Neurology Flashcards
Describe the cranial nerves and their functions
I - olfactory (sensory) - olfaction
II - optic (sensory) - vision
III - oculomotor (motor) - innervates pupil + lens, upper eyelid, majority of extraocular muscles
IV - trochlear (motor) - rotates down and in
V - trigeminal (both) - sensory in ophthalmic, maxilllary, mandibular; mandibular also muscles of mastication and some neck muscles
VI - abducens (motor) - rotates outwards
VII - facial (both) - muscles of facial expression, taste in anterior 2/3, lacrimal + saliva glands
VIII - vestibulocochlear (sensory) - hearing and balance
IX - glossopharyngeal (both) - muscles of swallowing, parasympathetic of parotid, taste of posterior 1/3 (assess with cough and soft palate - ah)
X - vagus (both) - parasympathetic control and sensory of thoracic / abdominal organs, motor control of pharynx + larynx
XI - accessory (motor) - sternocleidomastoid and trapezius
XII - hypoglossal (motor) - muscles of tongue, speech, swallowing
What are the affects of brain lesions in different sections
Frontal lobes lesions: disinhibition, perseveration, anosmia, inability to generate a list
Broca’s aphasia: located on the posterior aspect of the frontal lobe, in the inferior frontal gyrus. Speech is non-fluent, laboured, and halting
Parietal lobe lesions: sensory inattention, apraxias, astereognosis (tactile agnosia), inferior homonymous quadrantanopia. Gerstmann’s syndrome (lesion of dominant parietal): alexia (read), acalculia (arithmetic), agraphia (writing), finger agnosia and right-left disorientation
Temporal lobe lesion: superior homonymous quadrantanopia, auditory agnosia, prosopagnosia, (difficulty recognising faces)
Wernicke’s aphasia: this area ‘forms’ the speech before ‘sending it’ to Broca’s area. Lesions result in word substitution, neologisms but speech remains fluent
Occipital lobe lesions: homonymous hemianopia (with macular sparing), cortical blindness, visual agnosia
Cerebellum lesions: midline lesions: gait and truncal ataxia; hemisphere lesions: intention tremor, past pointing, dysdiadokinesis, nystagmus
How do upper and lower motor neuron lesions present
Upper (faulty input): weakness, hyperreflexive, increased tone, spasticity + rigidity, minimal paralysis, tremor, chorea + dystonia (twisting)
Lower (less): atrophy, loss of tone, flaccidity, weak reflexes, fasciculations
Describe the presentations of strokes in different circulations
Anterior cerebral: leg weakness, gait apraxia, incontinence, drowsiness
Middle cerebral: contralateral arm + leg weakness, contralateral sensory loss, hemianopia, aphasia + dysphasia
Posterior cerebral: contralateral homonymous hemianopia, cortical blindness, other visual
Ventral midbrain (Weber’s): ipsilateral CN III palsy, contralateral weakness of limbs
Posterior circulation: motor deficits, dysarthria, vertigo, altered consciousness
Anterior inferior cerebellar: Nystagmus, vertigo, sudden hearing loss, facial weakness. (A for audio)
Posterior inferior cerebellar (Wallenberg / LMS): Nystagmus, vertigo, Horner’s, dysarthria + dysphagia, ipsilateral hemiataxia. (P for poor balance)
Basilar: locked in syndrome
Pontine haemorrhage: reduced GCS (collapse), paralysis, bilateral pinpoint pupils
Supplies motor tracts (bilateral paralysis), cranial nerves V-IX, haemorrhage causes stimulation of parasympathetic - pinpoint pupils
Describe the bamford classification of stroke
Anterior (anterior and middle cerebral). Total = all 3 of: unilateral weakness of arm + leg + face, homonymous hemianopia, higher cerebral dysfunction (dysphasia, visuospatial)
Partial = 2 out of 3. Also: amaurosis fugax, dysarthria (speech defect due to muscles), dysphagia (receptive, expressive), higher cortical dysfunction
Posterior = one of: cranial nerve palsy + contralateral motor / sensory deficit, conjugate eye movement disorder (won’t move together), cerebellar dysfunction, isolated homonymous hemianopia
