Neurolocalisation and Neuro Physical Exam – Flashcards

1) Neurolocalise before trying to identify an etiology 2) Signs and symptoms may still leave multiple levels in the neural axis as possibilities, therefore investigations (which have differentiating/zebra stripe value) may be indicated 3) Sometimes actual signs/symptoms may not intuitively make theoretical sense (eg lesion is localised to nerve root yet only sensory involvement is described) but can be explained within the spectrum of variability in biological systems; in addition it may be the 'best fit' 4) Occam's razor can be challenged reconciled if the clinical picture is consistent with two super common pathologies that simultaneously occur Additional 1 Mainly motor symptoms - Muscle, NMJ, AHC (should also consider peripheral nerve, plexus usually mixed motor-sensory) 2 Mixed symptoms - Higher cortex, sub-cortex-the first 2 locale the sensory symptoms /signs may be mild, brainstem (CN involvement), spinal cord, peripheral nerve, nerve root, plexus

1. Cortex 2. Subcortex 3. Brainstem 4. Spinal cord 5. Anterior horn cell 6. Nerve root 7. Plexus 8. Peripheral nerve 9. Neuromuscular junction 10. Muscle

1. Congenital/inherited - young 2. Vascular - acute 3. Infective/inflammatory - subacute 4. Degenerative - chronic 5. Neoplastic - chronic 6. Toxins/iatrogenic - variable 7. Metabolic/endocrine - variable

- 1 Smell - 2 VA - CF; VF - see my face, any part missing - 3, 4, 6 pupils, EOM, diplopia (mono or binocular) - 5 Sensation, muscles of mastication (clench teeth) - 7 look up, close eyes, smile, blow balloon - 8 tuning fork - 9, 10 uvula, say 'ah' - 11 turn head against hand, lift shoulders up - 12 stick out tongue, move sideways

https://www.youtube.com/watch?v=0hhcxaeOCYs&feature=iv&src_vid=S7H1pqRlVqc&annotation_id=annotation_1997917961 Inspection SWIFT - scars - wasting - thenar, hypothenar, interossei - involuntary movements - fasciculations - tremor Tone - hard sign Reflexes - hard sign a. Biceps, triceps, supinator b. May need to perform reinforcement manoeuvre eg clench teeth Power a. Test all joints, stabilise joints to prevent compensation Sensation a. Pain (AL), temp (AL), light touch (AL/DC), vibration (DC), proprioception (DC) b. Chin and chest (in case of high lesions of SC) Cerebellar a. Dysmetria - Past pointing - limb ataxia b. Dysdiadochokinesia - inability to perform rapidly alternating movement To complete - LL, gait, CN

TRAP Observe resting tremor w/o intention tremor Cogwheeling, lead pipe rigidity Slow movements unilaterally Retropulsion, pull back test

Inspection SWIFT - scars - wasting - involuntary movements - fasciculations - tremor Tone Reflexes Power Sensation a. Light touch b. Pain c. Proprioception Cerebellar a. Heel shin test Gait (offer) a. Tandem Rhomberg's

UMN - anti-gravity muscles are stronger - weakness in extensors of UL and flexors of LL - hyperreflexia, hypertonia, no wasting

Biceps C5, C6 Brachioradialis C6 Triceps C7 Patellar L4 Achilles Tendon S1 Requires cutaneous innervation (sense), motor supply, cortical input *Hyperreflexia* Isolated Symmetric not worrying For Ix if - asymmetric - spreading reflexes - crossed adduction when medial aspect of knee tested

Contralateral spinothalamic tract Ipsilateral CN 5 posterior inferior cerebellar artery Case example - 44yo man unsteady gait and speech difficulties o Slurred speech, swallowing difficulties, veers to one side when walking o Left facial numbness, right hemisensory loss in limbs (pain and temp) left cerebellar signs, weak palatal movement on left, absent gag, nasal speech, no weakness

Contralateral limb and muscle weakness Ipsilateral tongue weakness (deviates to infarcted side) Anterior spinal artery

Localisation: NMJ Pathophysio - circulating Abs block ACh receptors at postsynaptic NMJ - a/w various autoimmune disease eg thyroid, CNS, lupus Presentation - initial: abnormal painless weakness of specific muscles esp eye - worsens towards end of day, relieved by rest - myasthenia crisis: resp muscle failure Diagnosis - blood tests: ACh Ab - ice pack test: 2mm raise in eyelid after removal of ice MGMT - acetylcholinesterase inhibitors eg pyridostigmine Case example - 35yo woman experiences intermittent diplopia and droopy eyelids for 2 months o Speech becomes slurred, difficulty chewing o Symptoms improve after nap o Neck flexion poor - surrogate for respiratory muscle weakness o Myasthenia Gravis w impending crisis, Lambert Eaton syndrome

Localisation: motor neurons no-muscle-nourishment lateral (motor neurons) sclerosis Presentation - 60yo - muscle weakness + atrophy throughout body due to degeneration of UMN and LMN - 75% limb onset, 25% bulbar (speech, swallow) onset - eventually requires ventilatory support Diagnosis - clinical Management - relive symptoms: breathing support, PT, nutrition - extend life expectancy: riluzole

