Brown-Séquard syndrome may be caused by injury to the spinal cord resulting from a spinal cord tumour, trauma [such as a fall or injury from gunshot or puncture to the cervical or thoracic spine], ischemia (obstruction of a blood vessel), or infectious or inflammatory diseases such as tuberculosis, or multiple sclerosis. In its pure form, it is rarely seen. The most common cause is penetrating trauma such as a gunshot wound or stab wound to the spinal cord.[citation needed] Decompression sickness may also be a cause of Brown-Séquard syndrome.[2]The presentation can be progressive and incomplete. It can advance from a typical Brown-Séquard syndrome to complete paralysis. It is not always permanent and progression or resolution depends on the severity of the original spinal cord injury and the underlying pathology that caused it in the first place.