A spinal cord injury (SCI) is damage to the spinal cord that causes temporary or permanent changes in its function. Symptoms may include loss of muscle function, sensation, or autonomic function in the parts of the body served by the spinal cord below the level of the injury. Injury can occur at any level of the spinal cord and can be complete, with a total loss of sensation and muscle function at lower sacral segments, or incomplete, meaning some nervous signals are able to travel past the injured area of the cord up to the Sacral S4-5 spinal cord segments. Depending on the location and severity of damage, the symptoms vary, from numbness to paralysis, including bowel or bladder incontinence. Long term outcomes also range widely, from full recovery to permanent tetraplegia (also called quadriplegia) or paraplegia. Complications can include muscle atrophy, loss of voluntary motor control, spasticity, pressure sores, infections, and breathing problems. In the majority of cases the damage results from physical trauma such as car accidents, gunshot wounds, falls, or sports injuries, but it can also result from nontraumatic causes such as infection, insufficient blood flow, and tumors. Just over half of injuries affect the cervical spine, while 15% occur in each of the thoracic spine, border between the thoracic and lumbar spine, and lumbar spine alone. Diagnosis is typically based on symptoms and medical imaging.Efforts to prevent SCI include individual measures such as using safety equipment, societal measures such as safety regulations in sports and traffic, and improvements to equipment.
People with SCI are at especially high risk for respiratory and cardiovascular problems, so hospital staff must be watchful to avoid them. Respiratory problems (especially pneumonia) are the leading cause of death in people with SCI, followed by infections, usually of pressure sores, urinary tract infections and respiratory infections. Pneumonia can be accompanied by shortness of breath, fever, and anxiety.Another potentially deadly threat to respiration is deep venous thrombosis (DVT), in which blood forms a clot in immobile limbs; the clot can break off and form a  pulmonary embolism, lodging in the lung and cutting off blood supply to it. DVT  is an especially high risk in SCI, particularly within 10 days of injury, occurring in over 13% in the acute care setting. Preventative measures include anticoagulants, pressure hose, and moving the patients limbs. The usual signs and symptoms of DVT and pulmonary embolism may be masked in SCI cases due to effects such as alterations in pain perception and nervous system functioning.Urinary tract infection (UTI) is another risk that may not display the usual symptoms (pain, urgency, and frequency); it may instead be associated with worsened spasticity. The risk of UTI, likely the most common complication in the long term, is heightened by use of indwelling urinary catheters. Catheterization may be necessary because SCI interferes with the bladders ability to empty when it gets too full, which could trigger autonomic dysreflexia or damage the bladder permanently.