Brain aneurysms may rarely cause any warning symptoms before they rupture. Symptoms may occur if the aneurysm is large or if it causes pressure on the structures, such as nerves or meninges (the three-layered covering over the brain), around it. Though most of the aneurysms do not rupture, the warning symptoms of unruptured aneurysms must be taken seriously and immediate medical help must be sought. These warning symptoms include:

Vision problems such as blurred vision, loss of vision or double vision
Headache
Neck pain or stiffness
Pain around or above the eyes
Numbness or tingling sensation
Weakness of any part of the body
Difficulty in balancing
Speech problems
Difficulty in focus or concentration
Memory issues

What is a brain aneurysm?

A brain aneurysm, also called intracranial or cerebral aneurysm, is an abnormal swelling or bulge in the walls of a blood vessel in the brain. It is caused by an area of weakness in the wall of the blood vessel. Usually, it occurs at the site where the blood vessel branches. When blood flows through such a weak blood vessel, the blood pressure causes the area to bulge like a balloon. The pressure may cause rupture of the aneurysm leading to an extremely serious condition known as a subarachnoid hemorrhage. 

 A ruptured brain aneurysm is a medical emergency and may manifest as:

A sudden and severe headache which the person often describes as the worst headache of their life
Nausea/vomiting
Neck stiffness
Seizure (convulsion)
Blurred or double vision
Intolerance to light
Confusion
Weakness or numbness
Loss of consciousness

What are the risk factors for brain aneurysm?

Many risk factors contribute to the formation of aneurysms, such as:

Smoking
High blood pressure (hypertension)
Age (over 40 years)
Family history of brain aneurysms (familial aneurysms)
Gender: women have a higher risk of aneurysms than men
Race: people of color have a greater risk of ruptured aneurysms
Certain chronic conditions such as Ehlers–Danlos syndrome, autosomal dominant polycystic kidney disease (ADPKD), Marfan’s syndrome, and fibromuscular dysplasia
Arteriovenous malformation (AVM) in the brain: AVM is an abnormal tangle of blood vessels connecting arteries and veins, which disrupts normal blood flow and oxygen circulation. 
Inborn abnormality in the artery
Drug abuse especially cocaine use
Excessive alcohol use
Infections
Severe head injury

What is the treatment for a brain aneurysm?

Advances in medical science and technology have provided various treatment options for brain aneurysms. The treatment option which is best for a person depends on:

The patient’s neurological condition
The patient’s general health and presence of other medical conditions such as high blood pressure and heart diseases
The patient’s age
The location, size and shape of the aneurysm
Whether the aneurysm is ruptured or not
The risk of aneurysm rupture
The availability of treatment options
Family history of aneurysm 
Family history of subarachnoid hemorrhage

The treatment options for brain aneurysms are:

Open surgery (clipping): Clipping is a popular surgical method for treating a brain aneurysm. In this procedure, the surgeon exposes the aneurysm with a craniotomy (surgically opening the skull) and places a tiny metal clip across the base of the aneurysm so that blood cannot enter it.
Endovascular therapy: The term endovascular means within the blood vessels or vascular system. Endovascular therapy requires a small incision to repair the aneurysm using coils, stents or flow diversion device
No treatment: Most of the brain aneurysms do not rupture. The doctor may advise observation, with control of risk factors, such as smoking and high blood pressure. They may advise to repeat imaging from time to time.