Surreptitious laxative use can lead to which of the following acid-base disturbances?

Surreptitious laxative use often leads to significant fluid and electrolyte imbalances, primarily due to excessive loss of water and electrolytes in the stool. This can result in metabolic disturbances, with metabolic alkalosis being a common phenomenon when laxatives that stimulate bowel movements (like stimulant laxatives) are used excessively. The loss of gastrointestinal fluids can lead to a loss of bicarbonate, while the loss of potassium and other electrolytes can also contribute to various metabolic conditions.

In particular, repeated or chronic use of laxatives can culminate in metabolic acidosis due to the loss of bicarbonate-rich fluids from the gastrointestinal tract. This scenario can also produce a mixed acid-base disturbance, where both metabolic and respiratory components may be affected depending on the underlying physiological responses, such as compensatory hyperventilation or hypoventilation that may occur in reaction to the metabolic imbalances.

Thus, the combined loss of bicarbonate and other electrolytes due to laxative misuse is the basis for the metabolic acidosis or mixed disturbance, making this option the most accurate representation of the physiological outcomes of surreptitious laxative use.