Bleeding in the Brain Runs in Families
The researchers found that first-degree relatives of SAH patients are three times more likely to develop SAH.
Next, the Danish group hopes to determine why SAH tends to cluster in families. "We feel fairly convinced that the reason ... is genetic, but we don't know it," Gaist says.
In addition, the overall incidence of SAH was only 9.25 per 100,000 person-years in the general population. "Increasing that risk three-fold still makes it pretty uncommon," Gress tells WebMD. "Physicians who don't deal with this a lot shouldn't make the family feel that they're at high risk because Grandma had SAH. The added risk isn't that great," he says.
Nevertheless, he says, the results "bring up the next common question: If my sister died of an SAH, should I get screened, looking for aneurysms?"
Gress says that the answer is not clear-cut. Since many people with aneurysms live their entire lives without them ever rupturing, and since treating aneurysms introduces new risk, screening may not reduce the risk of harm. "It's one thing to say that there's an increased risk, but it's another thing to say we can impact that risk by screening," he says.
"I'd shy away from saying family members should be screened and treated -- it's not clear to me yet that's the best thing to do," Gress tells WebMD. "But the take-home message from this [study] is that we need to keep asking that question."
- Subarachnoid hemorrhages (SAH) are a type of stroke that occurs when an aneurysm in the brain ruptures and bleeds into the space that covers the brain.
- People who have a close relative who has experienced SAH are three to five times more likely to experience this type of stroke compared to the general population, but the overall risk is still very low.
- Relatives of SAH victims may ask their physicians to be screened for aneurysms, but it is not clear whether screening will help patients in any way.