Brain aneurysm- Symptoms, Risk Factors and Treatment
A brain aneurysm is an abnormal, localised bulge or widening of the blood vessels in the brain. This condition is caused by a weakness in the wall of the vessel. The blood starts to accumulate in the bulge which can then rupture to cause brain haemorrhage.
Symptoms
Most unruptured brain aneurysms are asymptomatic and discovered incidentally. However symptoms such as severe and frequent headaches, cranial nerve palsy, difficulty in speech or vision and unexplained weakness and numbness of the body are common in patients.
Actual symptoms start to show when the aneurysm starts to rupture. It causes sudden and severe headaches, nausea and vomiting, stiffness in the neck, blurry vision, dilated pupils, photophobia, broken speech and seizure.
Causes and risk factors
There are four major blood vessels that provide blood and nourishment to the brain- 2 carotid arteries and 2 vertebral arteries. These branch into numerous smaller blood vessels that spread across the brain to form a complex mesh of blood vessels. The blood vessels have three layers- the outermost layer, the middle layer called tunica media and the innermost layer called endothelial cells which are in contact with blood. It is seen that most aneurysms happen due to the weakening of the middle layer of tunica media. The weakening of the blood vessels is due to tissue degradation. Other factors include inflammation, hemodynamics, genetics, environmental and hormonal issues. Most aneurysms occur at a branching point in the blood vessels. Blood comes from a vessel and branches out in two directions but due to the weakness in the wall a bulge begins to appear between the two branches. There are different types of brain aneurysms. Firstly, saccular aneurysms have a sack-like bulge referred to as an aneurysm dome. This is the most common type of brain aneurysm. Secondly, fusiform aneurysms are circumferentially bulging of the blood vessel. Thirdly, dissecting aneurysms form when there is a small tear in the blood vessel and blood starts accumulating into the tear itself.
Risk factors for brain aneurysms are divided into two subgroups- Modifiable (lifestyle) and non-modifiable factors. Modifiable factors include hypertension, smoking, alcohol consumption and usage of sympathomimetic drugs like cocaine. Hypertension weakens the walls of the blood vessels by increasing mechanical stress on them. Up to 80% of patients with brain aneurysms have a history of smoking. Non- modifiable factors include a family history of the same condition and genetic syndromes such as polycystic kidney disease. It is also found that the female sex has a higher chance of developing a brain aneurysm.
Treatment
Brain aneurysms can be of different shapes and sizes. The severity of brain aneurysms cannot be determined by size alone. Small aneurysms (about 1.5mm in diameter) may prove fatal if the wall is weak and thin because there are chances that it might burst and cause a haemorrhage. Diagnosis is done through imaging and screening through CT scan and MRI scans. In some cases, CT and MRI angiography cannot detect small aneurysms, therefore, a special catheter cerebral angiogram is performed. It detects small aneurysms and is more efficient than CT and MRI scans. Patients’ history and the aneurysm details are studied to come up with a treatment plan. According to the requirement, there are two treatment options doctors perform.
Aneurysm clipping- In this procedure, the neuro surgery doctor marks the position of the aneurysm and then performs a craniotomy over that area. A craniotomy is the removal of a small part of the skull to access the brain and blood vessels. Then the aneurysm is identified and separated from brain tissue. A small titanium clip is applied at the base of the aneurysm and then tightened to seal it, separating it from the blood vessel. The normal anatomy of the blood vessel is restored. The skull piece is placed in its place and the window is closed.
Endovascular coiling- Unlike aneurysm clipping, Endovascular coiling is a minimally invasive procedure. A small incision is made in the groyne or thigh of the patient and a narrow tube, called a micro-catheter, is inserted in the femoral artery all the way up to the brain. The micro-catheter is then slowly and selectively advanced into the aneurysm. Hair-like detachable platinum coils are then released through the catheter into the aneurysm. The coils fill the aneurysm, and the remaining slow blood flow starts to build clots in the aneurysm. In this way, the aneurysm is sealed. If the opening of the aneurysm is wider a stent is also placed in the blood vessel so that the coils don’t get out of the aneurysm.
It takes 4-8 weeks for complete recovery from the surgery in case of an unruptured aneurysm. Around 40% of aneurysms are fatal and some of the survivors may even have a permanent neurological disability.
In India, one can consider looking for the best hospital for neurosurgery in Bangalore, Mumbai, or Delhi as these cities provide cost effective treatments.
