Diagnosis of a ruptured aneurysm

Diagnosis of aneurysm rupture is based on the clinical picture described above and additional research methods. Age and information about concomitant diseases (vasculitis, diabetes, blood diseases, renal hypertension, hypertension) are always taken into account.

Most often, aneurysms rupture in young and middle-aged individuals who do not have a history of arterial hypertension, although the presence of the latter does not exclude the possibility of aneurysm rupture. If similar attacks of sudden headache with impaired consciousness and focal neurological symptoms have occurred in the past, it is highly likely that there is hemorrhage from an aneurysm. At the same time, if there have been more than three such attacks and the patient is functionally preserved, it is worth considering a rupture of an arteriovenous malformation, since their course is less severe.

An important method is to measure blood pressure in both brachial arteries. Arterial hypertension in individuals who have not had it before confirms the assumption of possible hemorrhage from an aneurysm.

A simple, accessible and diagnostically valuable method of verifying subarachnoid hemorrhage is lumbar puncture. It can be performed in the next few hours after the rupture and is absolutely indicated in the presence of meningeal syndrome.

Contraindications to lumbar puncture are:

• dislocation syndrome;
• occlusion of cerebrospinal fluid pathways;
• severe vital function disorders: respiratory disorders of the Cheyne-Stokes, Biot, and terminal types; unstable blood pressure with a tendency to decrease (systolic pressure 100 mm and below);
• the presence of an intracranial hematoma in the back
• cranial fossa.

It is not recommended to remove a lot of cerebrospinal fluid, as this may provoke repeated bleeding. It is only necessary to measure the cerebrospinal fluid pressure and take 2-3 ml for analysis to make sure that the admixture of blood in the cerebrospinal fluid is not the result of a technically incorrectly performed manipulation. As is known, a pathognomonic feature of the hemorrhage that has occurred is a significant admixture of blood in the cerebrospinal fluid. It is often difficult to visually understand whether it is pure blood or cerebrospinal fluid intensely stained with blood. Confirmation of the latter is high cerebrospinal fluid pressure measured by a manometer and a simple test consisting of applying a drop to a gauze napkin (a drop of blood has a uniform red color, while cerebrospinal fluid stained with blood leaves a two-color drop: in the center is an intensely colored spot surrounded by an orange or pink halo). If this is blood that has descended from the cerebral subarachnoid spaces, then during centrifugation there will be many hemolyzed erythrocytes in the sediment, and free hemoglobin in the supernatant, due to which its color will be pink or scarlet. When conducting a study in the delayed period, when the process of sanitation of the cerebrospinal fluid is already underway, the latter will have a xanthochromic color. Even in the case of late hospitalization, it is possible to determine the presence of blood in the cerebrospinal fluid using spectrophotometric analysis of the cerebrospinal fluid, which allows for the detection of hemoglobin breakdown products after 4 weeks.

An important modern method for diagnosing aneurysm rupture and monitoring constrictive-stenotic arteriopathy is transcranial Doppler ultrasound, the importance of which in diagnostics and selection of treatment tactics is very significant. The method is based on the well-known Doppler effect: an ultrasound signal reflected from moving blood cells changes its frequency, the degree of which determines the linear velocity of blood flow. Its acceleration indicates (according to Bernoulli's law) a narrowing of the lumen of the vessel under study - angiospasm or arteriopathy. Multisegmental and diffuse arteriopathy is characteristic of aneurysm rupture, and the more pronounced the lumen narrowing, the greater the systolic blood flow velocity and the higher the pulsation index (PI ^ LSCyst - LSCdiast / LSCaverage; where LSCaverage = LSCyst + LSCdiast / 2).

