Aneurysm

What is an aneurysm?

An aneurysm is a bulge or ballooning at a weak point in the wall of a blood vessel, usually an artery. Most aneurysms cause no pain and are only found by chance, for example during a scan for something else.

Aneurysms can develop in any artery but are most common in the aorta (the body’s largest artery, which carries blood from your heart). They can also affect the arteries in your brain, neck, legs and elsewhere. If an aneurysm bursts (ruptures), it causes internal bleeding and is a medical emergency.

What are the symptoms of an aneurysm?

Most aneurysms don’t cause any symptoms, especially while they’re small. Many are only found during tests or scans done for another reason.

If an aneurysm is large enough to press on nearby tissue, or if it’s growing, you might notice:

• pain in the area affected, such as your tummy, chest, back or head
• a pulsating lump, or swelling in your neck
• dizziness, tiredness or a rapid heartbeat
• vision changes, or a headache, if the aneurysm affects your brain
• difficulty swallowing, a hoarse voice, or noisy breathing, if it affects vessels in your chest or neck

Signs of a rupture

A ruptured aneurysm needs emergency treatment straight away. Symptoms can include:

• a sudden, extremely severe headache - often described as the worst headache of your life
• sudden, severe pain in your head, chest, tummy or back
• feeling lightheaded, or a rapid heartbeat
• sudden loss of consciousness, sometimes following a severe headache
• for a brain aneurysm specifically: a stiff neck, nausea or vomiting, sensitivity to light, blurred or double vision, confusion, or a seizure.

Call 999 (or your local emergency number) immediately if you or someone you’re with has these symptoms. Do not drive to hospital yourself; wait for an ambulance or ask someone else to drive.

What are the causes of an aneurysm and who is at risk?

The exact cause of an aneurysm often isn’t clear, but it develops when part of an artery wall weakens. A number of factors can raise your risk, including:

• high blood pressure
• smoking
• atherosclerosis (a hardening and narrowing of the arteries caused by fatty deposits)
• a family history of aneurysms, particularly in a first-degree relative (a parent, sibling or child)
• inherited connective tissue conditions, such as Ehlers-Danlos syndrome (a condition affecting connective tissue)
• polycystic kidney disease (an inherited condition that causes fluid-filled sacs to form in the kidneys)
• using drugs, particularly cocaine, or drinking heavily
• an injury or infection affecting a blood vessel
• being born with a weakness in a blood vessel wall.

Age and sex also play a part, though the pattern differs by type. Brain aneurysms are more common in adults aged 30–60 and affect women more often than men. Aortic aneurysms become more common with age and affect men more often, particularly over the age of 60.

Are there different types of aneurysm?

Aneurysms are usually grouped by where they occur and by their shape. By location:

• Aortic aneurysms are by far the most common, forming in the aorta. They’re described as abdominal (in the tummy) or thoracic (in the chest), depending on where they occur.
• Cerebral (brain) aneurysms affect an artery in the brain.
• Peripheral aneurysms form in other arteries, such as those in the neck (carotid), behind the knee (popliteal), in the spleen, or supplying the intestines (mesenteric).

By shape:

• A saccular aneurysm, also called a berry aneurysm, bulges out on one side only. It’s the most common type of brain aneurysm.
• A fusiform aneurysm bulges out on all sides of the vessel.
• A mycotic aneurysm develops after an infection weakens the artery wall.
• A pseudoaneurysm (false aneurysm) happens when only the outer layer of the vessel wall balloons out, often after an injury or previous surgery.

Are there different stages of an aneurysm?

Aneurysms don’t have formal stages, but doctors do track how they’re likely to behave, mainly based on size, growth rate and location.

Small, stable aneurysms often stay the same size for years and carry a low risk of rupture. These are usually monitored with regular scans, often every 6–24 months, rather than treated straight away. Larger aneurysms, or those growing quickly, carry a higher risk of rupture and are more likely to need treatment. Once an aneurysm ruptures, this is always a medical emergency, regardless of its earlier size or how long it had been monitored.

How is an aneurysm diagnosed?

Many aneurysms are found by chance, during a scan for an unrelated condition. If you have symptoms or risk factors, your doctor may arrange:

• a CT scan or CT angiogram, which uses a dye (contrast) injected into a vein to show your blood vessels in detail
• an MRI or MRA (magnetic resonance angiography) scan
• an ultrasound scan
• an angiogram, where a thin tube (catheter) is passed into an artery, usually in the groin or wrist, and a dye is used to show the exact site of the aneurysm on an X-ray.

The NHS Abdominal Aortic Aneurysm (AAA) Screening Programme invites all men for a one-off ultrasound during the year they turn 65. The aim is to detect abdominal aortic aneurysms before they become large enough to rupture.

How is an aneurysm treated?

Non-surgical treatment

If your aneurysm is small and stable, your specialist may recommend watching and waiting rather than treating it straight away. This usually involves:

• regular scans to check its size and growth rate, often every 6–24 months
• medicines to manage blood pressure or cholesterol, which can help slow its growth
• support to manage risk factors, such as stopping smoking, eating a balanced diet, staying active and reaching a healthy weight.

Surgical treatment

Whether surgery is recommended depends on the aneurysm’s size, location and growth rate, and your own age and general health.

For aortic aneurysms, options include:

1. Open surgery, where the surgeon makes a cut to access the aorta directly and repairs it using a graft (a tube-shaped patch)
2. Endovascular aneurysm repair (EVAR), a less invasive option where a stent-graft is guided into place through a small cut in the groin, without needing to open the chest or tummy.

For brain aneurysms, options include:

1. Surgical clipping, where a neurosurgeon removes a small section of skull to reach the aneurysm and places a tiny metal clip across its base to stop blood flowing into it
2. Endovascular coiling, a less invasive option where a catheter is used to pack the aneurysm with soft platinum coils, sealing it off from the blood supply.

Recovery from clipping can take several weeks to months, including time for the skull to heal, while coiling generally involves a shorter hospital stay. Your specialist team will discuss which option, or whether ongoing monitoring, is right for you.

When should I see a doctor?

See your GP, or call 111, if you have:

• a headache that keeps coming back, doesn’t go away, or is getting worse
• pain above or around one eye that doesn’t go away
• any other symptoms of an aneurysm that persist.

Call 999 or your local emergency number immediately if you or someone else suddenly develops a severe, unusual headache, or any of the other emergency symptoms described above. Don’t drive yourself or the person affected to hospital; wait for an ambulance or ask someone else to drive.