Smoker’s disease, also known as anomalous vascular network at the base of the brain, is a group of cerebrovascular diseases characterized by narrowing or occlusion of the siphon of the internal carotid artery and the beginning of the anterior and middle cerebral arteries, and the presence of anomalous small vascular network at the base of the brain. It is called smoky disease because the cerebral angiogram shows many dense piles of small blood vessels, resembling the smoke exhaled during smoking.
Causes
Some scholars have found that individual families with mothers and sons or siblings can have similar disease, which is considered to be related to congenital factors. However, based on clinical, pathological, immunological and laboratory studies, most scholars believe that this is a group of occlusive cerebrovascular diseases that occur later in life and may be related to metaplastic cerebrovascular inflammation; therefore, it cannot be concluded that it is a genetic disease, and patients with this disease need not worry too much about their offspring getting the disease.
Clinical manifestations
1.TIA type
It is the most common, and is seen in about 70% of all idiopathic smoker’s disease. It is characterized by recurrent transient paralysis or weakness, mostly hemiparesis, or alternating right and left hemiparesis or double hemiparesis. There is complete recovery of motor function after an attack. The course of the disease is mostly benign, with a tendency to spontaneous remission or complete cessation of attacks. Very few cases are associated with hemiplegic attacks, headache or migraine. Rarely, there is transient sensory impairment, involuntary movement or mental retardation.
2. Infarct type
Acute stroke resulting in permanent type of paralysis, aphasia, visual impairment and mental retardation.
3.Epileptic type
Frequent seizures, partial seizures or continuous status epilepticus with EEG epileptiform discharges.
4.Hemorrhagic type
Subarachnoid hemorrhage or brain parenchymal hemorrhage, seen in older children and adult cases.
The last three types of the above clinical typing are called “non-TIA type”, which has a complex and variable course and a poor prognosis, and mostly manifests as a mixed type, such as epileptic type plus infarct type, epileptic type plus TIA type. In case of simple seizures, the prognosis is not necessarily poor. Regardless of the type, the prognosis is worse in those with onset before the age of 4 years. In addition, the clinical symptoms and their severity are determined by the compensatory effect of the collateral circulation. If adequate cerebral perfusion is maintained, there may be no clinical symptoms, or only transient TIA seizures, or headaches. If cerebral perfusion is not maintained, the symptoms are severe and cause extensive brain damage.
Examination
1. Physical examination
Presence of fundus edema, limb paralysis, aphasia and meningeal irritation signs.
2.Laboratory examination
(1) General laboratory tests are mostly non-specific. General laboratory tests include routine blood count, blood sedimentation, anti-“O”, C-reactive protein, mucin determination, tuberculin test and serum leptospira coagulation test, etc. Most patients have a white blood cell count below 10×109/L; blood sedimentation may be slightly high, but most are normal; anti- “If the patient is caused by tuberculous meningitis, the tuberculin skin test may be strongly positive; if the patient is caused by leptospirosis, the serum leptospirosis coagulation test may be positive.
(2) Cerebrospinal fluid examination laboratory examination of cerebrospinal fluid is similar to other cerebrovascular diseases, children are mostly ischemic manifestations, cerebrospinal fluid examination is generally normal, lumbar puncture pressure can also be normal, if there is tuberculous meningitis, the patient’s cerebrospinal fluid shows tuberculous meningitis reaction, that is, cerebrospinal fluid cell count increased, sugar and chloride decreased, protein increased, if caused by leptospirosis, the patient’s cerebrospinal fluid leptospirosis immunoreactivity If rupture bleeding, lumbar cerebrospinal fluid examination can appear bloody cerebrospinal fluid or blood clots in cerebrospinal fluid, if bleeding after 24h lumbar cerebrospinal fluid is red, cerebrospinal fluid can be seen in uniform red cells, after 24h cerebrospinal fluid is brown or yellow, yellow disappears after 1 to 3 weeks, cerebrospinal fluid leukocytes are elevated, early neutrophilia, later lymphocytosis is predominant, this is The protein content can also be increased, usually around 1g/L, and the cerebrospinal fluid pressure is mostly in the range of 1.57-2.35kPa.
