Final answer:
The most common cause of hypertension in acute renal failure is hypervolemia, which is a result of the body's inability to excrete water and sodium, leading to fluid overload and increased production of vasoactive hormones such as angiotensin II.
Step-by-step explanation:
The most common cause of hypertension (HTN) in acute renal failure is hypervolemia. Hypervolemia, which is an excessive fluid volume in the body, may result from the retention of water and sodium due to various conditions such as heart failure, liver cirrhosis, certain kidney diseases, hyperaldosteronism, and glucocorticoid steroid treatments.
In the case of acute renal failure, the inability of the kidneys to excrete water and sodium leads to an increased blood pressure due to fluid overload. Additionally, the production of vasoactive hormones such as angiotensin II, which causes vasoconstriction and increases systemic blood pressure, contributes to the development of hypertension. Reversing hypervolemia and managing these hormonal changes are crucial for restoring homeostasis and controlling blood pressure in these patients.