A patient with untreated diabetes mellitus is admitted to the hospital for treatment. Laboratory findings include a blood pH below 7.2. Which of the following is likely to directly result from this level of acidemia?

Question

Quizplus · Accepted Answer

Acidemia can cause hyperkalemia because hydrogen ions enter cells in exchange for potassium ions, leading to an increase in serum potassium levels.  Acidemia is the presence of excess H+ ions in blood, which tends to create a rise in the extracellular potassium concentration. The rule of thumb for an inorganic acid that causes the acidity is that a decrease in pH of 0.1 unit leads to a rise in plasma potassium of 0.6 mEq/L. The effect of an organic acid is a lot less. The mechanism responsible for the relationship between pH and extracellular potassium concentration is not completely understood. One effect is that the intracellular acidosis inhibits K+ influx by reducing the activity of the Na+-K+-pump. An exchange of extracellular H+ for intracellular K+ might also contribute.

A Patient with Untreated Diabetes Mellitus Is Admitted to the Hospital