very slow to progress
MND drug
Riluzole
Cerebellar ataxia and peripheral neuropathy
Alcohol
RAPD also known as
Marcus Gunn
Features that might be associated with retinitis pigmentosa that indicate it is part of a syndrome
Sensorineural deafness
Ataxia
If suspecting Parkinson’s what other tests should you do during the exam and why?
Opening finger and thumb
Check for gaze paresis = progressive supranuclear palsy
Ataxia = multi systems atrophy
Also offer to assess function ie buttons, hand writing
Parkinson’s like but affecting lower limbs predominantly
Vascular PD
Which hemisphere is language centre?
Left
So aphasia associated with RSW
Which nerve palsy in raised ICP?
6th
Friedrichs ataxia genetics
Triplet repeat
Recessive
Frataxin gene
Friedrichs features
Young adult, wheelchair or ataxic gate
Pes Cavus
Bilateral cerebella ataxia
(Nystagmus, Dysarthria)
Leg wasting with absent reflexes but bilateral upgoing planters
Posterior column signs i.e. loss of vibration and proprioception
Plus
Kyphoscoliosis optic atrophy, high arched palette, sensory neural deafness HOCM diabetes dementia
Causes of upgoing planters with absent knee jerks
Friedrichs ataxia
Sub acute combined degeneration of the cord
Motor neuron disease
Taboparesis
Conus medullaris lesions
Combined upper and lower pathology i.e. cervical spondylosis with peripheral neuropathy
What is spastic paraparesis?
Increased tone and reflexes bilaterally with pyramidal weakness
Causes of spastic paraparesis
Demyelination i.e. MS
Cord compression
Trauma
MND ie anterior Horn cell differential
Cerebral palsy
Stroke
Differentials for spastic paraparesis plus a sensory level
Cord compression
Cord infarction
Transverse myelitis
Spastic paraparesis with dorsal column loss
Demyelination
Friedrichs ataxia
SACD of cord
Syphilis
Cervical myelopathy
Spastic paraparesis and spinothalamic loss
Syringomyelia
And anterior spinal artery infarction
Spastic paraparesis and cerebellar signs
MS
Friedrick ataxia and
Arnold Chiari malformation
Spinothalamic tract
Pain temperature
Decussates at spinal level
Dorsal column tract
Proprioception, vibration and fine touch.
Decussates at the medulla
Corticospinal
Movement of limbs/motor neurons and spinal cord.
Decussates at the pyramids in the medulla
Charcot Marie tooth disease what is it
Inherited peripheral neuropathy,
Autosomal dominant mostly but there are lots of types
Motor more than sensory
Features of CMTD
Distal wasting of limbs (inverted champagne bottle)
Claw hand pes Cavus weak ankle Dorsi flexion and toe extension i.e. foot drop with high stepping gait
stocking distribution of sensory loss scoliosis reduced reflexes
Why is EMG helpful in CMTD?
Help to differentiate between axonal/demyelinating to help direct genetic testing of family
Polio what is it
Enterovirus transmitted by Faeco-oral route affecting the motor neurons in the anterior horn and brain stem
MDT for Huntington’s
Dieticians important as increased basal metabolic rate
Neuro psych
Myasthenia gravis what is it
Acquired autoimmune condition with antibodies against the postsynaptic neuromuscular junction characterised by painless muscle fatigue and associated with thymus and other autoimmune diseases
Triggers for myasthenia gravis
Aminoglycosides, surgery and tapering Meds, starting steroids
Myasthenia gravis crisis
Need to do vital capacity at bedside.
Give IVIG sometimes plasmapharesis is needed
Causes of bilateral cerebellum syndrome and how to tell
1) MS - INO/ RAPD/ UMN weakness/ optic atrophy
2) paraneoplastic - cachexia, clubbing, tar staining
3) SOL or b/l POCS - weakness, visual field defect, papilloedema
Causes of unilateral cerebellum syndrome
MS
POCS/haemorrhagic
SOL in posterior Fossa
Mainly sensory causes of peripheral neuropathy
Alcohol
B12/ B1/ folate deficiency
Diabetes
Uraemia
Chemotherapy
Isoniazid
CIDP
Sarcoid
RA
Paraneoplastic
Causes of predominantly motor peripheral neuropathy
GBS
CMTD
Porphyria
Botulism
Lead toxicity
Causes of mononeuritis Multiplex
Diabetes
SLE RA
Vasculitis
Infection i.e. HIV
Malignancy
How does EMG study differ for axonal versus demyelinating conditions?
Axonal shows reduced amplitude.
