Case 7: basics of neurology Flashcards

1
Q

Causes of cerebellar ataxia

A
  • Acute: Vascular, alcohol, drugs (e.g. phenytoin), lithium, cerebellitis, cerebellar stroke
  • Sub-acute: Toxic/nutritional (medicine/ B12), inflammatory, neoplastic and paraneoplastic (distant cancer)
  • Chronic: Degenerative conditions (MSA, Friedrich’s Ataxia, chronic alcohol use, diabetes, B12 deficiency
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2
Q

UMN versus LMN weakness: areas affected

A
  • UMN: cortical, spinal
  • LMN: plexus, nerve, NMJ, muscle
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3
Q

Types of weakness

A
  • Neuromuscular weakness: Less than expected force generated from a movement. Varies between individuals
  • Constitutional weakness: Generalized fatigue and inability to carry out tasks due to systemic illness or frailty
  • Paresis vs plegia: Weakness (paresis) as opposed to paralysis (plegia)
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4
Q

Distribution of muscle weakness

A
  • Hemi: One side- usually CNS (UMN) in origin with rare exceptions i.e. stroke or spinal pathalogy
  • Mono (paresis): Weakness of one limb
  • Paraparesis: Weakness of both limbs (typically legs): i.e. LMN (GBS) or spinal cord issue
  • Tetra/quadriparesis: All four limbs involved
  • Also bulbar (speech, swallowing), axial/truncal (respiration and balance)
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5
Q

UMN pathology examination: CNS (brain and spinal cord)

A
  • Tone: increased- spastic (velcity dependent- cog wheel rigidity) or rigid (same stiffness all the way through movement- seen in extrapyramidal i.e. parkinsons)
  • Increased reflexes
  • Babinski/Plantar reflex: positive, upgoing
  • Pathological reflexes: Hoffman’s sign
  • Other: pronator drift (cortical or high spinal problems), clasp knife response (to removal of force)
  • Either Cortico-basal or cortico-spinal
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6
Q

LMN pathology examination: plexus, nerve, NMJ and muscle

A
  • Tone: decreased or flaccid (can say not increased)
  • Reflexes: decreased/absent
  • Babinski/Plantar reflex: negative/ down going
  • Other: muscle wasting and fasciculations possible
  • Causes: neuropathy (nerve damage- sensory or motor), neuromuscular junction (cant sustain strong movement (fatiguability)- often vision (ptosis), and speech), plexus, nerve root, muscle (just motor)
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7
Q

Pyramidal weakness

A
  • Cortico-spinal or cortico-bulbar weakness
  • Arm flexors stronger than extensors: arm bent, hand spastic or floppy often of little use
  • Leg extensors stronger than flexors: walks on tiptoe or outside of foot on affected side
  • Is Hemiplegic in stroke patients
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8
Q

Proximal weakness

A
  • Lower motor neurone pattern of weakness. See it mostly in muscle disease and some nerve disease
  • Weakness of shoulder abduction (more then distal), weakness of hip flexion
  • Difficulties climbing stairs, combing hair, standing up from a seat
  • Waddling gait (Trendelenberg’s)
  • Many causes-tend to affect muscle rather than nerve: Iatrogenic (long term steroid use), Inflammatory (myositis), Inherited myopathy (Duchenne’s), vitamin D and thiamine deficiency
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9
Q

Distal weakness

A
  • Weakness starting in hands and feet- such as foot drop
  • If painless: MS, MND
  • If painful: peripheral neuropathy, vasculitis, inflammation of nerve
  • Can be caused by knee crossing and trapping the common peroneal nerve
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10
Q

Functional weakness

A
  • May be fluctuant/not in keeping with disease patterns
  • Patient may find it hard to move limb when focussing but can when distracted
  • Patients can describe disassociation
  • Hoover’s sign
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11
Q

MRCP weakness scale

A
  • 5 – normal
  • 4 – weak, but some ooommphff needed to overcome the patient
  • 3 – very weak, you can beat them with little effort: can just raise limb against gravity
  • 2 – so weak that the power would only be useful to an astronaut: can move a bit but not completely against gravity
  • 1 – a flicker only
  • 0 – nil points
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12
Q

What’s involved in balance?

