Spinal Shock

What is Spinal Shock?

Spinal shock is a rare medical condition occurring as a result of a spinal cord injury and is characterized by loss of feeling or sensation with motor paralysis. Patient suffering from spinal shock also has loss of reflexes in the beginning, but it is followed by gradual recovery of the reflexes. Spinal shock is a combination of autonomic and motor dysreflexia.1 Motor dysreflexia is presented in four phase as areflexia (loss of reflexes), hyporeflexia (slow lethargic reflexes), normal reflexes and hyper (exaggerated) reflexes.1 Spinal shock comprises of a period of absent motor reflexes, which can be temporary or permanent, followed by another period of excessive reflexes or hyperreflexia.

What is Spinal Shock?

Spinal shock is different from neurogenic shock. There is no circulatory collapse in spinal shock. Neurogenic shock is caused by severe autonomic dysfunction or dysreflexia resulting in severe vasodilatation and heart malfunction.2 Neurogenic shock may not be associated with areflexia. Spinal shock does cause minor transient autonomic dysfunction. Patient enters spinal shock within a few minutes after the spinal cord injury; however, it can take many hours for the full effects of the spinal shock to occur. When in spinal shock, the nervous system loses its ability of transmitting signals; but there is gradual return of them after the spinal shock has started to subside. The duration of spinal shock can be anywhere from 4 to 6 weeks after the injury. Rarely, spinal shock can last for some months. The absence of reflexes or signals hampers the patient's ability to move, ability to feel and other functions. Patient often has complete loss of sensation and movement below the level of spinal cord injury. This can conceal the actual extent of the damage. Spinal shock patient commonly has gradual return of the reflexes and improvement in the body's function after the shock starts to recede. At this stage, it is difficult to predict the time and extent of recovery or come to any conclusion regarding paralysis.

What Happens To The Patient In The Different Stages of Spinal Shock?

Stage 1 of Spinal Shock: In this phase, there is weakening or complete loss of all reflexes below the level of spinal cord injury. This phase lasts for a day.

Stage 2 of Spinal Shock: This stage occurs over the next two days and there is gradual return of some of the reflexes below the spinal cord injury.

Stage 3 & 4 of Spinal Shock: In this stage, patient has abnormally strong or increased reflexes (hyperreflexia), which are produced with minimal stimulation.

What are the Causes of Spinal Shock?

Causes of Spinal Shock

As mentioned before, spinal shock occurs following injury or trauma to the spinal cord. The injury leading to spinal shock can occur as a result of motor vehicle accidents, penetrating injuries and accident at work place and even domestic accidents.

Spinal cord injury causes sensory, motor and autonomic nerve damage. Spinal shock or Spinal cord shock is a combination of autonomic and motor dysreflexia

About Dysreflexia-

  • Autonomic Dysreflexia or Spinal Shock is caused by injuries of sympathetic nervous system in spinal cord or parasympathetic nervous system of sacrum.
  • Motor Dysreflexia results in abnormal or absence of the bubocavernous and deep tendon reflexes. The abnormalities are caused by injuries of motor nerve in spinal cord.

About Autonomic Nervous System

The autonomic nervous system is divided in sympathetic and parasympathetic nerves.

Sympathetic System-

Sympathetic nerves lies in spinal cord.

  • Sympathetic Nerves in Neck-
    • Controls heart rate and diameter or expansion of blood vessels of arms as well as neck.
  • Sympathetic Nerves of Chest and Abdomen-
    • Controls diameter or expansion of blood vessels, trachea, stomach, urinary bladder and intestine.
  • Sympathetic Hyperactivity-
    • Hyperactivity of sympathetic nerve in neck causes tachycardia (increase heart rate) and hypertension (high blood pressure). 3
  • Decreased Activity of Sympathetic Nerve-
    • Results in bradycardia or hypotension.

Absence of Sympathetic Activity

  • Spinal Cord Injury in Neck-
    • Injury to the spinal cord in the neck causes absence of sympathetic activities in entire spinal cord below the level of injury, which results in bradycardia and hypotension.
  • Spinal Cord Injury Below Neck-
    • The spinal cord injury in chest and abdomen spares sympathetic nerves originating from neck, which supplies to heart and upper extremities.
    • Injury results in hypotension because of dilatation of all the blood vessels in chest, abdomen and lower leg.
    • The low blood pressure follows increased sympathetic nerve impulses from intact spinal cord in neck to heart resulting in increased heart rate.

