A brain aneurysm is a balloon-like bulge at a weak point in the wall of a brain artery. Unless it ruptures it usually causes no symptoms; when it ruptures it causes bleeding in the brain that requires emergency treatment.
What is a brain aneurysm?
An aneurysm is a sac-like bulge formed where the wall of a brain artery has weakened, most often at branching points. Most aneurysms are small and may never rupture or cause symptoms throughout life. Some are found incidentally on MRI or CT performed for headache or another reason.
Rupture of an aneurysm causes bleeding between the membranes surrounding the brain (subarachnoid haemorrhage). This is a life-threatening emergency that requires rapid diagnosis and treatment.
Risk factors
- Smoking
- High blood pressure
- Family history of aneurysm
- Polycystic kidney disease and certain connective tissue disorders
- Heavy alcohol use
Symptoms
An unruptured aneurysm usually causes no symptoms; larger ones may cause a drooping eyelid, double vision or pain behind the eye.
A ruptured aneurysm usually presents with the following symptoms and is an emergency:
- A sudden, extremely severe headache
- Nausea and vomiting
- Stiff neck and sensitivity to light
- Confusion or loss of consciousness, seizures
Diagnosis
When bleeding is suspected, a brain CT is the first investigation. The location, size and shape of the aneurysm are evaluated in detail with CT angiography, MR angiography and digital subtraction angiography (DSA).
Treatment Approach
The aim of treatment is to exclude the aneurysm from the circulation to prevent bleeding or re-bleeding. The main methods are:
- Microsurgical clipping: Through an opening in the skull, a small metal clip is placed across the neck of the aneurysm.
- Endovascular treatment: Through an artery in the groin or arm, coils are placed inside the aneurysm, or devices such as flow-diverter stents are used.
- Observation: Some small aneurysms considered to have a low risk of rupture can be monitored with risk-factor control and regular imaging.
The appropriate method is decided jointly by neurosurgery and interventional neuroradiology, taking into account the aneurysm's location, size and shape and the patient's age and general condition. Stopping smoking and controlling blood pressure are important in every case.