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Neurology block Four limb weakness and Focal weakness Benjamin Sharon Christina du FosséILOs - general • Apply clinical reasoning methodology to formulate a differential diagnosis, instigate investigation, and provide initial care for patients presenting with neurological conditions • Apply knowledge of epidemiology, clinical presentations and management in patients with common neurological conditions • Apply knowledge of the relevant anatomy and physiology for clinical neurological practice • Describe the ways in which neurological emergencies may present • Formulate a syndromic diagnosis by differentiating between upper and lower motor neurone features and defining the site of probable pathology by interpreting a patient's history and examination • Know how to initiate immediate management for neurological emergencies • Perform, interpret and record a neurological assessment (including history and examination) on a patient (and, when required, from a suitable informant), with particular regard to the following: a. Headache; b. Paroxysmal attacks; c. Unsteadiness; d. Limb weakness; e. Sensory symptoms; f. Tremor • Understand the principles of neurological investigation including indications for and interpretation of commonly performed testsILOs – four limb weakness (polyneuropathy) • Formulate and understand the differential diagnosis for patients presenting with four limb weakness • List the investigations that may be performed on the CSF of patients and be able to interpret these results to aid the diagnosis of neurological disordersImportant background anatomy / physiology Localizing a lesion Where How/ why https://ib.bioninja.com.au/standard-level/topic-6-human-physiology/65-neurons-and-synapses/nervous-system.htmlWhat Where How / why https://premierneurologycenter.com/blog/neurological-disorders-divided-by-the-cns-or-pns/What Where How / why https://www.researchgate.net/figure/The-central-nervous-system-CNS-and-peripheral-nervous-system-PNS-source_fig1_317485174What Where How / whyWhat Where How / whyWhat Where How / why How/wh y multimedia/fihttps://en.m.wikipedia.org/wiki/File:Neuromuscular_junction.svg of-a-nerve-cellBack to the cases - polyneuropathy • Guillain-Barré syndrome(GBS) • Myasthenia Gravis • Charcot Marie Tooth(CMT) • Cauda equina syndrome • Others • MS, Diabetes, drugs,alcohol,vitamin deficiency,thyroid disease,malignancy,infections, sarcoidosis • And more… • What • Immune-mediateddemyelination of the PNS often triggered by an infection Guillain-Barré • Pathophysiology • Molecularmimicry– B cells create antibodies against infective syndrome agent,however infective agents can be molecularly similar to myelin sheaths of axons • Common infectiveagents – campylobacterjejuni (think recent gastroenteritis) CMV,EBV • S+S • Polyneuropathy– Peripheral→ central • Progressive + symmetrical + ascending • Others – CN involvement (diplopia, oropharyngeal weakness), respiratory muscle weakness, autonomic involvement (urinary retention,diarrhea) • Complication – Miller Fisher syndrome • I/D • Neuroexam – power (reduced),reflexes (reduced/absent), sensory (distal paresthesia) • LP – increased protein (normal WCC) • NCS – decreasedmotor nerve conductivity(slower signals) • Management • IV IG,plasma exchange,supportive care,VTE prophylaxis(PE = leading cause of death) • What • Autoimmune disorder resulting in depletion of ACh receptors Myasthenia • Pathophysiology • A type-II hypersensitivity immune response gravis • Exacerbating factors – drugs (Penicillamine, beta blockers, lithium,phenytoin, other Abx) • S+S • Polyneuropathy– fatiguability: • Proximal muscles (face, neck,girdle) • Extraocular muscles (diplopia) • Cranial nerves (ptosis, dysphagia) • Association - thymoma • Complication – myasthenic crisis • I/D • Electromyography– high sensitivity (92-100%) • AChantibodies – increased protein (normal WCC) • CT thorax – thymoma • Management • AChE inhibitors (Pyridostigmine), Immunosuppression (Prednisolone – later in treatment),Thymectomy,Charcot-Marie Tooth disease (CMT) • What • Genetic disease (autosomal dominant) causing myelin + axon dysfunction • S+S • Polyneuropathy– mixed picture (both motor + sensory) : • LMN signs – commonly affects lower legs first • Distal muscle wasting – ‘inverted champagne bottle’ • Foot drop • Hammer toes • Pes cavus (high foot arches) • I/D • Clinical • Management • Supportive (PT, OT,podiatry),surgeryCauda equina • What syndrome • Compression of the lumbarsacral root • Causes • discitis), tumor, trauma,hematoma – L4/L5, L5/S1), infection (abscess, • S+S • Lower back pain,sciatica (50% of cases) • Saddle-shaped • Reduced sensation / paresthesia • Decreased anal tone • Urinary dysfunction (incontinence (late sign), lack of urge) • urinary/bowel incontinence)erve damage (long-term weakness, • I/D • MRI - urgent • Management • Surgical decompressionA note on CSFFocal neuropathies: CN3: - Check for double vision (diplopia) - binocular - monocular SO because only our trochlear and abducens nerve would work – we can only do these movement e.g.‘down and out’. There is also ptosis because the superior levator palpebrae muscle is not receiving the innervation it needs either. Rapidonset,withinhoursor 7thnerve palsy: Pain behind OR in the ear Facial(sometimes) Treatment: - Corticosteroids + anti-viralswithin 48hrs (+ eye drops) – but 85-90% recoverwithinweeksor monthswithout it Radial and ulnar palsies ULNAR PALSY: - Pressure to the elbow mainly - Pain and tingling - Wasting and weakness of hand sparing the thenar eminence. - TREATWITH: NSAID’s and splint - Froments sign. RADIAL PALSY : - AKASaturday night palsy - Due to prolonged period of abnormal posture of the upper arm e.g.draped over awkwardly due to alcohol intoxication. - TREATWITH: physical therapy and splintSciatic nerve – sciatica CAUSE: lateral prolapse of the L5/S1 disc usually causing irritation SIGNS: low back pain,tenderness,pain radiating from buttocks to ankle.Sensory loss and depressed ankle reflex. - Usually UNILATERAL - Numbness/ muscle weakness/ burning WORSE ON: passive straight leg raise (made worse by dorsiflexion) - MRI can confirm but not usually necessary MANAGEMENT: conservative or neuropathic medicationsCommon peroneal AKA foot drop Compression at the neck of the fibula due to squatting,kneeling etc. Weakness on foot dorsiflexion + eversion Normal reflexes Sensory loss over foot dorsum and lower lateral leg.Femoral, obturator and tibial Fractures and dislocation to the hip // and the knee (for tibial) Causes both motor and sensory symptoms to areas each nerve innervates. For example: - Femoral is L4/5 and S1 and so without it the knee cannot extend and the thigh cannot flex. There is also sensory loss to the anterior and medial aspect of the thigh and lower leg.Winged scapula