There are both physiological and pathological reasons for the increase in white blood cells. Physiological causes are transient increases that can return to normal after a change in environment, such as after strenuous exercise or a full meal, in a hot environment or a cold environment, which can lead to a transient increase in white blood cells. In addition, when inflammation occurs in the body, such as acute gastroenteritis, acute appendicitis, pyelonephritis, lobar pneumonia, purulent tonsillitis, etc., leukocytes may increase significantly. A significant increase in leukocytes can occur during severe trauma or after surgery, or in myocardial infarction. In cases of uremia and diabetic ketoacidosis, a significant increase in leukocytes can occur.