At first, Jess Boxley was sure the headaches were just a kind of “brain freeze.”

As the Daily Mail reports, the 22-year-old nursing student from Tipton, England, began experiencing bad headaches. But based on her medical knowledge, she wrote it off as a side effect of the drafty room she slept in.

Boxley told the Daily Mail that she even laughed off the temporary vision loss and pain:

“Sometimes everything would go completely black for 10 seconds, and I wouldn't be able to see. I joked to my mum that I was going blind. But over the next few days it got worse.”

She added:

“I thought I'd slept in a funny position, or that there was a [draft]. But then I developed really bad headaches, like migraines.”

Boxley began taking acetaminophen to deal with the constant pain in her head and neck. But it soon became clear that the headaches were getting worse.

Before long, Boxley began missing her nursing classes at Birmingham City University. The pain was so severe, it was impossible to concentrate. She told the Mail:

“The headaches were like a really bad pressure. It felt like my head was going to explode. I started going to bed at 8 pm every night, just to escape the pain.”

When the headaches started waking her up in the middle of the night, Boxley knew she needed help.

A visit to the doctor ended with Boxley being referred to an optician. To her alarm, after conducting a few tests and taking a photo of the back of her eye, the optician sent Boxley directly to the hospital. Boxley recalled:

“They sent me in an ambulance to the accident and emergency department straight away. They said it wasn't safe for me to walk the small distance between the departments.”

That's when Boxley learned that her headaches were actual the result of intracranial hypertension, a build up of pressure around the brain. The life-threatening condition is usually caused by an injury, stroke, or brain tumor. However, in Boxley's case, doctors couldn't figure out what caused it.

Boxley spent five days in the hospital, where she was treated with a series of lumbar punctures to remove excess fluid from her brain and relieve the pressure. Luckily, the treatments were successful.

Though she has since been discharged from the hospital, Boxley continues to go for frequent checkups to ensure that her intracranial hypertension has not become a chronic condition.

Knowing that she could have gone blind or died has made Boxley an advocate for frequent vision tests. She told the Mail that her narrow escape left her shaken, especially since she hadn't realized how serious her headaches really were:

“I researched it and found out it could be life-threatening if it's not treated. It was a huge shock to me. I knew the headaches were bad, but I never thought it could be such a serious brain issue.”

According to the National Eye Institute, the most common symptoms of intracranial hypertension are vision loss (including temporary blindness, double vision, poor peripheral vision, and blind spots), headaches, pain in the neck or shoulders, and ringing in the ears.

Intracranial hypertension is most common in women between the ages of 20 and 50. Risk factors for the condition include obesity (defined as a BMI over 30) or a gain in total body weight of five to 15 percent.

According to the Glaucoma Research Foundation, adults under the age of 40 should have their eyes checked every two to four years. Those between 40 and 54 should get checked every one to three years, and those over age 55 should get an exam every one to two. For those with higher risks, they should be checked every one to two years after age 35.