A tangle of veins the size of a cue ball are wrapped around an artery adjacent to her central brain stem.It’s called arteriovenous malformation (AVM for short), and is a rare and abnormal connection between the arteries and veins in her brain. In medical images, its appearance is similar to a ball of yarn, except that the strands (thin-walled veins) grow and bulge under the constant high pressure of blood flow. The risk of a devastating or deadly rupture is perpetual.

Also dangerous is the uncontrolled growth of this vein-tangled tumor — the more space it takes up in the brain, the more neurons and nerves are squished — leading to dizziness, headaches, seizures and loss of muscle control.The AVM is to blame for the loss of dexterity in Chloe’s right hand, the stiffness on the right side of her mouth, and the persistent spasms from her chin down to her collar bone.

AVM’s are found in about 1 percent of the population, according to Mayo Clinic. Often, it is in the brain or the spinal cord.

Chloe’s case is unique. The AVM is very large and deep in her brain — in the left thalamus, beneath the cerebral cortex and right at the top of the brain stem. The thalamus controls motor functions, receives and sends visual, auditory and other sensory signals to the cerebral cortex and controls sleep and wakefulness.

The AVM’s size and location make it too big to remove surgically and too risky to treat with the most recommended course of treatment: embolization, in which a gluelike substance is inserted into the artery at the vein, which cuts off its blood supply and causes the tumor to die.

Instead, Chloe is undergoing stereotactic radiation — in which radiation is beamed into specific points in the AVM. If the treatment works, the tumor will stop growing and ultimately shrink — perhaps even enough to be removed surgically.

Maybe …

“Chloe’s case is complicated,” explained Amber Nore, Chloe’s mother, a single parent who has raised her only child alone since Chloe’s birth on Jan. 19, 1999.

Hospital staff tell Chloe she’s a big deal there, alluding to her unique AVM and the treatment they are trying.

But Chloe shrugs it off.

“I don’t freak out that something could happen,” she said. “Nothing has happened. … That’s how I think about my whole life.”

Spoken like a 14-year-old.

Talented and poised, the Irving Middle School eighth-grader recently returned to the stage, landing a role in the upcoming Nebraska Youth Theatre production of “Much Ado About Nothing” at the Haymarket Theatre. She recently played Frenchie in the theater’s staging of “Grease.”

She loves to sing. Loves to dance. Loves to act. Her dream is to attend New York University. A Make-A-Wish trip to the Big Apple in June will allow her to check out the school, as well as take in a couple of Broadway shows, visit the Statue of Liberty and Empire State Building, and nosh on famous New York pizza, bagels and sushi.

Unfortunately, she has had to give up some dreams: cheerleading at Lincoln Southeast High School in the fall; en pointe ballet; gymnastics and tumbling; and a Campus Life visit to a water park this summer.

They’re all too risky. A minor bump to the head could cause a vein to rupture — leading to stroke-like consequences such as paralysis and loss of cognitive abilities. According to Johns Hopkins School of Medicine, about half of all AVM’s are discovered when they rupture. One in 10 of those people will die.

To date, Chloe has not experienced a brain bleed. She does not have seizures.

But she does have physical impairments.

Her balance is wobbly. Her right side — once her dominant side — is weak. Words sometimes get tangled in her mouth. She knows them, they just don’t come out right — or come to mind as quickly as they used to.

“What really bothers me is my right hand goes into position it does,” she said, noting how the fingers freeze in a claw-like grasp. “I get frustrated by the symptoms.

“And I’m always tired. I go to sleep and I wake up tired,” she said.

* * *

Cramping in Chloe’s right hand and foot were the first symptoms.

It started two years ago when Chloe was in sixth grade.

She had trouble holding a pen. She had trouble writing — especially keeping up with taking notes in class. Sometimes her right foot would drag. She was getting clumsy for a dancer.

The doctor could find nothing wrong.

Chloe will grow out of it, he assured mother and daughter.

