Aneurysm of cerebral vessels
An aneurysm of cerebral vessels is a limited local expansion of one or several intracerebral vessels, characterized by a rapid progressive increase in size and a tendency to form intraluminal thrombotic layers.
When a person's local enlargement of the venous vessel is noted, accompanied by a violation of the cerebral blood supply and manifested by headache, paresthesia, increased convulsive readiness and impaired motor function, the diagnosis of "arteriovenous aneurysm" is established. Under arteriovenous aneurysm, a local protrusion of the vascular wall of a blood vessel of a spherical or spindle-shaped shape is considered.
Aneurysmal dilatation of the cerebral vessels, which has undergone tearing or stratification of the vessel walls, is the most common cause of the formation of signs of subarachnoid hemorrhage of nontraumatic nature.
Causes of cerebral aneurysms
In a situation where the child has an abnormal structure or position of the vascular wall, an aneurysm of the cerebral vessels develops, which in most cases is combined with other congenital vascular anomalies ( coarctation of the aorta , arteriovenous malformation). Aneurysms of the cerebral vessels of the congenital genesis are characterized by a favorable course and a low risk of developing complications in the form of rupture and stratification of aneurysmal enlargement. There is evidence that the inherent nature of an aneurysm of cerebral vessels is most often due to genetic determination.
The acquired form of an aneurysm of cerebral vessels is most often formed against the background of traumatic damage to the vascular wall, which occurs in severe craniocerebral trauma. In addition, atherosclerotic vascular lesions can provoke the development of aneurysmal dilations of the vascular wall.
In neurological practice, a separate nosological form of cerebral aneurysm called "mycotic" is used, in the basis of its development, the wall of the vessel is infectious with embolic lesions. In addition to direct traumatic effects on the vascular wall, hemodynamic disturbances in the form of systemic arterial hypertension and uneven blood flow are of great importance in the development of aneurysms.
Predisposing factors that do not independently provoke the formation of an aneurysm, but promote the development of hemodynamic intraluminal disorders, include a systematic increase in blood pressure indicators, as well as changes in the vessel wall under the influence of nicotine with prolonged smoking.
The pathogenesis of cerebral aneurysm development develops as a result of underdevelopment or mechanical damage of one or all layers of the vascular wall and is manifested by dystrophic changes, thinning and loss of elasticity of the vascular wall in the affected area. As a result of these changes, conditions are created for local protrusion, which develops under the influence of high blood pressure, and since in the projection of the branching of the vessels the pressure gradient is maximum, this section of the vessel is most often affected.
In spite of the fact that aneurysmal enlargement can be formed practically on any part of the vascular wall, nevertheless the favorite localization of this pathology is the place of vascular bifurcation, that is, the site where larger vessels are divided into small branches.
Currently, there is an increase in the incidence of aneurysm of cerebral vessels, and this trend is explained by the use of progressive accurate imaging techniques, which even at an early stage of the disease can reliably verify the diagnosis.
Symptoms of an aneurysm of cerebral vessels
Depending on the prevalence of certain manifestations, as well as the nature of the progression of the disease, the apoplectic and tumorous variant of the course is divided. A tumor aneurysm of cerebral vessels is characterized by a progressive increase in the size of an aneurysmal expansion, sometimes to a gigantic size. Clinical manifestations in the form of neurological symptoms develop due to the compression effect of aneurysm on certain brain structures. Tumoroid aneurysm of cerebral vessels in almost a hundred percent of cases provokes the development of manifestations of intracranial hypertension.
Aneurysms localized in the cavernous sinus, after reaching large sizes, provoke the development of oculomotor disorders and defeat of the trigeminal nerve with severe pain syndrome and sensitivity disorder. With prolonged course of tumor aneurysm, bone-destructive changes in the skull can be developed, which can be recognized by X-ray examination. It should be borne in mind that with aneurysm localized in the cavernous sinus, it is impossible to develop intracavitary hemorrhage even when they are ruptured, which is explained by their extradural location.
A specific symptom accompanying the course of an aneurysm localized in the projection of the internal carotid artery with localization in its supraclinoid part is the selective lesion of the oculomotor nerve, which manifests itself in the expressed pain syndrome in the projection of the orbital region.