Parasympathetic System-

The parasympathetic nerve originates in brain and sacral nerves.

  • Parasympathetic Nerve from Brain-
    • Parasympathetic nerves known as vagus nerve originates in brain and travels along vagus nerve.
    • The vagus (parasympathetic) nerve also supplies abdominal and chest organs.
  • Parasympathetic Nerves of Sacrum-
    • Parasympathetic nerve from sacrum is supplied to anus, rectum, vagina, urinary bladder and urethra.

Parasympathetic Hyperactivity-

  • Increased activities of parasympathetic nerve is seen during fear.
  • Parasympathetic hyperactivity is also observed when sympathetic activities or impulses are paralyzed or absent.
  • The parasympathetic nerve stimulation causes increased diameter (dilatation) of blood vessels and decreased diameter (constriction) of viscera like intestine, bronchi, bladder, ureter and urethra.

Symptoms and Signs of Spinal Shock

Symptoms and Signs of Spinal Shock Based on the Level of Spinal Cord Injury-

  • If the level of spinal cord injury is at the Neck, then spinal shock symptoms would include the following -
    • Entire spinal cord is not functioning or is paralyzed.
    • Severe hypotension and bradycardia observed.
    • Abnormal reflexes (dysreflexia) are observed in all four extremities.
    • All four extremities are paralyzed also known as Quadriplegia.
    • Paralytic ileus caused by absence of peristalsis and dilatation of intestine and stomach.
    • Dilatation of bladder.
    • The parasympathetic predominance follows impulses from vagus nerve to dominate the function of heart and blood vessels, which result in slow heart rate (bradycardia) and low blood pressure (hypotension).
  • If the level of spinal cord injury is at the Chest (Thorax) and Abdomen (Lumbar Segment), then spinal shock signs and symptoms would include the following-
    • Spinal cord in neck is intact and functions normal
    • Entire spinal cord in chest and abdomen is not functioning.
    • Moderate hypotension since blood vessels in chest, abdomen and lower leg are dilated.
    • Heart rate is increased since sympathetic nerve to heart is not affected.
    • Abnormal reflexes (dysreflexia) observed in lower extremities and normal reflexes observed in upper extremities.
    • Lower extremity is paralyzed also known as paraplegia.
    • Paralytic ileus caused by absence of peristalsis and dilatation of intestine and stomach.
  • If the level of spinal cord injury is at the Sacral Segment then spinal shock signs and symptoms would include the following -
    • Spinal cord injury in sacral segment causes injuries to sacral autonomic nerves.
    • The paralysis of sacral parasympathetic nerve results in vasoconstriction of blood vessels of legs dominated by sympathetic action resulting in hypertension and dilatation of urinary bladder.
    • The reflexes are normal in all four extremities.

Prognosis of Autonomic Dysreflexia in Spinal Cord Injury Resulting in Spinal Shock-

  • This commonly resolves in 3 to 6 weeks.
  • Autonomic dysreflexia4 is characterized by low blood pressure, bradycardia, tachycardia, loss of bladder/bowel control, headaches, sweating and other sympathetic outcomes.
  • Extensive spinal cord injury causes distension of urinary bladder5 and intestine (paralytic ileus), which follows increased blood pressure (hypertension).

Abnormal Findings

  • Abnormal Sensory Nervous System-
    • Tingling
    • Numbness in legs, arms, chest and abdominal skin.
    • Paresthesias or dull pain.
  • Abnormal motor nervous system-
    • Absence of reflexes.
    • Tetraplegia (weakness in all four limbs)
    • Paraplegia (lower leg weakness and paralysis).
    • Atonic (loss of muscle tone) paralysis.
    • Increased reflex response.
    • Flexor spasms.
    • Flaccid muscles.
  • Abnormal Autonomic Symptoms-
    • Absence of sweating
    • Skin dryness.
    • Loss of autonomic activity.
    • Atony of the gastric muscles.
    • Paralytic ileus (lack of intestinal contractions).
    • Patient also experiences flushing.
    • Bladder incontinence.5

Skin Lesions-

  • Decubitus ulcers.
  • Skin pallor.
  • Profuse sweating.

