A woman has told of her holiday horror after being left both paralysed and blind following a five-day break to Mexico.
Mary Catherine Derin was born with excess fluid on the brain, hydrocephalus, and had a shunt fitted as a baby to relieve the pressure.
More than four decades later, Mrs Derin noticed her arms and legs were weak while celebrating her wedding anniversary with her husband Tony, 48, in Mexico.
The now 46-year-old dismissed her symptoms as dehydration or the start of flu. But within hours, she was completely paralysed from the waist down.
After flying home to Maryland, Mrs Derin was eventually diagnosed with Guillain Barré syndrome (GBS), which occurs when the immune system attacks nerve tissue.
By coincidence, the former fitness instructor then developed blurred vision, which is thought to be completely unrelated to her GBS.
The shunt she was fitted with as a newborn malfunctioned, which allowed pressure to build-up over her optic nerve. The ordeal has left Mrs Derin 'legally blind' and only able to walk with a cane.
Mary Catherine Derin suffered a holiday from hell after a five-day break to Mexico in May 2017 left her paralysed and blind. She is pictured left with her husband Tony in 2015. Mrs Derin is pictured right during a three-month stint in hospital being treated for Guillain Barré Syndrome
As well as suffering from Guillain Barré Syndrome, Mrs Derin also became 'legally blind'. This is thought to have occurred due to a malfunctioning shunt she had fitted as a newborn to relieve pressure on her brain. She is pictured in June 2017 after surgery to have the shunt replaced
Speaking of the ordeal, Mrs Derin said: 'It's believed my shunt malfunction and contracting Guillain Barré syndrome were completely unrelated, and just happened at the same time.
'The doctors said it was an incredibly rare situation.'
By the time Mrs Derin was five years old, doctors believed she had outgrown her hydrocephalus and no longer needed her shunt, however, it was not removed.
'I was born with hydrocephalus and had a shunt placed when I was 28 days old,' she said. 'The shunt drained the excess fluid from my brain.'
Life carried on as normal for more than 40 years, before Mrs Derin suddenly developed a weakness in her limbs while in Mexico in May 2017.
'The morning after we arrived, I started noticing weakness in my arms and I began to lose feeling in my legs,' she said. 'By that evening I could no longer walk.
'We thought I was coming down with the flu [but] we ended up going to the onsite doctor.
'He thought I was dehydrated so he gave me IV fluids. When that didn't help, we knew something was wrong.'
Mrs Derin soon starting suffering 'spells of blurry vision', which she also put down to flu.
'I would just have moments when things would go black and then come back blurry,' she said.
Pictured in July last year, Mrs Derin noticed her arms and legs were weak while celebrating her wedding anniversary with her husband Tony in May 2017, which she dismissed as flu
Mrs Derin is pictured in a specialist hospital in June 2017. It was here that a neurosurgeon discovered the pressure in her brain was pressing on her optic nerve, leading to vision loss
Guillain-Barré syndrome (GBS) occurs when the body's immune system attacks its nervous system.
It affects around one in 100,000 people in the UK and US.
Symptoms usually start with a tingling sensation in the leg, which may spread to the arms and upper body.
In severe cases, the person can become paralysed.
The condition can be life-threatening if it affects a person's breathing, blood pressure or heart rate.
GBS' cause is unknown, but it usually occurs after a viral infection. The NHS states campylobacter infections have been known to trigger GBS.
There is no cure.
Treatment focuses on restoring the nervous system.
Source: National Institute of Neurological Disorders and Stroke
Mrs Derin flew home but needed 'full assistance to do everything'.
'Over the course of five days I went from being able to walk to being completely paralysed from the waist
