Neuro pearls from revision lecture Flashcards
1
Q
What changes on nerve conduction studies and EMG in root lesions?
A
NCS: normal
EMG: denervation changes- fibrillations and positive sharp waves
2
Q
How do you differentiate between an L5 nerve root lesion and common peroneal lesion?
A
In L5, both foot eversion and inversion are affected + normal NCS + neurogenic EMG + usually associated with back pain.
In CPN lesion, eversion only is affected + EMG changes are confined to below the knee.
3
Q
What is the usual mechanism of CPN injury?
A
Compression at the fibular neck eg squatting, anesthesia
4
Q
How does a sciatic peroneal component nerve injury occur?
A
Generally restricted to post hip surgery or dislocation. EMG is abnormal above the knee
5
Q
What is meralgia parasthetica?
A
Painful numbness of the lateral cutaneous nerve of the thigh. Skinny jeans.
6
Q
How does diabetic amyotrophy present? Lumbosacral plexopathy.
A
Pain in legs first
Quads wasting
Patchy EMG changes iliopsoas, hip adductors, quads.
7
Q
Differentiate Radial nerve palsy from C7 radiculopathy?
A
C7 causes weakness of both wrist flexion and extension. In radial nerve palsy, there is wrist drop only, and flexion is preserved.
8
Q
Deep branch of the ulnar nerve in the palms supplies what?
A
The first dorsal interosseous
9
Q
What does brachial neuritis (inflammatory plexopathy) look like?
A
After carrying heavy back pack–>unilateral shoulder pain followed by weakness and often winging of the scapula.
(Long thoracic nerve)
Widespread patchy EMG/NCS changes
10
Q
What are common mechanisms of radial nerve palsies?
A
Crutches in axilla
Spiral groove of humerus from hanging arm over back of chair
11
Q
What are the classical findings of CIDP?
A
PROXIMAL weakness (often- unusual for a myopathy)
Absent reflexes
Mixed motor sensory involvement
Demyelinating NCS (including block)
Neurogenic EMG
Look at F waves to assess proximal segments which are not seen well by NCS
12
Q
What is the classic presentation of multifocal motor neuropathy?
A
Pure motor
Reflexes sometimes preserved or even brisk
May be able to identify particular nerves involved
NCS “conduction block” at non compressed sites
Profuse fasciculations so often mistaken for MND
Anti-GM1 antibodies
13
Q
MND what are the classical signs?
A
Pure MOTOR
usually mix of upper and lower motor neuron signs
Can have bulbar and respiratory muscle involvement.
14
Q
What do you see in axonal NCS?
A
- Reduced amplitude
- Absent sural sensory potentials.
15
Q
What do you see in demyelinating NCS?
A
Reduced velocity
Dispersion - fibres are both normal and abnormal so signal reaches not all at once
Delayed F waves
Focal block
16
Q
What is a “focal block” on NCS?
A
More than 50% drop in amplitude = demyelinating due to pressure or multi-focal motor neuropathy if occurs at a site not typically at risk of compression.
17
Q
What do delayed F waves on NCS imply?
A
Proximal demyelination
18
Q
On EMG, what does spontaneous activity signify? (Fibrillations and positive sharp waves)
A
Denervation
Inflammatory myopathy
A muscle should be “silent” when you put the needle in first
19
Q
What is a neurogenic vs a myopathic picture on EMG?
A
Neurogenic- high amplitude and duration, polyphasic from re-innervation
Myopathic = low amplitude and duration
Myotonia = dive bomber sound
20
Q
Differential diagnosis of acute flaccid paralysis
A
GBS Myasthenia gravis acute spinal cord lesion like transvere myelitis (spasticity and hyperreflexia can take weeks) Botulism Porphyria Tick paralysis Heavy metal poisoning (lead arsenic)
21
Q
Classic GBS presentation:
A
Preceding infective illness eg campylobacter
Ascending weakness, usually symmetrical
Sometimes parasthesiae
Diffuse BACK PAIN
Areflexia- may take a couple of days to develop
Usually minimal sensory signs despite parasthesiae
22
Q
CSF finding in GBS?
A
albumino-cytologic dissociation
Protein can take a few days to become elevated
INFLAMMATORY CELLS SUGGEST AN ALTERNATIVE DIAGNOSIS; except in HIV GBS - DO get lymphocytosis
23
Q
Nerve conduction studies on GBS?
