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Neurology Phase 2a: Lesion Location & Pathology Questions

Understand possible neurology sites, from muscles to cerebrum. Learn about Myasthenia Gravis, Carpal Tunnel Syndrome, and treatment options.

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Neurology Phase 2a: Lesion Location & Pathology Questions

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  1. Neurology Phase 2a David Gregg David Stewart-Watson The Peer Teaching Society is not liable for false or misleading information…

  2. Two questions to ask in neurology: • Where is the lesion? • What is the pathology? Weakness can be due to any location along the nervous pathway – what possible locations are there? The Peer Teaching Society is not liable for false or misleading information…

  3. Possible Sites Muscle • Cushing’s syndrome, thyroid disease, hyperparathyroidism, influenza, myositis, dermatomyositis, sarcoidosis, sarcoma Neuromuscular Junction • Myasthenia gravis, Lambert-Eaton myasthenic syndrome, Clostridium botulinum infection Peripheral Nerves (mono, multiplex, poly) • Carpal tunnel syndrome, trauma • PAN, SLE, RA, herpes zoster, HIV, sarcoid, DM, amyloid (multiplex) • Guillian-Barre syndrome, PAN, SLE, RA, CIDP, DM, renal failure, amyloid, Vitamin B1/6/12 deficiency Spinal nerve root • Infection, prolapsed disc, spinal stenosis, spondylosis, tumour, vertebral fracture dislocation Anterior horn cell • Motor neruone disease, polio Spinal cord • OA, HIV, TB, MS, sarcoid, RA, Paget’s, trauma, prolapsed disc, tumour, subacute degeneration of the spinal cord, MND Cerebral hemispheres • MS, Stroke, TIAMeningitis, encephalitis, HIV, malaria, TB, sarcoid, SLE, Wilson’s disease, tumour, The Peer Teaching Society is not liable for false or misleading information…

  4. Myasthenia gravis • Carpal tunnel • Guillian-Barre syndrome • Spinal nerve root lesion • Motor neurone disease • Spinal cord compression (+ cauda equina) • MS • Stroke (+TIA) The Peer Teaching Society is not liable for false or misleading information…

  5. Myasthenia Gravis Pathophysiology In normal muscle, the amount of Ach released with each AP decreases with repetitive activity, thus the magnitude of each end-plate potential falls. In MG, anti-Ach antibodies have taken out Ach receptors. This means that the decreased amount of Ach released becomes insufficient to cause sufficient end-plate potential to trigger a muscular contraction. Anti-MUSK antibodies are seen in a subsection of patients. The thymus is hyperplastic in half of MG patients, and a thymoma is present in 15%. If someone has MG look for a thymoma, and if someone has a big thymus check for MG! The Peer Teaching Society is not liable for false or misleading information…

  6. Myasthenia Gravis Clinical Features • Painless, fatiguable muscle weakness – particularly proximal limbs, extra-ocular, bulbar and facial muscles • Wasting can be seen after many years • Respiratory difficulties can be prominent especially during a myasthenic crisis • Average 20-40 years at presentation • More women than men • Associated with hyperthyroidism, RA, SLE • Other signs and symptoms include ptosis, diplopia, voice weakening with continuous speaking and dysphagia The Peer Teaching Society is not liable for false or misleading information…

  7. Myasthenia Gravis Investigations • Serum anti-AChR; serum anti-MUSK • Electromyography (used to confirm diagnosis) • Tensilon (edrophonium) test (rarely done nowadays – risk of cardiac arrest!) • Mediastinal MR for thymoma Course and Management • Fluctuates in severity, protracted, lifelong • Exacerbations are unpredictable, can be brought on by infections and aminoglycoside use • Emergency ventilation may be required The Peer Teaching Society is not liable for false or misleading information…

  8. Myasthenia Gravis Treatment • Oral anticholinesterases • Pyridostigmine is widely used, dose is determined by response • Prolongs Ach action by inhibiting cholinesterase • These help the weakness but do not alter the course of disease • Immunosuppressants • Used in those non-responsive to above/who relapse • Steroids are often used, azathioprine/mycophenylate are also used • Thymectomy • Useful in those with positive AchR antibodies, even if no thymoma. Anti-MUSK cases do less well. If a thymoma is present, then it is also necessary • Plasmapharesis/IV Ig • Useful during exacerbations The Peer Teaching Society is not liable for false or misleading information…

