Symptoms of Brown-Séquard

Classically, the symptoms of Brown-Séquard fall into three main categories: motor, sensory, and pain/temperature.  Spastic paralysis occurs of all muscles with nerves innervated at or below the level of the lesion; this is also known as hemiplegia.  (A spastic paralysis is a type of paralysis with increased muscle tone or tightness.)  One may see partial or total diminishment of tactile, vibratory, and positional sensations of all nerves taking in information at or below the level of the lesion.  Patients might also complain of abnormal prickling sensations or other uncomfortable sensations in these regions.  Both paralytic and sensory changes occur on the same side of the body as the injury to the spinal cord, e.g., an injury to the right side of the spinal cord would lead to paralysis and sensory changes on the right side of the body.  In contrast, pain and temperature sensation are also impaired, but on the opposite side of the lesion.  These impairments start a little lower than the lesion itself.  This is one example of a crossed-finding in spinal cord injury; it is ultimately explained by the different pathways groups of nerve take through the spinal cord.  (See “More detailed anatomy and physiology of Brown-Séquard.”)

The degree of paralysis and location of sensory findings depend on the level of the spinal cord that is injured.  For example, suppose an individual suffers from Brown-Séquard at the level of cervical nerve seven on the right side, right below the seventh cervical vertebra.  This individual would be expected to have normal sensation of the neck, the uppermost part of the back, and would have partial sensation along the length of his arms.  The rest of the arms, torso, back, pelvis, and legs would have impaired sensation on the right side only.  Many of the muscles of the arm would be weak but not paralyzed on the right side, since they normally utilize cervical nerves seven and below, but are also innervated by nerves higher up.  The individual’s ability to move his diaphragm would not be impaired, since this muscle receives nerves from higher up in the spinal cord.  Muscles to the right leg would be paralyzed.  This individual would also experience diminished pain and temperature sensations on the left side of the body, but starting a little lower on the torso.  Obviously damage to different regions of the spinal cord would result in slightly different symptom profiles, with the highest level spinal cord injuries causing the most disability.

More often than not, individuals have Brown-Séquard-plus and thus do not experience this exact symptom profile.  These individuals may experience only muscle weakness rather than outright paralysis in the affected areas.  Tactile sensation might not be diminished, etc.

An individual with Brown-Séquard-plus might also report additional findings due to involvement of other areas of the spinal cord.  For example, an individual might experience urinary retention or inability to control bowel movements.  Horner syndrome may also occur as part of Brown-Séquard-plus due to involvement of sympathetic nerves in the spinal cord.  This may result in drooping eyelid, decreased pupil size, and increased sweating on the affected side of the face.

There are also other potential complications, which go beyond the actual Brown-Séquard symptoms.  A condition called spinal shock occurs soon after the injury.  This can lead to low blood pressure, heart arrhythmias, and altered temperature regulation, all of which require careful monitoring.  Usually this resolves within a few months or sooner.  Immediately after the injury, individuals are also at risk for aspiration, inhalation of food or gastric contents into the lungs, as well as ileus, slowed or halted propulsion of materials through the digestive tract.  They may be at risk for deep vein thrombosis, pulmonary embolism, and bed sores from poor mobility.  There may be an increased risk of pulmonary infections and urinary tract infections, depending on the placement and degree of the lesion.  Patients are also at risk for depression and other psychiatric symptoms.  (See living with Brown-Séquard.)  Proper treatment and prevention of these secondary conditions helps speed rehabilitation.

Depending on origin, the symptoms of Brown-Séquard may occur suddenly or more gradually.  For example, in the case of traumatic injury to the spinal cord, symptom onset is acute.  In the case of Brown-Séquard due to a gradually increasing tumor in the spinal cord, an individual might experience less severe symptoms which then worsen.  In this case the individual might progress from weakness to paralysis, and might develop sensory deficits that had not originally been present.

Prognosis for recovery also varies due to the syndrome’s origin.  Syndromes due to compression (e.g., caused by a tumor) may fully resolve fairly quickly if the source of the compression is surgically removed and the tissue is able to work normally again.  Those with transection injuries also recover somewhat as other available pathways take on more of the work, but the original damage to the spinal cord is permanent.  Right after the damage, the symptoms appear most severe.  Motor recovery is greatest in the first 1-2 months following injury.  At this point the recovery slows, but continues for several months up to two years; after this, symptoms are likely to be permanent.   Most individuals with Brown-Séquard symptoms at initial examination eventually recover the ability to ambulate, though few are able to do so at hospital discharge.

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