Saccular aneurysm and subarachnoid hemorrhage

Saccular aneurysm pathophysiology and localization site

Saccular aneurysm localized in the forks of large cerebral arteries. These arteries are at the base of the brain, so when they rupture blood enters the subarachnoid space of tanks lying at its base (basal cisterns).

In contrast to mycotic saccular aneurysm located in areas overlying branches of the middle, anterior and posterior cerebral, vertebral or basilar artery. As a result, after the rupture of mycotic aneurysm of the blood which flows into the subarachnoid space beneath the surface of the cerebral cortex, but not in space at the base of the brain (basal cisterns).

These differences determine the features and clinical manifestations of saccate and mycotic aneurysm of the arteries of the brain. Typical options are localized saccular aneurysm location:

• fusion with anterior communicating artery anterior cerebral artery
• fusion posterior communicating artery with internal carotid artery
• splitting (bifurcation) of the middle cerebral artery
• the upper part of the basilar artery
• connect the main artery to the superior cerebellar or anterior inferior cerebellar artery
• connection with the vertebral artery, posterior inferior cerebellar artery

Approximately 85% of the localization of aneurysms of the forward pool circulation of arterial blood in the brain. In 12-31 % of patients have multiple aneurysms, the 9-19 % found bilateral identical ("mirror"), localization of aneurysms.

As of its formation at the aneurysm neck and formed the vault. Neck length and size of the aneurysm arch vary greatly. However, they are important when planning neurosurgical operations on their shutdown of blood flow. The internal elastic layer of the artery walls of the brain when it disappears at the base of the aneurysm neck. The middle layer of the vessel wall becomes thinner, its smooth muscle cells are replaced by connective tissue cells. In the place of rupture of the aneurysm (often in the set), the wall thins to less than 0.3 mm and the length of the gap is often less than 0.5 mm. Determine practically what an aneurysm in a patient prone to rupture, it is impossible. There are only limited guidance on what is an important parameter in this respect is the size of the aneurysm. In aneurysms larger than 7 mm is justified conducting prevention of neurosurgical operations on their shutdown of blood flow.

 

Unruptured intracranial aneurysms clinical symptoms

Neurological symptoms in a patient may indicate the localization of unruptured aneurysms, and sometimes point to a progressive increase in its size. The appearance of paralysis of the muscles innervated by the oculomotor cranial nerves III, especially combined with the expansion of the pupil (mydriasis), loss of its response to light and local pain at the eyeball behind him and points to the expansion of the aneurysm. It can be located at the junction of the posterior communicating and internal carotid arteries. In order to develop paralysis of the muscles innervated by the oculomotor nerve III, the length of the aneurysm from the place of its publication in the posterior communicating artery should be 7 mm or more and grow. In this clinical situation, the patient showed an immediate decision on surgery.

Paralysis of the direct external eye muscles (removes the eyeball outwards) innervated averting VI nerve may be a sign of an aneurysm of the cavernous sinus. Visual field defects in patients are often noted for increasing supraklinovidnoy carotid artery aneurysm. Pain in the back and lower neck, the patient may signal an aneurysm of the posterior / inferior cerebellar artery or the anterior / inferior cerebellar artery. Pain in the eyeball or behind and below the temple usually celebrated with an expanding aneurysm of the middle cerebral artery.

The question of whether the aneurysm result in a low, intermittent nature of the flow of blood into the subarachnoid space, remains unclear. However, the significance of documenting clinical relationships smallest aneurysm ruptures and bleeding is not in doubt.

A sudden unexplained headache of any location should cause suspicion of subarachnoid hemorrhage in a patient. It is necessary to conduct magnetic resonance (MRI) or computed tomography (CT) scan of the brain to detect blood in the basal cisterns. Often, minor subarachnoid hemorrhage not detected on computed tomography (CT) scan of the brain, so to establish the presence of blood in the subarachnoid space of such patients shows a lumbar puncture.

 

Ruptured aneurysm initial manifestations and acute extensive subarachnoid hemorrhage

For a short moment of rupture of the aneurysm, when acutely developed extensive subarachnoid hemorrhage, intracranial pressure reaches a value of mean arterial pressure, cerebral blood flow with a decrease (CPP, cerebral perfusion pressure).

