Tabes dorsalis is a progressive degeneration of nerve cells and fibers in the spinal cord that carry sensory information to the brain, caused by untreated syphilis. It is characterized by sensory deficits, loss of coordination, and diminished reflexes. The disease progresses through preataxic, ataxic, and paralysis stages. Clinical features include loss of sensation, Argyll Robertson pupils, dementia, hypotonicity, loss of coordination, and trophic ulcers. Treatment involves antibiotics, steroids, pain medications, exercises, and splinting to manage symptoms.