3.Imaging examination
(1) There is generally no specific change in EEG. Both patients with hemorrhage and patients with infarction have more or less the same EEG performance, which shows an increase in slow waves on the side or both sides of the lesion and extensive moderate to severe rhythm dysregulation, and can be divided into 3 types according to the different waveforms generated by the abnormal computer map and different locations.
①Posterior cerebral hemisphere type is dominated by high-amplitude one-way paroxysmal or non-paroxysmal delta waves, confined to the posterior cerebral hemisphere, with the ischemic side predominating.
The middle temporal gyrus type is dominated by moderate-to-high amplitude, sustained δ and theta waves, confined to the middle temporal lobe, and also dominated by the ischemic side.
The mechanism of slow waves induced by hyperventilation may be related to the dynamic changes of blood supply to brain tissue and the pH changes of arterial blood in the brain.
(2) Cerebral angiography (DSA) Cerebral angiography is the main means to confirm the diagnosis of this disease, and its cerebral angiographic manifestations are characterized by.
(1) Severe stenosis or occlusion of the superior segment of the bed process of the internal carotid artery and the anterior and middle cerebral arteries proximally on both sides, with stenosis or occlusion of the siphon of the internal carotid artery in the carotid 1 segment being the most common, almost 100%, extending to the carotid 2 segment in 50% of cases, and extending to the carotid 3 and 4 segments in a few patients, while the distal vessels of the occluded segment have normal morphology, and the cerebral angiographic manifestations are basically the same on both sides, but not completely symmetrical on both sides, and in a few cases only on one side The above vascular abnormalities usually start on one side and later develop into bilateral, involving first the anterior half of Willis’ ring and later the posterior half, until the whole arterial ring is occluded, resulting in occlusion of most of the basal penetrating arteries in the basal ganglia, thalamus, hypothalamus and brainstem, forming an abnormal vascular compensatory collateral circulation at the base of the brain.
(ii) There is a significant capillary dilatation network at the basal ganglia, i.e., a collateral circulation centered on the internal and external striatal arteries and thalamic arteries, thalamic geniculate arteries, and anterior and posterior choroidal arteries.
There is an extensive and abundant formation of collateral circulation, including the establishment of intracranial and extracranial anastomoses. There are three types of collateral circulation pathways: when the siphon end of the internal carotid artery is occluded, the collateral circulation is formed through the anastomosis between the posterior cerebral artery and the terminal branches of the anterior and middle cerebral arteries. The undamaged arterial ring and all branches of the siphon are involved in the blood supply to the basal ganglia, forming a collateral circulation to supply the branches of the anterior and middle cerebral arteries, thus, the formation of a very rich anomalous vascular network in the basal ganglia is the most important collateral circulation pathway in this disease. The anastomosis between the branches of the external carotid artery and the soft meningeal vessels on the surface of the brain forms a network.
(3) CT scan Smoke disease may appear in CT scan alone or in combination with the following manifestations.
(1) Multiple cerebral infarcts which are due to repeated occlusion of blood vessels in different parts of the brain. Multiple cerebral infarcts can be old or recent, and there can be foci of cerebral softening of varying sizes.
Secondary cerebral atrophy is mostly limited cerebral atrophy, which is directly related to the extent of occlusion of the internal carotid artery, and the more severe the narrowing of the internal carotid artery, the worse the blood supply, the more obvious the cerebral atrophy is, while in those with good collateral circulation, there is no cerebral atrophy on CT, and cerebral atrophy occurs in the temporal lobe, frontal lobe and occipital lobe, peaks in 2-4 weeks, and gradually improves later, and the reason for its improvement may be related to the establishment of collateral circulation. The reason for its improvement may be related to the establishment of collateral circulation.
The enlarged ventricle is ipsilateral to the lesion or bilateral, and ventricular enlargement often coexists with cerebral atrophy. the circulation of cerebrospinal fluid.
Intracranial hemorrhage can occur in 61.6%-77.3% of patients with smog, with subarachnoid hemorrhage being the most common, accounting for about 60%, and intraventricular hemorrhage is also more common, accounting for 28.6%-60%, mostly combined with subarachnoid hemorrhage, of which 30% of intraventricular hemorrhage is primary intraventricular hemorrhage, which is caused by the rupture of the thin abnormal vascular network, and intracerebral hematoma is common in the frontal lobe, with irregular shape and inconsistent size. The intracerebral hematoma is more common in the frontal lobe, irregular in shape and size, and may rupture and bleed into the ventricles if adjacent to the ventricles, or form a subarachnoid hemorrhage if adjacent to the brain pool.