A
May be normal early on- repeat in 1-2 weeks
Prolonged or absent F waves
Distal conduction velocities often normal- proximal block
24
Q
Which autoAb in GBS?
A
Anti-GM-1 (40-50% sensitivity)
GQ1b in Miller Fisher variant
25
Does cold improve or worsen neuromuscular transmission in MG?
Improves
26
NCS and EMG findings in Myasthenia gravis?
Repetitive stimulation -->decrement
| Single fibre EMG- "jitters"- very sensitive if tested in a weak muscle
27
Which antibodies are associated with MG?
```
ACh receptor Ab
MuSK antibodies (50% of ACh negative)- only do if ACh negative
```
28
How does botulism present?
```
History of contaminated food eg home canned veg, potatoes, fish, preserved sea food, or IV drug use skin wounds.
Dilated pupils
Ptosis, diplopia
Bradycardia/hypotension
Reduced reflexes
Minimal/no sensory features
```
Look for the toxin in faeces and food and serum
29
How does porphyria present?
```
Abdominal pain
Psychosis
Seizures
DESCENDING weakness, arms more than legs
meds/menstrual cycle may precipitate
Distal sensory loss and reduced reflexes
Urine discolouration on exposure to sunlight.
```
CLUE: often hyponatraemic
30
Should you use steroids in GBS?
NO!!
31
Management of GBS?
IVIg or plasma exchange are just as good
NO STEROIDS
resp surveillance- ICU when FVC 1.5 or less
Autonomic surveillance; cardiac and BP monitoring
DVT prophylaxis
Pressure care
32
Painful sensory neuropathy- what's in the differential diagnosis?
Diabetes
Alcohol abuse
Medications- chemo (vincristine, oxaliplatin), amiodarone, nitrofurantoin, perhexiline, cohchicine, thalidomide
Vitamin def- B12, folate, thiamine, pyridoxine
Thyroid- high or low
Renal failure -often K related rather than Cr
paraprotein
Vasculitis
HIV
paraneoplastic
33
Management of restless legs syndrome?
```
Exclude iron deficiency
Reduce alcohol, tobacco
Regular sleep pattern
Dopamine agonist- pramipexole
L-Dopa- wears off
Gabapentin
```
34
What is in the differential for progressive motor weakness?
MND/ALS
Cervival myelopathy (where arms are affected)
CIDP
MMN
plexopathy or malignant infiltration of nerve
Mononeuritis multiplex
Myasthenia gravis
Inflammatory myopathy- polymyositis, dermatomyositis, inclusion body myositis, statin
Other myopathies like dystrophy, metabolic or steroid myopathy
35
Where there is progressive weakness, sensory involvement excludes what causes?
MND, MMN, myopathy, myasthenia
36
Where do you see mixed signs eg wasting/fasciculations + brisk reflexes?
MND
cervival myelopathy
MMN can have preserved reflexes
37
Neck flexion and extension weakness seen in?
MND
MG
myopathy
38
Proximal predominant pattern of weakness seen in?
Myopathy
| CIDP
39
What does the following pattern point to:
loss of reflexes
weakness greater than wasting
motor greater than sensory
More likely demyelinating: ?CIDP
40
What did the INTERACT-2 study show in relation to ICH?
In patients with intracerebral hemorrhage, intensive lowering of blood pressure did not result in a significant reduction in the rate of the primary outcome of death or severe disability. An ordinal analysis of modified Rankin scores indicated improved functional outcomes with intensive lowering of blood pressure.
41
When would you consider doing a hemicraniectomy post stroke?
Younger than 60 with large MCA infarct
| Still saves lives over 60 but no meaningful return to function in these older patients
42
What DVT prophylaxis works post stroke?
Not teds
| Pneumatic compression
43
When would DAPT be the preference for short term secondary prevention post stroke?
Intracranial atherosclerosis subgroup (according to CHANCE trial)
For one month
No use for longer term A+C - Match, Charisma trials
44
How do you manage a cerebral venous sinus thrombosis?
