What causes alkalosis in patients with bulimia nervosa?

Bulimia nervosa is characterized by cycles of binge eating followed by compensatory behaviors, such as self-induced vomiting. The act of vomiting leads to a significant loss of gastric acid, which is rich in hydrogen ions. When there is a loss of these hydrogen ions, the body's overall acidity decreases, leading to an increase in blood pH. This condition is known as metabolic alkalosis.

In patients with bulimia nervosa, the self-induced vomiting causes a specific disruption in the body's acid-base balance, resulting in alkalosis. This can lead to various physiological effects, including muscle cramping, confusion, and cardiac complications if not addressed.

The other choices do not directly contribute to alkalosis in the same manner. Excessive carbohydrate intake typically affects glucose levels and insulin response rather than acid-base balance. Excessive alcohol consumption can lead to metabolic acidosis rather than alkalosis due to its effects on the liver and its potential to disrupt normal acid-base regulation. Low sodium intake can result in hyponatremia but does not specifically cause alkalosis. Thus, self-induced vomiting is the primary mechanism through which alkalosis occurs in bulimia nervosa.