The ‘other’ stroke: How brain aneurysms affect stroke risk


Ruptured brain aneurysms can cause “bleeding strokes.” Blood fills the space between the brain and skull, which can be deadly if not treated quickly.

When people hear about strokes, they think mostly about ischemic stroke – a blocked artery or a blood clot lodging in the brain, usually in someone older, and often because of plaque buildup. This is the most common type of stroke.

But we also see patients for another type of stroke, which is not caused by blocked blood vessels. Hemorrhagic strokes are caused by brain aneurysms that rupture. Let’s take a look at what brain aneurysms are, how we treat them, and how an aneurysm-related stroke can be prevented.

What is a brain aneurysm?

A brain aneurysm is a weakness in the wall of a blood vessel in the brain. The blood vessel inflates in the weak area, similar to blowing up a balloon. That area can get thinner and weaker over time, and at some point can rupture.

Ruptured brain aneurysm symptoms can include:

  • An excruciating headache
  • Blurred or double vision
  • Seizures
  • Sudden numbness of the arm, leg, or face, often on one side of the body

When a brain aneurysm ruptures, it causes bleeding in the subarachnoid space (the space around your brain) and into the head, which causes a hemorrhagic stroke (also known as a bleeding stroke). Once an artery has bled, it is likely to bleed again and needs to be treated right away.

We treat 200 to 300 brain aneurysms each year. To put that in perspective, a typical community hospital would likely see only five or six per year. The rest are referred to specialized centers such as ours.

Brain aneurysm treatment

There are two populations of aneurysm patients: those whose aneurysms have ruptured and those whose aneurysms have not ruptured. These unruptured aneurysms often are discovered by happenstance.

In the late 1980s to early ’90s, the use of MRI to look at the head became convenient and popular among nurses and doctors. With more MRIs being performed, more tumors and evidence of ischemic stroke were found. But we also started to find unruptured brain aneurysms.

Back then, we considered unruptured aneurysms as serious a diagnosis as ruptured aneurysms. We’ve learned since then that not all unruptured aneurysms put patients at risk. However, aneurysms become very dangerous when they rupture.

For decades, if a patient came in with a ruptured brain aneurysm, we would treat it with a craniotomy. This is a procedure that involves removing a piece of skull bone and navigating the brain to find the blood vessel with the weak spot and then sealing off the aneurysm with metal clips to keep blood from flowing into the aneurysm. The blood vessel from which the aneurysm arises must be preserved so blood can reach the brain.

In the 1990s and 2000s, new treatments that were much less invasive were developed. Today, we navigate the body’s natural highway system – the arteries – to find the affected blood vessel. We use X-ray guidance to send a send a small catheter and wire through the arteries to reach the aneurysm. Then we will seal off the aneurysm from the inside with a metal coil. No removal of skull bone required!

The surgery to repair unruptured aneurysms also has improved greatly. First, we seal off the aneurysm with metal clips, then we deflate the “balloon” part of the aneurysm – the sac that is at risk of rupturing. The surgery takes just a few hours, and patients will likely be in the hospital for just two to three days with a few weeks of recovery at home.

This is much different from recovery after an aneurysm ruptures. Patients who’ve suffered a ruptured aneurysm often are in the hospital for two to three weeks and typically require rehabilitation and additional treatment after brain aneurysm surgery.

Can an aneurysm or hemorrhagic stroke be prevented?

We don’t yet know exactly what causes a brain aneurysm, but there are certain risk factors for forming one, including:

  • Family history. Research suggests that 6 percent to 20 percent of people who are treated for hemorrhagic stroke have two or more family members who also had brain aneurysms.
  • Being female. Women are more prone to aneurysms than men for reasons we don’t fully understand yet.
  • History of smoking. Smoking causes high blood pressure (hypertension) and a generally unhealthy environment for the brain.
  • Hypertension. If you have high blood pressure, your blood vessels are more prone to weakening because of the long-term excess pressure on the vessel walls.
  • Inflammation. We think inflamed cells cause arterial walls to weaken. Research is underway to determine how much inflammation affects aneurysm risk.

Researchers also continue to study which combination of medical therapy is the secret recipe for preventing aneurysm-related stroke. We don’t yet have an answer, but we know lifestyle choices play a major role in prevention.

The strongest culprit is smoking. Not smoking is one of the most important things you can do to keep your blood vessels healthy. Smoking increases your risk for high blood pressure and creates a hostile environment for your blood to circulate in a healthy way.

There also have been major improvements in medications to lower high blood pressure with fewer side effects. Cardiologists have done a good job of figuring out what a reasonable blood pressure is. We now know that not every person has to have a blood pressure of 120/80, but we can’t have blood pressures up in the 150 to 160 range every day or our risk of stroke increases.

There’s also more public awareness about preventive medicine and making better nutrition and exercise choices. More people are choosing to see their doctors to have their risk factors explained, and doctors are offering more options for prevention as opposed to starting with medication.

What more medical professionals have come to realize is it’s much easier and more effective to help people make better lifestyle choices – eating right, staying active, not smoking – than to try to fix a complicated aneurysm or rehabilitate people from strokes that leave them paralyzed.

Though the absolute causes of brain aneurysm are still being researched, it’s vital that we make healthy choices every day to reduce our risk for stroke. Request an appointment to discuss your risk factors and what you can do to prevent aneurysms and strokes.