In 45% of patients after suddenly losing consciousness, which is then restored. Sometimes the sudden loss of consciousness preceded by the patient a brief moment a painful headache, but most patients regaining consciousness, first of all complain of headache.

In 10% of the ruptured aneurysm from bleeding may be massive enough to cause loss of consciousness and the patient for several days.

Approximately 45 % of patients after rupture of the aneurysm complained of intense headache, usually increasing with voltage, but the loss of consciousness while they have not. Patients often describe this headache as "the most terrible in my life". Often use such designations as "broken" and "broken up" headache. Typically, patients indicate that they have hurt "the whole head", or "posterior portions of head and neck".

Whatever the onset of the disease, one of its symptoms is vomiting rupture of the aneurysm. When combined sudden vomiting and headache in a patient should always occur suspected acute subarachnoid hemorrhage.

Although a characteristic sign of rupture of the aneurysm is a sudden headache with no focal neurological symptoms, patients often also arises neurological deficit.

Paralysis of muscles innervated by the oculomotor nerve III, arising in a patient on the side of hemorrhage makes one think of breaking posterior communicating artery aneurysm.

Often marked paralysis direct external eye muscles (innervated by the nerve of averting VI) is not important for the localization of lesions, but often a rupture of the aneurysm subtentorial.

When you break the aneurysm anterior communicating artery or the place of bifurcation (bifurcation) of the middle cerebral artery blood flows into the subdural space or into the basal cistern of subarachnoid space, and thus formed a clot burden may be large enough to cause local mass effect. As a result of developing neurological deficits, including muscle weakness, half of the body (hemiparesis), speech disorder (aphasia) in the dominant hemisphere lesions, impaired recognition (anosognosia for gemitipu), and non-dominant hemisphere in the damage - the loss of memory and abulia.

When you break the aneurysm, localized at the site of bifurcation (bifurcation) of the middle cerebral artery, blood can get into the Sylvian cistern, in the temporal lobe or upward in the frontal and parietal lobes. Such bleeding can be characterized by the patient displays surround the process and be mistaken for a doctor intracerebral hemorrhage. Often accompanying them leads to cerebral edema weighting of the patient, which requires in some cases, urgent neurosurgical intervention.

Sometimes the patients immediately after the rupture of the aneurysm developed acute unilateral swelling of the cerebral hemispheres, combined with focal neurological symptoms and stupor. The reasons for this swelling of the brain is not installed. It is not excluded that there transient cessation of cerebral circulation in the blood pool may be a secondary character in relation to vascular spasm in the trunk of the artery. Often it is difficult to explain the cause of the initial neurological deficit in a patient, and in most cases, symptoms regress with time. To determine the tactics of patients and time of occurrence and development of residual neurological symptoms, the importance of careful documentation of the source has a neurological deficit. This is necessary to determine its cause, and careful tracking of its dynamics.

 

Grading scales for subarachnoid hemorrhage:

Grade	Hunt-Hess scale	World Federation of Neurosurgical Societies (WFNS) scale
1	Mild headache, normal mental status, no cranial nerve or motor findings	Glasgow Coma Scalea (GCS) score 15, no motor deficits
2	Severe headache, normal mental status, may have cranial nerve deficit	GCS 13–14, no motor deficits
3	Somnolent, confused, may have cranial nerve or mild motor deficit	GCS 13–14, with motor deficits
4	Stupor, moderate to severe motor deficit, may have intermittent reflex posturing	GCS 7–12, with or without motor deficits
5	Coma, reflex posturing or flaccid	GCS 3–6, with or without motor deficits

Im subarachnoid hemorrhage initial clinical manifestations of ruptured aneurysm may be assessed taking into account the scale of Hunt-Hess or Glasgow Coma Scale (GCS) from the World Federation of Neurosurgical Societies (WFNS). When you break the aneurysm prognosis for the patient is deteriorating with increasing degree on this scale. For example, for patients who received the 1 on a scale of Hunt-Hess death is not typical, if timely treatment was made ruptured aneurysm. At the same time, mortality in patients with 4 or 5 degree scale Hunt Hess may be above 80%.

