COCO is a life-saver as far as Broadstone woman Karen Ruddlesden is concerned.

The chocolate Labrador is the first dog in the world trained to detect her rare disorder Addison’s disease, which can be fatal if not treated quickly.

Two or three times a week he alerts her in time to prevent her falling into a coma.

“He’s my knight in shining armour – with a tail,” said Karen.

Having the lively 17-month-old dog around has changed the life of Karen, 40, who had to give up work as a chef seven years ago after being diagnosed with the disorder.

“It is difficult to live with and difficult to plan too far ahead,” said Karen, but Coco has given her a new lease of life.

“People have already noticed that I am much more confident since having Coco.

“He’s totally changed my world.”

The disease is a complication of serious health problems she has had all her life and symptoms include severe pain in the legs, lower back or abdomen, vomiting and diarrhoea, loss of consciousness, confusion, convulsions and fever.

Her adrenal glands do not produce enough steroid hormones and in the last four years it has become even more difficult to control as she has had her adrenal glands removed due to tumours.

“Managing Addison’s disease is a bit of a juggling act, getting the correct balance of medication to lead a normal life,” she said.

Last year she had three emergency admissions to hospital and on one occasion she was not expected to last the night.

Coco has been trained by Cancer and Bio-detection Dogs in Aylesbury, Bucks, to act as an early warning system, detecting when Karen’s cortisol levels are low and giving her more time to inject herself with steroids.

He carries her injection kit in his vest and will lick her hand and sniff her breath if he detects her cortisol levels are dropping, jumping on her if she is asleep and persisting until she reacts.

“I ignored him once and within half an hour I was really ill.

“I did pay for it. That taught me,” she said.