A 55-year-old man is found unresponsive on the street during a cold winter night. He is hypothermic and does not follow commands. Medical history is unavailable. Despite rewarming efforts, the patient dies in the emergency department. An autopsy is performed. Light microscopy of a section of the patient's kidney is shown on the slide below. This individual's renal condition could most likely have been prevented by use of which of the following types of medication?

Question

A 55-year-old man is found unresponsive on the street during a cold winter night.  He is hypothermic and does not follow commands.  Medical history is unavailable.  Despite rewarming efforts, the patient dies in the emergency department.  An autopsy is performed.  Light microscopy of a section of the patient's kidney is shown on the slide below.  This individual's renal condition could most likely have been prevented by use of which of the following types of medication?

Quizplus · Accepted Answer

11ec160b_3a46_4e91_9249_d716637ac4b4_MD0001_00 Hypertensive (malignant) nephrosclerosis is the renal manifestation of hypertensive emergency, a condition in which severe hypertension results in end-organ damage. Markedly elevated blood pressure causes vascular endothelial damage, leading to inflammation, cell necrosis, and extravasation of plasma proteins (eg, fibrinogen, coagulation factors). In the kidneys, this results in a characteristic set of histologic changes: Leakage of fibrinogen and coagulation factors through the damaged endothelium causes fibrin deposition in vessel walls, which appear as circumferential, acellular eosinophilic deposits (fibrinoid necrosis). Over time, release of growth factors by damaged tissue stimulates the formation of concentric layers of collagen and proliferating smooth muscle cells, resulting in an "onion skin" appearance (hyperplastic arteriosclerosis) of the arteriole, as seen in this patient. These processes result in narrowing and obliteration of the arteriolar lumens, reducing glomerular perfusion and filtration, with subsequent activation of the renin-angiotensin-aldosterone system. This maladaptation can result in a further increase in blood pressure and compromised circulation in other organs. Treatment of hypertensive emergency includes antihypertensive therapy with the goal of lowering blood pressure to prevent end-organ damage. (Choices A and E) Antibiotics and hypoglycemic agents are not used in the treatment of hypertensive emergency. Although sepsis can cause acute kidney injury and unresponsiveness, histology would show evidence of tubular necrosis with sloughing of tubular epithelial cells and loss of basement membrane integrity. (Choice C) Antiplatelet agents would be useful if the endothelial dysfunction in hypertensive emergencies led to thrombotic complications (eg, acute myocardial infarction, acute ischemic stroke), but would not have any effect on preventing acute hypertensive nephrosclerosis. (Choice D) The mineralocorticoid activity of steroids leads to salt and water retention, increasing blood pressure and worsening hypertension. (Choice F) Nonsteroidal anti-inflammatory drugs inhibit prostaglandin secretion, resulting in vasoconstriction and decreased renal blood flow. This would worsen hypertension by activating the renin-angiotensin-aldosterone system. Educational objective: Hyperplastic arteriosclerosis ("onion-skinning") and fibrinoid necrosis of the renal arterioles are typical morphologic findings in hypertensive (malignant) nephrosclerosis. End-organ damage can be prevented by treatment of high blood pressure with antihypertensives.

A 55-Year-Old Man Is Found Unresponsive on the Street During