Hand, foot and mouth disease, a disease caused by a virus. There are more than a dozen viruses that can cause this disease. Most patients are mild cases and can recover spontaneously. There is no specific drug treatment. The focus is on intensive care and symptomatic treatment. However, heavy patients progress very quickly and require high priority and timely resuscitation. Therefore, close observation is important, because in heavy cases, the process of changing from mild to severe is very rapid and can be described as a rapid decline, with no time or opportunity for resuscitation, so the mortality rate in heavy cases is very high. The following points indicate that the child is in critical condition: 1. persistent high fever that does not subside; 2. poor mental status, trembling limbs, unstable standing; 3. poor breathing, such as poor respiratory rhythm, sighing, etc.; 4. poor circulation, such as poor facial color, cold limbs, dark skin color, etc.; 5. increased laboratory white blood cells significantly; 6. increased laboratory blood glucose, etc.