Ch. 55 SCI Flashcards
Incidence of SCI by age
Lowest for < 15 yo
Highest for 16-30 yo
Average age of onset 40.2
Incidence of SCI by sex
80% male
Divorce rate in SCI
Increased in SCI in 1st 3 years post-injury compared to general pop
MCC of SCI in order
MVA
Falls
Violence
Sports
MCC of SCI in elderly
Falls
MCC of SCI in African Americans
Violence
MC time fore SCI
Weekends and Summer
MC level of plegia in order
Incomplete tetra
complete tetra
complete para
incomplete para
Predictors of mortality
1st post-injury year older male injured by violence neuro complete ventilator dependent high neuro level
MCC of death
Resp dz, esp PNA "other" heart disease Infection/parasites HTN/ischemic heart disease Neoplasm PE GU dz Suicide
SC terminates at level
L1-2
What does the posterior horns contain?
Cell bodies of sensory neurons
What does the anterior horn contain?
cell bodies of interneurons and motor neurons
Where is the gracilis located?
posterior medial column
What does the gracilis contain?
Fibers from T7-L5 dermatomes that real touch, vibration and position sense
Where is the cuneatus tract?
lateral posterior column rostral to T6
What does the cuneatus tract contain?
Dermatomes above T7 that relay touch, vibration, position sense
Where do the gracilis and cuneatus ascend?
Ipsilaterally to the medulla
What does the lateral spinothalamic tract contain?
Fibers that relay pain and temp sensation
Where does the spinothalamic tract ascend?
Contralaterally to the thalamus
Where is the lateral corticospinal tract?
Centrally and posterior in the lateral column
What does the corticospinal tract contain?
Fibers from motor cortex that are responsible for voluntary and reflex movement
Where does the corticospinal tract ascend?
90% ascend ipsilaterally and cross midline in the caudal medulla forming pyramidal decussations. 10% do not cross in medulla
What is Brown-Sequard synd?
Damage to one side of SC resulting in > ipsi weakness & position sense loss w/ contralateral pain & temp loss
What is an upper motor neuron?
corticospinal neuron
What is a lower motor neuron?
motor neuron that synapses in the SC & exits SC to innervate muscle
What is UMN synd?
loss of voluntary movement spasticity hyperreflexia clonus Babinski's sign
What is conus medullaris synd?
Injury to sacral SC and lumbar nerve roots l/t areflexic bladder, bowel and lower limbs
What is Cauda Equina synd?
Injury to lumbosacral roots w/in spinal canal l/t arflexic bladder, bowel and lower limbs
What is spinal shock?
Transient suppression and gradual return of reflex activity below level of injury
Describe phase 1 of spinal shock
0-24 hrs post injury
Motor neuron hyperpolarization manifesting as hyporeflexia
Describe phase 2 of spinal shock
Days 1-3
Denervation super sensitivity and receptor upregulation
reflex return
Describe phase 3 of spinal shock
1-4 weeks post injury
interneuron synapse growth early hyperreflexia
Describe phase 4 of spinal shock
1-12 mo post injury
long axon synapse growth
late hyperreflexia
Where does the posterior spinal artery begin and supply?
Branch from vertebral a
suppl posterior 1/3 of SC
Where do the anterior spinal arteries begin and supply?
Branch from vertebral a
form single artery
supply anterior 2/3’s of SC
Where do the segmental radicular arteries travel?
from the aorta
through intervertebral foramina
divide into ant & post
anastomose w/ respective arteries
What is the artery of Adamkiewicz?
anterior radicular artery usually on left side that supplies T12-L2
Where does the artery of Adamkiewicz travel?
Divides into small ascending & large descending branches on anterior surface of SC. Descending branches anastomosic circule w/ terminal branches of posterior spinal arteries around the conus medullaris
What area of the SC is most prone to ischemia?
Anterior portion of T1-4 and T12-L2 as they are dependent on individual radicular arteries
What is the anterior cord syndrome?
Paraplegia w/ loss of pain & temp sensation w/ sparing of touch & position sense
MC location of fx or dislocation in the spine
T12 and L1 vertebrae
What is a Jefrerson fx?
Burst fx of atlas (C1)
caused by axial compression
What is a hangman’s fx?
Traumatic spondylolisthesis of the axis (C2)
caused by hyperextension & axial compression
What causes an odontoid fx?