With the localization of an aneurysmal enlargement in the projection of the anterior branch of the cerebral artery, severe psycho-neurological disorders in the form of paresis, speech disturbance and all kinds of sensitivity develop. Localization of an aneurysm in the arteries of the vertebrobasilar segment is manifested in the form of development of dysarthria, dysphagia, nystagmus , ataxia and alternating syndromes. In a situation where the patient is noted for the development of multiple aneurysmal enlargements in cerebral vessels, the specificity of the clinical manifestations depends on where the vascular wall has split.
When the aneurysm ruptures, there is a lightning increase in clinical symptoms, in the structure of which the pronounced pain syndrome prevails, which first has a limited character according to the projection of the location of the aneurysm, and subsequently becomes common. Signs indicative of the development of subarachnoid hemorrhage, as complications of cerebral aneurysm rupture, are nausea and multiple episodes of vomiting, which have no connection with food intake, the appearance of positive meningeal symptoms and stiff neck, a tendency to increase convulsive readiness.
A characteristic "clinical companion" of the rupture of cerebral aneurysms is a disturbance of consciousness of varying degrees of severity from short-term fainting to coma. Many patients before the onset of subarachnoid hemorrhage due to rupture of cerebral aneurysm, feel a prolonged diffuse painful aching syndrome in the head region.
Due to the fact that with the rupture of the vascular wall in the projection of the aneurysm, compensatory spasm of the arteries in the projection of the affected area is observed, conditions for the development of ischemic stroke are created, which is at least 60% of cases. In a situation where the rupture of an aneurysm provokes not a subarachnoid but an intracerebral haemorrhage, focal neurological symptoms, which significantly increase the patient's condition and may lead to a lethal outcome, appear to the forefront as clinical manifestations.
When using various instrumental imaging techniques, in particular angiography, in most cases it is possible to determine not only the size, but also the pathomorphological form of the aneurysm (saccate, lateral, spindle-shaped). The most common pathomorphological variant of an aneurysm is the saccate, which has a rounded shape and a narrow neck, with which it is attached to the main vessel. The lateral version of the aneurysm is visualized as a tumor-like vascular wall swelling, and the fusiform is a local expansion of the vessel.
Any of the pathomorphological variants of an aneurysm equally often causes the rupture and development of an intracerebral or subarachnoid hemorrhage, therefore the fundamental criterion is the determination of the size of an aneurysm rather than the shape. The critical size of the aneurysm is its achievement of 25 mm, which is an absolute indication for surgical intervention. In a situation where a person has contraindications to the use of angiography, as the most reliable method of verifying an aneurysm, computer or magnetic resonance imaging should be used.
In a situation where the patient has all the clinical signs of rupture of cerebral aneurysm, it is necessary to perform an analysis of cerebrospinal fluid for the presence of blood, which is the main diagnostic marker of intracerebral hemorrhage.
Treatment of cerebral aneurysms
If any pathomorphological variant of cerebral aneurysms is detected, the initial task of the attending physician is to determine the tactics of managing the patient and the volume of necessary medical care. The prevailing majority of aneurysm detection cases do not require specific treatment and only need dynamic instrumental observation. However, there are absolute indications for the use of emergency surgical treatment by the method of clipping or embolization, and such conditions include rupture of cerebral aneurysms and development of signs of subarachnoid hemorrhage. In this situation, one of the operational benefits should be applied no later than 72 hours from the moment of the break.
Patients with severe aneurysms of cerebral vessels with signs of deep impairment of consciousness are not subject to surgical treatment, but require a prior medical correction of neurological disorders. And yet, the only effective method of draining the ventricles of the brain with subsequent occlusion of an aneurysmal vessel is surgical, and with massive damage to the brain tissue, the use of micro-spirals instead of clips should be preferred.
Dynamic monitoring of aneurysms of cerebral vessels implies a planned annual passage of instrumental examination, in which there should be no increase in aneurysm parameters. Operative treatment is advisable to recommend to patients in whom an aneurysm is critically large in combination with clinical signs.
Symptomatic conservative treatment involves the use of antiemetics (Cerucal in a daily dose of 30 mg), antihypertensive drugs (Enalapril at a dose of 10 mg), calcium channel blockers (Fenigidine 10 mg per day orally). These drugs are used to alleviate the patient's condition and reduce hemodynamic disorders, but are not a means of treating an aneurysm.