A
  • Vision: to see wher we are in space
  • Vestibular System: semicircular canals to determine which way we are facing
  • Proprioception: muscle spindles (measuring degree of muscle length change) to determine where limbs are in space
  • Cerebellum integrates all this information and coordinates downward control from the cerebral hemisphere. Helps to facilitate and regulate eye movements, anticipate future limb position and modulating planned or ongoing movement with sensory information.
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13
Q

Different ways to describe dizziness

A
  • Ataxia: feeling unsteady, not knowing where they are putting their feet. Tending to fall over from starting or on mobilisation. Due to problems in the peripheral sensory system or cerebellum
  • Vertigo- feeling of spinning, rotational motion, can cause nausea. Due to problems in the vestibular system, cerebrum or cerebellum
  • Pre-syncope- light-headedness, feeling of faintness, the world going grey and distant. Can feel like they are about to go down, can feel unwell. Due to issues in the autonomic system, cardiovascular system or both
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14
Q

Nystagmus

A
  • Uncontrolled eye movement
  • Would be right sided nystagmus if the eye moves to the right fast and slow to the left
  • Bengin Proxysmal Positional Vertigo (BPPV) gives a vertical up-down and torsional (rotational) nystagmus on dix-hallpike.
  • Vestibular neuronitis gives a left-right nystagmus worse on gazeaway fromthe affected side i.e. a right-sided problem would cause a nystagmus worse on leftward gaze (and leftward would be the fast phase of the nystagmus)
  • A central cause of nystagmus can give a gaze-evoked nystagmus with no obvious unilateral component, can also have vertigal nystagmus
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15
Q

Nystagmus tests

A
  • Dix-hallpike
  • Head impulse test: shows corrective saccade (dont do if neck problems). Done in the HINTS test
  • Unterberger test: shows vestibular dysfunction
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16
Q

Types of ataxia

A
  • Sensory Ataxia - Where the unsteadiness comes from proprioceptive defects in the sensory fibres, dorsal root ganglion or dorsal column. A positive Romberg’s indicates sensory ataxia
  • Cerebellar Ataxia -Where unsteadiness comes from disease affecting the cerebellum. Causes DANISH
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17
Q

Vestibular causes of dizziness

A
  • Triggered Episodic Vestibular Syndrome -Discrete episodes of minutes or hours of dizziness, precipitated by a specific trigger e.g. BPPV, Orthostatic Hypotension
  • Spontaenous Episodic Vestibular Syndrome -Discrete episodes with no clear trigger e.g. Vestibular migraine, Meniere’s
  • Post-Exposure Acute Vestibular Syndrome -Persistent dizziness lasting days to weeks with history of adverse event such as drugs or trauma e.g. aminoglycosides, head injury
  • Spontaenous Acute Vestibular Syndrome -Persistent dizziness lasting days to weeks with no clear history of precipitating event e.g. vestibular neuronitis, posterior circulation stroke
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18
Q

BPPV

A
  • Middle-aged or older patient
  • Feeling of ‘spinning’ when turning in bed or when turning suddenly, tend to be short-lived
  • ++ Nauseous when this occurs
  • Nystagmus (vertical and torsional) noted on Dix-Hallpike
  • Treated through Epley manoeuvre
  • No further testing required if not suspicious for a different cause
  • Patients can have vestibular physiotherapy for symptoms
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19
Q

Vestibular neuronitis

A
  • Spontaneous, acute, constant vertigo
  • Resolves after a week. Can cause intense ongoing nausea and vomiting
  • Often preceding infection
  • Nystagmus: horizontal and unidirectional. Worse on gaze away from affected side. Positive head impulse test
  • Management: Anti-emetic (Prochlorperazine), treat underlying condition
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20
Q

