Neuroanatomy L4: Acquired spinal cord injury Flashcards
What are 3 conditions that affect spinal cord function?
- Neurotrauma
- Spinal tumours/abscesses
- Diseases
What is neurotrauma?
spinal cord / cauda equina (Traumatic spinal cord injury.
What are spinal tumours? What is the effect of a spinal tumour on the spinal cord?
A tumor inside or next to the spinal cord will narrow or compromise the space of the vertebral canal and begin to exert compression on the spinal cord.`
What is spinal abscess?
on outside of spinal cord
What can spinal tumours and abscesses cause?
Sensory and motor deficits
What is this? What will it cause?
Interspinal tumor - will affect local cells and descending/ascending pathways.
What are 4 diseases that affect spinal cord function?
- Poliomyelitis
- Syphilis
- Amyotrophic lateral sclerosis (ALS)
- Multiple sclerosis
What is poliomyelitis?
Viral infection (rare in the developed world due to vaccination) - infects and kills motor neurons, causing flaccid paralysis - not always uniform or symmetrical - generally unilateral.
How does poliomyelitis affect the spinal cord?
motor neuron loss In anterior horn => flaccid paralysis
What is syphilis?
Sexually trasnmitted disease - treatable and preventable -
How does syphilis affect the spinal cord?
- affects the sensory neurons of the dorsal root ganglia, and the sensory neurons in the dorsal columns degenerate (thus lose sensory input)
- can spread to the brain and cause insanity.
- no dorsal column- what do we use it for then? = sensory input (proprioception, fine discriminative touch (since this no longer there = use visual)
What is the cause of Amyotrophic lateral sclerosis (ALS)?
no known cause
How does Amyotrophic lateral sclerosis (ALS) affect the spinal cord?
lower motor neurons degenerated lower (spinal cord and peripheral nerves) and upper motor neurons (brain)
What is multiple sclerosis?
Autoimmune system becomes activated to proteins in the spinal cord, particularly those associated with myelin around axons - in the image the dark staining is myelin, and there are large areas where the myelin has been removed. If the nerves even survive the inflammation, removing the myelin causes major functional deficits.
How does multiple sclerosis affect the spinal cord? Be specific with which motor neurons are affected.
Autoimmune demyelinating disorder components of white matter (gets attacked) white matter is used for conduction Degeneration of upper (corticospinal) and lower (spinal) motor neurons => paralysis and muscle atrophy
Is ALS very debilitating?
Generally these people die within years of being diagnosed - due to breathing difficulties.
What is a traumatic spinal injury (tSCI)?
starts off with a mechanical force (eg. break back) –> reposition vertebrae –> compromised vertebral canal space
What are 5 examples of trauma that can cause spinal cord injuries?
- Work site/place injuries
- Driving into shallow water
- Sporting injuries
- Motor bike accidents
- Waves –> dumped on sand
Estimated 339,000 Australians living with acquired brain injury. and estimated 10,000 Australians living with spinal cord injury (SCI). This is estimated to cost Australia _______ dollars each year?
10 billion
Spinal cord injuries most affect ____ (males/female) in their _____ to _____ years.
Mostly affects males - the bracket of injury is late teens to 30/40 years.
What are 2 important things that can ensure people with spinal cord injuries can still have normal life expectancy although they are paralysed?
Medical care for early management and rehabilitation
Which horn does sensory information flow in?
Dorsal side
What does the grey matter (inside) consist of?
contains cell bodies of nerve cells that reside in spinal cord
What does the white matter (outside) consist of?
contains nerve fibres (pathways) running to and from the brain
What happens in the white matter?
Sensory feedback up to the brain via the dorsal columns or anterolateral system (pain).
Which matter (grey or white) will be affected first with impact?
White matter (as it on the outside)
Which horn does the motor command go out?
Ventral
What is the ventral horn important for?
Important for limb movement at the cervical and lumbar levels.
How is the spinal cord split up in terms of motor, sensory and intermediate grey?
The pathways located towards the mid-line innervates _____ muscles, and the lateral pathways innervate the _____ muscles.
axial; extremities/peripheral
What is the process from stimulus sensor to effector output happen?
What are 5 SCI management & repair strategies require?
- Preservation of neural tissue (at and around site of impact)
- Preservation of white matter (ascending and descending pathways)
- Replacement of lost cells (incl. grey matter at site of impact)
- Regrow damaged pathways
- Appropriately rewire circuitry
With spinal injuries, the primary injury is the mechanical injury due to the trauma. The only thing we can possibly do for this is stem cells to ____ pathways, and then link these up with the cortical mapping. This is probably far off into the future.
regrow
After a traumatic spinal injury, the first step after injury in the hospital is to relieve _______on the tissue, and to ______the spine as quickly as possible.
compression; realign
The only part of an axon that can survive a lesion is the part connected to the ________.Thus there is a loss of the _____ axons up to the brain above the lesion, and loss of _____ axons after the lesion peripherally in the spinal cord.
cell body (Wallerian degeneration); sensory; motor
Degeneration of the grey matter at the site of the injury due to the lesion - the immediate consequence is loss of ___ output and ___ input. Thus at the level of the lesion there will be ____ paralysis, and loss of _____ from that level. Symptoms indicate the number of segments affected.
motor; motor; flaccid; sensation
What are the 2 types of spinal cord injuries?
- Primary
- Secondary
What is classified as a primary SCI? What is it caused by?
Immediate cell death and neural circuit interruption compression and displacement of spinal cord
What are symptoms of a primary SCI?
There is immediate paralysis or loss of function due to the mechanical injury. There is an enormously heterogeneous population - due to different mechanisms and severity of injury. The primary lesion is almost always anatomically incomplete. To determine the extent of function loss, you test sensory discrimination in dermatomes, and motor deficits in myotomes.
What causes a secondary SCI caused by?
If the compression is maintained on the tissue, then progression of damage occurs. There are many factors that contribute to progression of damage beyond the area that was initially damaged. These are amenable to intervention to slow/limit progression.
What are 4 drivers of secondary SCI?
- Excitotoxicity
- Oedema & Ischaemia
- Oxidative stress
- Post-traumatic inflammation
What is excitotoxocity in regards to a secondary SCI?
Ion balances are disturbed with the lesion, and nerves release neurotransmitter as a result of the primary injury.
An excess of neurotransmitter overwhelms unaffected neurons (causing too much calcium in the cell) and death occurs. too much excitation= cell death