Tabes dorsalis is a rare neurological condition caused by untreated syphilis, typically developing years after initial infection. It results from damage to the dorsal columns of the spinal cord, leading to symptoms like severe “lightning” pains, loss of coordination (ataxia), numbness, and impaired reflexes. Other signs include Argyll Robertson pupils (small pupils that don’t react to light but constrict with accommodation), urinary incontinence, and sensory deficits. Diagnosis involves clinical evaluation, serologic tests for syphilis (e.g., VDRL, FTA-ABS), and sometimes cerebrospinal fluid analysis.