Spinal shock in humans

In neurology, spinal shock is defined as a clinical syndrome that occurs as a result of the initial neurological response to traumatic injury to the spinal cord - with reversible loss or reduction of all its functions below the level of the injury. [ 1 ]

According to ICD-10, its code is R57.8 (in the section on general symptoms and signs), but the spinal cord injury itself (the main diagnosis) has the code S14.109A.

Epidemiology

Because it can be difficult for physicians to distinguish symptoms that result directly from spinal cord injury from those of spinal shock, clinical statistics for this syndrome are extremely difficult.

Globally, according to WHO estimates, 250-500 thousand people suffer spinal cord injuries every year (an average of 10-12 cases per 100 thousand population).

Road traffic accidents account for 38-46% of cases of spinal shock, almost 35% of cases are due to domestic spinal injuries (and every fourth victim of such an injury was a fall), and 10-15% of patients had sports injuries.

Causes spinal shock

Acute spinal cord injuries at the level of the cervical (CI-CVII), thoracic (ThI-ThXII) or lumbar (LI-LV) spine are common causes or etiologic factors for the development of spinal shock. Although there is an opinion that this clinical syndrome is observed only with spinal cord injury localized to the sixth thoracic vertebra (ThVI). [ 2 ]

In addition to spinal cord injury with its intersection (violation of integrity), crushing or distraction (stretching) of nerves, spinal shock can occur with acute transverse spinal cord injury syndrome.

Risk factors

Risk factors for the development of spinal shock include injuries to the thoracic and lumbar vertebrae – with dislocation and/or fracture of their bodies, severe contusions (with concussion of the spinal cord), compression comminuted fractures of the bodies of the cervical vertebrae, etc.

These injuries can be sustained during a traffic accident, an industrial accident, a sports accident, as a result of domestic accidents, a fall from a height, or a gunshot wound. [ 3 ]

Pathogenesis

Explaining the pathogenesis of the immediate temporary suppression of all the main functions of the spinal cord in its segments below the level of damage that occurs during spinal shock, specialists put forward several versions that are quite substantiated from the point of view of neurophysiology.

The main mechanism of spinal shock is the abrupt interruption of the descending pyramidal and extrapyramidal, as well as the vestibulospinal and reticulospinal tracts (conducting pathways) of the spinal cord. Such manifestations of this syndrome as loss of tone and suppression of reflexes are associated with both a disruption of the corticospinal connections and a decrease in the excitability of the motor neurons (motor neurons) of the spinal cord, and with a decrease in the sensitivity of the stretch receptors and contraction of the muscles of the neuromuscular spindle. The process can be aggravated by presynaptic inhibition and blocking of the autonomic reflex arcs - pathways for conducting nerve signals to secondary ganglionic neurons outside the spinal cord.

In addition, a sharp neurological reaction to spinal cord injury may be caused by increased polarization of its motor neurons and/or an increase in the concentration of aminoacetic acid (glycine), a neurotransmitter that inhibits nerve conduction.

Read also – The structure of the nervous system

Symptoms spinal shock

In spinal shock, the first signs are manifested by a complete or partial loss of spinal reflexes - hyporeflexia, as well as a short-term increase in blood pressure and a slow pulse, which is quickly replaced by neurogenic arterial hypotension with cardiac arrhythmia in the form of bradycardia. At the same time, some polysynaptic reflexes (plantar, bulbocavernous) are restored several days after the injury. [ 4 ]

Also observed in spinal shock are the following symptoms:

• hypothermia and pale skin;
• sweating disorder in the form of hypohidrosis or anhidrosis;
• lack of sensory response - loss of sensation (numbness) below the level of injury;
• impaired muscle tone and flaccid paralysis with varying degrees of immobility;
• spasticity of skeletal muscles with hyperreflexia (increased manifestation of deep tendon reflexes).

The clinical picture may vary depending on the location and severity of the spinal cord injury. The duration of spinal shock also varies: from several hours to several weeks (on average, this syndrome is observed for one to three months from the moment of injury).

Complications and consequences

In cases of spinal shock, patients may have complications and consequences in the form of dysfunction of the detrusor (the bladder muscle that ensures the urination process), which causes urinary retention, and when the bladder is full, urinary incontinence, i.e. symptoms of the so-called neurogenic bladder. In some cases, the lack of vegetative tone leads to intestinal obstruction.

Complications may include: lower spastic paraparesis (paraplegia) of skeletal muscles or lack of mobility of all limbs - tetraparesis (tetraplegia); contractures, weight loss, muscle atrophy and pressure ulcers; muscle or joint pain; swelling of the lower limbs with the risk of deep vein thrombosis and pulmonary embolism; orthostatic hypotension; breathing problems with an increased risk of pneumonia; depression. [ 5 ]

Diagnostics spinal shock

In the case of spinal cord injury, diagnosis of spinal shock requires a complete examination of the patient, primarily an assessment of his condition and examination of reflexes (tendon, extensor-flexor, cutaneous). [ 6 ]

Instrumental diagnostics are used for visualization:

• X-ray of the spine and spinal cord;
• computed tomography of the spine;
• MRI of the spine.

Blood tests are performed: general, for coagulation, for the levels of lactic acid (lactate) in the blood and arterial blood gases.

Differential diagnosis

Differential diagnostics should be performed with degenerative diseases of the central nervous system, malignant neoplasms or infectious lesions of the spinal cord, spinal amyotrophy, spinal cord infarction, Brown-Sequard syndrome, myelopathic or myasthenic syndromes. Neurogenic shock, a sudden loss of vegetative tone due to damage to the spinal cord, but not below the level of injury, but above it, should also be distinguished from spinal shock.

Treatment spinal shock

Treatment of patients with spinal cord injuries and spinal shock is carried out in the intensive care unit. [ 7 ]

As a rule, treatment measures consist of spinal immobilization (which is carried out even during emergency care), ensuring respiratory function, and monitoring blood circulation. Infusion therapy uses a hypertonic solution with the addition of Atropine (for bradycardia), Dopamine, and Norepinephrine. That is, treatment is focused on the spinal cord injury as a whole.

The first task of a neurotraumatologist is to relieve the patient of symptoms caused by spinal shock. The use of corticosteroids, in particular Methylprednisolone, in spinal cord injury is not supported by all specialists, since its side effects often outweigh the expected therapeutic effect. Although this drug is prescribed to young patients in the first 24 hours after injury. [ 8 ]

At the same time, as practice shows, more than half of patients require spine stabilization with the help of surgical intervention.

Spinal shock and spinal cord injury require a variety of treatments, including exercise therapy to strengthen muscles and therapeutic massage; physiotherapy to stimulate nerve conduction; balanced nutrition to maintain a healthy body weight; prevention of bedsores, etc.

All patients require rehabilitation to restore spinal cord function. [ 9 ]

Prevention

Prevention of spinal shock development can be considered as reducing the risk of injury to the spine and spinal cord: fasten your seat belt in the car and follow traffic rules; do not dive into water in unfamiliar places and shallow pools; take precautions when playing sports, etc. [ 10 ]

Forecast

The most favorable prognosis is with minor damage to the spinal cord, when the most complete restoration of its functions is possible. [ 11 ] But many patients, especially those with a spinal fracture, have to move around in a wheelchair.