Aneurysm of cerebral vessels
An operative procedure for the removal of an aneurysmal enlargement of the cerebral vascular can be performed only in the conditions of a specialized neurosurgical department. Operative access in this situation is trepanation of the skull, performed under general anesthesia. Direct surgical intervention means performing surgical manipulations in the projection of an aneurysm through a trephination hole in the cranial vault. The method of aneurysm clipping is the imposition of a permanent clip made of a non-magnetic material on the aneurysm neck, thereby stopping the blood flow in its anisle. In a situation where the aneurysm neck can not be reliably identified, the clipping is performed on the vessel before and after the aneurysmal enlargement. In addition, the possibilities of microsurgical techniques allow to completely excise the aneurysm and impose an anastomosis between the vessels. In some situations, the clipping of an aneurysm is combined with the strengthening of the vascular wall with the help of a special medical gauze, but this surgical manual can provoke the development of bleeding in the early postoperative period, which limits its use.
The difference between endovascular embolization, as a microsurgical intervention, is that for its implementation there is no need to introduce the patient into general anesthesia, but only the use of sedatives, since during the manipulation there is a need to evaluate the patient's neurological status. Embolization is carried out by the method of insertion into the altered vessel of the catheter under the mandatory control of angiography followed by the introduction of the micro-spiral into the aneurysm, thereby turning off the altered portion of the vessel from the total blood flow. As for any surgical intervention, there is a specific area of application for embolization: the diameter of the aneurysmal expansion neck, not exceeding 4 mm, subarachnoid hemorrhage in the acute period with severe chronic diseases present in the patient, limiting the use of direct surgical intervention.
The limiting factor with regard to the use of the classical version of endovascular embolization of the aneurysm is the excessive crimp of the vessel, which makes it difficult to insert the catheter. In this situation, neurosurgeons use additional funds in the form of an intracranial stent or balloon, allowing to widen the lumen of the vessel and facilitate the advancement of the catheter.
In the long-term postoperative period after the application of endovascular embolization, an aneurysm of the cerebral vessels may develop, caused by the squeezing of the micro-spiral into the aneurysm with high blood pressure, which subsequently leads to the recanalization of the aneurysm. In this situation, the patient should be re-diagnosed aneurysm of cerebral vessels with a further solution of the issue and the application of another procedure for embolization.
To prevent possible recanalization of aneurysm in the long-term postoperative period, micro-coils impregnated with a special substance that forms a collagen mass upon contact with the endothelium of the vascular wall are used, which provides a dense closure of the lumen of the aneurysm.
Effects of aneurysm of cerebral vessels
The prognosis of an aneurysm of cerebral vessels depends most of all on the metric parameters of vessel expansion. Thus, the small size of an aneurysm almost never provokes the development of complications in the form of hemorrhages, while a large aneurysm is considered an extremely unfavorable pathological condition requiring immediate treatment.
It should be borne in mind that even the successful removal of cerebral aneurysms in the early and late postoperative period may be accompanied by the development of complications in the form of relapse of the disease or bleeding. Numerous randomized studies devoted to the study of the tactics of managing patients with unexploded cerebral aneurysms confirmed the inexpediency of surgical intervention for patients who have no signs of rupture, in view of the high incidence of complications in the postoperative period.
Even such non-invasive manipulation as endovascular embolization is associated with the possibility of developing severe complications in the patient, especially when the technique is violated (allergic reaction to the injection of contrast medium, perforation of the vascular wall, thromboembolism). However, the most dangerous is the intraoperative rupture of the aneurysm itself at the time of insertion of the catheter or the establishment of a micro-spiral, which in 40% provokes a detailed outcome.
Rehabilitation after an aneurysm of cerebral vessels subjected to surgical treatment takes several days, if the method of embolization was used, after which the patient has a full recovery of working capacity. Currently, there are no effective methods of primary prevention of aneurysm, but with the existing aneurysm of the cerebral vessels, patients should follow the recommendations of the attending physician in order to prevent the progression of the disease and the development of complications.
? An aneurysm of the cerebral vessels - which doctor will help ? If there is or suspected an aneurysm of cerebral vessels, immediately consult a specialist such as a neuropathologist or a neurosurgeon.