From the age of 15, Mia Elderkvist suffered from repeated urinary tract infections (UTIs), that left her feeling constantly unwell, disrupted her education and spoilt her social life.

Four years later, after countless courses of antibiotics that left her with thrush and stomach upsets, Mia was finally diagnosed with interstitial cystitis (IC).

Although she had a diagnosis at last, effective treatment, as many patients with the condition will know all too well, proved elusive — until Mia, now 26, discovered a novel and little-known DIY therapy.

Gendered: More than 400,000 people in the UK have interstitial cystitis — mostly women

Interstitial cystitis, also known as painful bladder syndrome, is a chronic form of cystitis where the lining of the bladder becomes inflamed. Exactly why it should happen is unclear, and unlike standard cystitis there is no obvious sign of infection.

Symptoms include pain that can radiate around the pelvis, a sudden urge to go to the loo, and needing to go to the loo with great regularity. Some people may be up through the night a dozen times, leading to fatigue from a lack of sleep.

For those with the condition, life can revolve around finding loos, while constant pain can mean that some patients can’t work or need a lot of time off.

Sex can be a trigger for flare-ups, so it can also damage relationships. Luckily Mia, who is from Wiltshire and works as a video editor for a technology company, has an understanding partner, but she was worried about dating for a long time.

One theory is that the symptoms arise from inflammation in the lining of the bladder, allowing ammonia from urine to leak through to outer layers, irritating the muscles and nerves there.

As the symptoms can be confused with other conditions, including cystitis caused by bacterial infections, some patients have to live with them for years before they are correctly diagnosed.

Yet it isn’t a rare condition. More than 400,000 people in the UK have interstitial cystitis — 90 per cent of them women — although it is thought many more may be undiagnosed.

Reality: For many the condition means constant pain and, in some cases, unemployment

There are medications that may help. Some patients, for instance, are given muscle relaxants and anti-spasm medications. Sometimes anticholinergics — drugs used to treat urinary incontinence — are prescribed, as these help block involuntary muscle movements.

However, it’s very much trial and error, because not enough is known about interstitial cystitis.

After trying various treatments with little effect, including the tricyclic antidepressant amitriptyline that is used in chronic pain conditions, three years ago, Mia found an unlikely answer to her problems: using a catheter to apply a treatment, called Gepan Instill, directly into the bladder.

The theory is that this creates a temporary lining on the inner wall of the bladder, blocking irritants such as ammonia. Gepan is what is known as a Glycosam-inoglycan (GAG) layer replenishment therapy. It is made of chondroitin sulphate, a compound found in cartilage and bone.

Relief: But using a catheter to apply a treatment called Gepan Instill directly could work

A study published in the journal Aktuelle Urologie in 2009 that compared Gepan with the urinary incontinence drug Tolterodine found that 72 per cent of Gepan patients had a reduction of symptoms after a year, versus 43 per cent of those on Tolterodine.

A further year after treatment ended, 56 per cent of Gepan patients reported improvements compared with only 15 per cent of those taking Tolterodine.

But there is a catch. The treatment, which comes in a filled and ready-prepared syringe, is normally administered via a catheter by a nurse at a hospital or clinic once a week for up to six weeks and then once every four weeks.

Now, however, people such as Mia are learning to do this themselves, self-catheterising at home. After inserting the catheter, they push the plunger that sends the treatment into the bladder. They then have to hold the solution for a minimum of half an hour before urinating to ensure the bladder lining is coated.

There are four types of GAG layer replenishment therapies, but some are viscous, making them harder for patients who are elderly to push through the syringe, while others need to be mixed from a bottle first.

Gepan is the easiest and was declared ‘the favoured therapy’ in an independent scientific review of all GAG layer replenishment therapies in 2013.

Every area of my life is better with this treatment, and I feel much more in control now Mia Elderkvist

‘There are many teenagers and young people trying to live their lives round this, so being able to self-medicate and get good results is very encouraging,’ says Ahsanul Haq, a consultant urological surgeon and clinical director of urology at Preston and Chorley Hospital.

‘When they are diagnosed, we talk about treatment options and they can make dietary changes and take tablets,’ he says, ‘but doing the Gepan themselves is very freeing, as there is a sense of being in control and they can manage the condition more effectively.’

Suzanne Evans, spokesperson for charity support group Bladder Health UK, adds that it’s an approach that is growing in popularity.

‘Increasingly, people use self-catheterisation to administer their treatment as this affords greater flexibility and freedom.’

When she was first diagnosed, Mia’s initial reaction had been relief. ‘Before my diagnosis, I was turning up to my GP surgery every couple of weeks with urinary tract infections.

‘I was given so many courses of antibiotics that I was sent for scans of my bladder and kidneys to see if there was an obvious cause for the infections — only to be told everything looked normal. Doctors kept advising me to watch for any triggers and to take care — which was frustrating because I was so careful.’

When Mia was 19, she underwent exploratory surgery. This revealed that her bladder was covered in open wounds, and she was diagnosed with interstitial cystitis. It’s a condition that her mother, Jan, 54, has too — there can be a genetic link.

WHAT IS CYSTITIS? Cystitis is inflammation of the bladder, usually caused by a bladder infection. It's a common type of urinary tract infection (UTI), particularly in women, and is usually more of a nuisance than a cause for serious concern. Mild cases will often get better by themselves within a few days. However, some people experience episodes of cystitis frequently and may need regular or long-term treatment. There's also a chance that cystitis could lead to a more serious kidney infection in some cases, so it's important to seek medical advice if your symptoms don't improve. Source: NHS Direct Advertisement

‘I was two weeks from starting university,’ recalls Mia. ‘I was scared of my future, being away from home for the first time, and I didn’t want to seem different from everyone else.

‘Worst of all was realising I had this condition for life. My mum’s a nurse, so it was good to talk to her in that capacity, as well as her being a fellow sufferer.

‘It’s hard to talk about it, especially new friends. Do you tell them what’s wrong? It was a very difficult time, realising how it would affect everything, from lectures to socialising.

Once, when I had a particularly bad episode, I woke up and I’d wet my bed — at 22.’

Mia found lifestyle changes helped — wine and asparagus are her triggers — but it’s the self-catheterisation that has made the most difference.

Initially, she underwent the treatment in hospital, which involved going to an NHS clinic every two weeks. Then the clinic suggested she try the home treatment.

When she went for her first appointment to learn how to catheterise herself, she found it hard to relax as it was painful and caused bleeding.

‘I thought I’d never manage it,’ she recalls. ‘Then, the third time I tried it, I relaxed and breathed calmly and it was fine.’

Life has now greatly improved. Recently, thanks to Gepan, Mia has been able to go on a 16-hour flight to Tokyo, and she has found her stress has reduced.

‘I use it every few weeks, but I do it more or less often depending on any flare-ups — it’s become my security blanket. Every area of my life is better with this treatment, and I feel much more in control now.’

bladderhealthuk.org