Depending on this, moderate, severe and critical arteriopathy are distinguished. These data allow choosing the right treatment tactics. If the patient has critical arteriopathy, surgical treatment is contraindicated. Transcranial Dopplerography in dynamics makes it possible to assess the state of cerebral blood flow, based on which to choose the optimal time for surgical intervention with a minimum degree of deterioration in the individual prognosis. As already noted, such a period most often occurs 12-14 days after the rupture of the aneurysm. The use of Nimotop from the first day of hemorrhage allows performing the operation at an earlier date. The dynamics of narrowing of the vascular lumen correlates with the clinical picture: deepening ischemia is accompanied by deterioration of the patient's condition, an increase in focal neurological symptoms, and a progressive impairment of consciousness.

A similar correlation is observed with axial computed tomography (ACT) data. The latter has not only diagnostic but also prognostic value, allowing to choose the right treatment tactics and predict the outcome. ACT data can reveal SAH, in some cases local accumulation of blood in the basal cisterns can provide information on the localization of the ruptured aneurysm. In 15-18% of patients, ACT reveals intracerebral hematomas of varying volumes, intraventricular hemorrhages. The severity of the dislocation syndrome is of great importance: deformation and displacement of the cerebral ventricles, visualization and condition of the enclosing pontine cistern. In case of temporotentorial herniation, the said cistern is deformed or not visualized at all, which has a poor prognostic value. Along with this, ACT makes it possible to visualize the zone of ischemic edema of the brain with detailing its size and localization.

Depending on the severity of the condition, clinical picture, transcranial Doppler sonography, ACT, electroencephalography (EEG), three degrees of severity of cerebral ischemia caused by angiospasm - arteriopathy are distinguished: compensated, subcompensated and decompensated.

1. Compensated ischemia is characterized by: the condition of patients corresponding to I-II degrees according to H-N; weakly expressed focal symptoms; CSA with the involvement of 2-3 segments of the arteries of the base of the brain; ischemia according to axial computed tomography, covering 1-2 lobes of the brain; type II EEG (according to V.V. Lebedev, 1988 - moderate disturbance of bioelectrical activity of the brain, zonal changes are preserved. In the occipital leads, a polymorphic alpha rhythm is recorded, in the anterior-central leads - mildly expressed a - 0 activity).
2. Subcompensated ischemia: the condition of patients corresponding to grade III according to H-H; a pronounced symptom complex corresponding to the area of arterial spasm and ischemia; the spread of CSA to 4-5 segments of the arteries; the spread of the ischemic process according to ACT to 2-3 lobes; type III EEG (pronounced disturbances of electrical activity, disturbance of the a-rhythm against the background of polymorphic activity of the a-0 range with the registration of bursts of high-amplitude bilaterally synchronous slow-wave activity lasting more than 1 ms).
3. Decompensated ischemia: severity of the condition according to H-N grade IV-V; gross focal neurological symptoms, up to complete loss of functions; CSA extends to 7 segments of the basal arteries or more; ischemia prevalence according to ACT is 4 lobes or more; type IV EEG changes (gross disturbances of the bioelectrical activity of the brain, activity of a bilaterally synchronous nature of the A-range dominates in all leads).

The severity of the patients' condition during the first day from the moment of aneurysm rupture depends not so much on arteriopathy (which has not yet had time to develop and the narrowing of the arteries is due to myogenic mechanisms and can be classified as arteriospasm), as on the massiveness of SAH, blood breakthrough into the cerebral ventricles, the presence and localization of intracerebral hematoma, while on the 4th-7th day, and especially on the 2nd week, the severity of the condition is mainly determined by the severity of arteriopathy. Taking into account this pattern, the above gradation is not entirely acceptable for all periods of the hemorrhage and makes it possible to determine the surgical risk due to the developed ischemia with late admission of patients using multifactorial analysis. Thus, in the case of compensation of cerebral ischemia, surgical intervention can be undertaken immediately, in a subcompensated state, the question of intervention is decided on an individual basis. Decompensated ischemia is a contraindication for surgical treatment and such patients are subject to active conservative therapy until their condition improves (as a rule, this becomes possible after 3-4 weeks in surviving patients).

