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Home , Dysdiadochokinesia, Fasciculation

Reverse Engineering your Exam

Alex Gillingham & Alex Reynolds

Lead Physician Associates National Hospital of Neurology & Neurosurgery FPA CPD Conference October 2019 Objectives

• Key history aspects • Simple neuro-anatomy • Localisation • Approach to exam • Case examples Why We Do What We Do

History = When & What

Exam = Where & Why Why We Do What We Do

History is KEY  focuses exam For each section: Think Why? What does it mean?

Exam: • Refine localisation and differential • Looks for additional signs -> change diagnosis Speed of symptoms

Tempo  pathology •Instantaneous  epilepsy (electrical) or vascular •Seconds – hours  Ischemia (evolving stroke) or infection •Hours – days  inflammatory, or infection •Weeks – months  autoimmune, neoplastic, infection (TB) Exam Section  Location

• Mental status  supratentorial, cerebral hemispheres • Cranial Nerves  brainstem & posterior fossa • Coordination  • Sensory  Spinal thalamic tracts • Motor  corticospinal tract & LMN • Gait  coordination various areas SUPRATENTORIAL

INFRATENTORIAL

TRACTS

SPINAL CORD

PERIPHERAL NERVE Tracts, lots and LOTS of Tracts

• About 150+ different tracts identified so far

• Each tract transmits signals from one part of the nervous system to another

• Most well known are: Corticospinal, corticobular and spinal thalamic What are tracts?

• Tracts themselves are specific UMN bundles with a specific origin and ending within the central nervous system.

• Still confused??? Imagine a power station (the Brain) The power station needs to supply electricity to a house (the limb) To send electricity, the power station uses electric pylons to transmit signals to the house (neural-tracts) The house uses the electricity as a light switch (Bicep), kettle (tricep), phone charger (brachio- radialis) etc. • This is an example of the corticospinal tract. Cortex

Spinal tract

LMN or peripheral nerves Case: ‘Facial Weakness’

• Fast onset • Differential diagnosis?

• Stroke/CVA, Bells palsy – Rarely – Ramsay hunt syndrome, brain stem tumours. Case: ‘Facial Weakness’

Key areas for exam? •CN exam – Specifically which CN nerves? •Motor •Sensation Location Location LOCATION!

• There are 3 key areas where a stroke can occur for isolated facial weakness.

– Motor cortex – Brain stem – Peripheral nerves • Have you ever asked the question:

• How do you get facial weakness in an MCA stroke? Cortico - bulbar tract

• Facial motor innervation is via the cortico- bulbar tract

• Nerve bundles which relay cortex signals to the brain stem.

• The cortico-bulbar tract innervates the NUCELUS of CN 7

But what about forehead sparing?

Bells Palsy But……

• Isolated facial weaknesses rarely happens.

• What if a patient comes to you with facial weakness, with arm weakness (1/5) and leg weakness (3/5)?

Case - Arm and leg weakness

• Its all about your history and examination! Strength scale

Out of 5 0 = no movement 1 = muscle flicker 2 = movement without gravity 3= movement against gravity, with no resistance 4= Movement against gravity with mild resistance 5 = full power Strength - exam pearls

• Test each side individually COMPARE AND CONTRAST EACH SIDE • Ask patient to do movement against gravity 1st  power at least = 3 • Only need maximal strength for 1 second – If ?pain limitation – prompt 1,2,3 GO! Case - Arm and leg weakness Corticospinal tract

• Information for motor function travels down the corticospinal tract.

• Contralateral nerve innervation happens because the tract crosses over the decussation in the medulla oblongata.

General principles of weakness in CVA

• If ARM weakness is GREATER than LEG weakness – MORE LIKELY AN MCA STROKE

• If LEG weakness is greater than ARM weakness – More likely ACA STROKE BUT…..

• Why do we do sensory exams???? • The central gyrus: – Motor- PRE-central (more forward) – Sensory- POST-central Sensory exam

• Sensory exam is divided into 5 separate segments:

• Light touch • Sharp dull • Vibration • Proprioception • Temperature Lets say…

• Our patient has facial weakness + arm weakness with reduced light touch in their arm. Somatosensory tracts

• A two stage tract

• These tracts usually go via the THALAMUS

• Motor tracts are usually 1 single tract which terminate in the cortex. Why is this important?

• Location • Location • LOCATION! Sensory exam 2 main sensory • 5 key areas: tracts:

• Light touch • Spinothalamic • Sharp dull • Dorsal column • Proprioception Supratentoral • Temperature • Vibration • Thalamus • Cortex Spinothalamic: Pain and Light touch

Dorsal column: Proprioception and vibration and temperature (Some light touch goes via dorsal column!!!!) Always use sharp dull when assessing the spinothalamic tract Spino-thalamic

• 3 key areas for a CNS lesion:

• Thalamus • Spinal cord • Cortex

Sensory exam

• The sensory exam examines different areas of the SPINAL CORD and to an extent the thalamus + cortex.

