Potassium homeostasis and transcellular shift

What it is

Potassium is an intracellular electrolyte, and that one fact explains most of what it does. It is highly influenced by physiological factors:

• Insulin
• pH
• Catecholamines

The main endocrine controlling force is RAAS. The symptomology of potassium is cardiac and neuromascular, so muscle weakness and lethargy belong to it.

How it is treated

The most important initial treatment to lower a high serum potassium is insulin-dextrose. Insulin shifts potassium into cells by stimulating the activity of the Na+-H+ antiporter on the cell membrane, promoting the entry of sodium into cells, which leads to activation of the Na+-K+ ATPase, causing an electrogenic influx of potassium.

IV bicarbonate, oral resonium and IV calcium gluconate are not the most important initial treatment to lower the serum potassium level. A potassium of 6.8 mmol/L with muscle weakness and lethargy is the kind of level at which this question is asked.