Case: lower limb weakness *Localise to 'where'* 1) A/w sensory 2) Bilateral or unilateral 3) Upper limbs affected 4) CN involvement *Thereafter, identify the etiology - 'what'* - congenital/acquired - degenerative/vascular - neoplastic - metabolic/endocrine - iatrogenic/drug induced/toxin

Subacute combined degeneration of the spinal cord Peripheral nerves to a lesser extent

autoimmune damage of peripheral nervous system - may be triggered by infection 3-6 weeks prior Presentation - numbness, tingling, and pain - alone or in combination - bilateral progressive limb weakness, often peaking by 2 weeks Case example - 30yo man progressive ascending limb weakness and numbness, beginning in lower extremity since ytd o No PMH except recent URTI 2 weeks ago o Swallowing difficulty and poor respiratory function o GBS - affects both CN and peripheral nerves

Symptoms dependent on level May be due to viral eg CMV

Chronic demyelineating disease of the CNS (optic nerve, brain, spinal cord), disrupting communication ability A person with MS can have almost any neurological symptom or sign, with autonomic, visual, motor, and sensory problems being the most common.

Motor pathway - corticospinal tract contralateral Medial lemiscus - dorsal column contralateral Motor nucleus and nerves (3, 4, 6, 12) ipsilateral Medial longitudinal fasciculus

Spinocerebellar - ipsilateral Spinothalamic - contralateral Sensory nucleus of 5th nerve - ipsilateral Sympathetic pathway - ipsilateral

4 above pons, 2 in midbrain 4 in pons - 5,6,7,8 4 in medulla - 9,10,11,12

Rule 1 - brainstem (midbrain, pons, medulla) signs - always assess pyramidal and cerebellar signs - presence indicates a brainstem localisation for CN palsies o All CN nerves except 1, 2 exit through brainstem Rule 2 - cranial nerve clubs - groupings - cavernous sinus - 3, 4, 6, v1, v2 - orbital apex - 2, 3, 4, 6, v1 - CP angle - 5, 6, 7, 8 - jugular foramen - 9, 10, 11, 12 Rule 3 - meningeal, CSF and skull base disease - meningitis - base of skull eg NPC ~CN6 susceptible due to long course ~radiation therapy for H&N cancers can damage multiple nerves Rule 4 - peripheral neuropathy - CN are part of the peripheral nerves - most peripheral neuropathies affect limb nerves, exception of Guillain Barre 3rd nerve - Posterior comm artery aneurysm - surgical 3rd (pupil involved) - ischaemia

Supply brainstem CN motor nuclei unilateral damage of one tract does not cause notable abnormality, w the exception of CN 7, 12 - for other CNs, each tract connects bilaterally w most CN motor nuclei

TRAP Dopaminergic responsiveness - supporting feature for clinical diagnosis Treatment via L-DOPA (crosses BBB) Chameleons - pain - hyposmia - REM sleep disorder - constipation Mimics - tremor disorders (T w/o RAP) - drug induced parkinson's - vascular parkinson's

Infective - neurosyphilis - CNS TB Inflammatory - wegener's - polyarteritis nodosa - RA

Describing hyperkinetic disorders - speed (Slow or rapid) - involuntary or voluntary - stereotypical? rhythmic? predictable? - purposeful, non, semi - style eg dancing, writhing - muscle group involvement (distal or proximal) Hypokinesia - akinetic/rigid Hyperkinesia a. non-jerky - tremor - dystonia (slow, writhing) b. jerky - myoclonus (shocking) - chorea (fidgety) - tics (repetitive, sterotyped eg facial) Chorea - punished thrice - fidgeting, breaking crockery, making faces at grandma - signs: darting tongue, pronator sign, milkmaid's grip

Consider in any patient w acute neurologic deficit or altered level of consciousness ~TIA <24hrs - suggests risk factors for subsequent stroke Ischaemic stroke 1. thrombotic - large vessel thrombosis - larger impact - small vessel disease eg lacunar infarct (pure motor, pure sensory, ataxic hemiparesis, dysarthria-clumsy hand, and mixed sensorimotor) 2. embolic (from elsewhere) Haemorrhagic - location of bleed rather than volume that influences severity 1. intracerebral haemorrhage - hypertension 2. subarachnoid haemorrhage Ix - CT - MRI w DWI - FBC to id trigger Management - aim to preserve tissue - fibrinolytic therapy - BP control

Ix is not for diagnosis but to rule out other 2' causes o Migraine Unilateral Throbbing or pulsatile May be a/w prodrome (hours to days prior) and/or aura (minutes prior) May be a/w N&V May be ppt by physical activity 30-40yo, F>M, strong genetic component Higher risk of vascular events eg stroke o Tension type Bilateral, usually occipitofrontal Throbbing, non pulsatile, gradual onset, constant quality Daily recurrence, a/w contracted muscles of neck and scalp Not ppt by physical activity Teenagers, F>M o Trigeminal neuralgia Unilateral, most often on right Stabbing, localised pain (often running along line dividing V1/V2/V3), paroxysmal Allodynia - can't touch/have wind 60-70yo, F>M

1. Muscle 2. NMJ = MG 3. Nerve - no brainstem signs - brainstem signs TRO HSV and Wernicke's MRI can pick up inflammatory/vascular lesions