IV heparin even if haemorrhagic infarction
| Then warfarin for six months
45
Causes of cerebral venous sinus thrombosis
```
Inherited thrombophilia
Acquired thrombophilia
-malignancy
-APLS
-Behcets
-IBD
-OCP
-dehydration
-nephrotic
-polycythemia
Local sepsis- sinusitis, mastoiditis
```
46
Treatment for idiopathic intracranial hypertension
```
Weight loss
Acetazolamide
Topiramate
Optic nerve sheath fenestration
LP/VP shunt
Venous sinus stenting
```
47
What is the major side effect associated with alemtuzumab?
Autoimmune- ITP, thyroid etc
48
What are the famous side effects of fingolimod?
First dose bradycardia
| Macular oedema
49
What is the famous side effect of glatiramer
chest tightness
50
Which agent can increase walking in MS?
Fampridine
51
What factors increase the risk of progressive multifocal leukoencephalopathy on tysabri ?
JC virus antibody positive
Use for more than 2 years
Previous immunosupression
If all three foes to 1.1% per year PML
52
What does optic neuritis present as?
reduced colour
reduced visual acuity
eye pain on movement
onset over hours to days, trough by one week then RECOVERY at least started by 4 weeks (if no recovery then different thing)
Fundus initially normal, one third swollen, later pale
Field loss can take any form
53
Treat optic neuritis?
IVMP x 3 x 1g
54
What proportion of optic neuritis patients have MS?
40% have a second demyelinating episode
If on MRI greater than two lesions-->80% get MS at 15 years
If normal MRI- 20% MS at 15 years
CSF OCB increase MS risk
55
Neurofibromatosis 1 and 2- which chromosomes?
NF-1 on chromosome 14 as there are 14 letters in neurofibromatosis
NF-2 is on chromosome 22 as that is where all the 2s are
56
Neurofibromatosis what type of inheritance?
Autosomal dominant
57
Features of NF-1 (6)
Cafe-au-lait spots - at least 5, 15mm in diameter
Axillary/groin freckles
Peripheral neurofibromas
Iris harmatomas (Lisch nodules) in more than 90%
Scoliosis
henochromocytomas
58
Features of NF-2
bilateral acoustic neuromas
| Multiple intracranial schwanomas, meningiomas, ependymomas
59
Treatment for cluster headaches
acute: 100% oxygen, subcutaneous or a nasal triptan
prophylaxis: verapamil, prednisolone
60
What does the CHANCE study say regarding patients with high risk TIA
CHANCE study (NEJM 2013;369:11). This study looked at giving high-risk TIA patients aspirin + clopidogrel for the first 90 days compared to aspirin alone. 11.7% of aspirin only patients had a stroke over 90 days compared to 8.2% of dual antiplatelet patients
61
Effect of steroids in relapse of MS
High dose steroids (e.g. IV methylprednisolone) may be given for 3-5 days to shorten the length of an acute relapse. It should be noted that steroids shorten the duration of a relapse and do not alter the degree of recovery (i.e. whether a patient returns to baseline function)
62
When is beta interferon used in MS?
Beta-interferon has been shown to reduce the relapse rate by up to 30%. Certain criteria have to be met before it is used:
relapsing-remitting disease + 2 relapses in past 2 years + able to walk 100m unaided
secondary progressive disease + 2 relapses in past 2 years + able to walk 10m (aided or unaided)
reduces number of relapses and MRI changes, however doesn't reduce overall disability
63
glatiramer acetate- mechanism of action?
immunomodulating drug - acts as an 'immune decoy'
64
Natalizumab Mechanism of action
a recombinant monoclonal antibody that antagonises Alpha-4 Beta-1-integrin found on the surface of leucocytes, thus inhibiting migration of leucocytes across the endothelium across the blood-brain barrier
65
Fingolimod MOA?
sphingosine 1-phosphate receptor modulator, prevents lymphocytes from leaving lymph nodes. An oral formulation is available
66
How is thallium SPECT important in toxoplasma vs lymphoma
positive in lymphoma
| negative in toxoplasma
67
What's the most common occular sign in Wernicke's encephalopathy?
