Neurlogy Flashcards
Features of myotonic dystrophy
General exam : frontal balding, bilateral ptosis, myopathic facies (wasted, expressionless), wasting of face and neck, and distal limbs, delayed eye opening
Hands: myotonia, weakness and wasting, percussion myotonia, NO SENSORY LOSS
Limbs: distal weakness and wasting, reduced tone and reflexes, downgoing plantars, fasciculations NO SENSORY LOSS
Gait: bilateral foot drop / high-stepping gait
AKA: Lower motor neurone, distal motor neuropathy
Conditions associated with myotonic dystrophy
cataracts, cardiomyopathy, diabetes, dysphagia, testicular atrophy
Genetics of myotonic dystrophy
autosomal dominant tri-nucleotide (CTG) repeat disorder on chromosome 19
anticipation shown
Differential diagnosis of lower motor neurone distal motor neuropathy
Myotonic dystropy Fascioscapulohumeral dystrophy Guillain Barre (sensory involvement expected) Myasthenia gravis (fatiguability) Polymyositis (usually proximal muscles)
Investigations for lower motor neurone distal motor neuropathy.
If myotonic dystrophy suspected what additional tests would you request?
CK
EMG +/- nerve conduction studies
muscle biopsy
genetic testing for myotonic dystrophy, also fasting glucose (diabetes), ECG & CXR (signs of cardiomegaly), slit lamp examination (for cataracts)
Differential diagnosis of bilateral ptosis
myasthenia gravis
myotonic dystrophy
congenital
Differential diagnosis of unilateral ptosis
3rd nerve palsy
horner’s syndrome
stroke
bell’s palsy
What is Horner’s syndrome and how does it present?
Damage to sympathetic pathways causing unilateral ptosis, miosis (small pupil), anhydrosis and apparent enophthalmos (sunken eye)
Causes of Horner’s syndrome?
Damage to sympathetic trunk can be;
central (lesion in spinal cord); cord tumour, syringomyelia, infarction (lateral medullary syndrome)
= complete anhydrosis of face and arm and trunk
Pre-ganglionic (before sympathetic ganglion); cervical rib, thyroid cancer/goitre/thyroidectomy, Pancost’s tumour of lung apex, trauma
= anhydrosis of face only
Post-ganglionic; cluster headache, migraine, caverous sinus thrombosis, middle ear infection, carotid artery dissection.
= no anhydrosis
Causes of cerebellar syndrome?
alcohol multiple sclerosis stroke tumour hypothyroisism Friedrich's ataxia paraneoplastic cerebeller syndrome phenytoin
Horizontal nystagmous worse towards the left suggests a cerebellar lesion on which side?
LEFT - towards the side of the lesion
(vestibular lesion would be away from)
What signs are seen in multiple sclerosis?
UMN weakness and spasticity, cerebellar signs, internuclear ophthalmoplegia, optic atrophy, autonomic dysnfunction (urinary retention/incontinence, impotence, bowel problems)
What is internuclear ophthlmoplegia?
Failure to adduct affected eye (i.e. look to opposite side) with nystagmus in other eye. I.e right INO causes failure to adduct right eye and nystagmous in left eye when looking left. Both eyes converge normally.
Caused by lesion in medial longitudinal fasciculus of CONTRALATERAL side.
What investigation should be done if MS suspected?
MRI brain/spinal cord (looking for periventricular white matter plaques)
Oligoclonal bands in CSF
Treatment for MS?
MDT approach interferon beta monoclonal antibodies e.g. natalizumab methylprednisolone for acute attacks baclofen
Causes of spastic paraparesis
MS (look for cerevellar signs, ask to do fundoscopy for optic atrophy)
Spinal cord compression/ cervical myopathy (examine for a sensory level to indicate level of spinal damage, look for spinal scar)
Trauma
Motor neurone disease (no sensory signs)
Anterior spinal artery thrombosis (dissociated sensory loss, preserved dorsalcolumns (proprioception, fine touch and vibration sense)
Syringomyelia (LMN at level, UMN below level)
Hereditary spastic paraparesis
Subacute combined degeneration of the cord (absent reflexes, upgoing plantars)
Friedrich’s ataxia
Cause of subacute combined degeration of the cord?
B12 deficiency
Causes of spinal cord compression? - an emergency
disc prolapse, malignancy, infection (abscess), trauma
Treatment of spinal cord compression?
Urgent MRI
DW neurosurgery re: decompression
Steroids/RTX if malignancy
Signs of syringomyelia;
LMN signs, weakness and wasting, dissociated sensory loss (loss of spinothalamic tracts, preserved dorsal column) AT THE LEVEL (REMEMBER SYRINX EXPANDS OVER MULTIPLE LEVELS)
UMN signs, pyramidal weakness (leg flexors, arm extensors) BELOW THE LEVEL
What is motor neurone disease?
progressive axonal degeneration of upper and lower motor neurones. Aetiology unknown but 10% familial. Over 20 genetic defects can cause condition.