Hyperflexion, hyperextensions or excessive lateral bending
What is a Chance fx?
Anterior wedge fracture of the vertebral body with horizontal fracture through posterior elements or distraction of facet joints and spinous processes
What causes a Chance fx?
Anterior force with hyperflexion
ex) passenger with lap belt but no cross body belt in a car accident
What is a clay shoveler’s fx?
avulusion fx of the SP of C6, C7 or T1 due to flexion w/ rotation
What is a flexion tear drop fx?
retropulsion of vertebral body into the spinal canal, detached from anterior fragment (teardrop)
What are flexion tear drop fx associated with?
incomplete anterior cord syndrome
What is central cord synd?
Cervical SCI d/t hyperext
sacral sparing
Weakness in UE>LE
Which is a more common cause of non-traumatic SCI, extradural or intradural tumors?
Extradural tumor (MC metastatic lesions)
What is an extradural tumor?
Arise from structures outside the dura, MC vertebral body
What the MC types of metastatic tumors to the spine?
Lung
Breast
Prostate
Kidney
What are the mech of metastasis to the spine?
Direct extension
Hemotogenous through Batson’s vertebral venous plexus
Valveless venous system draining through the thoracic, abdominal and pelvic viscera
What are primary spine tumors?
Multiple myeloma Ostoegenic sarcoma Vertebral hemangioma Chondrosarcoma Chondroma
What are intradural space tumors?
Ependmomas Astrocytomas Meningiomas Schwannomas Neurofibromas
Described the presentation of spinal tumors
Pain worse in supine Night sweats Fevers Unexplained weight loss Anorexia
Treatment of acute SC compression by tumor
Steroids (dexamethasone) to dec inflam changes and prostaglandin production
Radiation
Surgery
Who is at risk for bacterial vertebral osteomyelitis?
IVDA
Immunocompromised
DM
Renal disease on HD
MC bacteria and location of vertebral osteomyelitis
Staph aureus
Lumbar spine
Clinic presentation of vertebral osteomyelitis
Spine pain
Fever
Neuro deficit
Elevated CRP, ESR
What is Pott’s disease?
Mycobacterium tuberculosis to the spine
What should be in the DDx of rapidly evolving myelopathy without history of trauma
SLE MS Neuromyelitis optica Paraneoplastic syndrome Nutritional deficiency Vascular insufficiency Infection Transverse myelitis
What is transverse myelitis?
myelopathic process of unknown cause resulting in inflam of the SC
How many tetraplegic ASIA A patients convert to ASIA D in 1 year
2-3%
How man motor complete tetraplegic patients recover one motor level w/in 1 year of injur
30-80%
What is the most important prognostic factor for single level motor recovery in complete tetraplegics?
Initial presence of nonfunctional strength grade 1 or 2 at that level
What is a better sensory predictor of ambulation in an incomplete tetraplegic pt?
Presence of pinprick sensation near anus have >70% change of walking compared to light touch sensation
What is recovery of lower limb function with paraplegia dependent on?
Level and completeness of injury
What patient group has the best prognosis for ambulation in traumatic SCI?
Incomplete paraplegia
What is the goal mean arterial pressure for acute SCI?
85 mmHg for 7 days
What is neurogenic shock?
Hypotension and bradycardia due to sympathetic denervation
How is neurogenic shock treated?
Intravascular volume repletion and vasopressors
What is an ideal WC propulsive stroke?
Occurs at steady speed that maximizes handrim contact or push angle while keeping stroke frequency and force to a minimum
What neurologic level of injuries cannot operate a car?
C1-4
What are the leading causes of death in SCI?
Pulmonary complications Atelectasis Pneumonia Respirator failure PE
What is a Passy-Muir valve?
One-way airflow valve put in line with ventilator tubing to vocalize with exhalation. Used only with a deflated cuff
When is the risk greatest for DVT in SCI?
Between 7-10 days after injury
How long should motor incomplete SCI patients be on DVT ppx?
Until time of discharge
How long should uncomplicated SCI patients be on DVT ppx?
8 weeks
How long should motor complete SCI patients with additional risk factors be on DVT ppx?
12 weeks
Which patients are affected by Autonomic dysreflexia?
T6 or above which is above major splanchinc outflow
What are the symptoms of AD?
