A 41-years old gentleman underwent a brain MRI for evaluation of a suspected brain tumor. He was found to have an aneurysm in the left internal carotid artery. He underwent a catheter cerebral angiogram (similar to a heart angiogram) to assess the 3-D structure of the aneurysm and plan further management. As he had a large aneurysm with a wide neck, flow diversion stenting was planned. Post procedure, there was a significant reduction in blood flow into the aneurysm. Over the next 6 months to 1 year, the aneurysm will shrink and disappear.
What are brain aneurysms?
Brain aneurysms are a bulge in the wall of blood vessels supplying the brain. They are classified according to their shape, size of the bulge and size of the neck or entrance of the aneurysm. There are different treatment options for different aneurysms. According to Indian research, aneurysms are present in about 1% of the population.
What are the risk factors for developing an aneurysm?
The risk factors for developing aneurysms include high blood pressure, high cholesterol, smoking, alcohol and drug abuse. They can also develop following trauma or infections. Blood vessel malformations and some genetic disorders also contribute to aneurysm formation.
What are the symptoms of an aneurysm?
Brain aneurysms may be silent and get detected when an MRI is done for another complaint. If an aneurysm is large, it can press on surrounding structures causing vision problems, hormonal problems, weakness or memory problems.
The most devastating complication of an aneurysm is subarachnoid hemorrhage (aSAH), that is, bleeding into the coverings of the brain. aSAH can present as sudden severe headache (worst headache of life), altered consciousness, seizures or weakness. About 10% of patients who develop aSAH do not reach the hospital and around 25% die within the first 24 hours. Of those who survive, around 50% will have significant morbidity. aSAH occurs in around 6 – 16/100000 persons in India.
How are they diagnosed?
Aneurysms are usually diagnosed by either a CT scan or an MRI scan of the brain. However, the gold standard to evaluate aneurysms is a catheter cerebral angiogram (DSA). The procedure is done under local anesthesia. A small catheter is introduced through the leg or arm vessel and navigated into the blood vessels in the neck that supply the brain. Contrast material is then injected and images taken. A 3-D reconstruction can be done, precise measurements taken and treatment strategy planned.
What are the treatments available?
There are no medicines available to cure aneurysms. The main aim of treatment is to block blood flow into the aneurysm in order to reduce chances of rupture or re-rupture.
Endovascular treatment is done via a small puncture in the leg. Catheters are navigated to the aneurysm under X-ray guidance. The sac of the aneurysm is then packed with platinum coils which promote clot formation and thus block the aneurysm. Depending on the structure of the aneurysm and its neck, either coils alone may be used or additional support in the form of an expandable balloon or a stent may also be used. A newer treatment modality is placement of a flow diversion stent, as described in the case above.
Surgical treatment involves accessing the aneurysm by opening the skull. One or more metal clips are placed to block the aneurysm.