Hyperkalemia also inhibits the renal tubule cell's ability to excrete acid by inhibiting ammoniagenesis. I looked up the paper since I can already hear the naysayers 😉: Tannen RL: Relationship of renal ammonia production and potassium homeostasis. Kidney Int 1977; 11:453465.
You might remember that ammonia is generated by the kidney to trap H+ ions in the lumen of the tubule (NH3 + H+ --> NH4+). Ammonium ions (NH4+) are charged and can't diffuse back into the bloodstream, thus they get excreted with urine. This is one mechanism of how the body gets rid of excess acid. If you inhibit the ability to get rid of excess acid, you develop an acidosis. Whenever there is an acidosis, you have an excess of positive charge (H+). The body compensates with accumulation of anions so you remain net-neutral (in anion-gap, you accumulate lactate/salicylate/etc. For non anion-gap situations like hyperkalemia, the kidney holds on to chloride to even out the charge imbalance --> hyperchloremic acidosis).
As already mentioned, acidosis will tend to worsen hyperkalemia through ion exchange effects. Thus it's a vicious cycle! Hyperkalemia begets acidosis which begets more hyperkalemia.