Nystagmus - NOT ophthalmoplegia
68
Dementia lewy bodies- characteristic pathalogical changes in which areas
haracteristic pathological feature is alpha-synuclein cytoplasmic inclusions (Lewy bodies) in the substantia nigra, paralimbic and neocortical areas
69
Causes of a bilateral facial nerve palsy
sarcoidosis
Guillain-Barre syndrome
polio
Lyme disease
70
Causes of LMN facial nerve palsy that is unilateral
sarcoidosis
Guillain-Barre syndrome
polio, Lyme disease
plus
```
Bells palsy
Ramsay Hunt syndrome (HZV)
acoustic neuroma
parotid tumour
HIV
MS - or UMN palsy
DM
```
71
Miller Fisher variant GBS is associated with what antibodies?
anti-GQ1b
Present in over 90%
Ophthalmoplegia, areflexia, ataxia
72
Lateral medullary syndrome- which artery and which signs?
Lateral medullary syndrome - PICA lesion
```
cerebellar signs
dysphagia
contralateral sensory loss
ipsilateral Horner's
ipsilateral facial numbness
```
73
What is the most common cause of death in Friedreich's ataxia?
HOCM- seen in 90% and the most common cause of death
74
Causes of absent ankle jerks but extensor plantars?
```
Subacute combined degeneration of the spinal cord
MND
Friedreich's ataxia
Syringomyelia
Taboparesis (syphilis)
Conus medullaris lesion
```
75
How might pituitary apoplexy present?
Sudden enlargement of pituitary tumour secondary to haemorrhage or infarction.
Features:
- sudden onset headache like SAH
- vomiting and neck stiffness
- Visual field defect- bitemporal superior quadrant defect
- extraocular nerve palsies
- features of pituitary insufficiency; hypotension secondary to hypoadrenalism
76
When should you tell patient to pop a tryptan?
Onset of headache (not onset aura)
77
When are tryptans contraindicated?
When there is a history of IHD
78
Causes of a demyelinating peripheral neuropathy?
GBS/CIDP
Amiodarone
Paraprotein neuropathy
Hereditary sensorimotor neuropathies type 1
79
Anti-Hu antibodies are associated with what cancers and cause what neurological presentation?
Small cell lung Ca and neuroblastomas
Sensory neuropathy that may be painful
Cerebellar syndrome
Encephalomyelitis
80
Anti-Yo antibodies are associated with what cancers and cause what neurological presentation?
Ovarian and breast cancer
Cerebellar syndrome
81
Anti-GAD antibody associated with what cancers and cause what neurological presentation?
breast, colorectal, small cell lung
Stiff person syndrome or diffuse hypertonia
82
Anti-Ri antibodies associated with what cancers and cause what neurological presentation?
Breast and small cell lung ca
occular opsoclonus-myoclonus- eyes look like jittering bugs trying to escape!! see youtube vid
83
Acute treatment migraine
| Migraine prevention
Migraine
acute: triptan + NSAID or triptan + paracetamol
prophylaxis: topiramate or propranolol
84
Wernickes and Korsakoff syndrome- affect which area of brain?
Medial thalamus
| Mamillary bodies of hypothalamus
85
Hemiballism
Subthalamic nucleus of basal ganglia
86
Huntington's chorea
Striatum (caudate nucleus) of the basal ganglia
87
Kluver Bucy syndrome
Amygdala
88
Drugs causing parkinsonism
Metoclopramide
Butyrophenones: haloperidol, droperidol
Phenothiazines: chlorpromazine, prochlorpromazine
Not droperidol as does not cross the BBB
89
Stroke of which artery causes locked in syndrome?
Basilar
90
Anterior cerebral artery stroke causes
Contralateral hemiparesis and sensory loss; lower extremity more than upper
91
Middle cerebral artery stroke causes
Contralateral hemiparesis and sensory loss; upper extremity more than lower
Aphasia
Contralateral homonymous hemianopia
92
Posterior cerebral artery stroke causes
Contralateral homonymous hemianopia with macular sparing
| Visual agnosia
93
Webers syndrome is involving which arteries and produces what deficit?
branches of the posterior cerebral artery that supply the midbrain--> ipsilateral CN III palsy, contralateral weakness
94
PICA stroke causes what deficits
Called wallenberg or lateral medullary syndrome
Ipsilateral: face pain and temp loss sensation
Contralateral: limb/torso pain and temp loss
Ataxia and nystagmus
95
AICA stroke causes what deficits
lateral pontine syndrome
sudden onset of vertigo, nystagmus, vomiting, hemiataxia
Ipsilateral facial paralysis and deafness
Loss of all modalities to that side of the face
96
First line drug for trigeminal neuralgia
Carbamazepine
97
Does a preceding diarrhoeal illness in GBS confer a positive or negative prognosis
Poor
Other poor prognostic features are:
- age
- poor upper extremity muscle strength
- high anti-GM1 antibody titre
- need for ventilatory support
Rapidity of onset makes no difference
98
Upbeat nystagmus associated with what types of lesions?
