A 40-year-old woman comes to the physician because of a 1-month history of tingling in her feet and poor balance. Her only medical problem is hypothyroidism for which she takes levothyroxine. Physical examination shows conjunctival pallor and an ataxic gait. Proprioception and sense of vibration are decreased in her toes bilaterally. Physical examination shows mild conjunctival pallor.Laboratory results are as follows: Further evaluation shows a very low vitamin B₁₂ level and a normal folate level. Which of the following sets of physiologic alterations is most likely to be present in this patient?

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Quizplus · Accepted Answer

Eductional Objective: Pernicious anemia is an autoimmune disease characterized by CD4+ cell-mediated destruction of parietal cells. As parietal cells are destroyed, their ability to secrete hydrochloric acid decreases, resulting in an elevated intraluminal pH that leads to upregulation of gastrin secretion. Patients also develop vitamin B₁₂ deficiency as a result of decreased intrinsic factor secretion.

A 40-Year-Old Woman Comes to the Physician Because of a 1-Month