Cerebellar: vertigo, nystagmus, ataxia, dysarthria. Also aphasia, dysphasia
Lacunar = one of: pure motor, pure hemisensory, ataxic hemiparesis, mixed sensorimotor, clumsy hand dysarthria
One deep penetrating artery, subcortical so no cortical features
How are strokes investigated and what scores are used
Acute - CT (rule out haemorrhagic), next day MRI to confirm
ROSIER score: exclude hypoglycaemia; -1 for loss of consciousness, seizure activity; +1 for acute asymmetric facial weakness, arm weakness, leg weakness, visual field defect. Stroke > 0
BP, ECG (AF), FBC
NIHSS score used for severity / prognosis / thrombolysis decision, the higher the score also the higher the certainty of diagnosis. >20 severe, >16 moderate to severe, >5 moderate, >1 minor. Max 42
How are ischaemic strokes managed
Maximise reversible ischaemic tissue - hydration, sats > 95%
Ischaemic: thrombolysis only if < 4.5 hours after onset and haemorrhage ruled out - alteplase (plasminogen activator), aspirin 300mg (PPI) for 2 weeks then lifelong clopidogrel
Can also do mechanical thrombectomy alongside thrombolysis (very limited resource), 6 hour window for identified proximal anterior circulation (up to 24h if good perfusion scan - limited infarct core), longer for basilar, risk of reperfusion injury
Carotid artery endarterectomy if in carotid territory and not severely disabled, > 70% stenosis
Long term: clopidogrel (not tolerated aspirin + dipyridamole), aspirin + clopidogrel in high risk, atorvastatin, lifestyle advice, hypertension ((TCA) thiazide, long acting CCB, ACE / ARB)
How are haemorrhagic strokes managed
Haemorrhagic: frequent GCS monitoring, any anticoagulants should be reversed (vitamin K + beriplex (W), andexanet alfa (DOAC), protamine (LMWH)), control hypertension, manual decompression + diuretic for raised ICP, surgery - clipping, endovascular coiling
What are the causes of TIA
Small vessel occlusion, atherothromboembolism from carotid is the chief cause
Also hyperviscosity: polycythaemia, sickle cell, myeloma
Hypoperfusion: cardiac dysrhythmia, postural hypotension, decreased flow through atheromatous arteries
Describe the presentation of TIAs
Sudden loss of function, symptoms usually < 60 mins but can be up to 24h
Much more focal than strokes, 90% anterior / carotid, one or few: numb contralateral leg, hemiparesis, hemi sensory disturbance, dysphagia, amaurosis fugax (transient loss of vision in one eye)
How is TIA diagnosed
Often solely on history
Carotid artery doppler ultrasound (stenosis/ atheroma), MRI (diffusion weighted + blood sensitive), echocardiogram, ECG
CT only indicated if still ongoing pathology or other disease suspected
Rule out: FBC (polycythaemia), ESR (vasculitis), glucose, cholesterol
How is TIA managed
TIA: Aspirin 300mg (with PPI) immediately, carotid doppler, reviewed within 24h, if imaging required - MRI
If bleeding disorder, immediate CT scan to exclude intracranial haemorrhage, no aspirin if on medication already
Long term: clopidogrel (not tolerated aspirin + dipyridamole), aspirin + clopidogrel in high risk, atorvastatin, lifestyle advice, hypertension (thiazide, long acting CCB, ACE / ARB)
Describe Cushing’s triad
Cushing’s triad are the classical signs of raised intracranial pressure; widening pulse pressure (increase in systolic to combat pressure), bradycardia + slow deep breathing due to brainstem compression (Cheyne-Stokes respiration)
What is the pathogenesis and presentation of subarchnoid haemorrhages
Subarachnoid: rupture of saccular ‘berry’ aneurysms, i.e. rupture of junctions in circle of willis. 10% arteriovenous malformations. Tissue ischaemia, raised ICP
Berry: associated with polycystic kidney disease, hypertension, ehlers-danlos, coarctation of A