Cerebellar vermis
99
Downbeat nystagmus associated with what sorts of lesions?
Arnold Chiari malformation- a formen magnum lesion
100
Where is Broca's area?
Broca's area, located on the posterior aspect of the frontal lobe, in the inferior frontal gyrus
101
Why is nimodipine given post SAH?
post-operative nimodipine (e.g. 60mg / 4 hrly, if BP allows) has been shown to reduce the severity of neurological deficits but doesn't reduce rebleeding
102
What are some conditions associated with berry aneurysms?
Adult PCKD
Ehlers-Danlos syndrome
Coarctation of the aorta
103
What does incongruous and congruous mean in terms of the visual field defects?
Congruous means about the same defect in both eyes. The less congruous the lesion, the more anterior it is- eg the optic tract
104
What is the pathway from retina to occipital lobe of visual input?
```
Retina
optic nerve
optic chiasm
optic tract
lateral geniculate body
optic radiation
visual cortex
```
105
Why look for a high arched palate in CV exam??
Associated with Friedriech's ataxia which also gives HOCM!!
```
If suspected this would also look for...
optic atrophy
cerebellar ataxia
absent ankle jerks and extensor plantars
diabetes mellitus in 20%
spinocerebellar tract degeneration
```
106
Ataxia telangiectasia causes what? (5)
cerebellar ataxia
telangiectasia (spider angiomas)
IgA deficiency resulting in recurrent chest infections
10% risk of developing malignancy, lymphoma or leukaemia, but also non-lymphoid tumours
autosomal recessive, presents in childhood usually
107
How does anhydrosis location help to determine the site of a lesion in Horner's syndrome?
Horner's syndrome - anhydrosis determines site of lesion:
head, arm, trunk = central lesion: stroke, syringomyelia
just face = pre-ganglionic lesion: Pancoast's, cervical rib
absent = post-ganglionic lesion: carotid artery
108
What are the causes of a Horner's syndrome split into central lesions, preganglionic and post ganglionic lesions?
Central: Stroke, Syringomyelia, multiple Sclerosis, tumour, encephalitis
Pre-Ganglionic lesion: Thyroidectomy, Trauma, Pancoast Tumour, Cervival rib
Post ganglionic lesion: Carotid artery dissection, Carotid aneurysm, Cavernous sinus thrombosis, Cluster headache
109
In MND, what treatment is better- Riluzole or NIV?
NIV
survival benefit about 7 months
Riluzole prevents stilumation of glutamate receptors, used mainly in amyotrophic lateral sclerosis, prolongs life by about three months
110
WIlson's disease mode of inheritance?
Autosomal recessive
| Defect in ATP7B gene located on chromosome 13
111
Wilson's disease treatment?
Penicillamine first line in the past
| Trientine hydrochloride as alternative chelating agent
112
Wilson's disease affects the kidneys how?
Renal tubular acidosis- especially Fanconi syndrome
113
Visual field defects caused by which antiepileptic?
Vigabatrin
114
Is CK high in T4 toxic or hypoT4 cause of endocrine myopathy or both?
T4 toxic- low or normal
| T4 hypo high CK!
115
Which antibodies might you see in autoimmune necrotising myopathy?
HMGCoA reductase antibody
| Anti-SRP (signal recognition particle)
116
Drug induced myopathy-
```
statins/fibrates
amiodarone
colchicine
cyclosporine
zidvudine (ART)
Chloroquine
```
117
What are the risk factors for cholesterol lowering agent myopathy? (CLAM)
```
Female
Older age
Renal impairment
Hypothyroidism
Lipophilic >hydrophilic statin
```
118
What is acute steroid myopathy?
```
1 week post high dose
Generalised weakness
High CK
Myoglobinuria
Irritative myopathic on EMG
Biopsy shows loss of all muscle types.
```
