An untreated patient with long-standing syphilis develops lightning pains in the legs, ataxia with a wide-based stamping gait, loss of deep pain and vibration sensation, and pupils that accommodate but do not react to light. Which structure bears the brunt of the pathological process?

• A Frontal cortex with perivascular plasma cell infiltrate
• B Anterior horn cells of the cervical cord
• C Dorsal columns and dorsal roots of the lumbosacral spinal cord ✓
• D Middle cerebral artery leading to gummatous necrosis

Explanation

Tabes dorsalis is late neurosyphilis affecting the dorsal roots and dorsal columns, giving lightning pains, sensory ataxia, areflexia, impaired proprioception and vibration sense, and the Argyll Robertson pupil described here. Option A describes general paresis of the insane, where parenchymal cortical involvement causes dementia and tremor, which is the strongest distractor. Gummas are focal granulomatous mass lesions seen in tertiary syphilis anywhere in the CNS but do not produce this syndrome.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.