Intravenous fluids and vasopressors are administered, but the patient remains hypotensive and dies 3 hours later. Autopsy examination is performed and reveals bilateral hippocampal necrosis. Which of the following areas of the colon would be most likely to also demonstrate necrosis?

Question

Intravenous fluids and vasopressors are administered, but the patient remains hypotensive and dies 3 hours later.  Autopsy examination is performed and reveals bilateral hippocampal necrosis.  Which of the following areas of the colon would be most likely to also demonstrate necrosis?

Quizplus · Accepted Answer

11ec160b_38dc_f9d9_9249_d1fbe0e42a4e_MD0001_00 This patient's bilateral hippocampal necrosis is characteristic of the effects of global cerebral ischemia due to systemic hypotension. The hippocampus is particularly vulnerable during shock because of the high metabolic demand of its CA1 pyramidal neurons. Watershed areas located between the distal terminal branches of 2 different vascular territories (border zones) are also susceptible to ischemia because they have a low baseline perfusion pressure and poorly tolerate sustained decreases in systemic blood pressure. Important watershed areas in the body include: Splenic flexure: the border zone supplied by branches of the superior mesenteric artery and inferior mesenteric artery Rectosigmoid junction: the border zone supplied by the sigmoid arteries and the superior rectal arteries (Choices A, B, C, and D) The ascending colon, cecum, hepatic flexure, and ileocolic junction are well perfused by the superior mesenteric artery and do not lie in watershed areas. Educational objective: Severe systemic hypotension (eg, shock) is most likely to cause ischemia first in areas of high metabolic demand (eg, hippocampus) or watershed zones, which are areas that are supplied by the distal branches of two different major arteries. Commonly affected areas in the colon include the splenic flexure and rectosigmoid junction.

Intravenous Fluids and Vasopressors Are Administered, but the Patient Remains