What effect would a low-salt diet, upright position, and diuretics have on the following test results?

What effect would a low-salt diet, upright position, and diuretics have on the following test results?

• A. Renin increased, aldosterone increased, hypernatremia, hypokalemia
• B. Renin increased, aldosterone decreased, hypernatremia, hypokalemia
• C. Renin decreased, aldosterone decreased, hyponatremia, hyperkalemia
• D. Renin decreased, aldosterone increased, hyponatremia, hyperkalemia

Answer: (A)

When the body loses effective circulating volume from a low-salt intake, standing up (which pools blood in the legs and reduces venous return), and diuretic use, the kidneys sense reduced renal perfusion and delivery of sodium to the distal tubule. This triggers renin release, activating the renin–angiotensin–aldosterone system. Angiotensin II stimulates aldosterone secretion, so both renin and aldosterone levels rise as the body tries to restore volume. Aldosterone promotes sodium reabsorption to help reclaim volume, but it also drives potassium excretion. In this scenario, the combination of ongoing volume loss and diuretic-induced fluid and electrolyte shifts often concentrates the serum sodium, leading to hypernatremia, while the increased aldosterone pushes potassium out of the body, causing hypokalemia. So the expected pattern is higher renin, higher aldosterone, hypernatremia, and hypokalemia.

When the body loses effective circulating volume from a low-salt intake, standing up (which pools blood in the legs and reduces venous return), and diuretic use, the kidneys sense reduced renal perfusion and delivery of sodium to the distal tubule. This triggers renin release, activating the renin–angiotensin–aldosterone system. Angiotensin II stimulates aldosterone secretion, so both renin and aldosterone levels rise as the body tries to restore volume.

Aldosterone promotes sodium reabsorption to help reclaim volume, but it also drives potassium excretion. In this scenario, the combination of ongoing volume loss and diuretic-induced fluid and electrolyte shifts often concentrates the serum sodium, leading to hypernatremia, while the increased aldosterone pushes potassium out of the body, causing hypokalemia. So the expected pattern is higher renin, higher aldosterone, hypernatremia, and hypokalemia.