'At first, I thought I was just a burnt out mum. Then doctors told me the truth.'

When Penny first felt the strange, shallowness of her breath, she brushed it off as nothing important. When her chest began tightening during yoga meditations, she put it down to age and burnout. 

At 40, Penny had recently had her second child, and was juggling full-time work with a newborn and a four-year-old.

"I put it down to being older," she said. "And later, the fatigue of managing a newborn and a four-year-old."

What she didn't know then was that something far more serious was quietly unfolding in her lungs.

Watch: Multiple Chronic Conditions: A Day in the Life. Article continues after the video.

It started with shortness of breath — "SOB", as she calls it — and a sense that something wasn't quite right. 

She'd never felt breathless before. She had always been fit, strong, and healthy. Eventually, she decided to see a doctor. But, having just moved to a new town, she didn't have a regular GP. 

"When I was able to see one, it was only whoever was available at the time, so I had no continuity of care," she said.

It would take nearly a year to find out the truth. For months, Penny was told she may have asthma. Or even emphysema. 

"SOB persisted and got worse over the course of the year," she said. Eventually, a CT scan revealed the truth — Penny had Lymphangioleiomyomatosis, but no one sat her down to explain exactly what that meant. 

"I read this very strange word 'Lymphangioleiomyomatosis' on the CT report when I got home. I looked it up on the internet. I might have only 10 years to live. I had two small children. I was petrified."

Lymphangioleiomyomatosis, or LAM, is a rare and often misdiagnosed lung disease that almost exclusively affects women, particularly during their childbearing years. 

In Australia, only around 60 women are currently diagnosed. But experts believe there could be hundreds more experiencing symptoms just like Penny's, but are unable to put a name to it.

LAM occurs when abnormal smooth muscle cells grow in the lungs, replacing normal tissue and making it harder for oxygen to reach the bloodstream. 

It can lead to progressive breathlessness and — in more severe cases — spontaneous lung collapse. 

Because LAM is so rare, it's often confused with asthma, bronchitis, or even anxiety. But early diagnosis is critical. Unfortunately, misdiagnosis is common, leaving sufferers without treatment to slow its progression.

At first, Penny had no idea how rare it was, or how important it was to take quick action. But a lifeline arrived in the form of a support group. 

That connection led her to St Vincent's Heart and Lung Clinic, where she's been receiving care since 2009 — first from the late Associate Professor Alan Glanville, and now from Dr Deborah Yates, a LAM specialist.

Thanks to early intervention and medication, Penny's first few years with LAM were relatively stable. 

"The first six to seven years after diagnosis were very manageable," she said. "My SOB was under control with medication. I continued to work full-time as a teacher and, with my husband Cameron, raised our two girls."

Then, in 2015, everything changed.

"I had a collapsed lung — I didn't even realise it. I just felt 'fragile' and went to work. At recess, I drove myself to the ER." 

Penny's lung was reinflated in hospital, but collapsed again soon after. She was flown to Sydney and underwent a pleurodesis — a procedure that permanently sticks the lung to the chest wall. 

"It's effective — I've not had a collapse since — but bloody painful to recover from."

Now, more than a decade after her diagnosis, LAM affects her every single day.

"My mobility is limited by chronic SOB. But I'm committed to staying 'earthside' for my family," she said.

But Penny's manageable lifestyle is all thanks to early diagnosis. Without it, she'd have missed out on vital drug therapy that can slow the progress of LAM. 

"I'd probably not be able to work, or walk, or travel," she said.

More than anything, she'd have missed the support of her fellow LAM women.

"We may be breathless, but we're a feisty, friendly bunch," Penny said.

Penny is now an active member of Living With LAM, a group of Australian women raising awareness and funds for this rare condition. 

"Some of us are doing fine. But some (who aren't diagnosed) will have spontaneous lung collapses during pregnancy."

These days, Penny works around her energy levels. She's left teaching for less physically demanding work, plans her days carefully and watches her diet. 

She's also learnt to accept help — even when it's awkward. 

"I need to use a mobility car sticker. More frequently than I originally expected," she said. "I've learned to accept people offering to carry things for me."

Like many chronic illnesses, LAM is almost invisible, which, she says, can add a sting — especially when she parks in a disabled space.  

"I look well — which is great — but when I have to pause to catch my breath when walking, I look like the neighbourhood loiterer," she said.

Despite the challenges, Penny says she counts herself lucky.

"LAM is serious. And it's a pain in the neck. But in this country, we're lucky to have what we have. With Medicare, the PBS, and support for regional patients to travel to cities for specialist treatment, we have a chance to live well," she said.

Her message to other women is this: don't dismiss unexplained breathlessness. 

"Insist on a CT chest scan. Push for a respiratory specialist. It could save your life — or at least change it."

Feature image: Supplied.