NEET PG / USMLE – MCQ 46

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 include:
Day 1 Day 3
Hemoglobin 16.4 g/dL 18.4 g/dL
Serum Urea nitrogen 18 mg/dL 56 mg/dL
Glucose 100 mg/dL 89 mg/dL
Na+ 135 mEq/L 151 mEq/L
Creatinine 1.1 mg/dL 1.2 mg/dL
Which of the following is the most likely diagnosis?
(A) Acute renal failure
(B) Dehydration
(C) Diabetic ketoacidosis
(D) Gastrointestinal hemorrhage
(E) Syndrome of inappropriate ADH (vasopressin)

Correct answer : (B) Dehydration

The clinical features are suggestive of dehydration. The lab values show hemoconcentration due to dehydration.