A DENTIST who only found out she had a life-threatening brain tumour after being involved in a car crash is running a half marathon to raise money for a charity that supports people with brain injuries.

Kathryn Smith, of Chipping Sodbury, said she might not be here today if it wasn’t for a minor car crash she was involved in at the age of 17 while on an American exchange trip.

Initially doctors thought she had whiplash, but a few days later she started to see black spots in her eyes and couldn't move her left arm.

Checks at the hospital revealed a brain tumour that was haemorrhaging. Doctors said they believed it was a slow growing tumour that was likely to have been there several years and that in effect Kathryn was a ticking time bomb.

"Basically they told me I could have had a stroke and dropped down dead at any time," said Kathryn, now 29.

"It is strange to think that a car crash could save your life, but for me it did."

She was rushed into theatre for an operation to remove the tumour, which went well, but a few days after being discharged she came down with meningitis and had to return to hospital for treatment.

After recovering she continued on her exchange trip, but soon she noticed the back of her head becoming ‘squidgy’ and doctors found she had excess fluid on the brain.

This involved another serious operation, which resulted in Kathryn being fitted with a permanent small pipe to drain fluid from the brain which sits under the skin.

Looking back she said she had suspicions all along that she had a brain tumour.

"I had been suffering with bad headaches for two years before that accident," said Kathryn, who works at Chipping Manor Dental Practice in Wotton-under-Edge.

"I had seen GPs and neurologists but they just gave me painkillers and told me to go away, one neurologist even told me I was just a moody teenager.

"I had even had recurring dreams that I had brain cancer, but when you are told by doctors it is nothing serious you just believe it."

By the time Kathryn had fully recovered she had to re-do a year at school to get the grades she needed to go on and study to become a dentist.

She still believes she was incredibly lucky to have caught the tumour in time and to now be living and full and healthy life.

"I have met a lot of people with brain injury who are severely disabled and to look at me you would never know I had suffered serious brain injury, I just feel really lucky and want to give something back."

She will be running the Bath Half Marathon on March 7 to raise money for Headway, a charity that works to improve the life of those with brain injury.

To sponsor Kathryn visit her donation page at www.justgiving.com/katsmith1980