  9. Carpal Tunnel Syndrome Pathophysiology Due to median nerve compression in the limited space of the carpal tunnel. It is not typically associated with any disease. It can be seen in hypothyroidism, DM, obesity, RA, acromegaly, amyloid and renal dialysis Clinical Features • Patient wakes with numbness, tingling and pain in a median nerve distribution. • The pain radiates to the forearm • The fingers feel swollen but usually aren’t • Wasting of the abductor pollicis brevis develops with sensory loss in the palm and radial 3 ½ fingers • Tinel’s or Phalen’s sign may be positive The Peer Teaching Society is not liable for false or misleading information…

  10. Carpal Tunnel Syndrome Treatment • Splinting • Holds wrist in dorsiflexion overnight. If this relives symptoms, it is diagnostic. It can produce full recovery if used for several weeks • Corticosteroid injection • Helps in 70% of cases, but may recur • Nerve conduction studies + surgical decompression • Persistent symptoms or nerve damage requires referral for nerve conduction studies • A prolonged latency across the carpal tunnel demonstrates CTS and surgical decompression is needed • Weight loss helps in obese patients • CTS in pregnancy usually disappears post-partum • Other mononeuropathies occur with similar tingling and weakness distal to site of compression (ulnar, radial, lateral cutaneous nerve of the thigh and common peroneal) The Peer Teaching Society is not liable for false or misleading information…

  11. Cranial Nerve Lesion • Many causes • Symptoms are easy to predict • Learn what the cranial nerves do, the lesions at each nerve result in a deficit of that e.g • CN1 – Anosmia • CN6 – Failure of eye abduction The Peer Teaching Society is not liable for false or misleading information…

  12. Mononeuritis Multiplex • Occurs in DM, vasculitis, sarcoidosis, amyloidosis, malignancy and HIV • Clinical picture of multiple mononeuropathies occurring sequentially or simultaneously • Mononeuropathies are confirmed using nerve conduction • Appropriate investigation into underlying cause (BM, inflammatory markers, serum ACE) The Peer Teaching Society is not liable for false or misleading information…

  13. Guillian-Barre Syndrome Clinical Features • Commonest acute polyneuropathy • Usually demyelinating, though can cause axonal damage • Pt complains of weakness in distal limb muscles and/or distal numbness • Progresses proximally over days to weeks • Areflexia is invariable; autonomic features can occur • Follows 1-3 weeks after an infection (usually trivial) • C.jejuni and CMV are well-recognised causes of severe GBS; the organisms induce Ab responses against peripheral nerves. Similarity between epitopes on the nerves and microorganisms is thought to be the mechanism • In 20% respiratory and facial muscles become weak, sometimes to total paralysis The Peer Teaching Society is not liable for false or misleading information…

  14. Guillian-Barre syndrome Diagnosis • Made clinically; confirmed by nerve conduction studies • These studies show conduction slowing, prolonged motor latency and/or conduction block Course and Management • Monitoring of vital capacity and blood gases to recognise emerging respiratory muscle weakness – prolonged ventilatory support may be necessary • IV Ig reduces duration and severity of paralysis (screen for IgA deficiency due to potential for anaphylaxis) • Recovery begins within 6 weeks from outset • 15% are left disabled or die The Peer Teaching Society is not liable for false or misleading information…

  15. Other Polyneuropathies Diabetic neuropathy Several varieties • Symetrical sensory – starts distally, loss of vibration, pain and temperature sensation in the feet, ‘glove and stocking’ • Diffuse painful – burning/crawling pain in the feet, shin and anterior thighs, typically worse at night • Autonomic neuropathy – postural hypotension, GI symptoms, bladder problems, ED Does not typically involve the motor systems at all More common in T2DM due to long-term hyperglycaemia prior to diagnosis. Good management can largely prevent the above in T1DM. The Peer Teaching Society is not liable for false or misleading information…