Labyrinthitis

A
  • Same as vestibular neuronitis but also acts on cochlear- will have hearing loss
  • Add corticosteroids for hearing loss (prednisolone for 10-14 days)
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21
Q

Meniere’s

A
  • Recurrent rotatory vertigo
  • Sensorineural hearing loss: tends to be low frequency
  • Tinnitus
  • Sensation of fullness in the affected ear
  • Tend to have episodes
  • Investigations: pure tone audiometry, Electrocochleography to measure action potentials generated through sound
  • Damage to tympanic membrane: Tympanography and otoacoustic emissions
22
Q

Meniere’s treatment

A
  • Betahistine:for prevention
  • Prochlorperazine or an antihistamine (cyclizine)
  • Conservative: restrict salt intake, contact DVLA
  • Medical: antiemetic medication
  • Surgical: endolymphatic sac surgery, vestibular nerve dissection and chemical labyrinthinectomy
  • Gentamicin: chemical labyrinthctomy
23
Q

Vestibular migraine

A
  1. At least 5 episodes with vestibular symptoms of moderator or severe intensity, lasting 5 minutes to 72 hours
  2. Current or previous history of migraine with or without aura according to theInternal classification of Headache Disorder(ICHD)
  3. One or more migraine features with at least 50% of the vestibular episodes: one sided location, pulsating quality, moderate or severe pain intensity, aggravation by routine physical activity. Photophobia and phonophobia. Visual Aura
  4. Not better accounted for by another vestibular or ICHD diagnosis
24
Q

Vestibular migraine treatment

A
  • Migrainous features: aura, unilateral throbbing headache
  • Avoid triggers
  • Propranolol for prophylaxis
  • Triptans for acute attacks
25
Q

Sensory ataxia cause

A
  • Sensory afferent neurone: Diabetes, GBS, Vasculitis, Charcot-Marie-Tooth (inherited neuropathy), Chemotherapy (Platinum, Vinca Alkaloids, Taxanes)
  • Dorsal root ganglion: Sjogren’s , Paraneoplastic (anti-Hu antibodies)
  • Dorsal column: B12 deficiency , Tabes dorsalis (late neurosysphilis)
26
Q

Sensory ataxia

A
  • A defect in the system that carry’s sensory information to the brain- disruption in proprioception
  • Can have pain due to damage to pain fibres
  • Examination: high stepping gait and positive Romberg’s
  • Investigations: MRI to look at spinal cord for degeneration and inflammation, Nerve conduction studies to look at action potentials in sensory fibres (SNAP’s)
27
Q

Cerebellar ataxia

A
  • Problems with cerebellum coordinating movement and unsteadiness or difficulties with balance
  • Stroke - causes ischaemia or infarction
  • Alcohol - When we drink acutely, we poison the cerebellum. Chronic alcoholics can have ongoing damage and causes similar problems when withdrawing
  • Trauma - a direct blow to the cerebellum can cause damage
  • Multiple Sclerosis
  • Gluten ataxia - common, respond well to a gluten-free diet
  • Neurodegenerative diseases - Atypical Parkinsonism
  • Genetic conditions - the spinocerebellar ataxias (a group of multiple conditions), Friedrich’s ataxia and Ataxia Telangiectasia
28
Q

Spinocerebellar ataxia

A

Dominantly inherited disorders due to trinucleotide repeats. Present in middle age, demonstrate anticipation and cerebellar atrophy is the most common finding

29
Q

Friedrich’s ataxia

A
  • Autosomal recessive inheritance pattern - mutation in the Frataxin gene on Chr 9
  • Patients develop significant cerebellar problems as well as dysarthria and hyporeflexia
  • They develop heart problems like hypertorphic cardiomyopathy and conduction defects - these patients might need ECGs and Echocardiography
  • Many develop scoliosis and diabetes can be poor for prognosis
  • Patients often need walking aids in their 20s
  • Start in childhood, early adulthood
30
Q

