A 50-year-old man with a history of untreated syphilis presents with severe lightning pains in the legs, sensory ataxia, and a positive Romberg sign. Examination reveals Argyll Robertson pupils and loss of proprioception. What is the most likely diagnosis?
- A Multiple sclerosis
- B Subacute combined degeneration
- C Tabes dorsalis ✓
- D Syringomyelia
Correct answer: C. Tabes dorsalis
Explanation
Tabes dorsalis is a form of neurosyphilis affecting the dorsal columns and dorsal roots. It presents with lightning pains, sensory ataxia, Romberg sign, Argyll Robertson pupils, and loss of proprioception and vibration sense. Multiple sclerosis presents with disseminated CNS lesions and optic neuritis. Subacute combined degeneration is due to C12 deficiency. Syringomyelia causes dissociated sensory loss with preserved touch and proprioception.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.