When Mary McCreadie was 38, she developed such severe aches and pains in her arms and legs that she couldn't walk or even lift a cup of tea.
"It sounds dramatic, but I thought I was going to die," she recalls.
As it was, Mary, a musician, spent the next four months in bed, sleeping 18 hours at a stretch.
Her GP was unable to diagnose the illness, but Mary convinced herself it was the result of working "ridiculously" long hours.
She was referred to a Harley Street specialist who said it was ME. Mary followed the medical advice and rested as much as possible.
Her condition gradually improved and eventually she was able to take a degree in literature and music. But the effort exhausted her, and ten years ago, she collapsed with the same symptoms as before.
From being able to walk her dogs for five miles a day, she was reduced to using a wheelchair to get around.
The instability of her muscles also left her with a severely arthritic hip. Her beloved piano had to be sold because she was no longer strong enough to play it.
Then, three years later, after fruitless visits to numerous experts including immunologists, neurologists and physiotherapists, Mary saw an ME expert — 18 years after her first collapse — who said she didn't have ‘yuppie flu' at all, but post-polio syndrome (PPS).
"It was a blow, yet I was relieved," says the 57-year-old from St Briavels, Gloucestershire.
"At last, I knew what was causing the myriad aches and pains so many doctors had dismissed."
Mary is one of around 120,000 Britons who suffer from post-polio syndrome. Despite the numbers affected, very few doctors know much about it.
They've assumed, like most of us, that as the polio virus itself has now been eradicated in this country, it is a health concern of the past.
But the long-term effects of the disease — rife in the UK in the Fifties — can be as debilitating as the disease in its early stages.
Post-polio syndrome is the name for a collection of incurable symptoms — including muscle wastage, muscle and joint pain, and mental and physical fatigue — common to many who have suffered from the full-blown disease.
When the symptoms recur, it may be 20-40 years after the initial disease. Circulation may be impaired and breathing can become difficult due to weakening chest muscles.
Everyday life becomes difficult — even muscles not weakened by the polio become fatigued.
"Our bodies degenerate with age," explains consultant neurologist Dr Stephen Sturman of City Hospital in Birmingham, who has a particular interest in PPS.
‘If you've taken a hit earlier and already lost a large number of nerve cells, you only need to lose a few more and you'll notice the effect.
"This is what we call neurogenic weakness — one of the causes of PPS."
Another possible cause is inflammation in the nerve cells, brought on by the immune system's response to the original infection.
Sometimes it can be caused by a complication of the earlier polio — for example, the spine may have been left twisted, which causes premature ageing of the vertebrae.
As a result, up to 70 per cent of post-polio syndrome sufferers live in constant pain, according to a survey soon to be published by the British Polio Fellowship, a charity set up to support people with polio or post-polio syndrome.
However, it takes an average of six years for anyone with the syndrome to get a proper diagnosis.
There are also very few centres where they can seek specialist help.
The complication in Mary's case was that she wasn't officially diagnosed with polio as a child.
She was nine when she contracted a mystery virus that had caused a high temperature, a stiff neck, an aching head and partially paralysed her left side — all classic symptoms of polio.
Doctors visited Mary every day for three months, yet no one mentioned polio. It wasn't until she mentioned this ‘mystery illness' to the consultant with expertise in ME that PPS was diagnosed.
This is not unusual — there are a small but significant number of polio sufferers who do not have the typical paralysis and instead present with flu-like symptoms.
However, Hilary Boone, 60, should have found it easier to get a diagnosis of PPS. She knew she'd suffered polio, aged five, in 1952.
Her condition was severe; she was partially paralysed from the waist down, and had to learn to walk again. However, through sheer determination she became a swimming teacher, a lifeguard, gained an orange belt in judo and even joined the police force.
Then, 20 years ago, Hilary slipped on a school floor. The simple accident left her with a weakened body which doctors could not explain.
Her muscles lost strength, she felt tired constantly, yet every doctor she saw told her there was nothing wrong. Finally in 1995, Hilary mentioned her childhood illness to a locum doctor.
"There are some late effects of polio," he told her. "You need to see a neurologist."
It took a further two years to get a diagnosis of PPS, and the delay, she believes, may well have cost her years of good health.
Hilary has since set up an organisation to help other sufferers, the Lincolnshire Post-Polio Network, and given five international presentations on the syndrome to doctors.
But she is disappointed that she has been unable to make headway with the British medical establishment.
It seems PPS is often simply not on anyone's radar.
Nursing Standard, the weekly magazine for nurses, has just published a report suggesting ignorance is the problem.
Before the introduction of the polio vaccine in the early Sixties, the Standard points out, there were regular outbreaks of polio.
NOW the sufferers of these outbreaks are filling waiting rooms needing procedures such as MRI scans others of their age do not, yet doctors simply don't recognise that they need special care.
Indeed, the medical profession seems reluctant to admit the syndrome exists, thanks to a study by the Mayo Clinic, in America, published in the Lancet ten years ago.
Based on research into 50 polio survivors over five years, it claimed the syndrome was much rarer than previously thought.
This caused many doctors to dismiss their patients' claims, yet several leading neurologists have since cast doubt on the findings.
Dr Sturman believes the scepticism arises because there is no clear test for the condition.
However, he says, new tests are beginning to show some kind of "unique abnormality" in the affected nerves of PPS sufferers, perhaps paving the way for neurological tests.
Fast diagnosis is important, as some elements can be reversed — the right physical support can keep a weakened leg muscle going longer, so the patient will be less likely to fall over and break a bone.
Graham Ball, chief executive of the British Polio Fellowship, says: "Sufferers need access to a pain clinic, but also need to see specialists about their muscle wastage and atrophy."
Hilary's challenge is to get the diagnostic process simplified and speeded up.
"We need to change the way we manually test muscles — they should be tested to the limit of endurance, not to an arbitrary figure. And sufferers need to speak up more, too."
Her lowest point came when she learnt that one doctor had marked her down as a fantasist — that her suffering was all in her mind.
"That was simply cruel," she says.
Mary McCreadie, too, was told she was a malingerer and that her illness was imaginary. Now, seven years on from her diagnosis, Mary is positive.
"Yes, the future is daunting," she admits. "With more support from the medical profession, I am sure I could have lasted longer without needing a wheelchair and suffered less mental anguish.
"But there are plenty of people worse off than me, and the hospital I use now, Nevill Hall in Abergavenny, is fantastic.
"I have lots of friends, I can still listen to music and go to concerts even if I can no longer play. I have a pretty full life considering."