Brown-Séquard syndrome (BSS), also known as hemisection of the spinal cord or partial spinal sensory syndrome, is a rare condition caused by an incomplete lesion of the spinal cord. This damage, most often from physical trauma, results in a contralateral (opposite side of the body) loss of sensation and temperature and ipsilateral (same side of the body) paralysis or extreme weakness.
In 1849, French physiologist Charles Edouard Brown-Séquard published a document discussing the condition that now bears his name. Using information gathered through animal experimentation and human autopsies, he identified and described the hallmark signs of BSS: paralysis affecting only one side of the body (ipsilateral paralysis) and loss of sensation on the opposite side of the body.
Injury or damage to one side of the spinal cord, typically in the cervical (neck) region, results in BSS. The severity of the condition depends on the amount of damage to the spinal cord and associated neurons. The onset of symptoms may also vary depending on the cause.
Information on the prevalence of Brown-Séquard syndrome is collected from 16 spinal cord injury centers in the United States. According to The University of Alabama's National Spinal Cord Injury Statistical Center (NSCISC), which compiles the data, approximately 11,000 spinal cord injuries (SCIs) occur each year (as of 2003). Although specific incidence is unknown, BSS is estimated to occur in 200–400 of these injuries.
The average age of a patient sustaining a spinal cord injury is 32 years, with injuries most commonly occurring in individuals between 16 and 30 years. Men account for more than 80% of reported SCIs.
Within the United States, approximately 70% of individuals with BSS are white, nearly 20% are African American, and the remaining 10% comprise other origins, according to NSCISC reports. Little data is known regarding SCIs in countries outside the United States.
Causes and symptoms
In most cases, Brown-Séquard syndrome is caused by severe physical trauma such as a puncture wound or gunshot wound, which partially severs or damages the spinal cord. Nontraumatic conditions that compress the spinal cord may also cause BSS. Examples include tumors, multiple sclerosis , epidural hematoma (swelling in the area between the brain and skull), meningitis, myelitis (spinal cord inflammation), and tuberculosis.
Physical trauma usually causes a more rapid onset of symptoms than nontraumatic conditions. The two primary symptoms of BSS are loss of sensation and paralysis. The side of the body that sustained injury typically loses touch and vibration senses. The opposite side of the body tends to lose its sense of pain and temperature. In both cases, these symptoms occur below the site of the SCI. Paralysis or muscle weakness occurs on the same side of the body as the injury.
Loss of bladder and bowel control may result, but the majority of patients will regain control. Horner syndrome, a condition resulting from damage to the sympathetic facial nerves, has also been known to develop.
Brown-Séquard syndrome is diagnosed based on the patient's medical history and a physical examination. Imaging studies may be performed to isolate the extent and location of the SCI. These include magnetic resonance imaging (MRI) , computed tomography (CT) scans, or x rays. Additional testing may be required for secondary conditions or symptoms.
Several neurological disorders have symptoms similar to BSS, making differential diagnosis very important, especially in those cases related to nontraumatic conditions. The incomplete lesion of the spinal cord in conjunction with the unique presentation of ipsilateral sensory loss and paralysis are key for identifying BSS.
The team of specialists needed to treat a patient with BSS will vary. Primary members include:
- a neurologist to evaluate brain and nerve function
- an orthopedic specialist to monitor the spine and assist with walking therapy
- a physical therapist to help regain muscle strength and walking ability
- an occupational therapist to facilitate adaptation of new physical limitations
In cases of physical trauma, treatment begins at the accident site with proper immobilization and emergency medical care to prevent further spinal cord damage. Surgery may be required in these or nontraumatic cases to eliminate the cause, whether a bullet or a fluid-filled cyst.
Treatment of symptoms is the typical focus for this condition. Several studies have shown increased success with early administration of high-dose steroids such as corticosteroids, but this is not yet a standard practice. Other medications are prescribed as needed for secondary symptoms.
Physical therapy should begin immediately in order to maintain muscle strength and agility since most patients with BSS will regain mobility. Specialized devices, including wheelchairs or braces, may be necessary during this transition.
Recovery and rehabilitation
The recovery time for each patient depends on the extent of nerve damage and underlying cause of the syndrome. The NSCISC reports that individuals with SCIs spend an average of 16 days in the hospital and 44 days in rehabilitation. Rehabilitation may be required outside the hospital for several months or years.
Extensive physical therapy should take place immediately. Initial therapy focuses on respiratory exercises, upright positioning, and range of motion in affected muscles. Progressive therapy gradually helps the patient with the strength and control necessary to be mobile or begin walking again.
Occupational therapy is also important for helping patients return to their daily activities. This therapist provides methods for modifying everyday tasks, evaluates progress, and facilitates the necessary changes to restore independence when possible.
The National Institute of Child Health and Human Development is currently conducting a clinical trial to evaluate the effectiveness of walking on a treadmill by individuals with incomplete SCIs. As of early 2004, this five-year study was in Phase II and III clinical trials and still recruiting patients. The proposed end date for the study is January 2005. For additional information contact: Andrea L. Behrman, PhD (Principal Investigator), University of Florida, "Retraining Walking after Spinal Cord Injury" (Study ID: K01HD01348); Telephone: (352) 273-6117; E-mail: [email protected]
Patients with Brown-Séquard syndrome usually have a good prognosis. The extent to which a patient recovers depends on the cause of injury and secondary conditions or complications. According to the National Organization for Rare Disorders, more than 90% of affected individuals successfully regain the ability to walk. Additional studies have found that the majority of a patient's motor skills return within the first two months after injury. The recovery period is usually two years, but will vary by patient.
Not all patients with BSS make a full recovery. In these instances, long-term care options need to be considered. By working with the treatment team, individuals can determine their level of activity and recognize areas where adaptation may be required. Some patients and their caregivers could benefit from psychological therapy to discuss the variety of changes that occur after traumatic injury.
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Stacey L. Chamberlin