For Ellen Christian, 18, the pain started as a twinge in her knee while on vacation five years ago. In a matter of three months, she was bedridden.
"It just was burning, all the time, like someone had a flame right underneath my knee and it was burning, and then someone was just stabbing it, all the time," she explained.
Christian said there soon came a point when taking a shower was excruciating.
"The shower would be the most painful experience because water hitting it was not fun. So I had to learn how to shower holding my leg out of the water, which didn't really work, but it was just nothing could touch it, and it was unrelenting."
Dismissed as growing pains
At first, Christian's pain was dismissed as growing pains, but soon it was clear it was more than that. Her parents took her to their family doctor, who was baffled.
"We had had X-rays, there was no break. We then had an ultrasound, and there didn't seem to be any muscle damage," said Ellen's father, Jonathan.
"He'd referred us to an arthritis specialist who did all the blood tests, and said there is no arthritis. We looked at a pediatric surgeon, and then he looked at her X-rays and said there is nothing wrong, and at this point, the knee is almost three times the size of the other knee."
Christian's family doctor referred her to the pain clinic at B.C. Children's Hospital in Vancouver, but he said the wait list would be at least six months.
By then, Christian was in a wheelchair and unable to go to school, so her family made an emergency visit to the Children's Hospital, and she was able to see a pain specialist two days later.
That's when she finally got a diagnosis: complex regional pain syndrome, also known as CRPS.
'I'm not psychotic'
"It was a flooding of relief," Christian said. "I am not crazy. I am not psychotic. There is something wrong with me. It was just that complete relief of just, OK, at least someone believes me."
Pain specialist Dr. Gillian Lauder, who treated Christian, said CRPS is an immune-neurological condition, that can result in extreme pain and sensitivity in the affected area, usually a limb, and can spread to other parts of the body.
"CRPS is one of the most fascinating pain conditions that we have. There is no unifying mechanism of what's happening," she said.
'The younger they are, the less likely they are to be able to voice specifically what they are feeling.' - Gillian Lauder, pain specialist
In many cases there is no clear injury, and in some cases with children, there is not even an old injury to trace the pain back to, which Lauder said can make the pain hard to diagnose.
There are also some other challenges when dealing with pain in kids. Lauder said on average, kids have seen eight doctors before they have gotten to her.
"The younger they are, the less likely they are to be able to voice specifically what they are feeling," Lauder said.
And it is tough with older kids, too.
"All they see in a 10-minute appointment is an unhappy teenager, and it is difficult to tease out what are the barriers and what are the inciting events and what are the principle things that are preventing a return to function," she said.
Takes toll on parents
Lauder said it also takes a toll on parents, who are trying to do everything they can for their children and are confronted with a lack of answers.
"Presented with a child who is getting anxious and depressed and sad because no one is believing them and … their parents, who are the problem solvers in their family, are not the problem solvers anymore," she said.
"There is a change in the family dynamic."
As with most chronic pain, there usually isn't a silver bullet to solve the problem.
Christian needed a multidisciplinary approach with physiotherapy, counselling and drugs, which she is no longer taking.
She said she hasn't had a pain-free day in the five years since her problems started, but her condition has greatly improved and she had gotten nearly all of her movement back.
She just returned from a volunteer trip in the Solomon Islands and is now mentoring other kids in pain.
"It is that community of 'I understand, you are not crazy,' but you need to fight, and they and have inspired me to keep fighting," she said.