A fusiform aneurysm causes the artery to bulge or balloon on all sides. This type is less common than a saccular aneurysm, which causes a bulge on one side of the artery.

An aneurysm is a weakness in an artery wall that causes it to bulge.

Doctors may find it more difficult to treat a fusiform aneurysm, as this type does not feature a “neck” that they could seal off from the main artery. Because of this, fusiform aneurysms may present a higher risk of complications than saccular aneurysms.

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An aneurysm occurs due to weakness in an arterial wall.

Common causes of fusiform aneurysms include:

  • Atherosclerosis: Atherosclerosis occurs when a plaque buildup around the artery wall causes the arteries to narrow.
  • Arterial dissection: An arterial dissection is a tear inside an artery wall that allows blood to leak between the layers of the wall and separate them.
  • Disorders of collagen: Disorders that affect collagen, such as Marfan syndrome, can lead to a fusiform aneurysm. This is because low collagen levels can weaken the arterial walls.
  • Infections: Infections that affect the arteries may weaken arterial walls and lead to a fusiform aneurysm.

According to the American Heart Association, risk factors for aneurysms include the following:

Risk factors for atherosclerosis, which include smoking, high cholesterol, and diabetes, may also increase the risk of fusiform aneurysm.

Aneurysms do not always cause symptoms. However, fusiform aneurysms are more likely to be symptomatic than saccular types.

Fusiform aneurysms usually occur in the brain and may cause the following symptoms:

A brain aneurysm may rupture and cause bleeding in the brain. This is a medical emergency and may lead to severe complications, including permanent brain damage and death.

A ruptured brain aneurysm may cause the following symptoms:

  • sudden, severe headache
  • nausea and vomiting
  • neck stiffness or pain
  • blurred or double vision
  • weakness on one side of the body
  • sudden confusion
  • loss of consciousness
  • seizures

A doctor may diagnose a fusiform aneurysm using the following methods:

  • asking questions about symptoms
  • assessing a person’s medical history
  • using an MRI or CT scan to provide images of the aneurysm
  • using MRI or CT angiography to provide images of the affected arteries
  • using a cerebral angiography to help identify weak spots and blockages in the arteries
  • performing a cerebrospinal fluid (CSF) analysis to measure chemicals in the cerebrospinal fluid and detect bleeding around the brain

If a doctor considers the risk of rupture to be low, they may want to actively observe the aneurysm through regular imaging scans. If necessary, they may suggest lifestyle changes, such as maintaining a moderate weight and stopping smoking, and prescribe medication to lower blood pressure.

If a doctor believes preventive treatment is necessary, they may recommend surgical treatment.

Doctors may find it more difficult to treat a fusiform aneurysm than a saccular aneurysm.

Treatment for an aneurysm often involves:

  • Neurosurgical clipping: This is a surgical procedure in which a surgeon locates the aneurysm and seals it shut with a small metal clip.
  • Endovascular coiling (coil embolization): In this procedure, a surgeon guides a catheter through an artery in the leg or groin until it reaches the aneurysm. The surgeon then passes small platinum coils into the aneurysm through the catheter, which seals it off from the rest of the artery.

However, as a fusiform aneurysm balloons the artery from all sides, rather than causing a bulge on one side, as with saccular types, it may be difficult for a doctor to isolate it from the artery.

Doctors may use more advanced surgical techniques, which may include:

  • Flow diversion devices: In this procedure, a surgeon inserts a small tube called a stent into the artery to decrease blood flow to the aneurysm.
  • Stent-assisted coiling: During this procedure, a surgeon uses two small catheters to place a stent into the aneurysm and perform coil embolization.
  • Bypass: In this procedure, surgeons remove a blood vessel from another area of the body and use it to divert blood flow around the aneurysm.

A person will require emergency medical treatment if a fusiform aneurysm ruptures. A doctor will usually administer nimodipine (Nymalize), a calcium channel blocker, to help reduce the risk of blood supply disruption to the brain.

Surgeons will try to repair the ruptured aneurysm with clipping or coiling procedures.

A person should contact a doctor if they experience symptoms of a fusiform aneurysm. Active monitoring or preventive treatment can lower the risk of rupture and other complications.

A ruptured aneurysm is a medical emergency that can lead to severe complications and death. A person should seek emergency medical attention immediately if they or someone else experiences symptoms of a ruptured aneurysm.

A person can live with an unruptured aneurysm without symptoms or complications. However, a ruptured aneurysm may cause severe health complications and death.

Fusiform aneurysms may be more challenging for doctors to treat. Experts also associate this type of aneurysm with a higher risk of complications, such as rebleeding. Rebleeding is a second rupture that occurs before doctors have treated the initial rupture, which may cause further damage or death.

According to the Brain Aneurysm Foundation, 50% to 80% of brain aneurysms remain unruptured.

Aneurysms that rupture result in death for 25% of people within 24 hours and 50% of people within 3 months.

What is the most common location for a fusiform aneurysm?

Fusiform aneurysms usually occur in the brain.

How serious is a fusiform aneurysm?

The severity of a fusiform aneurysm can depend on several factors, including its size, location, and risk of rupture. Fusiform aneurysms can present a higher risk of complication than saccular aneurysms.

What is a saccular aneurysm?

A saccular aneurysm is a rounded, bulging sac on one side of an artery, which resembles a berry hanging from a branch.

A fusiform aneurysm causes the artery to bulge on all sides rather than ballooning on one side of the artery like a saccular aneurysm.

Doctors may find fusiform aneurysms more challenging to treat than saccular aneurysms due to their shape. Surgeons may need to use more advanced surgical techniques to seal the aneurysms, such as flow diversion or bypass procedures.

Fusiform aneurysms may present a higher risk of complications, such as rebleeding.

A person should contact a doctor if they have symptoms of an aneurysm and should seek immediate emergency medical care if they have symptoms of a ruptured aneurysm.