Signs and Symptoms of a Spinal Cord Injury
- Published on Monday, 05 November 2012 00:34
Signs observed by a physician and symptoms experienced by a patient will vary depending on where the spine is injured and the extent of the injury. These are all determined by the area of the body that the injured area of the spine controls and can result in different levels of disability. A section of skin controlled through a specific part of the spine is called a dermatome. A spinal injury can cause pain, numbness, or a loss of sensation in that area. A group of muscles controlled through a specific part of the spine is called a myotome, and injury to the spine can cause problems with voluntary motor control. The muscles may contract uncontrollably, become weak, or be completely unresponsive. The loss of muscle function can have additional effects if the muscle is not used, including atrophy of the muscle and bone degeneration.
The spine is divided into four regions: cervical, thoracic, lumbar and sacral.
A severe injury may also cause problems in parts of the spine below the injured area. In a "complete" spinal injury, all function below the injured area are lost. In an "incomplete" injury, some or all of the functions below the injured area may be unaffected. If the patient has the ability to contract the anal sphincter voluntarily or to feel a pinprick or touch around the anus, the injury is considered to be incomplete. The nerves in this area are connected to the very lowest region of the spine, the sacral region, and retaining sensation and function in these parts of the body indicates that the spinal cord is only partially damaged. An incomplete spinal cord injury involves preservation of motor or sensory function below the level of injury in the spinal cord.
A complete injury frequently means that the patient has little hope of functional recovery. The relative incidence of incomplete injuries compared to complete spinal cord injury has improved over the past half century, due mainly to the emphasis on better initial care and stabilization of spinal cord injury patients. Most patients with incomplete injuries recover at least some function.
In addition to sensation and muscle control, the loss of connection between the brain and the rest of the body can have specific effects depending on the location of the injury.
Determining the exact "level" of injury is critical in making accurate predictions about the specific parts of the body that may be affected by paralysis and loss of function. The level is assigned according to the location of the injury by the vertebra of the spinal column. While the prognosis of complete injuries are generally predictable since recovery is rare, the symptoms of incomplete injuries can vary and it is difficult to make an accurate prediction of the outcome.
Cervical (neck) injuries usually result in full or partial tetraplegia (Quadriplegia). However, depending on the specific location and severity of trauma, limited function may be retained.
- C-1/C-2 levels will often result in loss of breathing, necessitating mechanical ventilators or phrenic nerve pacing.
- C3 vertebrae and above : Typically results in loss of diaphragm function, necessitating the use of a ventilator for breathing.
- C4 : Results in significant loss of function at the biceps and shoulders.
- C5 : Results in potential loss of function at the shoulders and biceps, and complete loss of function at the wrists and hands.
- C6 : Results in limited wrist control, and complete loss of hand function.
- C7 and T1 : Results in lack of dexterity in the hands and fingers, but allows for limited use of arms.
Patients with complete injuries above C7 have disabilities that make it impossible to handle activities of daily living and cannot function independently.
Additional signs and symptoms of cervical injuries include:
Inability or reduced ability to regulate heart rate, blood pressure, sweating and hence body temperature.
Autonomic dysreflexia or abnormal increases in blood pressure, sweating, and other autonomic responses to pain or sensory disturbances.
Complete injuries at or below the thoracic spinal levels result in paraplegia. Functions of the hands, arms, neck, and breathing are usually not affected.
- T1 to T8 : Results in the inability to control the abdominal muscles. Accordingly, trunk stability is affected. The lower the level of injury, the less severe the effects.
- T9 to T12 : Results in partial loss of trunk and abdominal muscle control.
Typically injuries above the T6 spinal cord level can result in Autonomic Dysreflexia.
The effects of injuries to the lumbar or sacral regions of the spinal cord are decreased control of the legs and hips, urinary system, and bowel function. In that regard, it is very common to experience infections of the bladder and incontinence, after traumatic injury.
Sexual function is also associated with the sacral spinal segments, and is often affected after injury. During a psychogenic sexual experience, signals from the brain are sent to the sacral parasympathetic cell bodies at spinal levels S2-S4 and in case of men, are then relayed to the penis where they trigger an erection. A spinal cord lesion of descending fibers to levels S2-S4 could, therefore, potentially result in the loss of psychogenic erection. A reflexogenic erection, on the other hand, occurs as a result of direct physical contact to the penis or other erotic areas such as the ears, nipples or neck, and thus not involving descending fibers from the brain. A reflex erection is involuntary and can occur without sexually stimulating thoughts. As a result it may be possible to experience reflexogenic erection.
Other syndromes of incomplete injury
Central cord syndrome is a form of incomplete spinal cord injury characterized by impairment in the arms and hands and, to a lesser extent, in the legs. This is also referred to as inverse paraplegia, because the hands and arms are paralyzed while the legs and lower extremities work correctly.
Most often the damage is to the cervical or upper thoracic regions of the spinal cord, and characterized by weakness in the arms with relative sparing of the legs with variable sensory loss. This condition is associated with ischemia, hemorrhage, or necrosis involving the central portions of the spinal cord (the large nerve fibers that carry information directly from the cerebral cortex). Corticospinal fibers destined for the legs are spared due to their more external location in the spinal cord. The symptoms may be transient or permanent.
Anterior cord syndrome is often associated with flexion type injuries to the cervical spine, causing damage to the anterior portion of the spinal cord and/or the blood supply from the anterior spinal artery. Below the level of injury motor function, pain sensation, and temperature sensation are lost. While touch, proprioception (sense of position in space), and sense of vibration remain intact.
Posterior cord syndrome can also occur, but is very rare. Damage to the posterior portion of the spinal cord and/or interruption to the posterior spinal artery causes the loss of proprioception and epicritic sensation (e.g.: stereognosis, graphesthesia) below the level of injury. Motor function, sense of pain, and sensitivity to light touch remain intact.
Brown-Séquard syndrome usually occurs when the spinal cord is hemisectioned or injured on the lateral side. True hemisections of the spinal cord are rare, while partial lesions due to penetrating wounds (e.g.: gunshot wounds or knife penetrations) are more common. On the same side of the injury, there is a loss of motor function, proprioception, vibration, and light touch. On the opposite side of the injury there is a loss of pain, temperature, and crude touch sensations.
All spinal cord injuries that limit or increase the difficulty of completing daily activities are considered disabilities by the Social Security Administration.