neurology Flashcards
spastic gait
Pace shortens and narrow base is maintained
more pronounced in extensor muscles causing stiff and slow walking.
parkinsonian gait
posture is stooped and arm swing reduced
gait becomes hesitant with shorter rapid steps which slows down to a shuffle in advanced disease
Describe the presentation of cerebellar ataxia
In lateral cerebellar disease - stance becomes broad-based and uncoordinated
In midline (vermis) cerebellar disease - truncal ataxia leads to a tendency to fall backwards or sideways
Outline the effect of gait occurring in sensory ataxia?
Loss of proprioception - leading to a broad-based, high-stepping gait
syncope
a short duration (usually 20-30s) of loss of consciousness caused by a global reduction in cerebral blood flow
components of motor axis
motor cortex
corticospinal tracts
anterior horn cells
spinal nerve roots
peripheral nerves
neuromuscular junctions
muscle fibres
components of pyramidal system
corticospinal tract
corticobulbar tract
upper motor neurone lesion features
signs on opposite side to lesion
no muscle wasting
spasticity (+/- clonus)
hyperreflexia
extensor plantar response (Babinski signs)
lower motor neurone lesion features
signs on same side as the lesion
fasciculations
wasting
hypotonia
hyporeflexia
two patterns of clinical features which occur in an upper motor neurone lesion?
hemiparesis and paraparesis
hemiparesis
weakness of limbs on one side (usually caused by a lesion within the brain or brainstem e.g. a stroke)
paraparesis
weak legs.
indicative of bilateral damage to the corticospinal tracts (most commonly due to lesions below the T1 spinal level
lower motor neurone
motor pathway from anterior horn cell or cranial nerve via a peripheral nerve to the motor endplate
most common causes of a lower motor neurone lesion
anterior horn cells lesions e.g. motor neurone disease
spinal root lesion e.g. cervical and lumbar disc lesions
peripheral nerve lesions e.g. trauma, compression etc.
most common disease of the neuromuscular junction?
Myaesthenia Gravis
elevation of what plasma muscle enzyme indicates muscle disease?
creatine kinase
sensory peripheral nerves carry information from the dorsal root ganglion to the brain via three main pathways, what are they?
posterior columns
spinothalamic tracts
spinocerebellar tract
sensory modalities transmitted via the posterior columns
vibration
two-point discrimination
light touch
sensory modalities transmitted via the spinothalamic tract
pain
temperature
route of the posterior column
fibres ascend uncrossed to the gracile and cuneate nuclei in the medulla.
axons from the second-order neurones cross the midline to form the medial lemniscus and pass to the thalamus
route of the spinothalamic tract
fibres synapse in dorsal horn of the cord, cross the cord at that spinal level and ascend to the thalamus
sensory modalities are transmitted via the spinocerebellar tract?
proprioception
route of the spinocerebellar tract
does not decussate i.e. innervates the ipsilateral side of the body
The quality and distribution of the symptoms depend on the site of the lesion. Outline the potential sites of nerve lesions and their corresponding characteristics?
Peripheral nerve lesions - symptoms in the distribution of the affected nerve
Spinal root lesions - symptoms referred to affected dermatome
Spinal cord lesions - Symptoms are evident below the level of the lesion
Pontine lesions - Loss of all possible sensation on the opposite side of the lesion
Thalamic lesions - A rare cause of complete contralateral sensory loss
Cortical lesions - sensory loss, neglect of one side of the body and subtle disorders of sensation