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B12 Deficiency – Neurological Spectrum — SCE Neurology MCQ

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EasyPeripheral Neuropathy & NeuromuscularB12 Deficiency – Neurological SpectrumSCE Neurology

A 60-year-old man presents with progressive bilateral foot numbness and unsteadiness. He has a macrocytic anaemia (MCV 110 fL). His serum B12 is low at 95 pg/mL. MRI spine shows dorsal column T2 hyperintensity in the cervical and thoracic cord. What neurological complications does B12 deficiency cause?

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Correct answer: A — Subacute combined degeneration of the cord (dorsal columns + corticospinal tracts), peripheral neuropathy, optic neuropathy, cognitive impairment, and psychiatric symptoms — B12 deficiency can mimic MS

B12 deficiency causes a spectrum of neurological disease: (1) subacute combined degeneration (SCD) — demyelination of the dorsal columns (proprioception, vibration loss) and corticospinal tracts (spastic paraparesis, extensor plantars), (2) peripheral neuropathy (length-dependent, sensorimotor), (3) optic neuropathy, (4) cognitive impairment and dementia, (5) psychiatric symptoms (depression, psychosis). Neurological symptoms can occur without anaemia. Treatment is parenteral hydroxocobalamin. A: Multiple neurological systems affected. C: Multiple complications. D: Neurological disease can precede anaemia. E: Multiple systems.

Reference: ABN B12 Guidelines; NICE CKS B12 Deficiency