Exhaustion goes with the territory when you have two children under the age of 2. But by the time Jocelyn Barker’s second baby was 6 months old she knew her extreme tiredness wasn’t normal. She recalls: “When I put the babies into their car seats I was getting completely out of breath. I was 33 and didn’t want to believe that there was anything wrong and I kept resolving to get fit. But I just got worse.”

Barker, now 45, a vicar’s wife from South London and a former advertising manager for Harpers & Queen magazine, eventually was told she had pulmonary hypertension, a rare and incurable lung disorder. It affects about 4,000 people in the UK, but it is estimated that there are another 4,000 undiagnosed cases.

On average it takes two years to get an accurate diagnosis, partly because the symptoms are easily confused with other conditions, such as asthma, and partly because of a lack of awareness. Yet early intervention can mean the difference between life and death: with correct treatment and early diagnosis, almost two thirds of patients survive longer than five years. If untreated, about 50 per cent of patients die in less than two years.

It was thanks to sheer persistence that pulmonary hypertension was diagnosed in Barker in less than a year. Like many sufferers, her breathlessness was initially misdiagnosed as asthma by her GP and she was prescribed a Ventolin inhaler, which made no difference. When she developed a serious chest infection, another GP referred her to hospital for a chest X-ray. There the senior registrar put her symptoms down to panic attacks and the stress of life with two young children and, if Barker hadn’t been so determined, he would have sent her off with more asthma medication. She says: “I knew there was something wrong and that I had to fight to get the right diagnosis. But it was tough because I wasn’t confident about medical matters; I’d never had anything wrong with me before.”

She asked which tests they would do to detect a heart problem and persuaded the doctor to send her for an electrocardio-gram and an echocardiogram, which showed that there was indeed something seriously wrong. She was immediately referred to a cardiologist, who gave her the bad news. “It was a huge, huge shock,” she says. “The prognosis was pretty dire. I was told that the disease was incurable and progressive, that I would have a very shortened life, and one that would be very hospital-orientated. I went to a bookshop and found a medical text-book which said that the average survival time was 2.9 years [with treatment it is longer now]. I can still picture myself reading it with my baby daughter Hope in her buggy next to me.

“You think you’re on your life’s plan: I had two lovely children, my husband was about to be made a curate. I had thought that I would stay at home with the children in my thirties, then retrain in my forties. Suddenly I was praying that I’d live long enough to get them to primary school.” That was 11 years ago and Barker’s children, Caleb, 14 and Hope, 12, are now at secondary school. Each time her condition deteriorated over the years a new drug became available, which slowed the disease’s progress.

Barker is glamorous but very delicate – she has gone from a size 10 to a 6 – and she gets breathless after taking a few steps across the room. Although it’s a warm day, she keeps adjusting a cashmere-covered hot water bottle at her back to ease the pain of her latest drug, a vasodilator to lower her blood pressure, which is infused intravenously under the skin in her stomach. After nearly three years on the waiting list for a heart and lung transplant, she finally got a call a few weeks ago. Sadly, she was was ready for theatre and had said her good-byes when the surgeons retrieving the lungs detected a problem and it couldn't go ahead. It was a desperate disappointment.

Since they were very young, Barker’s children have known that their mother could die at any time. She says: “When they get upset about it, I say nobody knows when they’re going to die, and I could still be here in 10 or 20 years’ time. But I feel so guilty that they have had to grow up with the fear of what’s going to happen to me.”

Barker and her husband Cameron keep family life as normal as possible. Barker manages as much as she can of the admin of being a vicar’s wife, although she can’t cope with much entertaining. They’ve had holidays in Egypt and Venice. At home they are supported by friends and neighbours.

Barker also gets huge comfort from the pulmonary hypertension support group she set up four years ago, which is linked to the Pulmonary Hypertension Association. When the disease was first diagnosed, she was desperate to talk to other people in her situation but was hesitant because, as she says: “I knew that if I got close to other sufferers, they might die and that would be awful. Now I look forward to the meetings. Sometimes people cry, but we laugh a lot, too.”

But, she says: “I have a really rich life. I can still have lovely long teas with my friends, still read books and magazines and eat chocolate and watch TV or films. There’s no point thinking about all the things you can’t do, such as a walk in the park. I call it ‘positive avoidance’; concentrating on all the fantastic things you can do.”

The PH test

What is pulmonary hypertension? The condition raises the blood pressure in the lungs, which puts pressure on the heart and reduces the amount of oxygen that can reach the tissues of the body. The most common symptoms are breathlessness, dizziness, chest pain, palpitations, lethargy. Because these occur in other conditions, pulmonary hypertension can be hard to diagnose and is often confused with asthma.

Who gets it? It can affect people of all ages, but it is twice as common in women as men and the most common age at presentation is 40-50.

How can you treat it? There is no cure, but progress of the disease can be slowed and it is a rapidly developing field of research in the UK’s eight specialist centres. Treatments include oxygen therapy, warfarin, vasodilator drugs and heart-lung transplantation.

More information from www.pha-uk.com. Helpline 0800 3898156