Week 1 Neurological Symptoms and Pathologies Flashcards
Which of the following are lower and upper motor neurons
Subcortical tracts
Internal capsule
Peripheral nerve
Spinal cord
Muscle
Neuromuscular junction
Cortex
Brainstem (decussation in pyramids)
Anterior horns
Ventral roots
Plexi
What is the function of the internal capsule?
To transport motor information from the cortex to the brainstem and sensory information formt he brainstem to the cortex
What are basal ganglia?
The are subcortical nuclei that act as a check on motor signals
What neurons are affected in pyramidal weakness?
Upper motor neurons
What is the presentation of pyramidal weakness?
Distal muscles weaker than proximal (slow finger/foot taps)
In upper limbs, extensors (e.g. triceps) are weaker than flexors (e.g. biceps)
In lower limbs, the opposite is true; flexors are weaker than extensors
Hint - think of strength as a pyramid with the base proximal and top distal. Also to build a pyramid you need to pick up a block with your biceps and walk it up using your quads.
What do the suffixes paresis and plegia mean?
Mild-moderate weakness if often given the suffix -paresis
More severe weakness is given the suffix –plegia
What would weakness with this distribution be called?
Monoparesis/-plegia: single limb (can be arm or leg)
What would weakness with this distribution be called?
Paraparesis/-plegia: both legs
What would weakness with this distribution be called?
Tetraparesis/-plegia: all four limbs (quadriparesis is another term)
What would weakness with this distribution be called?
Hemiparesis/-plegia: weakness affecting arm and leg on one side
60 year old female
Awoke with weakness in right hand
On examination
- weakness affecting finger and thumb movements in multiple directions (not conforming to a nerve territory)
mild wrist weakness
Sensation normal
What is going on here?
Diagnosis: ischaemic stroke affecting motor hand region (‘hand knob area’)
If there is local motor weakness but sensory is unaffected then you can assume it isn’t a problem with the local nerve. If reflexes aren’t diminished then you can assume it isn’t a lesion in the spinal chord.
By exclusion we are left with a small localised motor cortex lesion/ infarct
65 year old female
Abrupt onset difficulty walking
Reduced power in left ankle movements including dorsiflexion, plantarflexion
Ankle reflexes preserved
Left plantar reflex upgoing
Sensation normal
Diagnosis: small haemorrhage in motor region supplying distal lower limb
If there is local motor weakness but sensory is unaffected then you can assume it isn’t a problem with the local nerve. If reflexes aren’t diminished then you can assume it isn’t a lesion in the spinal chord. Upgoing reflex hints at lesion above the segment of the reflex arc (part of spinal chord responsible for reflex)
By exclusion we are left with a small localised motor cortex lesion/ infarct
What parts of the body and in what ways would be affect by a Corona radiata or capsule lesion/ bleed?
Tracts travel closely together therefore lesions here affect broad anatomical territory with both motor and sensory effects e.g. hemiparesis +/- hemisensory disturbance
What is important to remeber with the side that effects of a brainstem lesion occur?
The lesion is above the decussation of the pyramids.
Hence, crossed signs arise:
- ipsilateral cranial nerve locations
- contralateral signs in limbs
What does a hyperactive stretch reflexe indicate?
Hyperactive stretch reflexes are seen when there is interruption of the cortical supply to the lower motor neuron, an “upper motor neuron lesion.” The interruption can be anywhere above the segment of the reflex arc aka anywhere above the part of spinal chord responsible for the reflex?
How does a cervical chord lesion present?
Lesion affecting bilateral cord will produce weakness in all four limbs (tetra-)*
Once established, spasticity and brisk reflexes will be present, with upgoing plantars
Other markers of a cord lesion include sensory loss (with a ‘level’) and disturbance to bowel and bladder (sphincter) function
40 year old man
2 weeks progressive walking difficulties
Weak and numb hands with clawing fingers
Difficulty emptying bladder
Tetraparesis, spasticity in all 4 limbs, hyperreflexic
Diagnosis: prolapsed intervertebral disc causing cervical myelopathy
Important part: affecting the cervical chord