  16. Other Polyneuropathies Toxic Neuropathies Causes include alcohol, prescribed drugs, lead, plastic industry by-products, arsenic and glue sniffing Vitamin Neuropathies Thiamine deficiency causes a polyneuropathy combined with cardiac failure. It also lead to Wernicke-Korsakoff psychosis. The commonest cause is alcohol abuse. Prophylactic thiamine is given to prevent Korsakoff’s Vitamin B12 deficiency leads to sub-acute degeneration of the spinal cord. Sensory loss, numbness and tingling and loss of reflexes distally are the usual presenting features. Pt will be anaemic. This is an irreversible consquence. The Peer Teaching Society is not liable for false or misleading information…

  17. Plexus Lesions Produce a variable picture that needs nerve conduction studies to fully understand Only one of any relevance to Phase 2 is a Pancoast tumour – an apical bronchial carcinoma which compresses the brachial plexus with consequent small muscle wasting, weakness and/or pain in the hand/arms The Peer Teaching Society is not liable for false or misleading information…

  18. Spinal Root Lesions • Also called radiculopathies • Due to mechanical compression of a nerve as it leaves the spinal cord • Commonest locations are C6+7 and L5+S1 • Causes include: • Osteophytic growth • Disc degeneration and lateral protrusion • Vertebral collapse – osteoporosis, infection (TB) • Tumour growth • Clinical features are: pain, sensory disturbance, loss of reflexes, tingling and numbness that occurs in a dermatomal/myotomal distribution • Treatment is rest and analgesia. If symptoms persist, then surgical decompression may be appropriate • MRI is required if considering for surgery; other investigations may be indicated by history e.g. in a Pt with one of the 5 Bs that go to bone The Peer Teaching Society is not liable for false or misleading information…

  19. Motor Neurone Disease Clinical Features Four broad patterns – usually merge as MND progresses. • Amyotrophic lateral sclerosis (ALS) • Progressive spasticity, weakness and wasting with added lower motor neurone signs and fasciculation • Also called Lou Gehrig’s disease • Progressive muscular atrophy • Wasting begins in the small muscles of the hand. Fasciculation is common. Cramps may occur • Progressive bulbar and pseudobulbar palsy • Bulbar describes LMN signs from the 9th, 10th and 12th CN lesions i.e. wasted fibrilating tongue; pseudobulbar palsy describes UMN lesions of the same i.e. spastic weak palate • Presents as dysarthria, dysphagai, regurgitation and choking on fluids • Eye movements are unaffected • Primary lateral sclerosis – tetraparesis, pseudobulbar palsy The Peer Teaching Society is not liable for false or misleading information…

  20. MND Diagnosis • Largely clinical • Denervation (seen in all forms except primary lateral sclerosis) can be confirmed by EMG • Potential mimics include subacute degeneration of the spinal cord, syringomyelia, motor neuropathy and bulbar myasthenia gravis. Course and Management • Survival of more than 3 years is unusual; death is often from bronchopneumonia • Symptomatic management and support (e.g ventialtion, gastrostomy) helps prolong survival • Accurate prognosis is difficult – think of Stephen Hawking! The Peer Teaching Society is not liable for false or misleading information…

  21. Multiple Sclerosis (MS) Pathophysiology • Caused my multiple demyelinating plaques due to T-cell mediated response • These heal poorly causing relapsing and remitting symptoms • Prolonged demyelination causes axonal loss and clinically progressive symptoms Epidemiology • Commoner in Northern latitudes - ?Vit D • Migrants take risk with them; 2nd generation acquires risk of where they settled • Commoner in women The Peer Teaching Society is not liable for false or misleading information…

  22. MS Clinical Features • Presentation is usually monosymptomatic – unilateral optic neuritis, leg weakness, numbness/tingling in the limbs or brainstem/cerebellar signs • In the long term, almost any neurological sign can become part of MS due to the pathophysiology • Uthoff’s sign is the worsening of MS when exposed to heat i.e. bath • Lermitte’s sign is the ‘barber chair sign’; electrical sensation down neck and into the limbs when flexing the neck Diagnosis • ‘Dr Who disease’ • 2 separate lesions required disseminated in time and space The Peer Teaching Society is not liable for false or misleading information…

