A 54-Year-Old Woman Is Evaluated in the Clinic Due to Easy

question 63

Multiple Choice

A 54-year-old woman is evaluated in the clinic due to easy fatigability.  The patient has had no weight gain or cold intolerance, and has no history of thyroid problems.  Her medical history is significant for gastrectomy due to a nonhealing gastric ulcer.  Physical examination shows a shiny tongue and pale palmar creases.  Her gait is unstable when her eyes are closed, and vibration sense is markedly decreased over the lower extremities.  There is mild symmetrical loss of strength affecting the proximal lower extremity muscles.  Blood hemoglobin level is 7.2 g/dL and white blood cell count is 3,600/mm³.  Stool tests for occult blood are repeatedly negative.  Which of the following spinal cord lesions is most likely present in this patient?

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Definitions:

Mixture of Gases

A combination of different gases, where each gas retains its own chemical identity and properties.

Soluble

Capable of being dissolved in a solvent, typically referring to the ability of a substance to dissolve in water.

Diffusion

Diffusion is the passive movement of particles from an area of high concentration to an area of low concentration until equilibrium is reached.

Tidal Volume

The volume of air inhaled or exhaled during a normal breathing cycle, without exertion.