Unit 3 Pathophysiology - Chapter 18 Disorders of central and peripheral nervous systems and the neuromuscular junction Flashcards
Primary brain injury
- impact
- focal or diffuses w/ open or closed-head injury
Severity of TBI graded by
glascow coma scale
Focal brain include which of the following (8)
1) coup - injury at site of impact (hit steering wheel)
2) contrecoup - injury frojm brain rebounding and hitting opposite side of skull (after hitting wheel, brain hits back of skull)
3) contusion - bruising of brain
4) laceration - tearing of brain tissue
5) extradural (epidural) hematoma - accumulation of blood above dura mater
6) subdural hematoma - blood between dura mater and arachnoid membrane
7) intracerebral hematoma - bleeding into the brain
8) open-head trauma
Open head injury
- skull fracture
- exposed cranial vault to environment
different kinds of skull fractures:
* compound fracture or perforated fracture (open visible fracture via observing skin)
* linear fracture: break in bone, however bone did not move
* comminuted fracture: broken in at least 2 places (car accidents for e.g); need surgery and year or longer to recover
* basilar skull fracture: substantial blunt force, break in at least one of the bones at the base of the skull (bottom)
basilar skull fracture (in-depth)
- r/t base of skull (can be multiple spots)
location of fossa w/ sx
* anterior: raccoon eyes, halo sign, partial/total loss of vision + smell, eye mvmt defects
* middle: damage to carotid A, hearing loss, loss of balance, battle sign
* posterior: cervical spine injury, vertbal a. injury, damage to lower cranial nerve
Battle signs (ecchymosis behind the ear), laceration in the ear canal, and blood or CSF in the ear canal may indicate a fracture of the skull base or of the glenoid fossa.
order – frontal bone => sphenoid bone => temporal bone (sides) => occiptal bone
closed head injuries
- precise location w/ mild severity for most cases
- more severity: include contusions, epidural, subdural, subarachnoid , and intracerebral hemorrhage
Diffuse axonal injury (DAI)
- d/t mechanical forces: acceleration, deceleration, and rotation that causes stretching and shearing of axons (only visible under microscope); can be mild, moderate, or severe
- such as shaking or strong rotation of head by physical forces (e.g car crash)
Secondary neuronal injury
- caused by indirect result of primary brain injury
- includes: hypotension, hypoxia, anemia, hypoglycemia, hyperglycemia, and hypercapnia or hypocapnia (systemic)
- cerebral contributions: inflammation, oxidative stress, alterations in the blood-brain barrier, excitotoxicity, cerebral edema, increased intracranial pressure (IICP), decreased cerebral perfusion pressure, cerebral ischemia, and brain herniation
Complication of TBI
- postconcussion syndrome:
1) headache, dizziness, fatigue, nervousness or anxiety, irritability, insomnia, photophobia, depression, inability to concentrate, and forgetfulness, and may last for weeks to months
2) drowsiness or confusion, nausea or vomiting, severe headache, memory deficit, seizures, drainage of CSF from the ear or nose, weakness or loss of feeling in the extremities, asymmetry of the pupils, and double vision - posttraumatic seizures (epilepsy):
1) 10% of TBIs, highest amongst open brain injuries
2) phenytoin used for moderate to severe TBI at time of injury - Chronic traumatic encephalopathy (CTE)
1) dementia pugilistica before…
2) progressive dementing disease that comes from repeated brain injury d/t sports, blast injuries as soldier, or work related head trauma (tau neurofibrillary tangles present in brain
3) sx’s include: violent behaviors, loss of control, depression, suicide, memory loss, and cognitive change.
Spinal cord and vertebal injuries affect who most?
- young men d/t rereational or travel
- OA d/t preesxisting degenerative vertebral d/o
Vertebral injuries include?