SA: sudden onset worst ever / thunderclap headache, vomiting, collapse, seizures, coma
What is the pathogenesis and presentation of subdural haemorrhages
Subdural: acute = high impact injury; chronic = small brain, rupture of bridging veins, vulnerable to deceleration injuries also dural metastases, haematoma forms and stops bleeding, weeks later starts to autolyse and grow in size, ICP rises leading to herniation. (Trauma may not be obvious as weeks before and can be very minor)
Patients on anticoagulants have ~10x risk of SD and worse outcomes
SD: fluctuating levels of consciousness, sleepiness, headache, personality change
What is the pathogenesis and presentation of extradural haemorrhages
ED: most commonly due to traumatic head injury (fracture of pterion causing laceration of middle meningeal), blood accumulates rapidly over minutes or hours
Pterion (temple): parietal, temporal, sphenoid, frontal
ED: head injury, brief loss of consciousness, lucid interval between injury and loss of consciousness. Severe headache, N+V, confusion, seizures, drowsy
How are intracranial haemorrhages investigated
SA: CT within 6h - blood in basal cisterns (star shaped); LP (CT more than 6h and inconclusive or after 12h) - xanthochromia (bilirubin from broken down RBCs); confirmed, CT angiography to find cause and anatomy
Other: clotting profile for coagulopathy, troponin I often raised, ECG (looks like STEMI)
SD: CT - crescentic and can cross suture lines; acute = hyperdense, chronic = hypodense; may be midline shift or effacement of sulci. Consider MRI / X ray is CT inconclusive
ED: CT - biconvex (lentiform) hyperdense, limited by suture lines
How are intracranial haemorrhages managed
Refer all SAH to neurosurgeon immediately. ABCDE + sedate, maintain perfusion - IV fluids, BP below 160, nimodipine. Endovascular coiling (promotes thrombosis and ablation of aneurysm) - first line if angiography shows aneurysm, clipping, also intracranial stents and balloon remodelling
Nimodipine prevents vasospasm and increases blood flow downstream
SD: ABCs, stabilise + reduce ICP, irrigation / evacuation via burr hole / craniotomy (small can be left)
Management of raised ICP: head of bed 30d, analgesics + sedation + paralytics, hyperventilation to reduce pCO2, mannitol
ED like SD, ABCDE, stabilise + reduce ICP, craniotomy / burr hole + clot evacuation, ligation of bleeding vessel
Describe the presentations of different epileptic seizures
Last 30-120s, ictal and post ictal symptoms, typical phenomena (tongue biting, deja vu), may occur from sleep
Grand mal (generalised tonic-clonic): loss of consciousness, tonic phase (rigid and stiff), clonic phase (bilateral muscle jerking), eyes open, bite tongue, followed by confusion / coma
Complex partial: loss of awareness, symptoms depending on area affected: temporal (most common) - aura, sensory hallucinations, fear, automatisms; frontal - motor features (posturing, peddling), Jacksonian march (moves down homunculus), post ictal paralysis of involved; parietal - sensory and tingling; occipital - visual phenomena
⅔ of partial seizures will spread to a generalised
Simple partial: awareness is unimpaired with focal motor / sensory / autonomic, no postictal
Absent: just stops and stares, does not realise
Myoclonic: sudden isolated jerk of one limb / face / trunk
Tonic: sudden increased tone, stiffening without jerking
How is epilepsy managed
Men:
Generalised / myoclonic / tonic / atonic: sodium valproate
Focal: lamotrigine or levetiracetam (carbamazepine SL)
Absence: ethosuximide (sodium valproate SL) (carbamazepine contraindicated)
Women:
Generalised / focal: lamotrigine or levetiracetam (carbamazepine SL)
Tonic / atonic: lamotrigine
Myoclonic: levetiracetam
Absence: ethosuximide (lamotrigine or levetiracetam SL) (carbamazepine contraindicated)
