Spinal cord injury

Question 1

what percentage of new spinal cord injuries occur in males?

Answer 1

80%

Question 2

why is pneumonia one of the leading complications and causes of death after a spinal cord injury (SCI)?

Answer 2

After a cervical or thoracic lesion, impairment of the respiratory muscles decreases respiratory function, which increases the risk of respiratory complications

Question 3

what is the leading cause of death in patients with SCI?

Answer 3

respiratory disorders

Question 4

why is septicaemia a common cause of death in SCI patients?

Answer 4

(as a patient is not able to move on their own they will get bed sores and not able to fight off infection
Sepsis can arise from virtually any type of infection and both incidence and clinical presentation vary between different patient populations. Since infections are a common complication in individuals with spinal cord injury (SCI), a comparable risk to develop sepsis can be assumed in this population.

Question 5

what are the most common causes of spinal cord injury?

Answer 5

• motor vehicle accidents 38%
• falls 30%
• acts of violence 14%
• sporting accidents 9%
• other 9%

Question 6

what are the 5 spinal cord levels?

Answer 6

Cervical 1- Cervical 8 (C1-C8)
Thoracic 1 – Thoracic 12 (T1-T12)
Lumbar 1 – Lumbar 5 (L1–L5)
Sacral 1 – Sacral 5 (S1-S5)
Coccygeal 1 (Co1)

Question 7

how many spinal nerves are there?

Answer 7

(31 spinal nerves)
Cervical 1- Cervical 8 (C1-C8)
Thoracic 1 – Thoracic 12 (T1-T12)
Lumbar 1 – Lumbar 5 (L1–L5)
Sacral 1 – Sacral 5 (S1-S5)
Coccygeal 1 (Co1)

Question 8

what information is carried in the spinal cord?

Answer 8

ascending sensory information moves up towards the brain from the sensory nerves
descending motor information comes from the brain to the muscles/motor neurons

Question 9

what information does the posterior columns carry?

Answer 9

they carry sensory information about vibration, light touch and proprioception along the ascending pathway to the brain

Question 10

what information does the lateral corticospinal tract carry?

Answer 10

it carries motor information on fine motor control along the descending pathway to the muscles

Question 11

what information does the anterioror spinothalamic tract carry?

Answer 11

sensory information about pain and temperature along the ascending pathway to the brain

Question 12

what is parapalegia?

Answer 12

paralysis that affects your legs, but not your arms.
This symptom is most likely to happen with injuries, but can also happen because of diseases or medical conditions

Question 13

what is quadrapalegia?

aka tetrapalegia

Answer 13

a symptom of paralysis that affects all a person’s limbs and body from the neck down.
The most common cause of quadriplegia is an injury to the spinal cord in your neck, but it can also happen with medical conditions.

Question 14

at C4 injury would result in…

Answer 14

quadriplegia - complete paralysis below the neck

Question 15

a C6 injury would result in…

Answer 15

partial paralysis of hands and arms as well as lower body
(quadriplegia but has control of shoulders)

Question 16

a T6 injury would result in…

Answer 16

Paraplegia - paralysis below the chest

Question 17

a L1 injury results in…

Answer 17

Paraplegia - paralysis below the waist

Question 18

an injury at which spinal nerve would result in loss of control of the lungs?

Answer 18

above C3 or C2

Question 19

which spinal nerves, if injured, is likely not survivable?

Answer 19

C1 or upper C2

Question 20

in a survey of paraplegics and quadriplegic, what function did each say they would most want recovered?

Answer 20

in quadriplegics they priotised arm/hand function
in paraplegics they priotised sexual function

Question 21

what is brown-sequard syndrome?

Answer 21

Brown-Séquard syndrome is a rare spinal disorder that results from an injury to one side of the spinal cord in which the spinal cord is damaged but is not severed completely.
results in weakness or paralysis on one side of the body and a loss of sensation on the opposite side (of the lesion).

Question 22

what is central cord syndrome?

Answer 22

(also known as central cervical cord syndrome) is the most common form of an “incomplete spinal cord injury”—one in which the spinal cord’s ability to transmit some messages to or from the brain is damaged or reduced below the site of injury to the spinal cord
It leads to motor deficits that are more pronounced in the upper extremities compared to the lower extremities, as well as bladder dysfunction (retention) with sacral sparing

is considered “incomplete” because patients are usually not completely paralyzed

is an incomplete traumatic injury to the cervical spinal cord – the portion of the spinal cord that runs through the bones of the neck.

Question 23

how are SCI diagnosed?

Answer 23

Using the ASIA (American Spinal Injuries Assiciation)

Question 24

what is the ASIA scale?

Answer 24

(American Spinal Injuries Association)
ASIA scale is an indicator of severity of SCI used clinically (A-E).
* Determines sensory levels for right and left sides.
* Determines motor levels for right and left sides.
* Determines single neurological level – lowest spinal level that is normal on both sides.
* Determines whether is injury is complete or incomplete.
ASIA A is a complete injury then ASIA E is normal

Question 25

what categories does the ASIA scale look at to determine the SCI severity?

Answer 25

* Determines sensory levels for right and left sides. * Determines motor levels for right and left sides. * Determines single neurological level – lowest spinal level that is normal on both sides. * Determines whether is injury is complete or incomplete

Question 26

on the ASIA impairment scale what does A indicate?

