Neuro
Neurogenic Shock
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Neurogenic Shock
, Vasogenic Shock
See Also
Spinal Shock
Hemorrhagic Shock
Severe Head Trauma
Spinal Cord Syndrome
Cervical Spine Injury
Thoracolumbar Trauma
Definitions
Neurogenic Shock
Distributive Shock
from neurogenic vasodilation mediated by loss of sympathetic tone
Follows cerebral or spinal cord injury (above T6) affecting sympathtic nervous system
Spinal Shock
In contrast to Neurogenic Shock,
Spinal Shock
is not a true shock syndrome
Results in
Flaccid Paralysis
and
Deep Tendon Reflex
loss below level of spinal cord injury
Pathophysiology
Results from
Severe Head Injury
or upper spine injury (above T6)
Peripheral
Sympathetic Nerve
denervation results in ungoverned
Parasympathetic Nerve
activity
Loss of vasomotor tone (vasodilation) leading to
Distributive Shock
Loss of cardiac
Sympathetic Nerve
activity, leads to paradoxical
Bradycardia
Causes
Severe Head Trauma
Cervical Spine Injury
Thoracic Spine Injury
(above T6)
Signs
Mnemonic: 70/70 = SBP 70, HR 70
Lack of normal sympathetic tone
Hypotension
Secondary to
Bradycardia
and vasodilation
Narrow Pulse Pressure
is absent
Lack of typical sympathetic response (increased SVR and diastolic BP)
Paradoxical
Bradycardia
Expected response is a reflex
Tachycardia
(a sympathetic response)
Decreased vascular tone (vasodilation)
Warm extremities
Absent diaphoresis
Associated Conditions
See
Severe Head Trauma
See
Spinal Cord Syndrome
See
Cervical Spine Injury
See
Thoracolumbar Trauma
Spinal Shock
Flaccid Paralysis
and
Deep Tendon Reflex
loss below level of spinal cord injury
Diaphragm Paralysis
C3-5
Cervical Spine Injury
resulting in phrenic nerve denervation
Differential Diagnosis
Hemorrhagic Shock
(first priority to manage)
Presents with
Tachycardia
,
Vasocon
striction and cold extremities
In actuality, distinguishing from Neurogenic Shock can be difficult
Hemorrhagic Shock
is more common, more immediately deadly and more treatable
Address possible
Hemorrhagic Shock
first
Pitfalls
Fluid Overload
(from aggressive fluid
Resuscitation
)
Management
Careful
Fluid Replacement
Vasopressor
s (
Norepinephrine
is preferred)
Target mean arterial pressure of 85 mmHg or higher (maximizes spinal cord perfusion)
Prognosis
Neurogenic Shock if due to critical
Head Injury
may indicate terminal event
Prognosis is often poor
References
(2012)
ATLS
, ACOS, p. 179-80
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