Ataxia Telangiectasia

A
  • Ataxia early in life but worsens into school age
  • Oculomotor apraxia that can casue problems with reading
  • Telangiectasias in the sclera
  • Immune problems (recurrent infections)
  • 25% lifetime risk of leukaemia or lymphoma
  • slow rising alphafetoprotein levels
  • Cerbellar atrophy
  • Autosomal recessive condition: due to mutation in ATM gene on Chr 11
31
Q

Management of cerebellar ataxia

A
  • MDT approach
  • Physiotherapy and rehabilitation
  • Treat muscle spasticity with muscle relaxants
  • Friedrich’s ataxia: control cardiac issues
32
Q

Peripheral neuropathy

A
  • Refers to damage of the peripheral nerves, can be: sensory nerves, motor nerves and autonomic nerves.
  • Patients can present with sensory change, muscle weakness, gait change
33
Q

How can damage to nerves occur

A
  • Demyelination -The lining of the nerves is stripped away. Causes include auto-immune such as GBS (peripheral) and MS (central) and genetic causes (Charcot marie tooth)
  • Axonopathy -The axon itself is damaged. Causes include chemotherapy agents, direct compression, systemic conditions (e.g. diabetes)
  • The longer the nerve the more vulnerable it is to damage, the longest nerve is in the feet
34
Q

Difference between nerves

A
  • Motor (alpha): muscle contraction
  • Sensory (alpha/beta): vibration, proprioception
  • Sensory (delta): pain and temperature
  • Autonomic (C): autonomic control
35
Q

Symptoms of neuropathy

A
  • Sensory: numbness, sensory/proprioception/temperature sensation loss, hypersensitivity, tingling, pins and needles, itching, neuropathic pain
  • Motor: weakness, muscle wasting, hyporeflexia, fasciculation, cramps
  • Autonomic: postural hypotension, reduced exercise tolerance, constipation, gastroparesis, incontinence, difficulty emptying bladder, erectile dysfunction
  • Other: reduced hypoglycaemia awareness, sweat disturbance
36
Q

Parasympathetic nervous system

A
  • Eyes: constrict pupil
  • Salivary gland: stimulates salivation
  • Heart: slows heartbeat
  • Lung: constricts bronchi
  • Stomach: stimulates digestion
  • Liver: stimulates bile release
  • Intestine: stimulates peristalsis and secretion
  • Bladder: constricts bladder
37
Q

Sympathetic nervous system

A
  • Eyes: dilate pupil
  • Salivary gland: inhibit salvation
  • Heart: accelerates heartbeat
  • Lungs: dilate bronchi
  • Stomach: inhibits digestion
  • Liver: stimulates glucose release
  • Kidneys: stimulates Epinephrine and Norepinephrine release
  • Intestine: inhibit peristalsis and secretion
  • Bladder: relaxes bladder
38
Q

How many nerves affected: vocabulary

A
  • Focal: one peripheral nerve area. ‘Mononeuropathy’.
  • Multi-focal: more than one peripheral nerve area. Patchy. ‘Mononeuritis Multiplex’.
  • Diffuse: affects a wide area. Classically starts bilaterally distally. ‘Polyneuropathy’.
  • Either sensory, motor, sensorimotor or autonomic
39
Q

Focal neuropathy

A
  • A functional problem in an isolated area: sensory, motor or both. Causes
  • Trauma
  • Local Swelling Compression
  • Body Weight Compression
  • Compartment Constriction
  • Joint Restriction
  • Inflammation/infection/autoimmune: more likely to cause diffuse neuropathy
40
Q