Prolonged seizure (> 3min) or repeated - buccal midazolam FL community / IV lorazepam FL hospital (rectal diazepam) *2, not responding - IV phenytoin
Describe the pathogenesis of Parkinson’s
Mitochondrial dysfunction + oxidative stress, progressive degeneration of dopaminergic neurons in the substantia nigra, striatum receives less dopamine
Lewy-bodies (clumps of protein) become gradually widespread
1% purely genetic, combination of genetic susceptibility and environment (toxin exposure)
Describe the presentation of Parkinson’s
Classic triad: bradykinesia (slow, struggle with fine movements, gait), tremor at rest, rigidity
Up to 7 years before motor: anosmia (smell), depression / anxiety, aches, REM sleep disorders, urinary urgency, hypotension, constipation
Onset is asymmetrical (that side will stay worse), gradual onset, first is usually impaired dexterity / foot drop
How is parkinson’s investigated and managed
Clinical by neurologist (history and examination), confirm with response to levodopa
Parkinson’s is urgent referral
MRI initially normal (may show atrophy later), exclude tumours, hydrocephalus
Compensate for dopamine: levodopa (L-dopa) and co-careldopa - decarboxylase inhibitor (prevents peripheral conversion of L-dopa to dopamine)
Also dopamine agonists (bromocriptine, ropinirole - disinhibition), MAO-B inhibitors (selegiline, rasagiline) not very powerful but help in some
Symptomatic: occupational, aids, SSRIs for depression, constipation etc
Describe the parkinson’s plus conditions
Suspect in poor response to levodopa
Multiple system atrophy: parkinsonism, cerebellar signs (ataxia, dysarthria, nystagmus), autonomic disturbance (erectile dysfunction, postural hypotension, atonic bladder)
MSA-P = predominant parkinsonian symptoms, MSA-C predominant cerebellar
Progressive supranuclear palsy: early onset parkinsonism (bradykinesia), cognitive + frontal lobe impairment, postural instability + falls (stiff, broad based gait), impairment of vertical gaze, speech and swallowing difficulties
Corticobasal degeneration: asymmetric parkinsonism, cortical signs (apraxia, alien limb phenomenon, cortical sensory loss), cognitive (progressive dementia + language)
Also lewy body dementia, frontotemporal dementia
Migraine: presentation and treatment
May be prodrome (can last days) - cravings, mood + sleep changes. Aura preceded and may persist: visual (dots, zigzags, scotoma (hole), hemianopia), somatosensory (paraesthesia). Headache has at least 2 of: unilateral, throbbing, moderate-severe, motion sensitivity. Also: N+V, photo/phonophobia
Without aura possible to, attacks can last up to 72 hours
M: Acute treatment: triptan (sumatriptan) and NSAID (maybe antiemetic - prochlorperazine). Prevention (more than 2 a month): propranolol + topiramate (anticonvulsant, teratogenic) FL, TCA antidepressant
avoid triggers (CHOCOLATE): chocolate, hangovers, orgasms, cheese, oral contraceptives, lie ins, alcohol, tumult, exercise.
Describe the presentation and treatment of cluster headaches
C: most disabling, abrupt onset, excruciating pain around one eye / temple / forehead (strictly unilateral), ipsilateral cranial autonomic (flushing, bloodshot + tears, pupil constriction). Rises to crescendo, lasts 15-160 mins, usually at same time, often nocturnal / early morning. Usually episodic - 4-12 weeks followed by months/ year of none
C: 100% oxygen, SC triptans (sumatriptan) reduce vascular inflammation, can try NSAID / paracetamol if helpful. Prevention: calcium channel blockers (verapamil) first line, avoid alcohol, prednisolone may help
Describe trigeminal neuralgia
Trigeminal neuralgia: at least 3 attacks of unilateral pain on one of the distributions of CN5 and no radiation beyond, lasting a few minutes, severe / electric shock, caused by innocuous stimulation of nerve. Can be nerve lesion, local pathology (aneurysm), compression by vein or artery.
