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Q- An 82-year-old woman comes to the office because of a 1-month history of increasing numbness of her feet. She has no history of serious illness. She has taken over-the-counter calcium carbonate tablets for intermittent abdominal pain during the past 40 years; she takes no other medications. She has drunk two glasses of wine with dinner nightly for 50 years. On examination, gastrocnemius deep tendon reflexes are absent. Babinski sign is absent bilaterally. Light touch to the distal lower extremities and feet produces a tingling sensation. Sensation to vibration over the great toes is severely decreased. There is a mild to moderate decrease in proprioception of the great toes. Which of the following is most likely to prevent progression of these neurologic findings?
(A) Alcohol cessation
(B) Calcium carbonate cessation
(C) Folic acid supplementation
(D) Niacin supplementation
(E) Vitamin B1 (thiamine) supplementation
(F) Vitamin B12 (cyanocobalamin) supplementation
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Answer
Her symptoms are indicative of peripheral neuropathy, including numbness of the feet, decreased vibration sensation, and mild to moderate impairment of proprioception. Regarding her history and symptoms, the most likely cause is a deficiency in Vitamin B12 (cyanocobalamin), which is commonly associated with long-term use of calcium carbonate.
Chronic use of calcium carbonate can lead to reduced absorption of Vitamin B12 because calcium is necessary for the proper functioning of intrinsic factor, a glycoprotein required for the absorption of Vitamin B12 in the ileum. A deficiency in Vitamin B12 can lead to subacute combined degeneration of the spinal cord and peripheral neuropathy, manifesting as the neurological symptoms observed in this patient.
Vitamin B12 supplementation will prevent the progression of these neurological findings.
The correct answer is F
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