What primary mechanism contributes to metabolic acidosis?

The primary mechanism that contributes to metabolic acidosis is bicarbonate deficiency. In metabolic acidosis, there is a decrease in bicarbonate ions in the bloodstream, which are crucial for maintaining the pH balance of the body. Bicarbonate acts as a buffer, helping to neutralize acids. When bicarbonate levels fall, the balance between acids and bases is disrupted, leading to a more acidic environment in the body.

This condition can arise from various processes, including increased production of non-volatile acids (like lactic acid or ketoacids), loss of bicarbonate (often through the kidneys or gastrointestinal tract), or decreased renal excretion of acids. The result is a net deficit of bicarbonate, which is the hallmark of metabolic acidosis.

In contrast, excessive retention of dissolved CO2 would lead to respiratory acidosis, not metabolic acidosis, as it indicates a shift in respiratory function rather than a direct deficit of bicarbonate. Accumulation of volatile acids pertains more to respiratory regulation and would not define a state of metabolic acidosis, which is characterized by a non-volatile acid excess. Hyperaldosteronism involves hormonal imbalances that can affect electrolyte levels and acid-base status but is not a direct cause of metabolic acidosis. Thus