 

Ruptured intracranial aneurysm diagnosis, laboratory evaluation and imaging

If the patient study conducted in the first 48 hours after the rupture of the aneurysm, then during magnetic resonance (MRI) or computed tomography (CT) scan of the brain without contrast enhancement more than 75% of patients show a change, indicating the presence of blood clots in the subarachnoid space. The number and location of blood in the subarachnoid space may help in determining the location of the aneurysm had broken through and find out why the initial neurological deficit. In addition, MRI and CT can assist in the prediction of which of the patients may develop delayed neurological deficits due to spasm of the arteries in the brain (cerebral vasospasm).

At the first stage of diagnosis to the patient with a suspected rupture of intracerebral aneurysms performed an MRI or CT of the brain without the administration of contrast material. Contrast CT angiography or MR angiography without intravenous contrast brain vessels are capable of detecting changes in the vascular bed in the patient, to detect an aneurysm, or is not supposed to show the patient's arteriovenous malformation (AVM, angioma, hemangioma). When an MRI or CT of the brain can not diagnose or subarachnoid hemorrhage, or to identify the bulk process or obstructive hydrocephalus, a lumbar puncture should be performed to determine the presence of blood in the subarachnoid space.

If a patient has a diagnosis of subarachnoid hemorrhage due to rupture of saccular aneurysms is set, then angiography is delayed until the surgical intervention. Cerebral angiography is usually performed immediately before surgery to refine the location and characteristics of the anatomy of the aneurysm, as well as to confirm the presence or absence of focal spasm of the arteries of the brain (cerebral vasospasm). If the presence of blood in the brain or the subarachnoid space over the cerebral hemispheres, but not in the basal cisterns suggests arteriovenous malformation (AVM, angiomu, hemangioma), or mycotic aneurysm, the angiographic study should be carried out immediately.

Another indication to perform emergency angiography, the patient is intracerebral hematoma, which appeared as a result of rupture of the aneurysm, which is the development of cerebral edema may be cause for emergency neurosurgery to remove it due to the danger of herniation of the temporal lobes of the cerebellum in the gallop, the displacement of the brain stem, etc.. Mandatory condition in preparation for the operation is to determine the exact location and anatomy of the ruptured aneurysm of the brain.

When intracranial hemorrhage on the ECG changes are often found, which are often secondary. Changing the interval - T, as in coronary artery disease. Extended complex QRS, increases the interval Q-T, act or inverted T- waves, suggest that the primary lesion of the heart.

Reducing sodium in the blood (hyponatremia) can occur secondary to inappropriate secretion of antidiuretic hormone (ADH) increases the volume or due to unknown factors causing the loss of salt and water, followed by a decrease in volume. Therefore, patients with intracerebral hemorrhage shows the definition of electrolytes in the blood serum.

 

The medical management of ruptured aneurysm and subarachnoid hemorrhage

After subarachnoid hemorrhage in a patient who is in a stupor or coma, intracranial pressure may be elevated. Therefore it is necessary to maintain adequate cerebral perfusion pressure (CPP) and at the same time ensure that there is no excessive mean arterial pressure. To estimate the alveolar ventilation of the lungs should monitor the content of arterial blood gas. During hypercapnia the patient must be an artificial lung ventilation (ALV). If the subdural or intracerebral hematoma causes an increase of neurological disorders, it is expedient surgical removal. During the operation the neurosurgeon can also be done off the aneurysm from the blood vessel clip found at its base.

To avoid re-bleeding, all patients recommend bed rest and placed in a quiet, preferably darkened room. To prevent constipation as a result of an inactive state, which then forces the patient with an aneurysm push, prescribe laxatives. At the same time excessive restrictions in activity can lead to agitation, so patients were allowed to read, listen to radio, to meet with relatives. In cases of severe headache and pain in the neck appoint lungs sedatives and analgesics. Acceptance of acetylsalicylic acid (aspirin), which has antiaggregatory effect, not recommended, but you can use paracetamol (acetaminophen) or meperidine and phenobarbital or other sedatives. Excessive sedation appointment to the patient with an aneurysm of the brain artery is undesirable because it complicates the assessment of his original and possible neurological symptoms.

