PAEA Surgery End Of Rotation (EOR) Practice Exam

What causes increased urine production at night in geriatric patients?

1. Increased fluid intake

2. Decreased renal blood flow

3. Intravascular volume increases

4. Medications

The correct answer is: Intravascular volume increases

In geriatric patients, increased urine production at night, known as nocturia, can often be attributed to changes in intravascular volume. As people age, various physiological changes occur, including alterations in fluid regulation and kidney function. In particular, older adults may experience decreased renin and aldosterone responses, leading to impaired sodium retention and increased diuresis at night. When lying down, as is common during nighttime, fluid that may have been previously sequestered in the lower extremities due to gravity can redistribute into the circulation. This phenomenon increases intravascular volume, leading to enhanced kidney perfusion and, subsequently, increased urine production. Additionally, the aging process can affect the ability of the kidneys to concentrate urine, further contributing to nocturia. In contrast, an increased fluid intake primarily indicates that patients would have more urine production throughout the day rather than specifically at night. Decreased renal blood flow would generally result in reduced urine production, and while some medications can affect diuresis, they are not the primary physiological cause of nocturia in geriatric patients when considering the role of intravascular volume changes. Thus, understanding how shifts in fluid balance directly contribute to nocturia is crucial in geriatric care and managing patient symptoms