The first consideration in this case is pre-infection, when the body temperature does not necessarily rise, patients should pay attention to monitoring temperature changes, if there is a fever, you can promptly go to the hospital to improve the blood routine, chest X-ray and other tests. If the fever does not persist, further tests such as thyroid function, blood glucose, routine blood tests and vascular ultrasound are needed to rule out hypoglycaemia, hypothyroidism, anaemia and peripheral vascular disease, which may also cause chills.