Question 160

Question:

Hospital discharge of a 75-year-old man is delayed due to unavailability of a bed in a nursing home. He is bedridden and unable to attend to his personal needs. During a 3-day period, his pulse increases from 82/min to 125/min, and blood pressure decreases from 124/72 mm Hg to 100/55 mm Hg. Laboratory values are above. Which of the following is the most likely diagnosis?

Correct Answer: B.  Dehydration

The increased pulse and decreased blood pressure indicate a loss of fluid (volume contraction.) The patient’s hemoglobin, urea nitrogen, and sodium all rise to above the normal values by Day 3, whereas his glucose and creatinine remain normal. These changes are consistent with an hyperosmotic volume contraction, a loss of water without losing solute. This typically occurs due to dehydration.
Choice A is incorrect because renal failure would decrease creatinine clearance.
Choice C is incorrect because diabetic ketoacidosis would cause increased blood glucose levels.
Choice D is incorrect because gastrointestinal hemorrhage would present with additional symptoms and hemoglobin would decrease.
Choice E is incorrect because SIADH would cause decrease in urine volume and retention of fluid, not loss of fluid.