Flashcards in CC4: Spinal Cord Injury Deck (13)
List 6 general immediate consequences of spinal cord injury.
1) weakness (quadriparesis/plegia; neck injury, injury)
2) Sensory loss
3) Sensory abnormalities
4) Hypotension (spinal cord ischemia)
5) Urinary retention
6) orthopedic pain (pain meds may further decrease B.P.
What are some long-term consequences of spinal cord injury?
1) Involuntary movements
-above T10 = spastic bladder aka neurogenic bladder --> bladder fills but can't relax sphincter unless bladder is so full with urine so bladder is alays full and urine flows in driblles= CHRONIC INFECTIONS
-below T12 = flaccid bladder --> constant leakage
3) decrease bowel motility
4) Sexual dysfunction
males --> decreased fertility, erection & ejaculatin rare
females --> unaffected fertility, delivery is possible
People with spinal cord injury have increased risks for?
1. blood clots
2. pressure ulcers (sores): cutaneous ischemia, therefore frequent re-positioning is vital to prevent this
3. autonomic dysfunction
-thermoregulation largely absent --> no sweating (overheat easily), limited vasoconstriction (can't conserve heat)
-autonomic dysreflexia --> episodes of crazy high blood pressure even though heart rate might drop to 40 bpm
4. metabolic disorders (e.g. diabetes): due to inability to move; not a direct consequence of injury
5. musculoskeletal breakdown: rotator cuff, carpal tunnel due to wheeling chair around for extended periods of time
7. Psychosocial issues
American Spinal Injury Association (ASIA) scale:
A - complete = no motor or sensory function below injury
B - incomplete = no motor but there's sensory
C - incomplete = limited motor + sensation
D - incomplete = significant motor + sensation
E - normal
Can acute spinal cord injury be treated?
If nerve cell bodies are crushed, then they are gone for good. Other nerves w/in region of region may be salvaged based on # of factors like blood flow, local toxins (e..g glutamate, O2 radicals)
List the 3 broad approaches to SCI injury
1) Neuroprotection --> protect surviving cells/axons
2) Neurorestoration --> replace cells, provide neurotrophins or establish a growth-permissive environment to promote regeneration & re-establishment of neural circuitry
3) Neurorehabilitation --> strengthen existing systems, re-train circuits
Is there a CPG for stepping in humans with spinal cord injury?
a patient with incomplete spinal cord injury has limited standing & walking capability. With no prior warning, the patient starts having spontaneous "stepping" movements that are described as "like walking, but can't stop them." Pt is terribly fatigued during spontaneous stepping, but pt shows improved walking ability. So there is evidence showing that there's CPG for stepping in humans. In this case, the stepping onset is caused by pain in right hip. When pain is alleviated, the stepping stops. Therefore, the spinal cord is plastic and can be rehabilitated
How is CPG for stepping in humans characterized?
-low gain (high threshold)
-spontaneous expression always associated with pathology (e.g. noxious input to the cord)
For instance, the male patient's onset of spontaneous stepping was correlated with the pain in right hip. When pain was relieved --> no stepping.
Can CPG be trained to improve voluntary walking in persons with incomplete spinal cord injury?
No, even patient can improve walking due to rehab, but not sure if it's due to neuroplasticity. Rather, the basis for improvement is due to better balance, stronger leg muscles, and improved fitness.
Interlimb reflex is observed in all persons with chronic cervical spinal cord injury. Interlimb reflex is most common in distal upper limbs, and is almost always an excitatory response. Explain the 2 theories involved in the appearance of interlimb reflex following spinal cord injury.
1) early (days to weeks post-SCI)
-connections are already established, but not functional --> latent synapses
2) later (months to years post-SCI)
-novel connections develop (or existing connections strengthen dramatically) --> regenerative sprouting.
Is interlimb reflex a good thing?
Not necessarily a good thing; could be a bassis for autonomic dysreflexia.
People with spinal cord injuries are at increased risk for many things. One is autonomic dysreflexia. What is it? Why does it occur?
Autonomic dysreflexia is when the sympathetic system is disturbed and the patient presents with crazy high blood pressure, but with very low heart rate (paradoxical HTN). HR is so low because vagus is intact and is responding to the increased b.p. Autonomic dysreflexia occurs in response to strong afferent input, such as 1) nociceptors (overly full bladder), 2) bladder-empyting if neurogenic bladder; 3) strong cutaneous inputs.