Stephanie Tubbs Jones—the first black woman elected to the U.S. House of Representatives from the state of Ohio—died yesterday evening in a Cleveland hospital, according to several news reports. The Democratic congresswoman was 58 years old.

According to her aides, Jones suffered a ruptured brain aneurysm while driving in Cleveland Heights, a suburb of Cleveland. A police officer saw her car swerve on the road and stopped her. She was rushed to Huron Hospital—part of the Cleveland Clinic—where officials said her condition deteriorated due to complications from a brain hemorrhage.

Tubbs Jones was pronounced dead at 6:12 P.M. Eastern time on Wednesday.

The five-term congresswoman was best known, according to a CNN report, as an outspoken critic of the war in Iraq and was the only representative from the Ohio delegation who voted against the war.

According to neurologist Sean Savitz of the University of Texas Medical School at Houston, two to six percent of the population has an aneurysm somewhere in their body that does not cause them any discomfort. ScientificAmerican.com called Savitz to get more information on brain aneurysms, like the one that precipitated the death of Tubbs Jones. An edited transcript of the conversation follows.

What’s an aneurysm? What happens is a blood vessel becomes like a bulge, and that’s due to a weakening of the wall of the blood vessel itself. The ones that we’re most concerned about are occurring in the arteries. They can occur in arteries that feed the brain and they can occur in arteries in the body, as well.

[In the case of brain aneurysms] the concern is that eventually that bulge will burst. And when it does burst, it leads to bleeding in one of the spaces of the brain called the subarachnoid space—the area [under the skull] that is actually covering the brain tissue. If the blood vessel bursts and you have all this blood that’s on top of the brain there’s going to be pressure that builds up in the brain itself and that can lead to all kinds of problems because the brain is in a closed box—and there’s a very limited number of openings. The brain can get squished through the hole in the skull.

Is there a typical part of the brain where aneurysms take place? According to Rep. Tubbs Jones’ doctors, the aneurysm took place in an “inaccessible” part of the brain. Inaccessible is maybe accessible depending upon the experience of the surgeon. And so, it’s hard to know unless they gave us the real location what they mean by that.

Sometimes they’re so deep in the brain that it would make it surgically difficult to be able to access it. There are lots of different sites that are known where aneurysms can form. They can occur for instance at areas where arteries are coming together. There are some common ones that occur: For instance, there’s the anterior communicating artery, there’s the posterior communicating artery. For the ones that occur in the brain that bulge occurs in a specific artery and then it can just expand over time. And eventually it can burst.

Unfortunately other arteries get affected and they start to constrict. This goes on for awhile. It classically happens between three and 12 days and it’s not really clear why the arteries spasm, but it’s a major cause of morbidity.

Are aneurysms normally found before they burst? They often are found during routine workups. For instance, I don’t know whether the congresswoman had a known aneurysm or if it was found after the workup was done for the hemorrhage that she had.

Often patients will be evaluated for various different reasons and during that workup, they are found to have an aneurysm. Sometimes the aneurysm is considered to be the cause of the patient’s problems and sometimes it’s considered to be incidental.

What would a patient be experiencing if an aneurysm is the cause of their discomfort? There’s a spectrum of possibilities with respect to the clinical symptoms that they have. The most common presentation for someone who is having a hemorrhage from an aneurysm is [a] severe and sudden headache.

Some people will say, “This is the worst headache of my life.” And when people hear that phrase—they’re taught this in medial school—they should be very worried that [the patient] just had an aneurysmal hemorrhage.

What we’ve come to recognize over time is that’s only one presentation. The presentation that should alert the physician to the possibility of an aneurysmal hemorrhage is sudden and severe [headaches]. You can imagine that there are a lot of people out there who have headaches, have migraine disorders. The tip-off is when the headache is different than their typical headache.

People can present with a range of different possibilities: They can lose consciousness. If the aneurysm is big enough, it can cause symptoms without actually bleeding. An aneurysm can cause pressure depending on where it exists in the brain and a number of different symptoms depending on where it is located in the brain.

So that would turn up as numbness or pain? Not usually pain, but weakness in a limb is certainly a possibility. People can get seizures. Cranial neuropathies. The one that is classically taught in neurology is when you may have a visual problem and there’s an exam finding that you have a problem with your pupils. That sometimes can point to an aneurysm in the posterior communicating artery.

Some aneurysms can actually harbor clots. And the clots can get released, and that can cause a stroke, so then they can have the symptoms of a stroke.

What’s the risk that an aneurysm will bleed out? The incidence of a subarachnoid hemorrhage from a ruptured intracranial aneurysm is one case per 10,000. There’s a two to one predominance women to men and peak incidence is 55 to 60 years old. Roughly half of people who have an aneurysmal subarachnoid hemorrhage will die within 30-days

If someone came into the hospital with a ruptured aneurysm, what could you do to treat it? There is a high rate of morbidity and mortality when it comes to an aneurysmal bleed. If the patient makes it in, doctors will grade them in terms of how bad off they are. There’s actually grading scales for aneurysmal hemorrhages. It gives you some prognostic information if you were to do something. For instance,  it depends upon what you’re intending to do.

With subarachnoid hemorrhages, they can cause, as I said, increased pressure on the brain, and people can die from intracranial pressure. So, you might need to put a drain [in] to be able to relieve the pressure. If there’s a huge amount of blood, it may be necessary to try to evacuate the blood.

But, a big issue for surgery is that the aneurysm is still bleeding, so you’ve got to do something about it. You may need to go in and try to clip the aneurysm or try to coil the aneurysm.

What do you mean by “clip” and “coil?” Imagine you’ve got this bulge. And if there’s a neck that’s coming off the artery, you could actually clamp it—put a clip on it. Coiling techniques are not surgery, they’re actually endovascular approaches with a catheter. You go up there and you seal off the bulge

If a patient does not die from a rupture, is he or she more or less certain to suffer lasting brain damage? Among those that don’t, it’s roughly estimated that a third can be disabled.

Would that be both cognitive and movement difficulties? That would be everything. Those people would be disabled because of cognitive problems or because they are weak. They can’t move a limb or are having difficulty moving a limb.

How do avoid having an undiagnosed aneurysm burst? Get screened if you have high blood pressure? Just high blood pressure has not been found to be enough of a risk factor to say those are the ones that should get screened. Family history of cerebral aneurysm is a reason to actually be screened. There are genetic predispositions to aneurysms.