But she didn’t. The pain increased. Her balance worsened. Never-ending fatigue consumed her. Always an A student, Chloe’s grades dropped. She failed tests — unable to finish in the time allotted.

“She was using her left hand to wrap and unwrap her fingers (around the pen),” Nore recalled.

“I was told so many times that I would grow out of it, that I just waited,” Chloe said.

Chloe’s difficulties came on top of other pressing concerns. Nore’s employer lost its contract with the Nebraska Department of Health and Human Services, and Nore lost her job. She enrolled in graduate school.

Sensing opportunities elsewhere, Nore and Chloe spent last summer in California, contemplating a permanent move and a fresh start.

At Nore’s insistence, Chloe’s doctor scheduled her for an MRI. She had it the day before they left. It revealed the AVM.

Nore consulted doctors in California. They said the best treatment for Chloe was Novalis Radiation — a highly precise and specific form of stereotactic radiation. Only 300 hospitals worldwide have the machine, including the University of Nebraska Medical Center in Omaha.

So Nore and Chloe returned to Nebraska.

Because Chloe’s AVM is so large, doctors performed the procedure in two phases six months apart — each time treating half of the AVM.

The first procedure was Nov. 20, 2012. The last was May 2.

The radiation part of the procedure lasts about 30 minutes. It’s the preparation that takes hours upon hours. A halo — similar in size to a football helmet minus the dome — is screwed into Chloe’s skull — two screws in her forehead, two in the back.

“The first time it felt like buffalo clomping around. I broke down,” Chloe recalled. “This last time, it wasn’t not so bad.”

Relatively speaking.

Both times, she waited eight hours between the installation of the halo and the actual radiation treatment — as doctors mapped out a precise plan targeting different degrees of radiation for different areas of the AVM.

Doctors warned them that it may take one year or longer to see if the Novalis Radiation is shrinking the tumor. Still, Nore and Chloe were hopeful that the MRI prior to the May 2 radiation would show improvement.

Instead, it showed no change in the AVM. Bittersweet news, Nore said. The tumor hasn’t grown, but it isn’t any smaller.

* * *

Chloe returned home the day after the procedure. She was back in school on Tuesday.

She relishes the normalcy — classes, friends and hanging out. She recently received the Irving School’s Excellence Award for character. Her grades are back to As and Bs. Adaptations to her schooling helped make it possible — instead of taking PE, she serves as the teacher’s assistant; she rides the elevator, rather than taking the stairs; she takes some of her tests orally and gives her answers in a different format; class notes are pre-typed for her. It’s nice, but Chloe wishes should could be just like everyone else.

“I love writing,” Chloe says. “I don’t free write anymore,” she said noting how hard it is to physically write. “Because of that I don’t have a way to express myself. I know I can do it through singing and dancing, but not through any type of art or writing.”

Nore would like to get Chloe a computer that types the words she speaks — or even a special keyboard. But both take money. Money that is spoken for in bills: uncovered medical expenses, living expenses and non-medical therapies for Chloe, such as massages to loosen taught muscles, visits to the chiropractor and yoga classes to improve her balance and synchronicity.

Compounding the struggles — last week the car suddenly stopped working.

It is overwhelming, said Nore, who works part-time in retail while taking college classes.

While Chloe finds friends, theater, classes and dance distracting from the time bomb in her skull, Nore isn’t able “to turn off my mom brain.”

The part of the brain that worries. The part that reminds her that something could go wrong in an instant. The part that needs to have someone always watching Chloe … just in case.

“It’s a total roller coaster all the time,” she said. “Best case … worst case … I don’t know how to handle it. I can’t hover and be by her side all the time. I wish I had control over things I don’t have control over. … I don’t want to live like she is going to die.

“Chloe is so bright and strong. … I am impressed by her spirit.”

The teenager shrugs.

“I don’t look at the negative,” Chloe states matter of factly. “I look at the positive.”