Cerebrovascular diseases occur very frequently in our country. Such high occurence results from our modern life style (improper diet, lack of excercise, smoking, drinking alcohol). The term covers very different diseases the common symptom of which is that they involve disorders of blood vessels in the brain. The following information describes these disorders in detail and includes options of possible neurosurgical treatment.
Subarachnoid hemorrhage is a serious disease characterized by bleeding into the the subarachnoid space – the area between the arachnoid membrane and pia mater surrounding the brain. Bleeding is most often caused by a ruptured aneurysm on a cerebral artery.This disease occurs in adults of any age (most frequently between 50-60 years of age), more often in females. Despite progress in the development of medicine, there is still a large portion of patients with SH who die or suffer permanent damage. Hypertension and smoking are important risk factors. The main symptom is a sudden thunderclap headache (often described by patients as the worst they have ever had), sometimes even seizures and decreased level of consciousness. When a patient is brought into a hospital, a CT scan of the brain is performed and then a contrast angiography of blood vessels. If an aneurysm is identified, a surgical procedure or neurointervention (coiling) follows. Aneurysm must be cut off from blood flow to prevent rebleeding because that has an even more dismal prognosis than the first bleed. Aneurysms are either clipped or filled with a platinum coil. Patients must remain in a horizontal position before and after the procedure because they are at risk of developing vasospasms which are more likely to occur in an upright position. If vasospasms are strong, blood flow and supply of oxygen in the brain may be impaired or obstructed which can lead to tissue necrosis at the given site similarly as in the case of an ischemic stroke. This condition is called delayed ischemic deficit. Another possible complication of subarachnoid hemorrhage is the development of hydrocephalus, i.e blockage of cerebrospinal fluid outflow or resorption. That may occur either shortly after the bleeding when the circulation of cerebrospinal fluid is obstructed or it may be delayed (for several weeks) thanks to impaired resorption of cerebrospinal fluid due to the bleeding.
Arteriovenous malformation is a congenital disease. Normally, blood flows from arteries into capillaries (microvessels which supply the brain with oxygen) and then from capillaries into veins. In arteriovenous malformations, capillaries are absent and blood flows from arteries directly into veins. The main risk is the fragility of this malformation which is prone to rupturing and bleeding. Cerebral veins have thinner walls than arteries and cannot stand the pressure of blood which is much higher in arteries. More than half of all arteriovenous malformations rupture at some point. Many patients with this malformation are affected by epilepsy, up to one third of patients suffer from epileptic seizures. AVM may be also accompanied with the so-called steal syndrome. The blood flow from arteries directly into veins is very quick. When blood flows through the malformation in such speed, it may ‘steal’ blood from surrounding tissues which suffer from poor blood and oxygen supply.
Arteriovenous malformation is a serious disease, but mortality is not high. However, it is often accompanied with some type of permanent neurological deficit. The treatment is quite complex and often requires a combination of various methods. Angiography must be performed first to discover how the malformation is fed with blood. Smaller malformations which are easily accessible are the best candidates for a surgical procedure. Those that are small but located in deep areas are best to treat with Gamma knife radiosurgery. In case of larger malformations, some of the feeding arteries are embolized with a special type of glue (this procedure is similar to angiography examination) and then the next step is either surgery or Gamma knife radiosurgery (available at Na Homolce Hospital).Arteriovenous malformations may also occur in the spinal cord with an increased risk of paralysis due to the bleeding itself, steal syndrome or even due to a potential surgical procedure.
Cavernomas are relatively frequent. They are characterized by grossly dilated blood vessels and the absence of neuronal tissue within the lesion. Most frequent symptoms of this disease include bleeding in the brain and epileptic seizures. Cavernomas occur anywhere in the brain and the spinal cord but the most serious is its location in the brainstem. The detection of cavernomas is possible only by MRI brain scan, the results of CT scan are inconclusive. Cavernomas are treated only surgically, they cannot be irradiated or embolized. This disease may be inherited in rare cases.
Bleeding in the brain – intracerebral hemorrhage
Bleeding in the brain is most likely to occur in older patients. The most frequent cause is a chronic untreated hypertension – high blood pressure. Bleeding may be also set off by a ruptured aneurysm, malformation or cavernoma. Some cases of bleeding in the brain are, unfortunately, inoperable. In the so-called hypertonic bleeding, high pressure blood flow from a ruptured artery damages surrounding brain tissue the function of which cannot be restored anymore. A CT scan of the brain must be performed in order to rule out other possible causes of a patient’s condition and make a precise diagnosis. A surgery is indicated for those patients who do not suffer bleeding in critical areas of the brain and a surgery has the potential to improve their condition.