Answer 26

complete - no motor or sensory function is preserve in the sacral segments S4-S5

Question 27

on the ASIA impairment scale what does B indicate?

Answer 27

Incomplete - sensory but no motor function is preserved below the neurological level and includes the sacral segments S4-S5

Question 28

n the ASIA impairment scale what does C indicate?

Answer 28

incomplete - motor function is preserved below the neurological level and more than half of key muscles below the neurological level have a muscle grade less than 3

Question 29

n the ASIA impairment scale what does D indicate?

Answer 29

incomplete - motor function is preserved below the neurological level and at least half of key muscles below the neurological level have a muscle grade of 3 or more

Question 30

on the ASIA impairment scale what does E indicate?

Answer 30

normal - motor and sensory function are normal

Question 31

what is spinal shock?

Answer 31

- A state of temporary loss of function in the spinal cord – often lasts 1 day, but can persist up to 1 month post-injury

Question 32

why can the ASIA scale not be used immediately after SCI?

Answer 32

in the days or even months following spinal shock means that you cant tell how bad the injury is going to be

Question 33

what symptoms occur after spinal shock fades?

Answer 33

* Flaccid paralysis below the lesion (due to removal of descending/motor input) (replaced by spastic paralysis following spinal shock) * Loss of tendon reflexes * Impaired sympathetic outflow to vascular smooth muscle can cause decreased blood pressure (high cervical injury) * Absent sphincter reflexes and tone

Question 34

what similarities are there between effects of SCI and TBI?

Answer 34

Lesion: * Contusion * Necrosis, apoptosis * Hemorrhage, oedema, breakdown of the BBB * Swelling * Excitotoxicity * Diffuse axonal injury (DAI) * Hyperthermia * Inflammation Loss of function: * Local versus global * Acute versus chronic (Primary versus secondary injury) (spinal shock or later on)

Question 35

what happens following a contusion (compression) injury in the spine?

Answer 35

in the instantaneous mins to days after, we see the tissue around the contusion spreading out in a responsive manner, after about a week you are left with a hole in the tissue that will have debris – any hole in the body will be filled with fluid (csf or other types) Could be myelin debris, dead neruons or any dead glial cells – as tissue goes into chronic stages then it is fully fluid fllled and becomes a strong capsule – we can't transduce an action potential through fluid – so motor and sensory deficits are goin to sit below this level

Question 36

what happens after traumatic injury when astrocytes become reactive?

Answer 36

* Become hypertrophic * Secrete chondroitin sulfate proteoglycans (CSPGs). * Increase expression of normal molecules (Ex: Glial fibrillary acidic protein or GFAP) * Result = formation of an glial scar. * Glial scar + myelin debris = area which growing axons cannot pass through

Question 37

what is a glial scar?

Answer 37

a dense limiting border around the SCI lesion core (the lesion core is also known as the fibrotic scar) formed predominately by scar-forming astrocytes after SCI

Question 38

what prevents axonal regrowth after SCI?

Answer 38

* Glial scar (CSPGs) + myelin/cell debris (NOGO-A, MAG) = area which growing axons cannot pass through * Inflammatory cells (such as microglia, lymphocytes, macrophages) flood the lesion and release pro-inflammatory cytokines = affect neuronal viability * Diffusible inflammatory mediators (nitrous oxide) = affect neuronal excitability all causing axon/neurons die or degenerate

Question 39

what is wallerian degeneration in the PNS? | what happens in system that regenerates after injury?

Answer 39

1. the axon becomes fragmented at the injury site. Myelin debris is released into lesion site and Schwann cells becomes reactive 2. Macrophages are recruited to the injury, Schwann cells and macrpohages clear debris 3. Schwann cells form regeneration tubes (bands of Bunger) and axons sprout and regrow through the tube

Question 40

what are the regeneration tubes called in wallerian degeneration?

Answer 40

Bands of Bungner

Question 41

describe the processes that underlie why walleriant degeneration doesnt occur in the CNS?

Answer 41

A normal axon undergoes injury Injury. Fragmentation of distal axon and myelin sheath. Microglia and astrocytes become activated. Inflammation ensues. Macrophages begin to remove debris. Myelin debris is not completely removed, although oligodendrocytes survive. Glial scar formed. Cell body undergoes chromatolysis, and synaptic terminals retract. Axons attempt to sprout but Regeneration fails as axonal growth is inhibited by persistent myelin debris and glial scar

Question 42

what is chromatolysis?

Answer 42

Chromatolysis is a reactive change that occurs in the cell body of damaged neurons, involving the dispersal and redistribution of Nissl substance (rough endoplasmic reticulum and polyribosomes) in order to meet an increased demand for protein synthesis such as is required to regenerate axons.

Question 43

what is Nissl substance?

Answer 43

a basophilic material primarily composed of ribonucleic acid (RNA) and proteins in aggregate with rough endoplasmic reticulum. This substance is involved in protein synthesis and cellular metabolism ## Footnote absent in the nucleus and axon

Question 44

what happens to the location of Nissl substance after neuron damage

Answer 44

it is displaced from being dense and thick within the cell body to ONLY the periphery of cell body this is called chromatolysis