Spinal Cord II

SNS thermoregulation

adrenal medulla increases metabolic rate, skin innervation controls blood vessel diameter, sweat gland secretion, and piloerection

SNS blood flow regulation

prevents pooling blood via vasoconstriction

SNS cardiac regulation

increased HR and contractility

SNS pulmonary regulation

bronchodilation

SNS GI regulation

decrease blood flow, peristalsis and digestion

SNS genitourinary regulation

stimulates orgasm, bladder and rectal wall relaxation/internal sphincter contraction

SNS head innervation

dilates pupil, elevates eyelid, innervates salivary glands

PNS CN

III, VII, IX, X

PNS head innervation

constrict pupil, widen lens, innervate lacrimal and salivary glands

PNS cardiac

decreased HR and decreased contractility

PNS pulmonary

bronchoconstriction

PNS GI

increased blood flow, peristalsis and digestion

Spinal nerves S2-4 GI

increased blood flow, peristalsis and digestion

Spinal nerves S2-4 Genitourinary

stimulates erection, bladder and rectal wall contraction/internal sphincter relaxation

acute ANS thermoregulation

hypothermia due to vasodilation

chronic ANS thermoregulation

hyperthermia due to loss of sweat gland innervation

OH Sx

decreased systolic >20mmHg or decreased diastolic >10mmHg, dizziness, nausea, lightheadedness, pallor, diaphoresis, LOC

preventative OH Tx

pharmaceuticals, ab binder, elastic stocking, tilt table protocol

treatment for symptomatic OH

recumbent position, elevate LE

autonomic dysreflexia

hypertension and bradycardia

autonomic dysreflexia most common in

T6 lesion and above

autonomic dysreflexia manifests (usually)

6 mo after injury as a result of maladaptive neuroplasticity

autonomic dysreflexia symptoms

pounding headache, flushing, profuse sweating, anxiety, nasal congestion, visual changes

autonomic dysreflexia preventative treatment

pharmaceuticals

autonomic dysreflexia symptomatic treatment

upright position /c dep LE, removal of noxious stimulus

injury above T6

interrupts descending modulation of thoracolumbar sympathetic neurons

thoracolumbar sympathetic neurons regulate

vasomotor tone in splanchnic vascular bed (organs)

splanchnic nerves arise from

T5-T12

splanchnic nerves? receive

25% of CO

AD can/cannot occur with an injury below T6

CAN (although uncommon, and HTN/HR changes more mild)

DVT common in

acute phase (72hrs to 2weeks)

underlying mechanism of DVT

peripheral vasodilation, decreased extremity function, immobility

Risk factors for DVT

M, flaccid paralysis, complete injury, paraplegia

S/S of DVT

edema, erythema, warmth

DVT prevention

anti-coagulants, compression devices, filters to minimize PE risk (sits in IVC)

80% of SCI pts have

neurogenic bowel dysfunction

enteric nervous system (ANS)

activated by rectal stretch, causes peristalsis and internal sphincter relaxation

ANS Bowel

parasympathetic division (spinal segments S2-4), works to augment intrinsic function

Without parasympathetic innervation there is

no defecation

Bowel cortex

stretch reflex ascends, volitional assist of evacuation/enhanced external sphincter functino

somatic motor neurons bowel

sacral spinal segments S2-4, volitional control of external spinchter and puborectalis

Arreflexive bowel

LMN lesion within/below conus medullar is affecting Parasympathetic and somatic cell bodies in S2-4, resulting in tonically active internal sphinchter and denervated external sphincter/puborectalis

in arreflexive bowel pt is at risk for

constipation/impaction and fecal incontinence

Reflexive bowel

UMN lesion above conus medullaris with preserved reflexive arc

bowel reflexive arc

• afferent rectal stretch

• triggers intrinsic and parasympathetic relaxation of internal sphincter

• defecation

with reflexive bowl pt is at risk of

incontinence

Bowel recommendations

• introduce consistent bowel routine

• promote physical activity

• abdominal massage

• maintaining optimal stool consistency-diet and medication

reflexive bowel treatment

stool softeners, digital stimulation

arreflexive bowel treatment

bulkers for solid stool, manual evacuation, valsalva maneuver

bowel complications

ileus, GERD, ulcers, hemorrhoids, autonomic dysreflexia, pain

potential other bowel treatments

biofeedback, sacral nerve stimulation, sacral anterior root stimulation, epidural/non-invasive electrical simulation, surgical intervention (colostomy, ileostomy, MACE), transanal irrigation

