For those already on insulin therapy, DKA risk is highest during times of acute physical stress or serious illness. Insulin is not present or is in short supply relative to an excess of counter regulatory hormones driven by significant stress or illness. Glucose levels rise in blood, but cells are unable to access it as fuel. Liver cells break down protein and glycogen, converting both into glucose. More glucose is released into the blood.
Fat cells release fats into blood as alternative fuel.
Muscle cells utilize fat as their primary fuel source, creating an abundance of its waste product, ketones. Ketone levels rise in the blood. They are acidic and change the acid-base chemical balance of the blood. Lungs try to neutralize acid by the changing respiration rate and gas exchange. Sodium, potassium and phosphorus shifts occur in cells.