Demyelinating shows reduced velocity
Causes of demyelinating peripheral neuropathy
CIDP and GBS
Surgical sieve for myelopathy causes
Trauma i.e. disc protrusion
Malignancy
Infections – abscess HIV
Autoimmune MSOSLE
Nutritional – B12 and copper deficiency
Radial nerve innovation and palsy
C5 to T1
Sensation loss over posterior arm/ forearm/ radial 3 1/2 fingers
Weakness of posterior
Absent triceps and Braco reflex
At rest wrist drop
Auxiliary nerve palsy
C5-6
Numbness over deltoid, weakness of deltoid, arm adducted and internally rotated
Median nerve palsy
C5 – T1
Ulnar nerve palsy
C8-T1
Weak wrist flexion, abd/adduction of fingers (claw hand)
MG clinical tests to confirm
Fatiguable ptosis - worse after looking up for a while
Complex ophthalmoplegia - not affecting one particular CN
Shoulder abduction strength - exercise it then recheck and expect it to be weaker
Ice on ptosis can resolve the ptosis
MG crisis management
A-E
Forced vital capacity
Involve ITU early
Important cause of mortality in Friedrichs ataxia
Arrhythmias and cardiomyopathy
Cerebellar ataxia causes
Acute - vascular stroke haemorrhage, infection ie varicella or autoimmune or demyelinating (then offer no RAPD or optic atrophy)
Chronic - alcohol or nutritional deficiencies or genetic, surgery, previous trauma
Peripheral neuropathy + Cerebellar signs =
Alcohol cause of both
Lateral medullary syndrome - what is it?
Wallenberg
Posterior inferior Cerebellar artery or vertebral artery
Lateral part of medulla
Lateral medullary syndrome signs
Ipsilateral- Cerebellar signs + loss of gag reflex, hornets and reduced pain and temperature sensation in trigeminal distribution on face
Contra lateral - loss of pain and temperature sensation over trunk and limbs
MND only affecting upper limbs
Primary lateral sclerosis
What is MND?
Progressive axonal degeneration of motor neurons in motor cortex and corticospinal tract, anterior horn cells or spinal cord and brain stem
MRI findings in multiple sclerosis
Hyper intense lesions on T2 weighted imaging
Non-pharmacological management for multiple sclerosis
Stop smoking
Vitamin D
Exercise
MDT i.e. physio and occupational therapy
Mental health
Bladder management
Commenest presentation of multiple sclerosis
Optic neuritis
Reduce visual acuity
Reduce colour perception
Horizontal gaze palsy
Paraesthesia pain spasticity hyperreflexia
Bladder dysfunction
Sexual dysfunction
Causes of central visual loss
Macular degeneration could be diabetic or ARMD
Retinal vein occlusion
Hypertensive retinopathy causing macular oedema
Optic neuritis
Cataract
Causes of peripheral visual loss
Retinitis pigmentosa
Glaucoma
Chiasmal lesion
Broad causes of gradual visual loss
Compressive cause
Inherited
Degenerative
Toxic
Nutritional
Describe INO
Failure of the ipsilateral eye to adduct with nystagmus on abduction of the other eye which indicates a lesion in the MLF indicating INO
Why do we check velocity dependent tone?
In spasticity the rapid movements make the hypertonia more obvious because it is velocity dependent
Spastic paraparesis differentials (broadly)
Trauma
Ischaemia
Inflammation
Infection
Neoplasia
Nutritional/ metabolic
Clinical signs of spastic paraparesis
wheelchair or walking aids
Disuse atrophy and contractures if chronic
Increased tone and ankle clonus
Generalised weakness
Hyperreflexia and upgoing planters
Gate is scissoring
Additional signs during examination of spastic legs
Examined for a sensory level suggestive of a spinal lesion.
Look at the back for scars or spinal deformity.
Look for features of multiple sclerosis e.g. cerebella signs endoscopy for optic atrophy.
Ask about bladder symptoms and look for presence of urinary catheter.
Offer to test anal tone
Causes of cord compression
Disc prolapse,
Malignancy
Infection e.g. abscess or TB
Trauma
L2/3
Hip flexion
L3/4
Knee extension
L4/5
Foot Dorsey flexion
L4/5
Foot Dorsey flexion
L5/S1
Knee flexion
Hip extension
L5/S1
Knee flexion
Hip extension
S1/2
Foot plantar flexion
Brown sequard
Asymmetrical spastic paraparesis and contralateral spinothalamic dysfunction
Aka spinal cord dysfunction
Myelopathy means
Spinal cord compression
Signs of syringomyelia
Weakness and wasting of small muscles of the hand
A reflexia in upper limbs.
Dissociated sensory loss in upper limbs and chest: loss of pain and temperature (spinothalamic) with preservation of joint position and vibration sense (dorsal columns)
Scars from painless burns
Charcot joints of the elbow and shoulder
Parador weakness in lower limbs with upgoing planters
Kyphoscoliosis
Horner syndrome.
If searing extends into brain stem there may be cerebella and lower cranial nerve signs
What is syringomyelia?
Caused by progressively expanding fluid filled cavity (syrinx) within the cervical cord typically spanning several levels
What is usually spared in syringomyelia?
Dorsal columns so joint position and vibration sense
What is lost at the level of the lesion in syringomyelia? What signs below the level of the syrinx?
Decussating spinothalamic neurones producing segmental pain and temperature loss at level of the syrinx
Anterior Horn cells producing segmental lower motor neuron weakness at the level of the syrinx
Corticospinal tract producing UMN weakness below the level of the syrinx
Usually spares dorsal columns
Syringomyelia association conditions
Arnold chiari malformation
Spina bifida
Most important causes of Charcot joint?
Hip & knee - tabes dorsales
Foot & ankle- DM
Elbow & shoulder - syringomyelia
C5/6
Elbow flexion and supination
C7/8
elbow extension
T1
Finger adduction
