Many of you will be unfamiliar with the term “smog”. Most people think of “smog” as a disease caused by smoking or inhaling other harmful gases, which can cause damage to the body. In fact, “smog” is a cerebrovascular disease, due to the chronic progressive stenosis or even occlusion of large blood vessels at the base of the brain, and the growth of many abnormal blood vessels into a network, especially in the cerebral angiography of the patient’s brain shows many dense piles of small blood vessels resembling the smoke exhaled by smoking and so named. In layman’s terms, the disease can be compared to a farming field: If the brain is compared to a farm, the areas of the brain that are in charge of various functions are the crops. The cerebral blood vessels are the channels used to water the crops. Under normal circumstances, the blood vessels are clear and the crops (functional areas) grow well. However, if the irrigation channels are blocked, the brain will be in a drought, and the crops will be dehydrated, gradually withering and yellowing (cerebral ischemia), and in severe cases, even dying (cerebral infarction). But our brain is very smart, if the main channel is blocked, it will automatically open up some small channels (blood vessels) to ensure blood supply. These small vessels are so thin and dense that they will appear as smoke on angiography. In general, the symptoms of smog usually start with dizziness and weakness, and will return to normal after the attack, so it is easy to be ignored or misdiagnosed, which affects the treatment. A girl in Shandong started to have long-lasting crying from the age of two or three years old that easily led to numbness and weakness of the left limb for many days, but the family did not pay attention to it. It was not until three or four years later that the girl was diagnosed with smog when she suddenly developed purple lips, walked crookedly, fell, and could not walk after being picked up. The clinical manifestations of patients with smog are complex and varied, including cognitive dysfunction, epilepsy, inability to move at will, or headaches, the most common of which are cerebral ischemia and cerebral hemorrhage. Pediatric patients present primarily with cerebral ischemia, while adult patients have a 50/50 split between cerebral hemorrhage and cerebral ischemia. If not actively treated, it may cause mental retardation, cerebrovascular blockage, cerebral infarction, hemiplegia, coma, etc. in pediatric patients; although adult patients are not involved in intellectual development, repeated onset may also impair neurological functions, leading to memory, intellectual decline, etc., and finally loss of normal social abilities, or lead to cerebral hemorrhage, which is serious and life-threatening. Whether it is a child or an adult, if you have symptoms of prolonged dizziness, headache, memory, mental decline, or weakness, you must pay attention to them and go to the hospital for examination in time, because it is very likely to be caused by “smog”.