Caroline McCaffrey usually runs in the morning, but on Father’s Day 2025, she felt tired and decided to work out in the evening instead. She invited her mother, Kim, to ride her bike with her.
Just minutes into her run, Caroline, then 18, felt a “huge headache.” She had experienced and been treated for migraines before, but this was a new sensation.
“It felt like I’d been punched in the face,” Caroline said. Within minutes, she started vomiting. She couldn’t walk, so Kim called her husband to pick them up. When the symptoms didn’t subside immediately, King began to panic.
“When she was vomiting, I Googled signs of a brain aneurysm (rupture). My husband said, ‘Do you think this is what it is?’ and I was like, ‘I don’t know. This isn’t normal,'” King recalled.
At an area hospital, Kim quickly raised her concerns, but Caroline’s doctor was skeptical.
“I was like, ‘I’m pretty sure she has a brain aneurysm or a ruptured brain aneurysm,’ and he said, ‘I don’t think we should go there yet,'” King recalled. Caroline took another dose of migraine medication, but it had no effect.
A few hours later, a second doctor ordered a CT scan. That test found bleeding on Caroline’s brain. Caroline said she was relieved to be able to receive treatment.
“I think I was in so much pain that I wasn’t even scared,” Caroline said.
Treating a fatal diagnosis
Caroline was transferred to the University of Maryland Medical Center. The next day, she woke up in the intensive care unit and discovered she was bald. Her parents told her: tests revealed two brain aneurysms. Dr. Gunjan Parikh, a neurointerventional specialist, said one of them ruptured and caused an aneurysmal subarachnoid hemorrhage, which caused her symptoms.
This condition usually affects people in their 50s. It’s a dangerous diagnosis, Parikh said: About a quarter of patients with aneurysmal subarachnoid hemorrhage die before reaching the hospital. Another 13% of patients died in hospital. But Carolyn was lucky: Dr. Jacob Cherian, a neurosurgeon, treated the ruptured aneurysm and repaired the damaged brain tissue. King said despite the delay in care, she was treated “very quickly.”
McCaffrey family 
Caroline said she was “completely shocked” by the news. It took her several days to “understand what was happening.”
“Once I did that, I was ready to get things moving and start treatment,” Caroline said. “Once I got rid of it, I just wanted to get the thing on the road.”
It’s going to be a long road. The drains were still draining fluid from her brain. She requires regular ultrasounds and monitoring to make sure she doesn’t have any strokes or seizures, as well as occupational and physical therapy. She then underwent another surgery to remove a second aneurysm. Three weeks later, she was finally discharged from the hospital.
McCaffrey family 
Find family connections
Meanwhile, Caroline’s parents are trying to figure out how their 18-year-old daughter ended up in such dangerous condition. As they worked through the family history with Caroline’s care team, they realized that Caroline’s great-grandmother suffered an aneurysm in the 1960s.
This suggests that Caroline’s condition has a genetic cause. The McCaffreys were encouraged to get tested for other potential aneurysms. Typically, about 1 in 50 people will have an aneurysm, but if you have a first-degree relative with an aneurysm, the chance may be about 1 in 50, Cherian said.
“Caroline was very young, 18, for something like this to happen. So that was already a clue that maybe there was something going on in the family,” Cherian said.
Kim was the first family member to be tested. A CT scan revealed two small aneurysms, which Cherian underwent surgery to remove in November 2025.
McCaffrey family 
Neither Kim’s husband nor her son had aneurysms, but her sister-in-law had two. King said other family members are continuing to be tested.
It’s unclear why both sides of the family are prone to aneurysms, but Parikh said there may be a genetic component. Cherian said neurologists aren’t sure why aneurysms form, but they can run in families.
“Caroline said, ‘Well, I’m tired of saving people’s lives,'” Kim joked.
“Now I have a reason”
The McCaffreys have now fully recovered from their aneurysm experience, although they will be monitored regularly for the rest of their lives. Carolyn, now 20, is a junior at Bucknell University and has returned to running competitively.
She also participated in a study by the National Institutes of Health. The study recruited thousands of patients to study the effects of aneurysms and strokes on the brain over many years. Parikh said the data she could provide were unique because she was young and suffered from bleeding symptoms common in older patients.
University of Maryland Medical Center 
“It really gives scientists an immediate way to see the human brain at its maximum potential to repair itself. It allows us to reverse engineer other people to some extent,” Parikh said. “You’re looking for a biological blueprint, and the ultimate goal of this research is to figure out how to use drugs or pharmacological or physiological approaches to trigger the exact same youthful healing pathways in patients who are 60 or 70 years old.”
Caroline is also participating in a study that is using blood tests to look for biomarkers that may indicate a person’s risk of developing an aneurysm. She also works with several charitable organizations and is interested in starting her own foundation dedicated to helping young aneurysm survivors. After college, she wants to explore becoming a nursing anesthesiologist—another goal inspired by her experience.
“I really fell in love with the nursing staff at the University of Maryland. They were like friends to me,” Carolyn said. “So now I’m doing advance care. I feel like that’s right up my alley and now I have a reason to do it.”