Patterns of Sensory Loss Flashcards
When thinking about lesions, which areas should be considered?
- right or left side?
- cortex
- brainstem
- cord (cervical, thoracic)
- peripheral nerves
What types of fibres are contained within the dorsal columns?
What sensations do they transport?
fast-conducting myelinated fibres
fibres travel uncrossed in the cord
carries fine discrete touch, position sense and vibration
What types of fibres are within the spinothalamic tract?
What sensations does it carry?
contains slow fibres
fibres cross in the cord
carries crude sensation, pain and temperature
What tracts are indicated here?
What is Brown-Sequard syndrome?
What is it caused by and what can it be associated with?
it is a hemi-chord lesion
it can be caused by inflammation of the spinal cord - myelitis
it can also be viral or the first presenting feature of multiple sclerosis (MS)
it is an example of dissociated sensory loss
What may someone feel like when presenting with Brown-Sequard syndrome?
What would they feel when sitting in a hot bath?
gradual onset tingly numbness starting in both feet and gradually ascending to a level around the upper chest
“like a tight band”
when sitting in a hot bath, they will notice that the water feels hotter on one side of the body
What is the definition of Brown-Sequard syndrome?
a lesion in the spinal cord that results in:
hemiparaplegia (weakness or paralysis) on one side of the body
and
hemianaesthesia (loss of sensation) on the opposite side
In Brown-Sequard syndrome, what symptoms tend to be ipsilateral and contralateral to the side of the lesion?
- affected person loses the sense of touch, vibrations and/or proprioception below the level of the injury (hemiparesis)
- sensory loss is particularly strong on the same side (ipsilateral) as the injury to the spine
- loss of sense of pain and temperature (hypalgesia) is on the contralateral side to the side of the injury
How much is the spinal cord lesioned in Brown-Sequard syndrome?
there is an injury to one side of the spinal cord
the spinal cord is damaged but is not severed completely
What is Wallenburgs syndrome?
What does it usually result from?
it is also known as lateral medullary syndrome
usually caused by occlusion of the posterior inferior cerebellar artery (PICA)
What causes Wallenburg’s syndrome?
a rare condition in which an infarction, or stroke, occurs in the lateral medulla
oxygenated blood doesn’t get to this part of the brain when the posterior inferior cerebellar artery (PICA) is blocked
What are the symptoms of Wallenburg’s syndrome?
- rapid development of vertigo, unsteadiness, hoarse voice and difficulty swallowing
- there may be a Horners syndrome on the left side, loss of pain and temperature on the left side of the face, but right side of the body
Which pathway is implicated in Wallenburg’s syndrome?
dorsal column medial lemniscus pathway
What is anterior spinal syndrome?
What can cause it?
it is caused by occlusion of the anterior spinal artery and infarction of the spinal cord
e.g. can be secondary to clamping the aorta during surgery
What are the symptoms of anterior spinal syndrome?
- paraplegia - loss of strength in both legs
- loss of pain and temperature sensation below the umbilicus ,but vibration and proprioception is preserved
What parts of the spinal cord are affected in anterior spinal syndrome?
ischaemia of the anterior spinal artery results in the loss of function of the anterior two-thirds of the spinal cord
Why are not all sensations affected in anterior spinal syndrome?
there is complete motor paralysis and loss of temperature and pain perception distal to the lesion
light touch, vibration and proprioception are preserved as the posterior (dorsal) columns are not affected
What is a “lacunar” stroke?
What is it associated with?
a type of ischaemic stroke resulting from the occlusion of small penetrating arteries that provide blood to the brain’s deep structures
can lead to thalamic infarct
usually associated with smoking, high blood pressure or diabetes
What are the symptoms of thalamic infarct due to lacunar stroke?
- sudden onset loss of sensation of the contralateral side of the whole body, including the face
- loss of sensation to all modalities
- later deep aching pain in the contralateral sided limbs
How does a lacunar stroke affect the parietal cortex?
- dysgraphaesthesia
- hemisensory neglect
- R/L confusion
What is dysgraphaesthesia?
graphesthesia is the ability to recognise writing on the skin purely by the sensation of touch
dysgrapheasthesia is the absence of this sensation
What is meant by hemisensory neglect?
neglect is a neurophyschological condition that occurs due to damage in one hemisphere of the brain after a stroke
there is a deficit in attention or awareness to one side of the field of vision or to an affected limb
individuals with right-sided brain damage often fail to be aware of objects to their left, demonstrating neglect of leftward items
What is syringomyelia?
What can it cause?
a rare expansion of the spinal canal
it affects crossing fibres first - this is pain and temperature sensation
later it can cause paraperesis and root lesions
What is paraparesis?
partial paralysis of the lower limbs
What are the symptoms and presentations of syringomelia?
- gradual development of loss of pain and temperature sensation in both hands and across the body in a cape-like distribution
- wasting in small muscles of the hands
- weakness in the legs
What is the origin of syringomelia?
syringomelia involves a cyst or cavity forming within the spinal cord
the cyst can expand and elongate over time and destroy the spinal cord
this damage results in loss of feeling, paralysis, weakness and stiffness in the shoulders and extremities
What are the causes of peripheral neuropathy?
- diabetes mellitus
- autoimmune conditions (Guillain-Barre, vasculitis)
- toxic (incl. drugs)
- vitamin deficiency
- paraneoplastic
- chronic kidney and liver disease
- inherited (charcot-marie tooth disease)
What are the presenting features of peripheral neuropathy?
- gradual onset of tingling and burning in the hands and feet
- numbness to pain, fine touch and vibration with a “glove and stocking” distribution
- absent reflexes
What investigations are conducted in suspected peripheral neuropathy?
- MRI scan will be normal
- nerve conduction studies will show axonal sensorimotor polyneuropathy
- arsenic levels may be toxic in a hair sample
What is peripheral neuropathy?
conditions that result when nerves that carry messages to and from the brain and spinal cord from and to the rest of the body are damaged or disrupted
these are the peripheral nerves
What is subacute combined degeneration of the spinal cord?
What is it usually caused by?
Lichtheim’s disease
this is degeneration of the posterior and lateral columns of the spinal cord
it is most commonly caused by vitamin B12 deficiency
What other things can cause subacute combined degeneration of the spinal cord?
What can it cause?
it can also be caused by vitamin E deficiency and copper deficiency
it is usually associated with anti-parietal cell antibodies
it can also cause a peripheral neuropathy or dementia
What would someone with subacute combined degeneration of the spinal cord present with?
- gradual onset of numb feet
- feeling unsteady and tendency to fall on uneven ground or in the dark
- patient is often anaemic with a high mean cell volume
What would someone with subacute combined degeneration of the spinal cord look like on examination?
- loss of vibration sense up to waist
- loss of proprioception in the feet
- can still feel pinprick
- normal strength
- walked with “sensory ataxia”
What is meant by “sensory ataxia”?
a form of ataxia (loss of coordination) caused not by cerebellar dysfunction but by loss of sensory input into the control of movement
Why does dissociated sensory loss occur?
due to lesions in the spinal cord or brainstem
What causes pure sensory stroke?
thalamic infarct
What is the distribution of peripheral neuropathy?
it has a “glove and stocking” distribution
When is Horner’s syndrome present in Brown-Sequard syndrome?
loss of ipsilateral autonomic function can result in Horner’s syndrome
this is only present if the lesion is above T1
