SITTING in her dad's car outside Liffey Valley shopping centre, Alison Walsh felt a pang of jealousy as she watched a girl her age walk past.
"She was carrying her shopping bags and had Starbucks in her other hand," she remembers. "It was such a simple thing but I remember looking out the window thinking 'I wish that was me', just living a normal life."
But it was the end of 2011 and Alison's life was anything but normal. She had lost the ability to walk and was suffering terrible headaches. She couldn't sleep, found it hard to eat and had couldn't stop her hands from shaking.
Her symptoms were so severe she could no longer go to work at the Blood Transfusion Service where she was employed as a medical scientist, and was now largely bedridden.
Most terrifying of all -- no one seemed to know what was happening to her.
It all began in 2008 with a series of seemingly innocuous problems.
"I just started feeling a bit rubbishy. I felt tired and run down and I wasn't sleeping well," explains Alison (35) from Enfield, Co Meath.
"At first I thought it was stress related. I was getting over a bereavement -- my uncle had been killed in a road accident and his death had been a huge shock, I thought it could be that."
Because the lymph nodes in her armpit were swollen, Alison's GP scheduled a biopsy, which revealed sarcoidosis of the lymph nodes.
The condition, which worldwide affects between 10 and 20 people in every 100,000 of the population, causes small lumps of inflamed cells to collect in the organ tissue affecting the performance of that organ.
It's commonly found in the lungs or lymph nodes, and initially doctors were pleased with Alison's diagnosis.
"I was put on steroids and it was expected I'd make a full recovery but instead I started developing other symptoms. I had night sweats, a dry cough and a terrible thirst all the time.
"Then I began getting horrendous headaches and vomiting sporadically. My walking became seriously compromised. It started with jerks in my legs at night, then my balance went."
Alison had been born with spina bifida and, although she was largely healthy and able to walk, it was initially suspected that she might have been suffering from hydrocephalus, also known as 'water on the brain', a condition closely associated with spina bifida and consistent with many of her symptoms, but this wasn't the problem.
"By this stage I was six and a half stone and could do nothing for myself," explains Alison. "My husband, Gary, was looking after me as if I were someone in my 90s with dementia. He had to clean up my vomit, put me in the shower and put me on the toilet.
"At a time in our lives when we should have had prams and baby toys to trip over in the house, he was caring for me and tripping over my walking aides."
With Gary, a hotel personnel manager, out at work most of the day Alison made the difficult decision to temporarily move back to her mum and dad's home where her 58-year-old father, Pat, came home early from work to care for her. "I couldn't do anything. I was so anxious I couldn't sleep or read, I couldn't even roll over in bed," she explains.