  23. MS Course Three major courses • Relapsing and remitting (80%) • Primary progressive (20%) – from presentation there is a gradual decrease in neurological function • Secondary progressive – R&R turning into primary progressive There are cases of fulminant MS, where a massive demyelinating episode causes critical illness and death over the course of days The Peer Teaching Society is not liable for false or misleading information…

  24. MS Management • Non-pharmaceutical – education, PT/OT, MS nurse involvement, social services involvement, minimise disability • MS Pts with stress-free happy lives get less attacks • Active pharmaceutical treatment include • Methylpredinisolone IV, other oral – for acute relapses, use sparingly • Interferons – prevents relapses in R&R MS • Natalizumab – reduces relapses in R&R • Other treatments are being considered, many patients are willing to into research trials • Once the disease is secondary progressive, clinical trials are the sole option The Peer Teaching Society is not liable for false or misleading information…

  25. Spinal Cord Compression Anatomy The spinal cord runs from the medulla oblongata (C1) to the conus medulllaris (L1). Clinical Feature • Wasted intercostal muscles, sensory loss, root pain (sensory level) • Loss of contralateral pain and temperature sensation (spinothalamic tracts decussate at cord) • Ipsilateral UMN signs • Diminished proprioception and light touch • Depending on exactly where the cord is being compressed, all the above can be bilateral i.e. total obliteration The Peer Teaching Society is not liable for false or misleading information…

  26. Spinal Cord Compression Causes • Primary tumour – glioma, ependymoma, meningioma, neurofibroma • Metastases – the five Bs • Vertebral body destruction – osteomyelitis, osteoporosis • Trauma • Degenerative prolapse • Abscess Management • Spinal MRI ASAP • Biopsy/exploration to determine nature of mass may be necessary • Consider bloods to rule out pathologies (e.g. PSA) • CXR useful for excluding lung primaries and TB lesions • If malignant, give IV dexamethasone. • Surgery is the definitive cure; may not always be possible • Malignancy needs an oncological input The Peer Teaching Society is not liable for false or misleading information…

  27. Cauda Equina Syndrome • Due to a central disc protrusion, which can be acute or chronic • Causes a syndrome of • Bilateral flaccid paralysis • Areflexia • Sacral numbness • Retention of urine • Incontinence of urine and stool • Erectile dysfunction • Back pain • Requires urgent MRI and surgical decompression IF someone with back pain develops urinary retention, sacral numbness or incontinence, this is an emergency! The Peer Teaching Society is not liable for false or misleading information…

  28. Stroke Pathology A sudden event in which disturbance of CNS function occurs due to vascular disease. This can be ischaemic (the majority) or haemorrhagic (the worst). Ischaemic causes include arterial stenosis due to atherosclerosis, arterial occlusion due to emboli, arterial dissection, SLE, antiphosphoplip, thrombophilc states, and infections (TB, HIV) Haemorrhagic causes include AVM, amyloid angiopathy, tumours, venous thrombosis, aneurysm and hypercoaguable states The Peer Teaching Society is not liable for false or misleading information…

  29. Stroke Risk Factors • Age – 5x more likely over 75 than 55-64 • Hypertension – 7x more likely over 160/95 than 120/80 • Smoking – 2x more likely • Diabetes – 2x more likely • Ischaemic Heart Disease – 3x more likely • Atrial Fibrilation – 5x more likely – use CHA2DS2-VASC • Previous TIA – 5x more likely The Peer Teaching Society is not liable for false or misleading information…

  30. Stroke Stroke Syndromes Strokes to different parts of the brain give characteristic clinical patterns. Here are some: • Partial Anterior Circulatory Stroke (PACS) • Higher dysfunction or partial unilateral motor/sensory defect • The addition of homonymous hemianopia to one of the above • Total Anterior Cicrulatory Stroke (TACS • All of higher dysfunction, partial motor/sensory defect and homonymous hemianopia • Posterior Occiptal Circulatory Stroke (POCS) • Any of: cranial nerve palsy, bilateral motor/sensory defect, eye movement problems, cerebellar dysfunction • Isolated homonymous hemianopia • Lacunar Stroke (LACS) • 5 classic LAC sub-syndromes – pure motor stroke/hemiparesis, ataxic hemiparesis, dysarhtria/clumsy hand, pure sensory stroke, mixed sensorimotor The Peer Teaching Society is not liable for false or misleading information…

