What is Neurogenic Shock?
Neurogenic shock is a medical condition which occurs as a result of disturbance in the sympathetic outflow causing loss of vagal tone. Patient experiences neurogenic shock after injury to the spinal cord and when there is disruption in the blood circulation throughout the body due to injury/illness. It is a serious and life-threatening condition, which requires prompt medical attention without any delay. If the treatment is delayed, then it causes irreversible tissue damage and even death. Out of the different types of the shocks, neurogenic shock is the most difficult to manage, mainly because of the irreversible damage to the tissues. Neurogenic shock mainly affects the spinal cord; the function of which is transmitting neural signals from the brain to the entire body and back.
Neurogenic shock is different from spinal shock in that spinal shock is often temporary and will last for a day or two, where there is loss of sensory and motor tone, which is also temporary. Whereas, neurogenic shock can last for many days to weeks and leads to loss of muscle tone due to lack of muscle usage. Neurogenic shock can also occur with an incomplete or complete spinal cord lesion. The primary symptoms of neurogenic shock are hypotension and bradycardia. The severity of the symptoms that the patient experiences depend on the level/region of the spinal cord affected. The higher the level of the spinal cord affected, the more severe the symptoms will be.
Treatment comprises of medications to stabilize blood pressure, bradycardia, temperature, preventing tissue damage and to revive the patient.
Causes of Neurogenic Shock
Injury or trauma to the spinal cord is the main cause of neurogenic shock. Patient experiences neurogenic shock immediately after an injury to the spinal cord. The symptoms experienced by the patient occur as a result of interference in the sympathetic outflow caused by the loss of vagal tone. The injury to the spinal cord can be with an incomplete or a complete cord lesion. With an incomplete cord lesion, there is a probability of a neurogenic shock. The spinal cord injury disrupts the exchanges of impulses between spinal cord and paravertebral sympathetic system resulting in damaging effects on heart rate and blood pressure.1
The Common Causes Of Neurogenic Shock Include:
- Blunt or penetrating trauma/injury to the spinal cord from rotation, dislocation and over- flexion/extension of the spinal cord.
- Trauma to the spinal cord from motor vehicle accidents, sports injuries, falls, stab and gunshot wounds.
- Improper administration of spinal regional anesthesia can also cause neurogenic shock.
- Drugs and medications which affect the autonomic nervous system can also cause neurogenic shock.
Signs & Symptoms of Neurogenic shock
Other Symptoms Of Neurogenic Shock Include The Following:
- Hypotension (low blood pressure) occurs as a result of decrease in the systemic vascular resistance, which causes pooling of blood within the extremities resulting in decreased sympathetic tone.
- Bradycardia is another primary sign of neurogenic shock. Nerve injury causes relaxation of the blood vessels walls resulting in decreased heart rate. Bradycardia in spinal cord injury is also found to be worsened by hypoxia or decreased blood supply. The resting heart rate in bradycardia is below 60 beats/ minute and can even go lower when the patient is in neurogenic shock.
- Post traumatic neurogenic shock may result in irregular heart beat because of beat to beat variation of heart beat.2
- Hypothermia (decreased body temperature) can occur in neurogenic shock due to loss of sympathetic tone leading to decreased core circulation, excessive loss of heat and massive decrease in body temperature. Patient feels very cold, with warm limbs and the rest of the body is cold to touch.
Additionally To The Above Symptoms Of Neurogenic Shock, Patient Also Experiences:
- Difficulty in breathing and has rapid and deep shallow breathing.
- The skin feels cold and clammy to touch.
- Facial pallor.
- Dizziness, lightheadedness, fainting.
- Nausea and vomiting.
- Faint and rapid pulse.
- Patient experiences weakness due to insufficient blood supply.
- Patient stares blankly at nothing.
- Feels anxious and there can be changes in mental state or disorientation.
- Does not respond to any stimuli.
- Has bluish discoloration of lips and fingers (cyanosis).
- Decreased or absent urine output.
- Sweats profusely.
- Considerable chest pain.
- Loss of consciousness.
Diagnosis of Neurogenic shock
Complete physical examination and medical history of the patient is carried out. Various tests, such as blood and urine tests, CT scan, MRI scan, x-rays, ultrasound etc. are carried out to assess the patient's medical condition and the extent of injury or damage.
Treatment For Neurogenic Shock
Neurogenic shock is a serious condition and requires emergent medical care in order to save the patient's life. The aim of treatment in neurogenic shock is stabilizing the patient and preventing irreversible tissue damage.
- The patient is examined carefully and his/her general condition is assessed thoroughly. Special attention is given to the patient's airway, breathing pattern and circulation.
- It is important to immobilize the patient, especially the spinal region to prevent any further damage to the spinal cord.
- Administration of IV fluids is done to stabilize the patient's blood pressure.
- Inotropic agents, such as dopamine may be infused for fluid resuscitation, if needed.
- Atropine is given intravenously to manage severe bradycardia.
- Low blood pressure is treated with intravenous fluid and vasopressor. Pseudoephedrine,3 ephedrine and epinephrine may be necessary to treat severe hypotension.
- Patient with obvious neurological deficit can be given I.V. steroids, such as methylprednisolone in high dose, within 8 hours of commencement of neurogenic shock.
- Surgery is needed in case of accident/trauma/ injury/ to the patient.
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