BrownSéquard

Brown-Séquard syndrome refers to the neurological deficits produced by a unilateral lesion of the spinal cord, most commonly a hemisection. The term honors Charles-Édouard Brown-Séquard, a 19th-century physician and physiologist who described the condition in the context of spinal cord injury and contributed to early ideas about the nervous system and internal secretions. The syndrome is typically described when a motor and sensory deficit affects one side of the body more than the other due to a lateralized cord injury.

Clinical features arise from disruption of distinct tracts. Ipsilateral weakness or paralysis and loss of vibration and proprioception occur below the level of the lesion, reflecting corticospinal and dorsal column involvement. On the opposite side, pain and temperature loss develop starting a few levels below the injury due to disruption of the crossing spinothalamic tract. Autonomic disturbances, such as bladder dysfunction, may be present. Early in the course, spinal shock can obscure outward signs, but the asymmetrical pattern becomes clearer over time.

Causes include penetrating trauma (for example, stab wounds), spinal tumors, ischemia, infections, demyelinating or inflammatory processes, and other lesions that damage one side of the cord. Diagnosis is established clinically and confirmed with imaging, most often magnetic resonance imaging (MRI). Management targets the underlying cause, along with supportive care and rehabilitation. Prognosis varies with the level and extent of the injury and the speed of treatment, with outcomes ranging from substantial recovery to persistent deficits.