Neuro Flashcards
(268 cards)
What is weakness
objective loss of muscle strength (formally tested)
Recording muscle strength
5 normal
4 moves against resistance but can be overcome
3 moves against gravity but not resistance
2 moves only when positioned to eliminate gravity
1 flicker of movement
0 complete paralysis
UMN signs
normal bulk
Increased tone (velocity dependent)
Brisk reflexes
localizing UMN weakness to the cortex
Aphasia (L hemisphere)
Spatial neglect (R hemisphere)
Face and arm>leg weakness - lateral motor cortex
Opposite - medial motor cortex
Localizing UMN weakness to the parietal cortex
Normal somatic and decreased cortical sensation
localizing UMN weakness to spinal cord
Presence of a sensory level, and sphincter disturbance
Above T1= arm and leg
Below T1= leg only
Localizing UMN weakness to the brainstem
Cranial nerve involvement
Above facial nucleus (pons) = F, A & L equal
Lower pons/medulla = A & L equal
Weakness in myasthenia
variable with abnormal fatiguability.
Onset pattern of myasthenia gravis
Ocular 65% (50% have AChR +ve Ab)
Bulbar 10%
Leg 10%
Generalized 10% (80% +ve Ab)
Differentials with proximal LMN weakness
subacute myopathy, chronic myopathy, myasthenia gravis
Differentials with distal LMN weakness
Motor neuron disease, motor multifocal neuropathy
Differentials LMN weakness with atrophy
chronic myopathy (proximal)
Motor neuron disease (distal)
Late motor multifocal neuropathy
Differentials LMN weakness without atropjy
Subacute myopathy
Myasthenia gravis
Differentials LMN weakness with ptosis
Myasthenia gravis
Mitochondrial chronic myopathy
Rarely in subacute myopathy
Differentials in LMN weakness with diplopia
Myasthenia gravis
Rarely in chronic myopathy
CK in subacute myopathy
Very high
CK in chronic myopathy
Normal-mildly elevated
CK in motor neuron disease
Normal-mildly elevated
CK in myasthenia
Usually normal
Mean age of onset in MND
65, but quite variable, and variable onset pattern. Median survial’ is 30 months from symptoms onset
Symptoms of MND
Progressive painless weakness
UMN: Weakness, spasticity, brisk reflex, planters up
LMN: Weakness, wasting, fasciculation
No sensory or sphincter dysfunction
Acute phase features of UMN localisation
generally hypotonia
Low/absent reflexes
Plantar responses extensor or mute
Chronic phase features of UMN localisation
clasp-knife (velocity dependent) increased tone
Brisk reflexes
Extensor plantar responses
Acute phase features of LMN localisation
no atrophy
Normal/reduced tone
Low/absent reflexes
Flexor plantar response