Types of motor neurone disease
amyotrophic lateral sclerosis (50%); corticospinal tracts causing spastic paraparesis
progressive muscular atrophy (25%): affects anterior horn cells produces mainly LMN signs - best prognosis
progressive bulbar palsy (25%) ; affects lower cranial nerve and suprabulbar nuclei producing speech and swallow problems - worst prognosis.
Patient has progressive weakness and wasting of the hands and feet. Absent knee jerks with upgoing plantars. Sensation is normal. What is the diagnosis? How would you investigate?
Mixed UMN and LMN with normal sensation = motor neurone disease
Ix: EMG (fasciculations), Nerve conduction study (normal as problem is anterior horn cell), MRI brain and spine to exclude cord compression and meylopathy and brain stem lesions, B12/folate/glucose/CK.
Management of motor neurone disease.
Multidisiplinary team approach with PT,OT, SW.
Genetic couselling
PEG feeding or NIV if required
riluzole (slows progression expanding life by 3 months)
Parkinson’s plus syndromes
Multi systems atrophy; ask for L&S BP, look for cerebellar signs
Progressive supranuclear palsy; abnormalities of eye movements and speech, pseudobulbar palsy
Lewy body dementia
Corticobasal degeneration(apraxia, aphasia, alien hand syndrome)
Treatment of Parkinsons
When to start; when symptoms problematic and patient wishes as treatment as earlier start doesn’t delay progression.
Mild disease;
1: MAOB inhibitors e.g. rasagaline
2: Add a dopamine agonist (pramipexole, ropinirole or rotigotine) or carbidopa/levodopa
3: Amantidine (an anticholinergic) can also be used in mild disease
Moderate disease (''worsening symptoms and medication side effects")
1: Use carbidopa/levodopa and dopamine agonist
''Wearing off'' > increase frequency of dopamine agonist medication to 4 times daily, add COMT inhibitor (entacapone) to prolong duration of levodopa, add a MAOB inhibitor is not already on this.
'' ongoing tremor'' > add amantidine (SE: worse cognitive impairment)
"dyskinesias" > reduce levodopa, if severe add amantine
Severe disease
- switch to subcut/dissolvable or patch preparations if dysphagia a problem
- deep brain stimuationif motor fluctuations and dyskinesia are main issue
what causes parkinsonism
degeneration of the dopaminergic neurones between the substantia nigra and basal ganglia
what is the diagnosis;
wasting of distal muscles, pes cavus, sticking sensory loss, high stepping gait….
hereditary motor sensory neuropathy (aka Charcot Marie Tooth)
— look for a palpable lateral popliteal nerve
what is the genetics of Charcot Marie Tooth? what is the difference between types 1and 2?
AD
type 1 = demyelinating, type 2 = axonal
causes of a predominately sensory peripheral neuropathy…
diabetes, alcohol, isoniazid, vincristine, b12and b1 deficiency
causes of a predominately motor peripheral neuropathy
Guillain Barre, HSMN
causes of mononeuritis multiplex?
diabetes, vasculitis, hiv, malignancy, sle, rheumatoid arthritis
signs of freidrichs ataxia
ataxic gait, cerebellar signs, pes cavus, peripheral wasting, absent reflexes, upgoing plantars, dorsal column signs (loss of propioception and vibration)
optic atrophy (30%), high arched palate, sensorineural deafness (10%), HOCM, diabetes (10%)
genetics of freidrichs ataxia
AR, symptoms develop in teens
extensor plantars with absent knee jerks. ddx??
Freidrichs ataxia
subacute combined degeneration of the cord
motor neurone disease
tabes dorsalis (syphilis)
combined pathology e.g. peripheral neuropathy and cervical spondylosis
causes of CN VII nerve palsy?
Bell’s palsy
Ramsay-Hunt syndrome (due to herpes zoster, look for vesicles in ear canal or oropharynx)
mononeuropathy due to diabetes, sarcoid or Lyme’s
tumour or trauma
MS/ stroke (forehead will be spared)
causes of bilateral facial nerve palsy
Guillain Barre/ Botulism Sarcoidosis Myasthenia gravis Lymes bilateral Bells palsy
If patient suspected of having myasthenia gravis (diplopia/bilateral ptosis) on cranial nerve exam what extra should you test?
look at chest for sternotomy (thymectomy scar)
prove fatiguable weakness
normal reflexes
state you want to assess respiratory muscle function (FVC)
what is the cause of myasthenia gravis?
anti-acetylcholine receptor antibodies affect motor end-plate neurotransmission. it is associated with other autoimmune conditions
investigations for myasthenia gravis
anti-AChR antibodies (90%), anti-MUSK, EMGm nerve conduction studies
CXR and CT of chest
TFTs (concurrent Grave’s in 5%)
treatment of myasthenia gravis
acute: IV IGg, plasmapheresis
chronic: acetylcholine esterase inhibitor (pyridostigmine), steroids, azathioprine, thymectomy
Causes of third nerve palsy
Medical : (pupil spared) Diabetes MS Lymes Webers syndrome (midbrain stroke causing ipsilateral third nerve palsy and contralateral weakness)
Surgical
PCA aneurysm
Tumour
