WHEN little Samuel Cheetham's alarm goes off his school friends rush to specially trained teachers for help.

The pump in his backpack must be changed immediately to maintain the delivery of life-saving medication being fed into his bloodstream 24 hours a day.

Because Sam, six, has primary pulmonary hypertension which, unchecked, would destroy his lungs and bring him to an early grave.

The condition has been relatively stable for nearly two years but he has been assessed for a heart-lung transplant in case it proves necessary later.

Parents Tim and Karen didn't know there was anything seriously wrong until he was nearly four. His lethargy and shortness of breath was put down to a virus, a chest infection and asthma before the real reason for his rare condition was discovered.

"He went downhill very quickly," said Karen from her Ashley Heath home. "His disease was so vicious - we didn't think we were going to keep him."

Now a patient of world-famous paediatric unit Great Ormond Street Hospital, Sam receives a constant dose of epoprostenol, a vasodilator which relaxes the blood vessels and partly eases the strain on his heart.

"Without it he wouldn't be here," said Karen, 43. "We feel very fortunate to have him treated at Great Ormond Street."

At one time the Cheethams were warned Samuel could die within 10 to 18 months.

"But since he's been on this medication he's been better," said his mother.

The Cheethams try to give Sam as normal a childhood as possible.

"When you know you have got this hanging over your head you want to make the best of every moment, even when he's really poorly in hospital," former insurance worker Karen said.

Sam attends St Ives First School. Karen can't speak highly enough of the children or staff - teachers have gone to GOSH in their holidays to undertake training to care for Sam.

The family is putting on a fund-raising event next week in aid of the Pulmonary Hypertension Association and GOSH to whom sales engineer Tim, 45, and Karen are especially grateful.

"They are the people that have given us a future with Samuel, even though it might even be a short one," Karen added.

Crafts will be on sale at the cream tea event in the Cheet-ham's garden at 101 Woolsbridge Road, Ashley Heath, from 1.45pm until 4pm on May 19.

Factfile

Primary pulmonary hypertension

Primary pulmonary hypertension is extremely rare, occurring in about two per million of the population per year

The arteries in the lungs narrow so that blood flow is restricted. The heart has to work much harder to pump the blood through the lungs which can in turn cause cardiac problems

Symptoms include chronic fatigue, shortness of breath, angina and collection of fluid in ankles, legs and abdomen

There is no cure

PH is called primary when there is no known cause

Secondary PH - which is not quite so rare - can occur following breathing disorders such as bronchitis. Less commonly it occurs in patients with congenital heart disease, liver disease and inflammatory disorders like lupus

First published: First published: May 13