Within this text passage, we would like to focus especially on the intracranial, cerebral aneurysm. Those aneurysms have a bad prognosis if they are not successfuly treated. More precisely, the bleeding resulting from the aneurysm has a bad prognosis. Simplified you can say that after the occurence of a bleeding half of the patients die before reaching a hospital. One third of the lucky patients reaching the hospital dies, one third survives with disabilities, and only the last third successfuly recovers from the aneurysm without any permanent damage.
Due to this reasons, it is very important to detect and treat aneurysms before they cause a cerebral bleeding, the so-called subarachnoid bleeding (SAB). This sort of bleeding protrudes into the subarachnoid space (the brain is completely surrounded by cerebrospinal fluid). It is also possible that the bleeding affects the cerebral tissue itself.
The subarachnoid bleeding secondarily leads to vascular spasms (constrictions or stenoses) that can cause apoplectic stroke. In addition, the subarachnoid space sticks togetherso that a normal circulation of the cerebrospinal fluid is not possible anymore. Consequently, the intracranial pressure rises (hydrocephalus).