Carbamazepine (gabapentin) suppresses attacks, surgery may be required
Describe idiopathic intracranial hypertension
Idiopathic intracranial hypertension: headache worse on lying / bending forwards, blurred vision, papilloedema, enlarged blind spot, CN VI palsy
Weight loss if applicable, acetazolamide (carbonic anhydrase inhibitor), topiramate, lumbar puncture can temporarily relieve. Damage to optic nerve - sheath decompression, lumbo / ventriculoperitoneal shunt
Usually obese younger women, pregnancy, COCP / steroids / tetracyclines / lithium
Describe the pathogenesis of multiple sclerosis
Combination of genetic and environmental, exposure to EBV / low vit D may contribute
Autoimmune T cells (not harmful until crosses blood brain barrier), activate B cells, autoantibodies against myelin (only CNS white matter), cascade of destruction and demyelination
Myelin sheath does regenerate but less efficient and high heat degrades. Repeated demyelination cause axonal loss and sclerosis forms along neurones, plaques form around veins
What is the presentation of multiple sclerosis
Usually 20-40, monosymptomatic initially, symptoms worsen with heat / exercise
Unilateral optic neuritis (pain, reduced central vision), numbness / tingling of limbs, leg weakness, spasticity + pyramidal, brainstem (vertigo, facial weakness), cerebellar (ataxia), trigeminal neuralgia
80% relapsing and remitting: attacks for days, recovery (partial or complete) over weeks. Disability accumulates over time
How is MS diagnosed
Two or more attacks in different parts of CNS
MRI diagnostic if history matches, 95% periventricular lesions, 90% discrete white matter abnormalities
Lumbar puncture shows oligoclonal IgG bands - not specific; electrophysiology shows delayed conduction
How is MS managed
Reduced stress, good diet, vitamin D
Acute relapse: IV methylprednisolone for 5d can help shorten but aim to use no more than twice a year
Disease modifying: natalizumab (IV monoclonal, best evidence), ocrelizumab (mono), fingolimod (s1p modulator). Against leukocytes / lymphocytes
Indications: 2 replases in past 2 years + able to walk 100m unaided (RR) / walk 10m (SP)
Symptomatic: spasticity - baclofen + gabapentin FL, physio, (cannabis + botox evaluation); bladder dysfunction - US study, residual volume - self catheterisation, not - anticholinergics (oxybutynin)
Describe the types of motor neurone disease
ALS - upper and lower; progressive muscular atrophy - lower only, starts in one limb and spreads, distal first; progressive bulbar palsy - LMN only, cranial nerves 9-12 initially (swallowing, talking); primary lateral sclerosis - upper only, marked spastic leg weakness, progressive tetraparesis + pseudobulbar P
How is MND diagnosed and managed
Clinical findings, confirm with nerve conduction studies and electromyography
MRI to exclude structural, lumbar puncture to exclude inflammatory
Antiglutamatergic (riluzole) have modest effects, prolong life by 3 months
Symptomatic: propantheline for drooling, baclofen for spasms, analgesia
Specialist MDT support (speech + language, occupational, physio)
What are the most common pathogens that cause meningitis and what are the complications
Acute: neisseria meningitidis (G -ve, can lead to septicaemia), strep pneumoniae / pneumococcus. Pregnant / old - listeria, neonates - E. coli + group B strep. Viral - herpes simplex, varicella zoster
Chronic - TB, syphilis (also cryptococcus fungi)
Bacterial meningitis causes 5% mortality and 20% permanent damage - hearing loss, seizures
What is the presentation of meningitis
Classic triad: headache, neck stiffness, fever
Also: altered mental status + confusion, vomiting, photophobia, seizures, focal neurological
Examination: KErnig sign: can’t Knee Extend when hip is flexed; BrudziNski: Neck flexion when knees flexed causes knee + hip extension
Acute bacterial: sudden onset, papilloedema (raised ICP - vision changes, disk), intense malaise / fever / rigours within hours
