What Are the Most Common Causes of Brain Aneurysm?

Intracranial aneurysm refers to a tumor-like protrusion of the artery wall caused by the abnormal enlargement of the cerebral arterial lumen. Intracranial aneurysms are mostly caused by local congenital defects of the cerebral arterial wall and increased intraluminal pressure, which is the first cause of subarachnoid hemorrhage.

Basic Information

English name

cerebral aneurysm

Visiting department

neurosurgery

Common locations

Intracranial artery

Common causes

Local congenital defect of cerebral arterial wall, cystic bulge caused by increased intraluminal pressure

Common symptoms

Severe headache, frequent vomiting, sweating, fever; rigid neck, unconsciousness, coma

Causes of cerebral aneurysms

The cause of aneurysms is not very clear. The etiology of aneurysm formation can be summarized as follows: congenital factors; arteriosclerosis; infection; trauma. In addition, there are some rare reasons such as tumors that can cause aneurysms, abnormal vascular network of the skull base, cerebral arteriovenous malformations, intracranial vascular development abnormalities and cerebral artery occlusion can also be accompanied by aneurysms.

Cerebral aneurysm clinical manifestations

Aneurysm rupture bleeding symptoms

Once the aneurysm ruptures and bleeds, the clinical manifestations are severe subarachnoid hemorrhage, the onset is sharp, and the patient has a severe headache, which is described as "the head is about to explode". Frequent vomiting, sweating, body temperature may rise; neck rigidity, positive Kirschner's sign. There may also be disturbances of consciousness and even coma. Some patients have fatigue, emotional excitement and other causes before bleeding, and some have no obvious cause or develop symptoms during sleep.

2. Focal symptoms

Oculomotor nerve palsy is common in internal carotid artery- posterior communication aneurysms and aneurysms of posterior cerebral arteries. It is characterized by drooping unilateral eyelids, dilated pupils, inability to adduct, upper and lower vision, and indirect and indirect light reactions disappear. Sometimes the focal symptoms appear before the subarachnoid hemorrhage, and are considered as a precursor to aneurysm bleeding, such as mild migraine, orbital pain, followed by oculomotor nerve palsy. At this time, the accompanying arachnoid should be alert Inferior cavity bleeding. Aneurysm bleeding in the middle cerebral artery, such as the formation of a hematoma; or cerebral hemorrhage after cerebral aneurysm bleeding in other parts of the aneurysm, patients with hemiplegia, motor or sensory aphasia. A huge aneurysm affects the visual pathway, and patients may have visual field disturbances.

3. Classification

After bleeding from the aneurysm, the condition was mixed. In order to facilitate the judgment of the condition, choose the timing of angiography and surgery, and evaluate the curative effect, Hunt five-level classification is often used internationally:

(1) Grade 1 is asymptomatic or has mild headache and neck stiffness.

(2) The secondary headache is severe, the neck is stiff, and there are no other neurological symptoms except for cerebral palsy such as the oculomotor nerve.

(3) Level 3 mild disturbance of consciousness, restlessness, and mild brain symptoms.

(4) Grade 4 semi-consciousness, hemiplegia, early denervation and autonomic nerve disorders.

(5) Level 5 deep coma, denervation, and endangered status.

Cerebral aneurysm examination

1. Blood routine, ESR and urine routine

Generally, there are no specific changes. In the early stage of aneurysm rupture and bleeding, leukocytes often exceed 10 × 109 / L, and the erythrocyte sedimentation rate usually increases slightly to moderately. The rate of increase is consistent with the increase in the number of white blood cells, and proteinuria may appear in the early stage , Diabetes, severe cases may appear cast urine, proteinuria continues to be short, usually return to normal after a few days.

2. Waist wear

When the aneurysm is not ruptured, the lumbar puncture cerebrospinal fluid examination usually shows no abnormal changes. When the rupture is bleeding, the lumbar puncture is the direct evidence for diagnosis of subarachnoid hemorrhage after aneurysm rupture.

3. Cerebrospinal fluid biochemical examination

Most sugars and chlorides are normal, and the protein is increased. This is due to the release of a large amount of hemoglobin after hemolysis of red blood cells and the exudation reaction after bleeding. It is usually about 1 g / L. Some people think that every 10,000 red blood cells in cerebrospinal fluid can increase 150 mg / The protein of L generally increases the largest in 8 to 10 days after bleeding, and then gradually decreases. In addition, attention should be paid to distinguish bloody cerebrospinal fluid caused by lumbar puncture injury. Generally, the upper layer of liquid after centrifugation does not have red. Or yellow change, no positive reaction to benzidine.

4.CT inspection

Although it is not as good as cerebral angiography in determining the existence, size or location of aneurysms, it is safe, rapid, painless for patients, does not affect intracranial pressure, can be used at any time, and can be repeatedly followed up for observation.

5.MRI examination

6. Somatosensory evoked potential examination

Somatosensory evoked potentials can be recorded when the median nerve is stimulated, and subarachnoid hemorrhage and clinical symptoms in patients with intracranial aneurysms.

7. Doppler ultrasound

Preoperative blood supply to the common carotid artery, internal carotid artery, external carotid artery, and vertebrobasilar artery, and blood flow direction and blood flow after ligation of these arteries or after anastomosis of internal and external cranial arteries can be estimated.

8. Cerebral angiography

It was finally determined that the diagnosis relied on cerebral angiography. Patients with subarachnoid hemorrhage, spontaneous III-IV cerebral palsy, or posterior cerebral neurological disorder should be examined by cerebral angiography.

Cerebral aneurysm diagnosis

Diagnosis is based on etiology, clinical manifestations, laboratory and imaging examinations.

Cerebral aneurysm treatment

1. Non-surgical treatment of intracranial aneurysms

The main purpose is to prevent rebleeding and control arterial spasm. It is suitable for the following situations: the patient's condition is not suitable for surgery or the general condition cannot tolerate craniotomy; the diagnosis is not clear and further examination is needed; the patient refuses surgery or fails; As an adjuvant treatment before and after surgery.

2. Surgical treatment of intracranial aneurysms

Patients with intracranial aneurysms who have subarachnoid hemorrhage should undergo early surgery (clamping the tumor pedicle or embolizing the aneurysm), and take measures to protect the brain (mannitol, barbiturates, etc.) during the operation. At present, aneurysms of the anterior and posterior semicircular aneurysms, aneurysms of the vertebrobasilar arteries, anterior and inferior cerebellar arteries, and posterior inferior cerebellar arterial aneurysms are operated early after subarachnoid hemorrhage. The aneurysm in the first part of the posterior artery is usually waited for its neurological symptoms to improve and stabilize before reoperation.

3. Treatment of special types of aneurysms

(1) Multiple aneurysms are more likely to bleed than a single person, so some people claim that it is better to treat one aneurysm than not to treat it. It is better to treat all aneurysms than only one. In addition, use one incision to treat all arteries Tumors are most beneficial to patients. If the tumors are far apart, staged surgery is required. Staged surgery should first deal with bleeding or bleeding-prone aneurysms. According to a comprehensive analysis of imaging and clinical symptoms, about 96% of bleeding aneurysms can It was identified that multiple aneurysms were treated the same as single aneurysms, and the mortality rate was similar.

(2) About 1/5 of patients with giant aneurysms can only be treated conservatively due to various reasons, and 4/5 can undergo surgical treatment.