Epileptic seizures at the time of rupture of the aneurysm are rare. Small tremors, twitching and extensor posture often associated with the patient unconscious, probably due to a sharp increase in intracranial pressure. Since generalized seizures increase the risk of re- rupture of the aneurysm, as a preventive therapy is sometimes prescribed phenytoin (300 mg per day) or phenobarbital (30 mg 3 times daily).

Steroid drugs may reduce pain in the head and neck caused by irritant located in the subarachnoid space of the blood. No data on their effectiveness in swelling of the brain, sometimes marked in patients immediately after subarachnoid hemorrhage.

 

Clinical manifestations and delayed neurologic deficits after intracranial aneurysm rupture

There are three main reasons for a distant neurological deficit at rupture of the aneurysm of the brain arteries. They are observed after the stabilization of the patient or reduce the severity of initial neurological symptoms, both objective and subjective. These reasons include:

• re-rupture of the aneurysm
• communicating hydrocephalus
• spasm of cerebral arteries (cerebral vasospasm)

To recognize the origin and determine the severity of each of these options complications after rupture of the aneurysm, it is necessary to know the cause and severity of initial neurologic disorders. Important in the diagnosis of these three complications have an early magnetic resonance (MRI) or computed tomography (CT) scan of the brain associated with angiography (24-48 h after hemorrhage). This helps determine the size of cerebral ventricles, the number and location of blood in the subarachnoid space at rupture of the aneurysm.

 

Complications after subarachnoid hemorrhage

After suffering a subarachnoid hemorrhage, rupture of the aneurysm of the brain arteries of the patient's own complications. These relating complications:

• thrombophlebitis with pulmonary emboli
• perforated stress-induced duodenal ulcer
• ECG changes indicating a heart attack or myocardial ischemia

Subarachnoid hemorrhage in the cranial cavity starts the increased activity of the sympathetic nervous system. This causes the myofibrillar degeneration of the heart muscle (myocardium). When you break the aneurysm with subarachnoid hemorrhage may develop cardiac arrhythmias. Such patients recommended the appointment of beta-blockers. Their use in patients must be associated with care, especially in the presence of atrioventricular block. A possible complication in a patient and a reduction in plasma sodium (hyponatremia). Hyponatremia occurs when an inappropriate secretion of antidiuretic hormone (ADH) secretion or natriuretic hormone. Treatment of such patients is reduced to the limitation of free fluid in the maintenance of adequate intravascular volume.

 

Open surgery and endovascular treatment of intracranial aneurysm

Microsurgical aneurysm ruptured off with the help of her doctor performed clipping neurosurgeon. To enlarge the image in the operative field using an operating microscope. Thanks to this intervention to prevent possible complications in a patient after re-rupture of the aneurysm.

Most neurosurgeons postpone surgical intervention for a ruptured aneurysm of the arteries of the brain at 10-14 days in order to stabilize the patient's clinical condition. If deferred transactions have the time for removal of brain edema arising after the first rupture of the aneurysm. Minimizes the risk of symptomatic vasospasm in a patient in the postoperative period.

Surgical treatment is not advisable to delay, if the patient is absent neurological symptoms. Surgical intervention within the first 48 h solves the problem of re-bleeding from the aneurysm. This also makes it possible to remove from the liquor spaces based on the brain (basal cisterns), blood clots, prevent the development of spasm of the arteries (vasospasm) of this localization.

Technically, the performance of the local removal of hematomas and ruptured aneurysm clips off easy, but some of the blood clots too large in size, so they can be removed completely and without consequences for the patient. Therefore, the time of neurosurgical operation in case of rupture of an aneurysm of the brain arteries chosen individually for each patient. If the magnetic resonance (MRI) or computed tomography (CT) scan of the brain in a patient in the subarachnoid space do not show large blood clots or potentially dangerous if a clot burden can gently and effectively remove, it is possible early surgical intervention.