Complication: progressive drowsiness, materialising, cranial nerves
Chronic: long history, vague symptoms (headache, anorexia, vomiting), triad often absent or late
How is meningitis diagnosed and treated
Blood cultures before lumbar puncture, lumbar puncture only diagnostic (if can’t after 30 mins give empirical antibiotics). Also: blood tests, CT, throat swab, serum PCR. Petechial rash = septicaemia
CT before LP (60+, immunocompromised, history of CNS, seizures, GCS). No LP if septicaemia (not sepsis)
Bacterial meningitis is a medical emergency, if suspected start antibiotics before test results - ceftriaxone, 60+ / immunoC - amoxicillin (listeria), vancomycin if travelled
Children: >3m IV cefotaxime (or ceftriaxone), <3m IV amoxicillin + cefotaxime
Viral - aciclovir
Dexamethasone, IV fluids
Prophylaxis for contacts - ciprofloxacin, rifampicin. Consider steroids for oedema
Describe Wernicke’s encephalitis
Wernicke’s: thiamine (B1) deficiency caused by excessive alcohol or prolonged vomiting. Ataxia, confusion, ophthalmoplegia (weakness of muscles), nystagmus
If untreated progresses to Korsakoff syndrome - amnesia + confabulation (gaps filled with false memories)
Immediate thiamine, CT / MRI
Describe the presentation of encephalitis
Triad of: fever, headaches, altered mental status. Onset usually days, problems with consciousness
Begins with viral features (myalgia, fatigue, nausea) and progresses to personality + behavioural changes, GCS symptoms, focal signs, raised ICP
Herpes encephalitis: petechial haemorrhages in temporal (and inferior frontal)
How is encephalitis investigated and managed
MRI - inflammation, swelling (herpes = temporal), maybe midline shift. Also EEG, lumbar puncture (false negatives common), blood and csf serology
Viral: immediate antiviral (aciclovir) before results, anti-seizure (primidone). If bacterial benzylpenicillin
Mostly supportive treatment
Describe the presentation of brain tumours
4 cardinal presenting symptoms: raised ICP (progressive headache, papilloedema), progressive neurological deficit (depends on area of brain), seizures (focal more common), lethargy
Raised ICP: headache worse in morning and wakes up, pain increased by coughing and bending forwards
Papilloedema (swelling of optic disk), retinal oedema, haemorrhages
Low grade: seizures, incidental finding. High grade: rapidly progressive neurological deficit
Cushing’s triad: widening pulse pressure, bradycardia + irregular breathing
Describe the investigations and management of brain tumours
Lumbar puncture is contraindicated, withdrawing CSF may cause immediate coning and potential death
MRI / CT, size + location, high grade have irregular edges
Biopsy (skull burr hole) - grade and confirmation, MGMT positive
Surgery to remove mass if possible
Chemo (temozolomide) for glioma - same time as surgery and 6 weeks post
Determine if sensitive first - high MGMT enzyme it is not, methylated MGMT will be
Oral dexamethasone (powerful steroid) rapidly improves brain performance in all tumours
Radio often palliative but can be radical, anticonvulsants for seizures
What is the pathogenesis and presentation of cauda equina
CE most commonly caused by herniation (L4-S1). Also: spinal stenosis, cancer, trauma, epidural abscess
CE has leg weakness that is flaccid and areflexic (doesn’t respond to stimuli) - LMN
Bilateral sciatica, saddle anaesthesia, bladder + bowel dysfunction, ED
What are the causes and presentation of spinal cord compression
Compression: neoplasms (secondary malignancy), spinal pathology (disc herniation, disc prolapse)
Rare: infection haematoma, primary tumour
Herniation = nucleus pulposus has moved out annulus; prolapse = NP presses against annulus
Spinal or root pain, progressive leg weakness, upper neurone signs (contralateral spasticity and hyperreflexic), arm weakness if cervical, sensory loss below level of lesion, bladder/ anal sphincter involvement later