The “gold standard” in the diagnosis of arterial aneurysms of the cerebral vessels is cerebral angiography. It allows to identify the aneurysmal sac, the artery that carries it, the severity of the neck and sometimes the daughter sac (rupture site), the presence of thrombi inside the aneurysm, the severity and prevalence of arteriopathy. The information content of angiography depends on the research method and the resolution of the diagnostic ability of the angiographic apparatus. Modern angiographs are equipped with a system of computer mathematical processing of the angiographic image, which allows to increase the contrast of the required section of the artery, increase its size, eliminate the image of bone structures and secondary vessels superimposed on the examined area (digital subtraction angiography). This method has advantages over the conventional multi-series method due to the following capabilities: contrasting of all pools in one study with minimal use of contrast agent, continuous demonstration of the movement of contrast agent through the vascular bed (video monitoring) with the ability to calculate the linear velocity of blood flow; performing multi-axial angiography at any required angle.

The diagnostic accuracy using this technique reaches 95%. However, an angiographic study performed in the acute period may be false negative. In some cases (2%), this is possible due to the filling of the aneurysmal sac with thrombotic masses or severe spasm of the adjacent arterial segment with no contrasting of the structure. Repeated studies are performed after 10-14 days and allow to detect an aneurysm. According to world literature, these pathological structures are detected in 49-61% of patients with SAH. Other hemorrhages are caused by other reasons (microaneurysms that are not visualized angiographically, arterial hypertension, neoplasms, amyloid angiopathy, coagulopathy, atherosclerotic vascular wall lesions, vasculitis, hereditary hemorrhagic telangiectasia).

Contraindications for the study are:

• severe central respiratory disorders (tachypnea, abnormal breathing, spontaneous respiratory arrest), severe tachyarrhythmia;
• unstable systemic arterial pressure with a tendency to hypotension, including medication-supported at a level of 100 mm (at pressure below 60 mm, during angiography, the phenomenon of “stop-contrast” or pseudocarotidothrombosis is observed, caused by excess pressure in the cranial cavity over pressure in the internal carotid artery, in which blood with contrast does not penetrate into the intracranial vessels and diagnosis of aneurysm is impossible);
• respiratory disorders due to airway occlusion (until it is eliminated).

If the patient's condition is IV-V according to H-H, the examination can be carried out only if urgent surgery is necessary; otherwise, it is advisable to postpone it until the patient's condition improves.

The methods of performing angiography are different, but they can all be divided into two groups: puncture and catheterization. Puncture methods are performed according to Seldinger and differ only in which of the arteries is punctured to introduce a contrast agent. Most often, carotid angiography (introduction of contrast into the common carotid artery) and axillary angiography (introduction of contrast into the axillary artery) are performed. The latter allows the vertebral artery to be contrasted, and if it is performed on the right, the basins of the right vertebral and right carotid arteries are simultaneously contrasted.

The puncture method allows for good contrasting of the arteries, is better tolerated by patients and has fewer complications, since it requires the introduction of a smaller amount of contrast agent. Its disadvantage is the impossibility of obtaining information about all the arterial basins of the brain in one study. Therefore, the method of catheterization or selective angiography is often used in the diagnosis of aneurysms. Usually, a catheter is inserted through the femoral artery into the aortic arch, and from there it is sequentially passed into all the arteries supplying blood to the brain. Thus, in one study, it is possible to obtain information about all the arterial basins of the brain. This is especially important when the clinical picture and data from additional research methods fail to establish the localization of the aneurysm. In addition, information about all basins is also needed because, as already mentioned, 10-15% have several aneurysms of different arteries. The disadvantage of the method is its labor intensity. The duration of the study and the need to use a large amount of contrast agent, which in some cases can cause complications in the form of deepening angiospasm and increasing cerebral ischemia. As a rule, these phenomena are reversible and are successfully eliminated with medication.

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