Effects of Spinal Cord Injury

The spinal cord may become severed or injured due to accidents, acts of violence or physical diseases such as polio, according to Dr. Edward Benzel of the Cleveland Clinic Spine Institute. Depending upon the extent and location of the spinal cord damage, a range of motor, sensory or autonomic nervous system functions (involuntary functions such as breathing) may be affected.
Loss of Motor Function
Spinal cord injury can cause partial or complete paralysis, or loss of motor function. Loss of movement may occur as a result of bruising, compression, lacerations or complete severing of the spinal cord. Partial paralysis (called paresis) can occur in all four limbs (quadraparesis), or slight paralysis may develop only in the lower extremities (paraparesis). In some cases, complete paralysis of the lower extremities and lower trunk may occur while the upper limbs remain unaffected (paraplegia). According to Dr. Edward Benzel, chairman of the Cleveland Clinic Spine Institute, loss of motor function typically occurs below the level of impact to the spinal cord, and paralysis may be temporary or permanent depending upon the severity of the injury. For example, if the cervical spine in the neck region is affected, loss of motor function is often seen in the hands, arms and neck. If the spinal cord in the lower back region is injured, loss of function may occur in the hips and legs.
Loss of Sensation
Spinal cord injuries may be associated with damage to the sensory nerve fibers. Nerve damage can cause temporary or permanent loss of sensation in one or more areas of the body, leading to loss of sensations such as touch, pressure and temperature.
Respiratory Problems
According to a review published in a 2007 issue of the Journal of Spinal Cord Medicine, spinal cord injuries--particularly those in the cervical or neck region--may lead to paralysis or paresis of the muscles that are responsible for involuntary respiration. Those who aren't able to breathe sufficiently on their own may require long-term mechanical ventilator support to survive; however, mechanical ventilation increases the risk of complications such as pneumonia, infection and death. The review’s authors note that respiratory insufficiency is the top cause of morbidity and mortality after a spinal cord injury.
Autonomic Dysreflexia

Autonomic Dysreflexia, or hyperreflexia, is a life-threatening over-activity of the autonomic nervous system (responsible for controlling involuntary actions of muscles and organs in the body) that occurs uniquely in patients with spinal cord injury. According to the University of Washington Department of Rehabilitation Medicine, people with a severed spinal cord at or above the T-6 vertebrae are at greater risk of developing the condition. When pain or pressure (or a full bladder or bowel) below the level of spinal cord injury occur, blood vessels constrict and blood pressure rises. Nerves in the sympathetic nervous system relay a message to the brain that blood pressure is getting too high, and the brain in turn sends a signal down the spinal cord to relax blood vessels and lower blood pressure. However, spinal cord injuries may prevent this message from reaching the part of the body below the severed cord. Consequently, blood pressure acutely rises and stroke, seizures or death may occur.