Cardiovascular System- 6

  • Hypertension- Sympathetic predominance seen following sacral segment injury
  • Hypotension- Parasympathetic predominance seen following neck, chest and abdominal spinal cord injury.
  • Decreased Heart Rate (Bradycardia)- Parasympathetic predominance seen following neck injury.
  • Increased Heart Rate (Tachycardia)- Seen in chest, abdomen or sacral spinal cord injury, which is associated with intact sympathetic activities in neck.

Four Recovery Phase of Motor Dysreflexia-7

The characteristics of bubocavernous and deep tendon reflex during recovery phase changes. Accordingly the recovery phase is divided in four phases as follows-

  • Hyporeflexia- Reflexes are absent immediately following spinal cord injury and lasts 24 hours or 1 day.
  • Reflex return- Reflexes become normal for next 1 to 3 days. The recovery phase may be shorter and normal reflexes are often not observed.
  • Hyperreflexia- The knee, ankle, elbow and worst reflexes are exaggerated known as hyperreflexia. This phase lasts for 1 to 4 weeks before reflexes become normal.
  • Late Hyperreflexia- In few cases hyperreflexia phase prolongs to 1 to 12 months or longer.

Investigations For Spinal Shock

  • X-rays.
  • CT scan.
  • MRI.
  • Arterial blood gas test.
  • Blood cultures.
  • Complete blood count.
  • Electrocardiogram.
  • Electrolyte profile.
  • Kidney profile.
  • Liver profile.
  • Urinalysis and urine culture.

Treatment of Spinal Shock or Spinal Cord Shock 8

Spinal Cord Treatment depends on the injury sustained.

Immediate Treatment Following Spinal Shock or Spinal Cord Shock

  • Patient's neck and back is immobilized by using neck support and braces to prevent further damage to the spine.
  • Patient is moved in neutral position.
  • Airway is maintained so patient can breath normal.
  • There is swelling of the spinal cord after the injury, so, it is imperative to start medical care within the initial 8 hours after the injury for patient's recovery.
  • Intravenous catheter is inserted to inject medications to control tachycardia, bradycardia and hypotension
  • Intravenous fluid is initiated if patient is suffering with low blood pressure.
  • Nasal oxygen is provided to maintain normal blood oxygenation.
  • If immediate medical attention is not sought, or if the patient is not handled properly while transporting to hospital, then the spinal injury could worsen and there may even be permanent damage.

Follow-Up Treatment For Spinal Shock in ER and Hospital-

Intravenous Fluid-

Continue intravenous fluid and volume injected as necessary to maintain normal blood pressure.

Medications For Spinal Shock

  • Corticosteroids For Spinal Shock-

Steroids are given after the spinal cord injury to reduce inflammation and to prevent further nerve damage.

It is vital to prevent further nerve damage, therefore, steroids, such as methylprednisolone are given immediately upon arrival to the hospital and should be given preferably within 8 hours of injury to prevent and reduce nerve damage.

  • Vasopressors For Spinal Shock -

Medications such as dopamine, epinephrine, are given for extremely low blood pressure.

These medications are known as vasopressors

  • Antibiotics For Spinal Shock

Antibiotics are given to prevent sepsis.

  • Blood Transfusion -

Blood transfusion is needed in case of severe blood loss, as is seen in motor vehicle accidents.

Surgery For Spinal Shock or Spinal Cord Shock

  • Surgery is required if there is any misalignment of the spinal cord.
  • Surgery is also done to remove any piece of bones, herniated discs, foreign objects, or fractured vertebrae or tissue, which appears to be compressing the spinal cord or nerves.
  • Surgery is also done for stabilization of spinal cord and for preventing further damage.
  • Surgery is also done to excise any infected tissue and to repair any bleeding blood vessels
  • Patient may also need mechanical ventilation for breathing.


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Written, Edited or Reviewed By:


Last Modified On: May 2, 2016

Pain Assist Inc.

Pramod Kerkar
  Note: Information provided is not a substitute for physician, hospital or any form of medical care. Examination and Investigation is necessary for correct diagnosis.

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