• VERY important in spinal cord injury patients, as it affects management and rehabilitation potential • ASIA scores-

• Single biggest indicator for spinal cord injury is weakness and reduced/absent sensory examinations

• You can then locate the level of the injury at level of the dermatome. So…. Lets say…

• Facial weakness + arm weakness with reduced sharp dull in their arm.

• Where are the possible lesion locations?

• If the patient had reduced vibration and proprioception.

• Which part of the spine are you examining for?

• Where could the lesions be?

Almost there…

• Our patient has facial weakness, arm weakness and reduced light touch in their arm

• Where are the possible locations for their lesion?

• If our patient has facial weakness, arm weakness and a NORMAL sensation exam

• Where are the possible locations for their lesion?

Finally…

Leg weakness with abnormal vibration?

Case: ‘Clumsy walking’

D/Dx •Neuro –cerebellar disease – sensory issues –Vestibular •Neurosurgical – stroke – hydrocephalus Case: ‘Clumsy walking’

Key areas for exam?

•Gait – normal & tandem •Coordination •Proprioception (eye movements) Exam: Gait High stepping gait Exam: Gait

Gait Disturbance – helps localise the problem

•Sensory/ Proprioception – ‘high stepping’ – AND Joint-position, vibration reduced

•Vestibular – veers to affected side • AND Nystagmus Exam: Gait

Wide-based gait

Tandem walk elicits earlier signs of

Note Exam: Gait

• Bradykinesia Parkinsonism • Shuffling • Stooped • Reduced arm swing Exam: Gait

Gait Disturbance – helps localise the problem

•Cerebellar – broad-based, irregular – AND Incoordination, rebound

•Basal Ganglia (parkinsonism) – shuffling, festination, stooped, no arm-swing – AND bradykinesia, resting , rigidity

What to examine Next? Exam: Coordination

– Rapid-alternating movements • rate, amplitude, rhythm, force • – clumsy, irregular – Upper Limb: Finger-nose • • – past-pointing – Lower Limb: Heel – Shin • Ataxia – Rebound/ Overshoot Cerebellum Controls…

•INTEGRATES sensory & Motor subsystems

VESTIBULAR SYSTEM LIMB & POSTURAL MUSCLES PROPRIOCEPTIVE (spinocerebellar) CEREBELLUM

MOTOR PLAN THALAMUS (Cerebral Motor Cortex) Exam Pearls: Coordination Clear instructions & Demo

Dysmetria - Past-pointing/ overshoot – requires extension away from the body

Dysdiadochokinesia– listen to ask much as you hear it! – Irregular rhythm

Lack of smooth movements Sign  Cerebellar location

Truncal ataxia – Midline Ataxia Cerebellar MIDLINE

Exam Tests: • Truncal stability • Walking/ Gait • Tandem gait Sign  Cerebellar location

Appendicular ataxia – extremities control Cerebellar Hemispheres

Exam Tests: • Rapid alternating movements • Finger-to-nose • Toe-to-finger • Heel-to-shin • Rebound • Speech - Rombergs NOT a specific cerebellar test! Localisation

UMN Brain  Brain stem or cord

- Cerebral cortex - Brainstem - White matter- tracts (spinal cord) LMN Brain stem or cord  Skeletal muscles

- Motor cranial nerves - Anterior horn (Spinal cord) - Neuronal Axons - NMJ Signs  Localisation

LMN UMN • Wasting • No wasting • Weakness • Increased tone • (spasticity) • Reduced tone • Hyper-reflexia • Reduced reflexes • Upward plantars

BUT WHY??? Lower

• ‘Final common LMN • Wasting pathway’ lost • Weakness • Immediate innervation • Fasciculation • Reduced/ loss of tone to muscle lost • Reduced/ loss of reflexes • Muscle is de-nervated • LOSS of innervation Upper Motor Neuron

• Unregulated innervation • No inhibitory effect from the UMN • Constant “firing” developing into spasticity • INCREASE in all areas • Isolated weakness – anywhere in cortex to spinal cord

• Global weakness + facial weakness – Cortex and/or brainstem

• Global sensory with global weakness- Cortical or spinal if there is a level.

• Complete loss of proprioception with preserved motor function –Dorsal column lesion

Take away points

1. Always compare and contrast by isolating muscle groups

2. Think about where in the CNS you want to examine

3. Take your time getting a great history

4. Watch your patient walk in and shake their hand! Resources www.neuroexam.com

Uni of Utah NeuroLogical Cases

Uni of Toronto Neurological Exam ANY QUESTIONS?