Causes of focal neuropathy

A
  • Carpal tunnel syndrome: tingling and numbness or the median nerve distribution of the hand and sometimes weakness. Manged with splints and physiotherapy
  • Cubital tunnel syndrome: compression of ulnar nerve through elbow. Causes tingling/numbness in ulnar distribution of hand and issues with grip strength
  • Meralgia Paresthetica: entrapment of lateral femoral cutaneous nerve. Pain and paraesthesia over the lateral aspect of the thigh especially light touch and hypersensitivity to heat. Managed with local anaesthetic
  • Peroneal nerve injury: foot drop, abnormalities in dorsiflexion, knee flexion and sensory abnormalities
41
Q

Facial nerve palsy: focal neuropathy

A
  • Isolated facial weakness: has forehead involvement so a LMN lesion
  • Causes: Bell’s palsy (idiopathic- most common), Ramsay-Hunt (Herpes zoster activation in the geniculate ganglion- can cause pain, deafness, vertigo and vesicular rash in the ear)
  • Management: oral steroids, if eye affected hourly eye drops, eye patch at night and eye ointment
  • 6-8 weeks to recover
42
Q

Seizure

A

Sudden and uncontrolled, synchronous electrical discharge in the brain, either generalised (unconscious) or originating in a part of the brain which then may subsequently spread, with symptoms relating to this

43
Q

Epilepsy

A
  • Disorder of the brain due to tendency to seizures manifested as at least two unprovoked seizures occurring >24 h apart. OR
  • One unprovoked seizure and a high probability of more occurring due to predisposing factors e.g. brain lesion. OR
  • Diagnosis of an epilepsy syndrome
44
Q

Types of seizures

A
  • Partial/focal- simple motor seizure but depends on area affected i.e. if occipital visual changes
  • Complex partial/focal- as above but with altered consciousness i.e. jerking one arm and appearing glazed over
  • Generalised- whole body convulsion which can lead to resp compromise if prolonged, are unconscious (tonic-clonic or ‘grand mal’)
  • Secondary generalisation- partial seizure which then spreads to involve the whole brain (full generalised). Can be seen in tumours
45
Q

Aura

A

Consider as part of the seizure though patients see this as preceding or ‘seizure warning’. Aura often helps localize the location or source of the seizure e.g. deja vous, automatisms, smelling burning in temporal lobe seizure. Seizure will then become generalised.

46
Q

Status epilepticus

A

Sustained and non-terminating event. Where there is no recovery or gain in consciousness. Life threatening

47
Q

Non-convulsive status

A

Continuous seizures with altered awareness but few physical manifestations i.e. jerking or convulsing. Can have automatisms, eyes deviating, flicking of eyes. Diagnosed by EEG. Treated with emergency anti-convulsive therapy

48
Q

Seizure symptoms to expect from temporal lobe

A
  • Majority of focal onset.
  • Get Deja vu, feeling of unfamiliarity ‘jamais vu’, feel they are about to make a great revelation.
  • Can originate from mesial or hippocampal scarring after febrile convulsions.
  • Automatisms i.e. picking or chewing.
  • Autonomic i.e. goosebumps, feeling fear. Unpleasant smells
49
Q

Epilepsy: symptoms to expect from other brain lobes

A
  • Frontal: cycling of legs, pelvic thrusting, head turns away from seizure origin, fencers posture (one arm flexes the other extends). Very brief, often at night, often children
  • Occipital: stroke in the area. Altered eye movements, flickering of eyelids, crude visual manifestations (orbs of coloured lights)
  • Parietal: they feel small or big compared to world, hands seem massive
50
Q

Diagnosing seizures

A
  • Prodromal symptoms: aura, syncopal symptoms (lightheaded, hot, not enough water), head injuries, drugs (withdrawal or taking)
  • Collateral history
  • Seizure form: facial features, breathing, recovery, movement
  • Investigations: cranial imaging (to see if caused by stroke, tumour or bleed)
  • EEG: useful if<25. May have changes between events (juvenile myoclonic seizures). Helpful in any age if you capture a seizure
  • Safety info and driving- if suspected seizure cant drive and must inform DVLA