Pounding headache Systolic and diastolic HTN Profuse flushing of face, beck and shoudlers Nasal congestion Pupillary dilation Bradycardia
Causes of AD
Distended bladder Fecal impaction Ingrown toe nails Labor & delivery Orgasm Surgery
Tx of AD
Sit patient up Remove restrictive clothing or garments BP monitored ~2-5 minutes Evacuation of bladder Remove fecal impaction Nitro paste or nifedipeine Monitor BP for 2 hr after resolution
What SCI level can have impaired thermal regulation?
T6 and above due to loss of supraspinal control
What is poikilothermia?
Inability to regulate core body temperature. Have higher body temp in hot environments and lower temp in cold
When is primary bone resorption most prominent in SCI?
First 7 months after SCI
What are markers of bone resorption and when should they be monitored?
Urinary calcium and N-telopeptide elevated 8-12 weeks after SCI
What are markers of bone turnover?
Parathyroid hormone & 25-hydroxyvitamin D low after SCI despite normal Ca
What is a marker of bone formation?
Serum ostocalcin
Low after injury and inc after 6 mo
What are risk factors for hypercalcemia in SCI?
Children/adolescents Recent injury Male complete injury Tetraplegia Dehydration Prolonged immobilization
What is treatment of hypercalcemia?
IVF
Diuretics
Bisphosphonates
Calcitonin
How is secondary hyperparathyroidism treated?
Ca & vitamin D supplmentation
Where is the greatest risk of loss of bone mineral density?
Lower limbs below level of lesion great from proximal to distal
What should be spared in loss of bone mineral density?
weight bearing vertebral column. look for secondary causes of osteoporosis
What can help protect against bone loss in SCI?
Passive weight-bearing in standing frame
FES cycle ergometry
Oral bisphosphonate
Ca & vitamin D supplementation
What are factors that contribute to dysphagia in cervical SCI?
Immobilization of c-spine
ST swelling
nerve trauma after anterior spine surgery
Limited laryngeal elevation by trach tubing
How long and what medications should be given in SCI for GI ppx?
histamine-2 receptor antagonist or PPI for 3 mo post-injury
What is a GI complication associated with high paraplegia?
Gallblladder dz and pancreatitis d/t dec SNS stimulation
When does adynamic ileus typically occur in SCI?
1-2 days post injury d/t loss of SNS and PNS tone during spinal shock
Resolves 2-3 days with bowel rest
What does the vagus nerve innervate?
PNS innervation to Esophagus to splenic flexture of colon
modulates peristalsis
What does pelvic nerve innervate?
S2-4 PNS innervation to descending colon to rectum
What does the somatic pudenal nerve innervate?
External anal sphincter and pelvic floor mucles
What is a reflexic or UMN bowel?
SCI above sacral segement
defecation cannot be initiated by voluntary relaxation of external sphincter
Reflex mediated colonic peristalsis
What is an areflexic or LMN bowel?
Destruction of anterior horn cells of S2-4
no reflex-mediated colonic peristalsis
slow stool propulsion by myenteric plexus
Atonic anal sphincter prone to stool leakage
What does PNS innervation of the bladder control?
modulates contraction of the urinary bladder with opening of bladder neck to allow voiding
Pelvic splanchnic nerve S2-4
What does SNS innervation of the bladder control?
Relaxation of bladder body and narrowing of neck to inhibit voiding
Hypogastric nerves T11-L2
What does the pudendal nerve control in bladder?
External urinary sphincter
S2-4
What is a UMN bladder?
Unable to voluntary contract
Reflex voiding possible
Damage above sacral segments
What is a LMN bladder?
Damage at S2-4
No reflex voiding
Bladder atonic and prone to leakage
What is detrusor-sphincter dyssynergia?
simultaneous reflex contractile activity of bladder and external urinary sphincter
What is the targeted cath volumes for I/O cathing?
500 ml for total fluid intake of 2,000 ml/day
What medication can help to inhibit voiding between I/O cath?
Anticholinergics
Botox
What is an augmentation cystoplasty?
Adding portion of small intestine to bladder to create high capacity low pressure reservoid
What is reflex voiding?
Bladder tapping in males to stimulate urination
What are risks of reflex voiding?
high PVR Vesicoureteral reflux Hydronephrosis Renal failure UTI Bladder stone formation
What are risks associated with indwelling catheter?
UTI Bladder stone formation Epidiymitis Prostatitis Hypospadias Bladder cancer
What can indicated at UTI in a SCI patient?
