A 65-year-old man presents with numbness and tingling in both feet, difficulty walking, and loss of vibration sense and proprioception in the lower extremities. Romberg sign is positive. CBC shows Hb 7.8 g/dL, MCV 118 fL. Peripheral smear shows hypersegmented neutrophils. Which neurological condition is most likely responsible?
- A Subacute combined degeneration of the spinal cord ✓
- B Tabes dorsalis
- C Multiple sclerosis
- D Amyotrophic lateral sclerosis
Correct answer: A. Subacute combined degeneration of the spinal cord
Explanation
Megaloblastic anemia with A12 deficiency causes subacute combined degeneration affecting the dorsal columns (loss of vibration and proprioception) and lateral corticospinal tracts. The positive Romberg sign and hypersegmented neutrophils are characteristic. Tabes dorsilis in neurosyphilis also affects dorsal columns but does not cause macrocytic anemia or hypersegmented neutrophils.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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