parasympathetic bladder

S2-4, role in detrusor muscle contraction and internal sphincter relaxation

sympathetic bladder

T11-L2, role in detrusor m relaxation and internal sphincter contraction

brainstem bladder

pontine micturition center sends info via reticulospinal tract, resulting in inhibition of SNS and excitation of PNS

bladder somatic motor neurons

spinal segments S2-4, control of external urethral sphincter and pelvic floor musculature

cortex bladder

stretch signal to cortex, descending cortical inhibition for volitional urination/retention

arreflexive bladder

LMN within/below conus medullaris affecting parasympathetic and somatic cell bodies in S2-4, resulting in loss of parasympathetic input to bladder

pt with arreflexive bladder is at risk for

urinary retention and dribble incontinence

reflexive bladder

UMN lesion above conus medullaris with preserved reflexive arc

bladder reflexive arc

• afferent urinary stretch

• triggers parasympathetic contraction of detrusor m and relaxation of internal sphincter

• urination

Pt with reflexive bladder is at risk for

incontinence and may develop dyssynergia

arreflexive bladder treatment

catheterization, manual pressure

reflexive bladder treatment

catheterization, reflex voiding

bladder dysfunction complications

UTI, urinary stones, renal damage, vesicoureteral reflux, AD

vesicoureteral reflux

pee goes up rather than down

reflexive erection

response to SA stimulus, PNS S2-4

psychogenic erection

response to whatever, origin in cortical centers, SNS T11-L2

Seminal emission is under control of

supra spinal centers and T10-T12 sympathetic spinal segments

ejaculation is mediated by

sacral reflexive activity

ejaculation reflex

semen in urethra, S2-4 sacral segments, somatic efferents

Erection in T11 lesion and above

reflexive arousal only

erection in sacral lesion

psychogenic arousal only

after SCI sexual dysfunction

most have erection capacity retained, infertility due to inability to ejaculate, decreased sperm count and motility

reflexive F arousal

response to SA stimulus, PNS segments S2-4

psychogenic F arousal

response to whatever, origin in cortical centers, SNS T11-L2

smooth m activation

uterine and fallopian tube activation

smooth m activation (sexual) under control of

supra spinal centers as well as T11-L2 sympathetic spinal segments

striated m contraction

mediated by sacral reflexive activity, continued afferent stimulation to S2-4 segments to SE

F arousal Complete T6 and above

only reflexive arousal

arousal sacral lesion (F)

only psychogenic arousal

striated m contract F SCI

more likely to achieve if reflexive arc is intact

F acute fertility

cessation of period for ~4mo /p injury

chronic fertility F

generally remains fertile

Risks of labor /c SCI

inability to feel contractions, AD

a pt in labor /c a SCI needs

an epidural or C section

neurological heterotrophic ossification

NHO or HO

NHO diagnosed by

radiograph

NHO/HO

formation of bone in soft tissue

NHO/HO may cause

skin breakdown, pain, ROM restriction

NHO/HO occurs in

10-50% of SCI, below NLI

NHO/HO frequently occurs

1-6 mo after injury

risk factors for NHO/HO

complete lesions, microtrauma, M, genetics, DVT, pressure ulcers, UTI, spasticity

osteoporosis in SCI develops

in extremities below lesion (more severe in LE)

etiology of osteoporosis

Poorly understood, likely reduced tensile forces from m, reduced WB, altered circulation, reduced innervation, endocrine/immune system changes

osteoporotic changes most rapid

first few months /p injury

increased likelihood of fractures after SCI

25-40%

fracture risk factors

motor complete (a/b), paraplegia, white, time since injury, advanced age, F, lower BMI

C1/2 VC

5-10% of baseline

C3-4 VC

24% of baseline

C5-8 VC

30% of baseline