Fever Spontaneous voids between caths Hematuria AD Increased spasticity Foul smelling urine Malaise
What is needed to generate erection and lubrication psychogenically in SCI?
Some degree of LT and PP sensation in T11-L2 dermatomes
Bulbocavernous reflex
In what patients are orgasms unlikely to occur?
Absent bulbocavernous reflex
Absent anocutaneous reflex
No sensation S4-5
What is first line therapy for erectile dysfunction?
Type phosphodiesterase inhibitors
What has been shown to decrease sperm quality?
Deteriorates 2 weeks post SCI
Ejaculatory frequency >1/week
Reflex bladder emptying compared to I/O cath
When can women with SCI experience amenorrhea?
Post injury up to 4 months
What functional complications are associated with pregnancy in SCI?
Difficult transfers WC propulsion Respiratory compromise Self cathing Labor increasing spasticity Not recognizing labor in Patients with T10 and above injury
What is the distribution of pressure ulcers in acute hospitalization for SCI?
Sacrum 39% Calcaneus 13% Ischium 8% Occiput 6% Scapula 5%
What is the distribution of pressure ulcers 2 year after SCI?
Ischium 31% Trochanter 26% Sacrum 18% Calcaneus 5% Malleolus 4%
What is autolysis?
Moisture retentive barrier applied to superficial ulcer causing endogenous enzyme degradation of nectrotic tissue
What is Chemical debridement?
Application of commercially available enzymes to selectively degrade necrotic tissue
What is sharp debridement?
Excision o f necrotic tissue with sharp instrument
What is mechanical debridement?
Hydrotherapy or application of wet to dry dressings
What are the nutritional requirements in SCI with pressure ulcers?
25 kcal/kg/day
1.5-2g protein/kg/day
What is nociceptive pain?
Pain arising from activation of peripheral nerve endings or sensory receptors encoding noxious stimuli
What is neuropathic pain?
Pain arising due to lesion or disease affecting somatosensory system
What is At-level SCI pain?
neuropathic pain in segmental pattern in dermatomes at NLI and 3 levels below but not lower
What is Below-level SCI pain?
Neuropathic pain >3 dermatome levels below NLI d/t lesion of SC
Typically pain in region rather than dermatomal
Tx of At-level and Below-level SCI pain
Gabapentin Pregabalin Tramadol Amitriptyline SSRI or SNRI Oipids Itnrathecal ziconotide (neurotoxin) Desensitization CBT
What is the 1st line tx of spinal spasticity?
Oral baclofen
GABA analog that binds to GABA B receptors, main inhibitory of the SC
What is the maximum recommended dose of baclofen and side effects?
80 mg/day
Fatigue
Dizziness
Seizures
What medications bind to GABA A receptors?
Benzodiasepines
What is the MOA of tizanidine and its SE?
Central alpha2-adrenergic agonist
Sedation
Liver function ABN
What is the MOA and SE of dantrolene?
Inhibits release of calcium from muscle sarcoplasmic reticulum inhibiting excitation-contraction coupling in muscle
SE: Hepatoxicity
What is the MOA of botox?
Binds to receptor sites on presynaptic nerve terminal at NMJ inhibiting release of Ach
When is intrathecal baclofen used?
Severe generalized spasticity
What is Heterotopic ossification?
True bone in extraskeletal etopic sites
localized warm swelling with reduced ROM
When does HO develop in SCI and what there the MC locations?
W/in 4 mo of injury Hips (90%0 Knees Shoulders Elbows
How is HO diagnosed?
Elevated alkaline phosphatase
Bone scan
Xray positive when HO matures
Tx of HO
IV etidronate 300 mg/day for 3 days
Oral etidronate 20 mg/kg/day for 6 months
Surgical removal once HO mature
What are causes of SCI in children?
Lap belt injuries
Birth injury
Child abuse
Carnioverebral junction injury (RA, Down syndrome, skeletal dysplasia)
What is the management of bladder and bowel emptying in children with SCI?
Infant: diaper
3-4 yo: I/O cath
5-7 yo: self caths
2-4 yo: bowel program
What are common ortho problems in children with SCI?
Hip instablity
Scoliosis
What are some characteristics of SCI in elderly?
Incomplete injury MC
Cervical stenosis
Women >men
Inc comorbidities & complications
