Typically, the cell's mitochondria break down glucose to make energy. When there is no insulin, glucose can't enter the cell. The cell still needs energy, so it uses fatty acids, which can enter the cell, as a replacement for glucose, which can't enter the cell. The byproducts of fat catabolism are ketone acids. These acids have a hydroxyl group. The acids donate the hydrogen from their hydroxyl groups. Bicarbonate picks up the hydrogen. This results in an anion gap acidosis. Due to the acidosis, H-K exchangers pump H into the cells and K into the blood. This leads to an initial hyperkalemia. Blood sugar is increased past the point that the kidneys can reabsorb it. As a result, sugar leaves through the urine. The sugar draws water along with it, resulting in dehydration. Due to the dehydration, the kidneys attempt to reabsorb water using the Na-K exchanger. They secrete K into the urine and reabsorb sodium in an attempt to maintain volume. The result is K depletion. So, your serum K is high while your body K is depleted. The dehydration also leads to increased Creatinine due to renal failure. Treat with insulin + fluids.