A 70-year-old male shows parathesia of the lower extremities and decreased vibratory sense. What is the most likely diagnosis?

The symptoms presented—which include paresthesia of the lower extremities and decreased vibratory sense—are indicative of peripheral neuropathy, which can arise due to vitamin B12 deficiency, commonly associated with pernicious anemia. Pernicious anemia is an autoimmune condition that leads to the impairment of intrinsic factor production, resulting in poor absorption of vitamin B12 in the gastrointestinal tract. This vitamin is essential for proper nerve function and the formation of red blood cells.

In cases of pernicious anemia, the lack of vitamin B12 can lead to neurological symptoms such as tingling or numbness in the extremities and reduced sensation, particularly in vibratory sense, which is often tested using tuning forks. In older adults, the incidence of pernicious anemia is higher due to potential atrophic gastritis and diminished intrinsic factor secretion, further elevating the risk of vitamin B12 deficiency.

The other options, while they may lead to anemia, typically do not present with neurological symptoms like paresthesia and vibratory sense loss. Anemia of chronic disease is characterized mostly by low iron levels and does not primarily impact neurological function. Folic acid deficiency, while it can contribute to anemia, typically leads to megaloblastic changes and does not usually present with the specific neurological symptoms