USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

What is a common outcome of acute kidney injury on potassium levels?

1. Hypokalemia

2. Hyperkalemia

3. Normokalemia

4. Increased tubular reabsorption of potassium

The correct answer is: Hyperkalemia

Hyperkalemia is a common outcome of acute kidney injury because the kidneys are primarily responsible for the excretion of potassium. When acute kidney injury occurs, the ability of the kidneys to filter and eliminate potassium from the body is impaired. As a result, potassium levels in the blood can rise, leading to hyperkalemia. This condition can be particularly dangerous, as elevated potassium levels can result in serious cardiac complications, including arrhythmias. In contrast, hypokalemia, normokalemia, and increased tubular reabsorption of potassium do not typically occur in the context of acute kidney injury. Instead, the impairment in kidney function and filtration leads more commonly to an accumulation of potassium in the bloodstream, making hyperkalemia the expected outcome.