- fractures
- dislocations
- compressions
- penetrating bone
types:
1) simple - fracture of only bone
2) compressed - cause the vertebrae to collapse, making them shorter in height. This collapse can also cause pieces of bone to press on the spinal cord and nerves, decreasing the amount of blood and oxygen that gets to the spinal cord
3) comminuted - at least 2 places
Primary spinal cord injury
- damage to neural or vertebral injury d/t
1) shearing (opposite directions when force applied)
2) compression
3) traction (pulling force)
Secondary spinal cord injury
- d/t edema, ischemia, excitotoxicity, inflammation, oxidative damage, activation of necrotic and apoptotic cell death and beings w/ minutes of injury while continuing for weeks
Neurogenic shock
- vasogenic shock
- occurs w/ cervical or upper thoracic cord injury above t5
- can be seen with spinal shock
- loss of sympathetic acitivity w/ unopposed vagal parasympathetic activity, including sx of hypotension, bradycardia, and hypothermia
Paraplegia vs quadriplegia
- paralysis of lower half of body with both legs
- involve all 4 extremities
How does reflex activity return to those w/ acute spinal cord injury?
Slow
* reflex activity can return in 1-2 weeks in most people w/ this condition
* flexion reflex patterns return, first the toes then feet + legs
* eventually reflex voiding and bowel elimination appear (only when full)
* mass reflex (flexor or bending spasms w/ sweating, piloerection, automatic bladder emptying) may develop too
Autonomic hyperreflexia (dysreflexia)
- syndrome of masssive reflex sympathetic discharge d/t sinpal cord injury at t5-t6 or above and can cause life-threatening HTN; accompanied by low heart rate
- What can trigger AD? => bladder (blocked catheter), bowel impacted (constipation), skin + pressure wound (d/t infection and fluid loss can trigger as well), fractures/dislocations, gastric ulcers, surgeries, labor + delivery
1) stimulus from below injury (distended bladder or bowel)
2) afferent stimulus
3) massive sympathetic response at injury site (release norepinephrine)
4) cause skin and abdomen to constrict raising BP
5) baroreceptors in heart/neck detect HTN, which then send signals to brain (cranial nerve IX, X)
6) cranial nerve X send signals to hear to slow down heart via parasympathetic vagus nerve (HR)
7) finally reaches spinal cord to attempt to open vessels again but d/t injury signals stop at site and only vessels above injury dilate; this is not enough to overcome the constricted vessels below injury level so BP continues to increase!
Pathologic findings of Degenerative disk disease (DDD)
1) disk protrusion - occurs when the spinal discs and associated ligaments are intact, but may form an out pouching that will press on the spinal nerves. This condition causes pain in the neck, shoulder and the arms.
2) spondylosis - spinal defect or fracture of a bone structure called the pars interarticularis, which connects the facet joints of the spine.
3) subluxation - misaligned vertebrae within the spine from its normal position
4) spondylolisthesis - degeneration of vertebrae
5) spinal stenosis - narrowing of the spinal canal in the lower part of your back. Stenosis, which means narrowing, can cause pressure on your spinal cord or the nerves that go from your spinal cord to your muscles.
Low back pain
- between lower rib cage and gluteal muslces; often radiating to thigh
cause of low back pain?
mainly unknown
1) disk prolapse (outer fibers of intervertebral disc are injured and soft materal, nucleus pulposus, enclosure ruptures
2) tumor
3) bursitis (small, fluid filled sacs called bursae that cushion bones, tendons, muscles near joints => inflammed) // elbows, knees [line outside of bone]
4) synovitis (inner lining of the joint [synovium] becomes inflamed)
5) DDD - cushioning in your spine beings to wear away
6) osteoporosis - bone minieral density and bone mass decreases or when quality of bone changes [l/t fracture]
7) hyperparathyrodism - too much PTH causes Ca++ to rise in blood l/t bone thinning and kidney stones (detects low calcium in system)
8) fracture
9) inflammation
10) sprain
Causes of DDD
- part of normal aging d/t continued vertical compression of spine mainly in lumbar
- genetic + environmental factors contribute to loss of disk connective tissue
- disks can tear + herniate => pinch nerves and spine strain
- spondylolysis or spondylolisthesis (or both) plus degeneration of vertebrae and spinal stenosis
Spondylolysis, or spinal osteoarthritis, is a painful condition that’s caused by aging and wear-and-tear on the spine.
Spondlylolisthesis occurs when one of the vertebrae in the spine slips forward and out of place.
Spondylolysis
Spondylolysis is a spinal defect or fracture of a bone structure called the pars interarticularis, which connects the facet joints of the spine => deficient vertebra (spondyloisthesis) => lower back pain
