Adult-Gerontology Clinical Nurse Specialist (CNS) Practice Exam

Which of the following is considered a metabolic cause of constipation?

1. Spinal cord lesions

2. Hirschsprung's disease

3. Anorexia nervosa

4. Hypokalemia

The correct answer is: Hypokalemia

Hypokalemia is recognized as a metabolic cause of constipation due to its direct effect on muscle function, including smooth muscle contraction in the gastrointestinal tract. Potassium is essential for maintaining cellular homeostasis and is critical for muscle contractions. Low levels of potassium can lead to decreased muscular activity, which results in slowed intestinal transit time and an increased likelihood of constipation. This is particularly relevant in the context of the colon, where motility can be diminished, leading to difficult bowel movements. In contrast, conditions like spinal cord lesions and Hirschsprung's disease pertain more to structural or neurological factors affecting bowel function rather than metabolic imbalances. Anorexia nervosa involves a range of psychological and nutritional issues, but while it can lead to constipation, the underlying cause is not primarily metabolic in nature, focusing instead on dietary insufficiencies and psychological effects on the body. Thus, hypokalemia stands out as specifically linked to metabolic mechanisms influencing bowel motility.