Mimicking aneurysm in a patient with chronic occlusion of the left middle cerebral artery

Abstract

The chronic occlusion of intracranial arteries generally has no or mild clinical symptoms, and the clinical symptoms of acute cerebral artery occlusion are mostly manifested as severe cerebral infarction symptoms, which often make early diagnosis difficult, thus losing the best treatment opportunity. Once cerebral infarction occurs, the consequences are difficult to recover. This is also an important reason for the high misdiagnosis rate and mortality of this disease. In this paper, the characteristics of the disease were analyzed to provide clinical reference.

Key Words: Chronic occlusion; Misdiagnose; Arterial occlusion; Middle cerebral artery occlusion; Aneurysm

Core Tip: The chronic occlusion of intracranial arteries generally has no or mild clinical symptoms, and the clinical symptoms of acute cerebral artery occlusion are mostly manifested as severe cerebral infarction symptoms, which often make early diagnosis difficult, thus losing the best treatment opportunity. Once cerebral infarction occurs, the consequences are difficult to recover.

INTRODUCTION

Intracranial artery occlusion is one of the main causes of ischemic stroke, and the occlusion time of more than 4 weeks is generally considered to be chronic intracranial artery occlusion[1,2]. Studies have found that about 1.5% to 3.0% of ischemic stroke patients have chronic intracranial artery occlusion[3]. Intracranial artery occlusion can cause external carotid artery, internal carotid artery and/or vertebral artery-subclavian artery to steal blood, which is the main factor causing acute cerebral infarction, and is closely related to the collateral circulation and disease development of patients[4]. Chronic intracranial artery occlusion is more common in the elderly and men, about 70% of which is caused by atherosclerosis[5]. There are also reports of chronic occlusion of arteries due to craniocerebral trauma, which is also one of the important complications worthy of clinical attention.

MECHANISM OF CHRONIC INTERNAL CAROTID ARTERY OCCLUSION

The chronic occlusion of intracranial arteries is mainly caused by distal thromboembolism and hemodynamic disorders[6-8]. The clinical manifestations of chronic internal carotid artery occlusion vary greatly, and many of them are asymptomatic. Due to chronic occlusion, the intracranial blood vessels can be compensated, and the symptoms are not obvious, which can be found during perfect examination. The symptoms of such patients are mild and the prognosis is reasonable. If the acute occlusion or the failure to form a compensatory vessel in time, it can lead to obvious symptoms and even life-threatening.

EXAMINATION OF CHRONIC INTERNAL CAROTID ARTERY OCCLUSION

Vascular examination mainly includes ultrasound examination, magnetic resonance angiography, computerized tomography angiography, and digital subtraction angiography (DSA)[9,10]. Since the late 1980s, transcranial doppler ultrasound (TCD) has been used in the clinic, and with the introduction of new devices that can detect blood flow in intracranial arteries, TCD has become widely used in the clinic. TCD is simple, rapid, non-invasive, reproducible and practical, and is widely used in diagnosing intracranial artery stenosis and judging the establishment of collateral circulation[11]. But TCD also has drawbacks, it cannot directly reflect the situation of the inner wall of the blood vessel, only through the blood flow velocity of the sampling point, indirectly reflect the situation of the inner wall of the blood vessel. However, the blood flow velocity itself is also affected by many physiological factors[12], and the level of operator also has an impact on the result. Therefore, TCD has some limitations in the diagnosis of intracranial artery stenosis.

At present, DSA is the gold standard for the diagnosis of ischemic cerebrovascular diseases, especially in recent years, the application of DSA three-dimensional reconstruction technology and simulated vascular endoscopy function can observe the degree of stenosis in the narrow vascular lumen, the location and shape of plaque, and judge the shape of the occlusion stump, the length of the occlusion vessel, distal reflux and compensation. However, it also has certain defects, such as complicated operation, high cost, and invasive examination, which may cause severe complications such as cerebral artery spasm and plaque detachment during intubation or contrast agent injection. Moreover, for severe stenosis and occlusion of blood vessels, the remote situation cannot be shown[13-15].

The accuracy of computerized tomography angiography is second only to DSA, and it is better than DSA in judging the shape of occlusion vessels, and can clearly show the occlusion length and first-order compensation, which is also widely used in clinical practice at present[9]. Although magnetic resonance angiography is a non-invasive examination, its sensitivity and specificity for intracranial arteriole occlusion are not high, and it is expensive, so it cannot be tested frequently.

TREATMENT OF CHRONIC INTERNAL CAROTID ARTERY OCCLUSION

At present, there is no unified treatment standard for chronic internal carotid artery occlusion at home and abroad. The treatment of chronic internal carotid artery occlusion includes[9]: (1) Drug therapy: Anti-platelet aggregation therapy is currently the basic treatment for ischemic cerebral vessels; (2) Intracranial and external bypass: For patients with chronic internal carotid artery occlusion who are ineffective in drug therapy and have obvious hemodynamic disorders, intracranial and external bypass therapy can be tried, but the effect is not exact; and (3) Vascular recalibration treatment: The opening of chronic intracranial artery occlusion helps to improve the blood supply to the brain of patients and prevent the occurrence of stroke. However, recanalization of cerebral vascular occlusion has many risks, such as intraoperative embolization, vascular dissection, vascular rupture, and hyperperfusion syndrome. Therefore, occlusive recanalization requires strict preoperative evaluation and strict surgical indications[16,17].

CONCLUSION

Intracranial artery occlusion is one of the main causes of ischemic stroke, because once cerebral infarction occurs, the consequences are difficult to recover. Attention should be paid to the chronic occlusion of intracranial arteries. Pay attention to prevention, improve inspection and exclusion in time to prevent missed diagnosis leading to adverse consequences.