A 56-year-old man is evaluated for progressive visual impairment. The patient works as part of the grounds crew at an airport, and says he has trouble identifying aircraft at a distance and with filling out paperwork at the end of his shift. His medical history includes poorly controlled diabetes mellitus, hypertension, and gout. A year ago, the patient underwent an uncomplicated repair of a right inguinal hernia. Physical examination shows bilateral clouding of the lens. The remainder of the examination is unremarkable. Which of the following metabolic conversions is most likely contributing to this patient's current condition?

Question

A 56-year-old man is evaluated for progressive visual impairment.  The patient works as part of the grounds crew at an airport, and says he has trouble identifying aircraft at a distance and with filling out paperwork at the end of his shift.  His medical history includes poorly controlled diabetes mellitus, hypertension, and gout.  A year ago, the patient underwent an uncomplicated repair of a right inguinal hernia.  Physical examination shows bilateral clouding of the lens.  The remainder of the examination is unremarkable.  Which of the following metabolic conversions is most likely contributing to this patient's current condition?

Quizplus · Accepted Answer

Eductional Objective: In hyperglycemic states, aldose reductase converts glucose to sorbitol at a rate faster than sorbitol can be metabolized.  Sorbitol accumulates in certain cells such as lens cells, causing an influx of water and resulting in osmotic cellular injury.  Depletion of NADPH by aldose reductase also increases oxidative stress, which accelerates development of cataracts and diabetic microvascular complications (eg, neuropathy, retinopathy).

A 56-Year-Old Man Is Evaluated for Progressive Visual Impairment