  31. Stroke Investigations - Imaging • CT to exclude haemorrhage • MRI for diagnosis • Carotid dopplers to investigate stenosis If MRI demonstrates a stroke and dopplers show stenosis, then order CT angiogram for confirmation of stenosis. If CT angio shows stenosis, refer to vascular MDT for stenting/endarterectomy If MRI demonstrates a stroke but dopplers show no stenosis, order a 72 hour tape and an echocardiogram The Peer Teaching Society is not liable for false or misleading information…

  32. Stroke Investigations – Bloods • Calcium – exclude hyper/hypocalcaemia • U+E – exclude hyponatraemia • LFTs – exclude mimics (i.e. acute liver failure) • FBC – exclude polycythaemia, thrombocytopenia, anaemia • Creatinine – exclude renal problems • TFTS • Cholesterol - risk factor for stroke • Clotting screen – exclude coagulopathy and check suitability for anti-clotting agents • BM – exclude hypoglycaemia The Peer Teaching Society is not liable for false or misleading information…

  33. Stroke Second Line Investigations If 1st line bloods and dopplers have not pinpointed a cause, consider: • Thrombophilia screen – Factor V Leiden, SLE, antiphospholipid • Blood cultures – thinking of infective endocarditis or TB • HIV test • Syphilis serology – not as usual, if appropriate from history • Homocysteine – always think of if Pt has a weird vascular presentation • Lactate • Cardiac enzymes • Haemophilia/Von Willlebrand screen (haemorrhagic only) – especially if non-HTN, non-aneurysmal and under 60. If +ve family history for any of the above revealed in basic history, go for the test in the first line. The Peer Teaching Society is not liable for false or misleading information…

  34. Stroke Management in Hospital - General • Admit to stroke unit • Treat BP if >220/120 (>185/115 if haemorrhagic) • Oxygen if sats <92% • Monitor BMS as hyperglycaemia results in poorer outcomes • Arrange SALT assessment if any suspicion of dangerous swallow • PT/OT input • Prevent DVTs – keep hydrated, LMWH if immobilised >2 weeks, compression stocking • Look out for psych problems – depression is common in old people • Start on a statin, especially if cholesterol is high The Peer Teaching Society is not liable for false or misleading information…

  35. Stroke Management in Hospital – Ischaemic • Thrombolysis if within 4.5 hours (NICE guidelines) – possible change due to evidence from IST-3 trial. Lots of contraindications • Be aware haemorrhagic transformation is a risk – especially with thrombolysis • Start antiplatelet drugs once CT was excluded haemorrhage. Aspirin is usually given for 2 weeks. • If patient has AF or stroke was cardioembolic, oral anticoagulation is given after 2 weeks. Typically, this is warfarin The Peer Teaching Society is not liable for false or misleading information…

  36. Stroke Management in Hospital – Haemorrhagic • Stop anticoagulants and antiplatelets • Correct coagulation problems • If hydrocephalus develops due to mass effect and midline shift, refer to neurosurgery for decompression/shunting. NB: This can occur in ischaemic stroke due to oedema around infarct The Peer Teaching Society is not liable for false or misleading information…

  37. What are the modifiable vascular risk factors?

  38. Stroke The Peer Teaching Society is not liable for false or misleading information…

  39. Stroke Secondary Stroke Prevention • Post TIA – dipyrimadole + aspirin • Post-ischaemic stroke – clopidogrel  dipyrimadole+aspirin If intolerant to any of the above, give either dipyrimadole or aspirin in isolation If prescribing aspirin, a PPI should be given as well. Control BP to a target of 130/80 The Peer Teaching Society is not liable for false or misleading information…

  40. Transient Ischaemic Attack • Cause sudden neurological deficit, onset is over seconds and lasts less than >24 hours • Can be separated into anterior (carotid circulation) and posterior (vertebrobasilar circulation) • Investigations should be tailored towards looking for future causes of stroke • Follow the same investigations you would for a stroke • Important mimic include mass lesions (spot on CT), focal epilepsy (picked up in history), migraines (headaches rare in TIA) and Bell’s palsy (look for forehead sparing) • Treat any underlying conditions and reduce risk factors – 30% for TIAs become a stroke in 5 years, 15% become MIs The Peer Teaching Society is not liable for false or misleading information…

