A 4-year-old boy is brought to the emergency department with…
A 4-year-old boy is brought to the emergency department with lethargy, dry mucous membranes, and decreased urine output for the past two days. His mother reports that he had severe vomiting and diarrhea after a recent gastroenteritis outbreak at daycare. On examination, he appears pale, tachycardic, and has a delayed capillary refill time. On examination, the child has decreased blood pressure. Which of the following is the most likely cause of this child’s pre-renal acute kidney injury (AKI)?