Neurogenic shock: Causes, Symptoms, Diagnosis & Treatment

Photo by Billy McCrorie, CC BY-SA 2.0, via Wikimedia Commons

Neurogenic shock is a life-threatening condition in which blood pressure drops suddenly after a spinal cord injury (SCI). Without enough blood pressure, organs and tissues don’t get enough blood and oxygen, which can cause lasting damage.

It mainly happens with injuries to the neck (cervical spine) or upper back, at or above the T6 level. A review in the Journal of Medicine and Life notes that low thoracic injuries do not cause neurogenic shock.

The injury cuts off signals from the sympathetic nervous system, the part of the nervous system that tightens blood vessels and speeds up the heart. The parasympathetic side, carried by the vagus nerve, keeps working unopposed.

The result is a classic pattern: low blood pressure (hypotension), a slow heart rate (bradycardia) and widened blood vessels (peripheral vasodilation). Body temperature can also drop. This needs emergency treatment.

What Causes Neurogenic Shock?

Neurogenic shock is usually caused by injury to the spinal cord. The damage disrupts the sympathetic nervous system, which normally raises blood pressure, speeds up the heart and narrows blood vessels when needed. Losing that control lets blood pressure fall and slows the heart.

The main causes of spinal cord injury may include:

Automobile or car accidents
sport injuries
gunshot wounds to the spine
rare complications of spinal anesthesia
Disc herniation
Others diseases such as osteoporosis and osteoarthritis etc
Falling from height
A violent attack
Diving into the shallow water

Neurogenic shock symptoms

The main sign of neurogenic shock is low blood pressure with a slow heart rate. In other types of shock, such as from blood loss, the heart usually races instead. Other symptoms may include

Nausea
Vomiting
dizziness
Anxiety
Lightheadedness
Headache
Warm, flushed, dry skin below the injury
blank stares
fainting
Weakness, numbness or paralysis below the injury

In severe cases, it can cause further symptoms such as

Difficult breathing
Hypothermia
Chest pain
Decrease heart rate or bradycardia
Cyanosis of fingers and lips
Confusion or reduced alertness

How Neurogenic Shock Can Be Diagnosed?

Doctors first check breathing, blood pressure and heart rate, and do a physical and neurological exam. Imaging shows where the spinal cord is injured and how badly.

Tests and steps used include

Detailed history
Proper physical examination like monitoring of blood pressure, heart rate
Examination of symptoms
CT scan
MRI scan
Urinary catheter to monitor urine output

Doctors also rule out other causes of low blood pressure, such as internal bleeding, which is common after major trauma.

Management of Neurogenic Shock

Neurogenic shock is managed in an emergency department and intensive care unit. Treatment aims to restore blood pressure and heart rate and to protect the spinal cord from further damage.

Following steps are used to treat this emergency treatment.

Keep the airway open and support breathing
Give intravenous fluids, while avoiding too much fluid
If blood pressure stays too low, give vasopressor medicines that tighten blood vessels, such as phenylephrine or dopamine
Treat a dangerously slow heart rate with medicines such as atropine or glycopyrrolate
Provide oxygen to maintain the oxygen saturation
Keep the spine still with a rigid neck collar and careful positioning to prevent further injury

Treatment varies with the level and severity of the spinal cord injury. Neurogenic shock is usually temporary. It often improves over days to weeks, although heart rate problems can be most severe in the first few weeks.

The spinal cord injury itself may cause lasting weakness or paralysis. Rehabilitation starts as soon as the patient is stable.