  41. TIA ABCD2 Score Age >60 – score one Blood pressure systolic >140/diastolic>90 – score one Clinical features Speech impairment – score one Unilateral weakness – score two NB: Use highest, don’t add Duration <60 minutes – score one >60 minutes – score two Diabetes Present – score one The higher the score, the higher the risk of stroke in the next 90 days – a score of >4 is good justification for admission. Less than that should still be followed up in the community The Peer Teaching Society is not liable for false or misleading information…

  42. Exam Qs An 82 year old female patient wakes up with weakness in the entire right side of her body A 56 year old patient with badly controlled diabetes has developed numbness, pins and needles in his feet over the last 6 months A 36 year old male patient presents with increasing unsteadiness which started two days ago. Two years ago he had blurred vision in his left eye which improved considerably within a few weeks, but left him with some minor deficit. Eight years ago he had a 3 week episode of numbness in his left arm. The Peer Teaching Society is not liable for false or misleading information…

  43. Exam Qs A 72 year old man with uncontrolled blood sugar has presented with ulcers in his right foot & bilateral loss of sensation below knee A 77 year old lady with 15 year history of hypertension is brought to A&E. She is unable to speak & cannot move her right arm & leg. A 17 year old boy comes to the clinic with his mother. He complains of recurrent transient episodes of tingling & weakness in his left leg. You also notice his mother has swollen MCP joints & ulnar deviation in both hands. The Peer Teaching Society is not liable for false or misleading information…

  44. Exam Qs A 66 year old woman presents with fatigue, breathlessness & paraesthesia in all limbs. Examination reveals pallor, loss of position sense & impaired vibration sense. A 40 year old man with pulmonary tuberculosis is in the second month of treatment with isoniazid, rifampicin & pyrazinamide. He complains of a burning sensation in his hands & feet. There is impaired sensation to pin prick & light touch. A 67 year old overweight Asian woman presents with painful feet. Direct questioning revealed that she has had nocturia for the last 3 months. The Peer Teaching Society is not liable for false or misleading information…

  45. Exam Qs A 50 year old man develops sudden onset of weakness, numbness & paraesthesiae on the left side of his body. His symptoms faded gradually before disappearing 12 hours later. A 30 year old lady presented with pain in the left eye; numbness & weakness of her right leg. 2 months earlier she had an episode of double vision in the left eye A 40 year old lady with pain & tingling in the left hand, worse at night time when she had to get out of bed to shake the hand for relief. A 25 year old pregnant lady with increasing muscle weakness. She also complains of double vision & drooping eye lids. The Peer Teaching Society is not liable for false or misleading information…

  46. Neuro-pharmacology Pharmacology will come up – learn this • Name • Routes • Classes • Mechanisms • Common, severe, idiosyncratic side-effects For these drugs: • Pyridostigmine • Immunosupressants/modulators – corticosteroids, azathioprone, natalizumab, interferon, Ig • Strokes – alteplase, warfarin, aspirin, clopidogrel, dipyrimadole • Anti-epileptics – valproate, carbamazepine, lamotrigine, phenytoin, benzos • Anti-Parkinson drugs – L-Dopa, carbidopa, MAOIs • Triptans • Antibiotics – cefatexmine, benzylpenicillin Seems like a lot but steroids, stroke drugs, immune system drugs and antibiotics all come up in other systems as well The mechanism for immunoglobulin is ‘actually magic’ according to McDermott The Peer Teaching Society is not liable for false or misleading information…

  47. Case 1 The Peer Teaching Society is not liable for false or misleading information…

  48. Causes of Epilepsy The Peer Teaching Society is not liable for false or misleading information…

  49. Types of Epilepsy The Peer Teaching Society is not liable for false or misleading information…

  50. Management • Generalized Tonic-Clonic Seizure • Sodium Valproate • Levetiracetam • Location Related Epilepsy • Carbamazepine • Lamotrigine • Myoclonic Epilepsy • Sodium Valproate • Levetiracetam The Peer Teaching Society is not liable for false or misleading information…

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