Neurology Revision Flashcards
What are the findings of NCS for a nerve root lesion?
normal NCS, but denervation on EMG
What are the causes of foot drop?
L5 nerve root
common peroneal nerve
sciatic peroneal nerve component
What is the most common site of a common peroneal nerve palsy?
compression at the fibular neck
How can you differentiate an L5 nerve root injury from a common peroneal nerve injury?
L5 affects inversion and eversion whereas common peroneal is just eversion
What are the classic findings of a lumbosacral plexopathy (diabetic amyotrophy)?
pain, quadriceps wasting, EMG changes in iliopsoas, hip adductors, quads
Is sensory or motor usually affected first in carpal tunnel syndrome?
sensory then motor
What are the common sites of compression of the ulnar nerve?
elbow, palm
What are the common sites of compression of the radial nerve?
axilla, spiral groove of humerus
How can you differentiate a radial nerve palsy from a C7 radiculopathy?
a radial nerve palsy will have wrist drop but flexion is preserved
Which antibody is associated with multifocal motor neuropathy?
anti GM1
What are the NCS findings for multifocal motor neuropathy?
conduction block at non compressed sites
What are the NCS findings for CIDP?
demyelinating
What is the best test to diagnose myasthenia?
NCS - repetitive stimulation decrement or single fibre EMG ‘jitter’ in an involved muscle
What is the key clinical feature of myasthenia?
fatigability
What are the findings on NCS for axonal injury?
reduced amplitude
absent sural sensory potentials
What are the findings on NCS for demyelination?
reduced velocity
dispersion
delayed F waves
focal block (>50% drop in amplitude)
What are the findings on EMG for a neurogenic injury?
high amplitude and increased duration polyphasic units
What are the findings on EMG for a myopathic injury?
low amplitude and duration
What are the findings on EMG for myotonia?
‘dive bomber’ sound
What are the typical features on history for GBS?
preceding illness
ascending weakness +/- paraesthesia
diffuse back pain
What are the typical features on examination for GBS?
areflexia
symmetrical weakness
usually minimal sensory signs
What are the CSF findings for GBS?
elevated protein
What are the NCS findings for GBS?
prolonged/absent F waves
What proportion of patients with GBS have anti GM-1 antibodies?
40-50%
What are the features of Miller Fischer?
ataxia, ophthalmoplegia and areflexia
What are the examination features of botulism?
dilated pupils ptosis, diplopia bradycardia, hypotension reduced reflexes minimal/no sensory features
What are the clinical features of porphyria?
abdo pain psychosis seizures descending weakness precipitated by medications/menstrual cycle distal sensory loss reduced reflexes urine discoloration when left in sunlight
What is the management for GBS?
IVIG OR PLEX (equivalent but can’t do both)
What is the treatment for a myasthenia crisis?
IVIG or PLEX
steroids
pyridostigmine
check for thymoma
check for other autoimmune diseases (B12, TFTs)
start long term steroid sparing agent e.g. azathioprine
What is the differential diagnosis for a painful sensory neuropathy?
diabetes alcohol medications vitamin deficiency thyroid disease renal disease paraprotein vasculitis HIV heavy metals paraneoplastic
What is ‘split hand’ and what does it usually indicate?
wasted FDI and thenar with preserved hypothenar, usually indicates MND
What is the management for cerebral venous sinus thrombosis?
IV heparin or enoxaparin followed by warfarin for 6 months
What are the risk factors for cerebral venous sinus thrombosis?
inherited thrombophilia
acquired thrombophilia
local sepsis (sinusitis, mastoiditis)
What is the main concern with alemtuzumab?
autoimmune complications - ITP, thyroid etc
What is the classic presentation of optic neuritis?
reduced colour vision and visual acuity
eye pain on movement
onset over hours to days, recovery over weeks
What percentage of patients with optic neuritis will have a second demyelinating episode?
40%
What is the usual starting medication for focal seizures?
carbamazepine
What is the usual starting medication for generalised seizures?
valproate
What is the most specific sign for Bell’s palsy?
loss of taste
What does anti Hu usually cause?
limbic encpehalitis or peripheral neuropathy
What does anti Yo usually cause?
cerebellar degeneration
What does anti GAD usually cause?
stiff person syndrome
What malignancy is anti Hu associated with?
lung cancer
What malignancy is anti Ma associated with?
testicular cancer
What malignancy is anti Yo associated with?
cerebellar
What is the classic MRI finding for CADASIL?
anterior temporal white matter disease