⑤ Intensified CT scan shows thinning of blood vessels near the basilar artery ring with poor or no visualization, and dotted or arcuate reinforced abnormal vascular masses with irregular distribution are seen in the basal ganglia area and around the ventricles.
(6) CTA can see the same performance as cerebral angiography (DSA), which can confirm the diagnosis of smog disease.
(4) MRI magnetic resonance can show the following pathomorphological changes in smog disease.
(1) Both old and recent cerebral infarcts show long T1 and long T2, and cerebral softening foci also show long T1 and long T2, with hypointense signal on T1-weighted images and high signal on T2-weighted images.
(ii) Intracranial hemorrhage showed high signal in all imaging sequences.
(③Limited brain atrophy is most evident in the base of frontal lobe and temporal lobe.
MRA has a similar effect to CTA, but not as effective as CTA for smoke-like changes after obstruction. It can be used as an adjunctive test.
Diagnosis
The internationally accepted criteria for the diagnosis of smog are those established by the Japanese Society for the Study of Smog in 1997: the cause is unknown and the DSA or MRA findings are consistent with progressive stenosis and/or occlusion of the end of the internal carotid artery and the beginning of the anterior and middle cerebral arteries; the arterial phase shows an abnormal smog-like vascular network; the lesion is bilateral; and the following diseases should be excluded: atherosclerosis, autoimmune diseases, meningitis, brain tumors, Down syndrome, traumatic brain injury, radiation head exposure, and hyperthyroidism; possible smoldering disease, i.e., unilateral lesions in children or adults, also need to be excluded.
Imaging is currently the main means of diagnosing smog, and the domestic application of transcranial Doppler ultrasound (TCD) has screened many patients with clinically suspicious or unanticipated smog. TCD is able to detect more adult smog patients with ischemic and presenting clinical symptoms of atypical vascular disease, and in terms of confirming the diagnosis, digital subtraction angiography (DSA) is still the most accurate and reliable diagnostic method, and CTA is also CTA is also one of the main tools for confirming the diagnosis, and magnetic resonance imaging/Magnetic Resonance Angiography (MRI/MRA) can provide a definitive diagnosis for most patients with smog.
Treatment
1.Medical treatment
Patients with infarcts are generally treated as thrombosis. Treatment with volume expansion, vasodilators, calcium antagonists, etc. is available, and hormone therapy is also possible. For ischemia, vasodilators are used; for hemorrhage, lowering cranial pressure and stopping hemorrhage are the main treatments. If the cause is clear, the cause should be treated actively.
2.Surgical treatment
It has been reported in domestic and foreign literature that smog can be treated by intracranial and extracranial vascular anastomosis, cerebrovascular combination surgery and other surgical procedures to reconstruct blood flow and improve prognosis. However, vascular anastomosis can cause new injuries, such as infarction, hemorrhage, etc., and longer observation is needed; ischemic patients can be considered for cervical sympathectomy or intracranial and extracranial arterial anastomosis. If there is intracranial hematoma formation, smoke disease should be promptly excluded.
Prognosis
The prognosis of this disease depends in most cases on the natural progression of the disease, i.e., it is related to the age of onset, the primary cause, the severity of the disease, the degree of brain tissue damage, and other factors. Whether the treatment is timely and appropriate also has a certain impact on the prognosis. The prognosis is generally considered to be good, with a low mortality rate and few sequelae. The mortality rate is 1.5% in pediatric patients and 7.5% in adults. 30% of pediatric patients may be left with mental retardation and adults with intracranial hemorrhage have a high mortality rate, but most of them do not have sequelae if the coma period is passed quickly. From a radiological point of view, the natural course of the disease is usually between one and several years. Once the arterial ring at the base of the brain is completely occluded, the lesion may stop developing when collateral circulation has been established, but the opportunity for hemorrhage and/or ischemia may still occur, sometimes accompanied by aneurysm formation. Overall, the prognosis is still optimistic.