Prognosis

About 1/3 of all affected people survive such a bleeding without major physical and mental limitations. Unfortunately, the other 2/3 of patients retain brain damage or die mainly due to compression of vital centers in the brain stem (respiratory center, circulatory center) or oxygen deficiency (ischemia) of vital brain areas due to vasospasms.

Causes

This is therefore a bleeding into the space between the spider’s web (arachnoidea) and the soft meninges (pia mater), which is filled with liquor. Such a bleeding is usually caused by a suddenly ruptured blood vessel (in this case: artery). The reason for this tear (med.

rupture) is usually a so-called aneurysm. An aneurysm describes a bulging of the blood vessel wall, the main complication being that it can rupture at any time. Until then, such an aneurysm usually remains asymptomatic, so the patient has no complaints.

Aneurysms can be either acquired or congenital. Acquired aneurysms usually occur as a result of pathological changes in the arterial wall in the form of calcification, which is called atherosclerosis (also: arteriosclerosis). So if such a vessel ruptures, blood from the artery enters the subarachnoid space. Because of the high pressure in the arterial blood vessels, the blood is pumped in at high pressure, so a lot of blood flows from the vessel into the subarachnoid space in a very short time.

Diagnosis

Since subarachnoid hemorrhage is a very acute clinical picture with potentially serious complications, it is crucial to ensure a rapid diagnosis. For this reason, computer tomography is the primary method used, as this procedure quickly confirms the diagnosis in most cases.In some cases, an MRI can also be helpful. For visualization and localization, a so-called digital subtraction angiography (DSA), in which a catheter is usually inserted through a vessel in the groin until the suspected bleeding occurs, and the vessels are visualized in the X-ray image with a contrast medium.

The advantage of this procedure is the possibility to treat directly on site under certain conditions. If the CT (computed tomography) does not produce a result, a lumbar puncture can be performed if necessary. In this procedure, nerve water (liquor) is taken from the subarachnoid space.

Afterwards, a visual diagnosis can be made to determine whether there is blood in the cerebrospinal fluid. As with any other procedure, there is a certain risk for the patient, and the location of the bleeding in the head cannot be determined. Computer tomography is the most sensitive form of diagnosis for subarachnoid hemorrhage.

This means that about 95% of bleeding is detected by CT. The reason for this is that CT is particularly good at identifying acute bleeding, which is usually the case with subarachnoid hemorrhaging. With this form of imaging, many sectional images are taken.

It should be noted that a CT involves a relatively high radiation exposure compared to other imaging methods. However, this plays a subordinate role in view of the great advantage of rapid diagnosis. Occasionally, the CT of the brain does not offer sufficient exclusion of whether it is a subarachnoid hemorrhage or something else.

In this case, magnetic resonance imaging can help. The advantage of this sectional imaging method is that so-called subacute bleeding can be detected. So if there is no heavy bleeding leading to acute neurological impairment, but “only” a small bleeding that, for example, continues to bleed slowly over several days, this can be easily detected by MRI.