Motor, reflex and sensory with normal findings above lesion. LMN at level, UMN below
How is spinal compression investigated and managed
Imaging straight away, MRI gold standard (cause and site)
Surgical decompression, epidural steroid, laminectomy (removal of lamina between discs to remove pressure), microdiscectomy (removal or herniated tissue), spinal fusion
Malignancy - dexamethasone, radio +/- chemo
Describe autonomic dysreflexia
SCI at or above T6 can cause autonomic dysreflexia - triggered (urinary retention, impacted faeces etc), sensory info can’t get to brain, excessive autonomic reaction from body
Pounding headache, profuse sweating (above injury), hypertension
Can be life threatening (HTN), remove trigger and treat BP
Describe Brown-Sequard syndrome
Brown-Sequard: injury causing hemisection of spinal cord; damage to corticospinal, spinothalamic + dorsal → ipsilateral upper motor, ipsilateral dorsal (fine touch, proprioception, vibration) and contralateral spinothalamic (pain and temp)
Describe syringomelia
Syringomyelia: collection of CSF within cord, syringobulbia CSF in the medulla
Cape like loss of temp sensation but others kept (spinothalamic first - anterior commissure)
Spastic weakness (legs), neuropathic pain, upgoing plantars, autonomic - Horner’s
Full spine + brain MRI. Treat cause: chiari malformation, trauma, tumours, idiopathic
Describe Trigeminal nerualgia
Trigeminal neuralgia: compression of trigeminal nerve: vein or artery, aneurysm, meningeal inflammation, tumours, MS (in brainstem). Results in demyelination and excitation - erratic pain
3 attacks of unilateral facial pain in one or more distributions (no radiation beyond). Pain is: paroxysmal attacks, severe intensity, electric shock / stabbing, precipitated by harmless stimuli of affected side
Typical analgesics don’t work. Carbamazepine (anticonvulsants) suppress attacks, gabapentin and lamotrigine less effective. Surgery if drugs fail: microvascular decompression, radio
Describe Bell’s palsy
Bell’s palsy: acute unilateral facial nerve palsy, LMN so forehead included. Also altered taste, dry eyes, hyperacusis + post auricular pain
Unknown aetiology thought to be related to herpes virus, 3* more common in pregnant women
Prednisolone within 72h onset, (antiviral debatable), eye care to avoid keratopathy - artificial tears, taping shut at night
Should resolve - not after 3 weeks urgent ENT referral
What are the causes of peripheral axonal and demyelinating polyneuropathies
Peripheral neuropathy causes ABC2D2E: alcohol, B12, cancer + CKD, diabetes + drugs, every vasculitis
(Systemic: diabetes (50%), vitamin deficiency, gluten sens, chronic renal, alcohol abuse etc
Chronic (6 months) idiopathic axonal: commonly length dependent, may develop risk factor later - follow up)
Chronic demyelinating: chronic inflammatory demyelinating polyneuropathy (AI), multifocal motor neuropathy, genetic (charcot marie tooth), toxins (lead)
Describe Guillain-Barre syndrome
Guillain-Barre: acute inflammatory ascending polyneuropathy, peripheral only (targets schwann cells), following upper respiratory tract or GI infection (campylobacter jejuni)
Back / leg pain, ascending paralysis and milder sensory deficits, reduced reflexes. Also respiratory muscle weakness, cranial nerve (diplopia, bilateral facial paralysis, oropharyngeal weakness), retention, diarrhoea
Lumbar puncture (increased protein with no other changes), nerve conduction (decreased velocity, prolonged latency). Need immediate IV Ig / plasma exchange
Describe Charcot-Marie Tooth
CMT: dominant, reduced motor and sensory, myelin or axon depending on type, characteristic signs
High foot arches, distal wasting, lower leg weakness (ankle dorsiflexion) - high stepping gait
No cure or treatment
Describe the pathogenesis and presentation of myasthenia gravis
