Neurogenic shock is a serious condition that happens when a trauma to the spinal cord causes the disruption of blood circulation in the body. It is life-threatening and can cause the blood pressure to drop suddenly. When left untreated, it could lead to irreversible damage to the body tissues.
This kind of shock can cause the sympathetic nervous system to malfunction. The decrease in tissue perfusion can cause hemodynamic problems, where the cells and organs of our body do not receive enough oxygen supply.
Pathophysiology
The autonomic nervous system is divided into 2 systems, the parasympathetic nervous system, and the sympathetic nervous system. They control the functions of our body that we can’t consciously control such as digestion, heart rate, and pupil response.
Parasympathetic NS helps us relax by slowing down the heart rate and helping us digest the food we eat. It is also known as the “rest and digest” system. The sympathetic NS, on the other hand, is the “fight and flight” response of the body. It helps us stay alive when threatened by increasing blood pressure and heart rate. It also regulates the blood vessels to constrict or dilate when needed.
The interruption of the sympathetic function of the autonomic nervous system can affect three parts of the cardiovascular system, namely: cardiac contractility, coronary blood flow, and heart rate. This is also known as the hemodynamic triad.
Hemodynamic changes are usually seen when the spinal cord injury is above T6 level. Primary spinal cord trauma causes direct damage to the neural membranes and axons in the grey matter, anterior root, and intermediolateral nucleus that lead to interrupted sympathetic tone.
The secondary damage to the spinal cord happens hours or days after the primary assault. This results in electrolyte shifts, vascular insult, and edema that can lead to gradual central hemorrhagic necrosis of the grey matter at the area of the injury.
Signs and Symptoms of Neurogenic Shock
The main symptoms of neurogenic shock are bradycardia, hypothermia, hypotension and dry/warm extremities, and cold body. Symptoms usually persist for 4-5 weeks. Other symptoms include:
- Nausea
- Vomiting
- Dizziness
- Fainting
- Increased sweating
- Pale skin
In severe cases:
- Chest pain
- Difficulty Breathing
- Body malaise due to the disruption of blood circulation
- Discoloration of the lips and fingers
- hypothermia, or a drop in body temperature
Causes of Neurogenic Shock
This condition usually follows after an injury to the spinal cord, especially if the site of the injury is from T6 and above. The body loses the function of the sympathetic nervous system. The blood pressure drops and the brain tissues do not receive an adequate supply of oxygen.
Other causes may include:
- A vehicular accident that caused spinal cord or central nervous system damage
- Gunshot wound that damaged the spinal cord
- Sports accident that caused trauma to the spinal cord
- Inaccurate administration of anesthesia in the spinal cord
Treatment of Neurogenic Shock
The primary management of neurogenic shock is mainly focused on stabilizing hemodynamic function. Treat hypotension first to prevent secondary injury. The most effective treatment of hypotension is through IV fluid resuscitation. Vasopressors, inotropes, or euvolemic can also be effective in compensating vasogenic dilation. The patient should be properly resuscitated in a hemodynamic perspective before going through operative spinal decompression.
Phenylephrine is an alpha-1 agonist that allows peripheral vasoconstriction to prevent the loss of sympathetic tone. The absence of beta activity can lead to reflex bradycardia which enhances the unopposed vagal tone.
If bradycardia is evident, atropine, vasoactive infusion with chronotropic, dopamine, and norepinephrine may also be effective. Norepinephrine has both beta and alpha activity that can correct both bradycardia and hypotension.
A C-spine immobilization is also vital in preventing further spinal injuries. Philadelphia collar or Miami J can be used. Surgical procedures may sometimes be needed to decompress spinal cord injury to improve neurogenic shock.
Nursing Intervention for Neurogenic Shock
- Assessing patients with neurogenic shock involves ABC assessment. The nurse should follow the airway, breathing, and circulation approach, especially for trauma patients and protecting the spine from further damage.
- Assess for neurologic deficits. The general level at which signs and symptoms began should be noted.
- Nursing intervention should be mainly directed to support neurologic and cardiovascular function until neurogenic shock is resolved.
- Elevate the head of the bed to prevent anesthetic agents from spreading up the spinal cord after the patient receives spinal anesthesia.
- Apply anti-embolism stockings and elevate the foot of the bed to avoid the pooling of blood in the lower extremities and the formation of a thrombus.
- Administer oxygen via nasal cannula or mask when needed.
- Help the patient with passive range of motion exercises to promote circulation.
- Maintain a patent airway by keeping the head of the patient in a neutral position or by elevating the head of the bed if tolerated.
