Localisation in Neurology Flashcards
Mode of onset
Acute
- sudden onset - VASCULAR
- mins - epileptic seizure, trauma
Subacute
-days to weeks - inflammation, infection, expanding mass
Chronic
-months to years - degenerative (AD, PD)
Disease course
Relapsing remitting = inflammation
Slow progressive = neoplastic?
Episodic = seizures, migraines, TIAs?
UMN vs LMN
UMN - brain, corticospinal tract
- no wasting (except in chronic cases due to disuse)
- no fasciculations
- increased tone (initially flaccid => spastic), reflexes, +ve Babinsky
LMN - nerve root, peripheral nerve
- wasting, fasciculations
- decreased tone, reflexes, -ve Babinsky
CNS (UMN pattern)
- hemisphere
- brainstem
- spinal cord
Hemisphere => CL hemiparesis
Brainstem => IL CN palsy, CL hemiparesis
-quadriparesis, LOC if severe
SC (C1-T12) => tights distribution
- quadriparesis - if high up
- paraparesis (legs) - if low down
PNS (LMN pattern)
- spinal cord
- anterior horn cell
- nerve root
- nerve plexus
- mononeuropathy
- polyneuropathy
SC (L1-S5) - paraparesis (legs) in tights distribution
Anterior horn cell (motor neuron that projects from ant part of SC grey matter to skeletal muscle) - localised, generalised
Nerve root - myotome
Nerve plexus - multiple myotomes
Mononeuropathy (cranial or peripheral) - single peripheral nerve (eg, median)
Polyneuropathy (many peripheral nerves, often length dependent) - feet and legs > hands and arms
PNS sensory
- single nerve
- all peripheral nerves
- nerve root
- cauda equina
Single nerve - single peripheral nerve
All peripheral nerves - glove and stocking
Nerve root - dermatome
Cauda equina -both legs and perineum
CNS spinal cord
- anterior
- posterior
- lateral
- central
Anterior - infarct of anterior spinal artery
- loss of pain, temp, CST
- proprioception and fine touch preserved
Posterior - B12 deficiency, syphilis, HIV, NO use, demyelination
- loss of proprioception and fine touch
- pain, temp, CST preserved
Lateral - trauma, tumour, compression
- ipsilateral proprioception, fine touch, CST loss
- contralateral pain and temp loss
Central - syringomyelia, cord tumour, demyelination
- bilateral pain, temp, motor loss
- cape like numbness
- motor, upper, distal affected more than sensory, lower, proximal
Brain sensory
- brain stem
- parietal lobes
Brainstem - ipsilateral face, contralateral limbs
Parietal lobe - contralateral homunculus testing
- numb, loss of 2 point discrimination, astereognosis, graphesthesia
- agnosia, sensory inattention
Cortical lesions
- higher cortical function
- visual tract involvement
- frontotemporal
- frontal
- motor homunculus
- sensory homunculus
Higher cortical function - aphasia, apraxia, agnosia
Visual tracts, occipital - hemianopia, quadrantanopia
Frontotemporal - memory, executive function
Frontal - loss of smell
Motor homunculus in frontal - UMN, weakness contralateral to lesion
Sensory homunculus in parietal - loss contralateral to lesion
Brainstem lesion
- cranial nerve
- motor
- sensory
Cranial nerves
- 3,4,6 - diplopia
- 5 - loss of facial sensation
- 7 - drooping eyelids and mouth
- 8 - deaf and dizzy
- 9, 10, 12 - dysarthria, dysphagia
- 11 - can’t shrug or rotate head
Motor - UMN hemiparesis
Sensory - hemisensory loss
Cerebellar lesions
- presentation
- common causes for unilateral and bilateral ataxia
Dysdiadochokinesia, dysmetria Ataxia Nystagmus Intention tremor Slurred speech (dysarthria) Hypotonia
Unilateral ataxia - ipsilateral to sign
- CVA
- SOL (cancer)
- demyelination
Bilateral ataxia
- Toxic - alcohol, drugs (phenytoin)
- Metabolic - B12, VitE deficiency
- Paraneoplastic - SCLC, breast, ovarian, lymphoma
- Degenerative - MSA (Parkinsonian condition)
- Genetic - Friederichs ataxia
Spastic paraparesis
- what is it
- how would you identify the location of the lesion
- possible causes
CNS issue - weakness and spasticity in legs
-Bilateral UMN below level of lesion
Localise by working up
- if reflex unaffected, lesion is below area being tested
- jaw jerk => cerebral issue
Look for other signs pointing towards other differentials
- MS - RAPD, INO, dysarthria
- MND - bilateral CN7 weakness, tongue fasciculations, dysarthria
Extrinsic causes -trauma, cord compression Intrinsic causes -vascular - AVM, ant spinal artery -Inflammatory - NMO, TM, MS -infective - HSV/HIV -tumour -metabolic - B12 deficiency,
NMJ
Myasthenia gravis - fatigability
- proximal, symmetric weakness worsened by use
- facial involvement (ptosis, diplopia)
- sensory saved
Muscle disorders
Cranial nerves - ptosis, diplopia, dysphagia, dysphonia
Motor - proximal weakness, atrophy fasciculations, low tone
Normal sensory
Reflexes preserved until late in disease
Root lesion
- motor
- sensory
- reflexes
- main reflexes you can test
Motor - asymetrical myotome weakness
Sensory - dermatomal loss
Reflexes - reduced if root involved
Ankle - S1-2 tibial
Knee - L3-4 femoral
Biceps - C5-6 musculocutaneous
Triceps - C7-8 radial
