Initial cause of metabolic alkalosis is _______.

• A. Increased bicarbonate retention
• B. Increased chloride loss
• C. Loss of hydrogen
• D. Vomiting

Answer: (C)

Metabolic alkalosis starts with a loss of hydrogen ions from the body. When H+ is reduced, the pH rises because there is less acidity in the body fluids. This directly creates an alkaline state, and bicarbonate begins to appear relatively higher in the system. Gastric losses of acid, such as vomiting or gastric suction, are classic ways this hydrogen loss occurs in practice.

While vomiting is a common scenario that leads to hydrogen loss, the fundamental event driving the alkalosis is the reduction of hydrogen ions themselves. Increased bicarbonate retention can happen as the body attempts to balance or compensate, and chloride loss can influence how the alkalosis is expressed or maintained, but they are not the initial disturbance.