The treatment of smoker’s disease has no very satisfactory method at home and abroad because the cause of its pathogenesis is unknown. Internal medicine is based on symptomatic treatment with vasodilators and antimicrobials, but the efficacy is not satisfactory. Although more than 10 surgical procedures have been developed since the discovery of smog in Japan in 1961, the core of these procedures is to divert the external carotid artery into the skull. The former is more difficult because of the thin diameter of the middle cerebral artery in smog patients, especially in children, and the need to temporarily block the middle cerebral artery during surgery may further aggravate cerebral ischemia. Therefore, most scholars use the EDAS indirect anastomosis method invented by Japanese scholar Mr. Yoshiharu Matsushima in 1979, in which the extracranial vessels are led across the skull and dural barrier into the skull to promote the blood supply to the cerebral cortex. Current status of treatment of smog disease There is no doubt about the surgical treatment of smog disease in Japan, Europe, America and Korea. Since the late 1970s, under the guidance of the famous neurosurgeon Prof. Duan Guosheng, the neurosurgery department of our hospital has treated more than 100 cases of smog disease and other cerebral ischemic vascular diseases by using temporal muscle patching, intracranial transplantation of large omentum and direct anastomosis of intracranial and external vessels, and has accumulated a lot of treatment experience. He also won the Army Medical Achievement Award. So far, the neurosurgery department of PLA 307 Hospital has adopted the new method to treat more than 1000 cases of smog disease with satisfactory results. Prof. Gao Shan talks about the main reasons for misdiagnosis of smog disease Smog disease is easily missed or misdiagnosed in clinical practice. We summarized 54 cases of smog disease in Peking Union Medical College Hospital from 1991 to 2004, and found that most of the patients experienced a long period of time from the appearance of clinical symptoms to the diagnosis, which took two and a half years on average. Most patients were diagnosed with simple symptoms before diagnosis, and a few had been misdiagnosed as encephalitis, mitochondrial myoencephalopathy, and gray matter heterotopia. There are several reasons why patients with smog are underdiagnosed or misdiagnosed: 1. The clinical symptoms of smog are complex and variable Some symptoms of smog, such as episodic limb numbness and weakness or paralysis of one limb, are easily thought of as vascular disease, but certain symptoms are difficult to think of directly in relation to vascular lesions, such as blurred vision, headache, dizziness and vertigo, episodic disorders of consciousness, limb twitching or mental retardation, etc. Therefore, if clinicians are Smoker’s disease lacks sufficient knowledge and does not arrange corresponding examinations related to cerebral arterial lesions for patients, such as transcranial Doppler ultrasound (TCD), magnetic angiography (MRA) and digital subtraction angiography (DSA), etc., it will lead to missed diagnosis. Many patients and even many doctors mistakenly believe that there is no problem as long as the head CT or MRI is normal, but this is actually not true for the diagnosis of smog. The first lesions in smoker’s disease occur in the arterial ring at the base of the brain, and the arteries do not develop from stenosis to occlusion in a short period of time, but usually over a long period of time, from a few years to several decades. In addition, without experience or careful observation, clinicians may overlook the sparse vascularity of the large arteries at the base of the skull and the increase in vascular flow space at the base of the brain as shown on the T2 phase. Some physicians have repeatedly performed cranial CT and cranial MRI examinations on patients, but have not examined the cerebral arteries once, resulting in patients with milder symptoms of smog being undiagnosed for a long time. 3. Some patients with cranial MRI changes are easily confused with other diseases. After the gradual occlusion of the skull base arteries in patients with smog, it leads to the formation of extensive intracranial and extracranial and cortical side branches, which causes changes in the blood supply range of the major cerebral arteries, therefore, the foci of cerebral infarction in some patients do not match the distribution range of cerebral arteries and are easily confused with encephalitis or mitochondrial myoencephalopathy. Such patients also often have many head MRIs but have not been examined for cerebral arteries. 4. Adult ischemic symptoms can be easily labeled as cerebral atherosclerosis and cerebral thrombosis without looking for the cause of stroke. After summarizing their patients with smog, Prof. Duan et al. first suggested that the incidence of smog in China was different from that reported abroad, and found that there were more adult smog patients than children. The incidence of smog in the 54 cases we summarized was consistent with the findings of Prof. Duan et al. and was also higher in adults than in children. Therefore, even adults with ischemic symptoms should be examined for cerebral arterial lesions, and some of these patients may not have atherosclerosis but smog disease. The common causes of clinical misdiagnosis or underdiagnosis of smog disease are mentioned above. From our practice, we have found that, while it is important to recognize the complex clinical phases of smog disease, performing noninvasive screening for cerebral artery lesions is even more decisive for the detection and diagnosis of smog disease. Because cranial CT does not provide information directly relevant to the diagnosis of smoldering disease except for the detection of hemorrhagic or infarcted lesions, cranial MRI may provide valuable information such as abnormal basal vascular flow space shadowing, but in many cases only suggests ischemic or hemorrhagic lesions. The best way to diagnose smog disease is to visualize the arteries with DSA and MRA, but for screening smog disease, non-invasive and inexpensive TCD is preferred. TCD is a non-invasive method for screening cerebral artery stenosis and occlusion. The Department of Neurology at Peking Union Medical College Hospital has been using TCD as a routine screening method for cerebral artery stenosis or occlusion in outpatients and wards since 1991. In many years of clinical practice, many patients with clinically suspicious or unanticipated smoldering disease have been screened, many of whom would not undergo invasive DSA or expensive MRA directly based on clinical presentation alone. In other words, TCD can screen out many patients with mild symptoms or atypical clinical symptoms. Therefore, TCD should be used as a routine screening method for cerebral artery stenosis and occlusion in neurology outpatient clinics and wards, and only in this way can more patients with smog disease be diagnosed in a timely manner at the early stage of symptoms and possibly receive appropriate treatment before serious cerebral thrombosis or cerebral hemorrhage occurs.