What are the causes and symptoms of spinal shock

Spinal shock is an idiopathic disease that follows a spinal cord injury. After the spinal cord injury is repaired, there will be a period of spinal shock, the length of which varies with the extent of the original spinal cord injury. If you are in the spinal cord repair stage, you should have a certain understanding of the causes and symptoms of spinal shock.

1. What is spinal shock?

After severe spinal cord injury, the spinal cord nerve function below the injury plane is immediately and completely lost, and the reflex activity is temporarily lost, leaving the patient in an unresponsive state. Symptoms include loss of sensation below the level of injury, loss of muscle tone, peripheral vasodilation, decreased blood pressure, decreased cardiac output, bradycardia, hypothermia, respiratory dysfunction, sphincter dysfunction, disappearance of sweating reflex, and decreased or absent visceral reflexes.

Spinal shock usually recovers quickly, lasting from several hours to several weeks, mostly 1-6 weeks, but it may also be several months.

After the spinal shock ends, the extent to which the spinal cord function recovers depends on the type of spinal cord damage. If it is a partial injury, it may be partially recovered, but if it is a transverse complete severance, it may not be possible to recover.

During the recovery process, primitive and simple reflexes are restored first, followed by complex and advanced reflexes.

2. Causes of spinal shock

The production of spinal shock is not caused by the transection stimulus itself, because a second spinal cord severing does not cause spinal shock to reappear. Therefore, the cause of spinal shock is that the severed spinal cord segment loses the regulatory influence of higher centers, especially the facilitating influence from the cerebral cortex, vestibular nuclei and reticular formation of the brainstem. Under normal circumstances, these parts form synaptic connections with spinal neurons through their descending fibers, keeping these spinal neurons in a subthreshold state of excitation, which is called facilitation. Due to the transection of the spinal cord, this facilitating effect is lost, and the excitability of spinal neurons is temporarily reduced, which manifests as spinal shock.

Symptoms of spinal shock

In spinal shock, the tone of the skeletal muscles innervated by the spinal cord below the cross section decreases or disappears, peripheral blood vessels dilate, blood pressure drops, sweating reflex disappears, the bladder is filled with urine, and feces accumulates in the rectum, indicating that the somatic and visceral reflexes of vertebrates are reduced or disappeared. Spinal shock is a temporary phenomenon, and various reflexes will gradually recover later. The speed of recovery is closely related to the level of evolution of the animal species. In lower animals such as frogs, reflexes can be restored within minutes after spinal cord severance, but in dogs it takes several days and in monkeys it takes several weeks. In humans, recovery from spinal shock due to trauma and other reasons may take weeks or even months. The recovery time of various reflexes is also different. For example, simpler reflexes such as flexor reflex and tendon reflex recover the earliest, followed by more complex reflexes such as the contralateral extensor reflex and scratching reflex, as well as partial recovery of urination and defecation reflexes.