Autoantibodies target nicotinic acetylcholine receptors interfering with neuromuscular junction (IgG complement deposited), less receptors = less excitation = muscle weakness
In 5% (45% of those without AcR) have muscle specific tyrosine kinase (MuSK) autoantibodies
Majority of patients have thymus hyperplasia or tumour (thymoma) - more prone in generalised / early onset. Thymus responsible for production of faulty T cells and immune modulation
Increasing muscular fatigue. Order of muscles affected: extraocular, bulbar, face, proximal limbs / neck / trunk. Respiratory difficulties in generalised
Initial presentation often double vision and ptosis
Tendon reflexes are normal. Muscle weakness is worsened with repeated / prolonged contraction
Describe the investigations and treatment of myasthenia gravis
History, examination - ptosis (ice pack test), limb fatigability
Single fibre electromyography (92% sensitivity)
Serum anti-AChR (raised in 90%) if negative anti-MuSK (40% remaining)
Electromyography and nerve conduction studies, CT of thymus, normal CK
Tensilon test: IV edrophonium (reversible acetylcholinesterase inhibitor) temporarily reduces weakness
Less commonly used due to risk of arrhythmia
Pyridostigmine (acetylcholinesterase inhibitors) so ACh stays in (give hyoscine butylbromide for antimuscarinic)
Steroids (prednisolone) to suppress immune, steroid sparing agents / immunosuppressants (azathioprine, cyclosporine), thymectomy (10-15% thymoma, 50-60% thymic hyperplasia)
Acute crisis: IV immunoglobulin + plasmapheresis
Describe Lambert Eaton syndrome and Miller Fisher variant MG
Lambert-Eaton syndrome: myasthenic syndrome (AI or small cell lung cancer), repeated contractions lead to increased strength.
Proximal weakness, affects lower limbs first, eyes not commonly affected, hyporeflexia, autonomic dysfunction (dry mouth, impotence, difficulty micturating, blurred vision)
Investigate voltage gated calcium channel antibodies
Treat cancer, amifampridine, prednisolone / azathioprine, IV immunoglobulin + plasmapheresis
Miller Fisher variant: progressive proximal weakness, ophthalmoplegia, areflexia, ataxia
Describe Myasthenic crisis
Myasthenic crisis (weakening of respiratory muscles) caused by infections, stress, withdrawal of treatment, anaemia, drugs (beta blockers). MuSK more likely
Crisis: respiratory crisis, impaired swallow, severe limb weakness
Monitor FVC (< 1L), ITU, treat with plasmapheresis (antibody removal) + IV Ig, treat cause
Describe Huntington’s
Autosomal dominant condition, incurable progressive neurodegenerative disorder; atrophy of corpus striatum, less ACh and GABA, GABA usually inhibits dopamine, excessive thalamic stimulation and movement
Onset 36-55, prodromal psychotic and behavioural (irritability, depression), begins as general restlessness and lack of coordination, becomes relentless jerky and explosive involuntary movements that cease during sleep. Behavioural also develop: aggression, addictive, self neglect, dementia
Diagnosis mostly clinical, genetic test, benzodiazepines, sulpiride (depresses nerve function), tetrabenazine (depleted dopamine), antidepressants, antipsychotics
Describe Tuberous sclerosis
Autosomal D, neurocutaneous condition; neuro: developmental + intellectual, epilepsy; cutaneous: ash-leaf spots (fluoresce under UV), shagreen patches (rough patches over spine), angiofibromas - adenoma sebaceum (papules / spots) butterfly shape over nose and beneath nails
Causes growth of benign tumours: rhabdomyomas of heart, gliomatous changes → brain lesions, polycystic kidney, renal + lung angiomyolipomata (cysts)
Genetic testing, MRI / CT / echo of affected organs. Antiepileptics, surgery
Describe Neurofibromatosis
T1+2 both autosomal D, neurocutaneous
T1: cafe au lait spots (>6 15mm), axillary / groin freckles, peripheral neurofibromas, iris hamartomas (Lisch), scoliosis, pheochromocytomas
T2 (tumours): bilateral vestibular schwannomas, multiple intracranial schwannomas, meningiomas, ependymomas
