The first time David Napier’s legs turned to “blocks of concrete”, he was driving home one night in 2002. Suddenly unable to move his foot from the accelerator to the brake pedal, the then 55-year-old only made it home safely by using both hands to move his leg.
Over the years, Napier’s spasms became “tighter and tighter”, until they had become a twisting sensation inside his legs from his foot to his hip that left him in “indescribable pain”. He began to fall over, and soon found himself bedridden.
The seizures also affected his speech, leaving him nonverbal for months at a time, but doctors told him it was all in his head.
It wasn’t until 2019 that Napier was diagnosed with stiff person syndrome, a progressive, neuroimmunological condition estimated to affect one in a million people. Stiff person syndrome is an autoimmune condition caused when the body’s immune system attacks healthy tissues, with spasms flaring up when the immune system is stressed.
Awareness of the condition has increased after the release of the documentary I Am: Céline Dion, which shows the severity of one of the singer’s seizures for five minutes as the pain and symptoms leave her immobile.
Prof Matthew Kiernan, the CEO of Neuroscience Research Australia, said most GPs – which are often a patient’s first point of call – will “never see stiff person syndrome in their life”.
He says patients suffering from the syndrome are often “highly sensitive” and can experience painful spasms from triggers like hearing loud noises.
Diagnosis is complicated. First, specialists look for high levels of antibodies in a patient’s blood – around two-thirds of patients have high levels of anti-glutamic acid decarboxylase antibodies, which means their bodies don’t produce enough of the enzyme essential for preventing excess muscle activity.
However, Kiernan says, “people can have antibodies and not have stiff person syndrome … and people can have stiff person syndrome without having antibodies”.
Another difficulty with diagnosis is that it is “not uncommon” for a person with stiff person syndrome to be misdiagnosed as having a functional neurological disorder because the symptoms are “so strange and the examination so nonspecific”, according to Prof Victor Fung, a professor of neurology and motor control at the University of Sydney.
A functional neurological disorder is where the physical symptoms are a manifestation of underlying psychological distress or trauma, rather than a deficiency in the brain or nervous system, Fung says.
The standard treatment for stiff person syndrome involves medicines including muscle relaxants and pain medications, along with drugs to suppress the body’s abnormal immune reaction like intravenous immunoglobulin, steroids and plasma replacement.
While these treatments work for the majority of people, many patients don’t respond to routine therapy, Fung says, and more intensive immune suppression is required. While there is no cure for stiff person syndrome, he says the majority of patients – when treated and diagnosed early – see improvement.
“I’ve looked after people who, when I first met them, were using walking frames because their mobility was so limited, but [once treated] they could walk independently without aids,” Fung says.
Now 77, Napier takes 129 tablets a week, but still undergoes immunoglobulin therapy via an IV drip because “nothing seems to be working”.
Although it was originally named stiff man syndrome, there is a higher incidence in women, with two affected by the condition for every one man. For Nuna Mpandanyama, the condition has left her with more injuries than she can count, from a dislocated shoulder while brushing her hair to a fractured rib, a cracked scapula and injuries from falls.
Mpandanyama first noticed a pain in her back during her first pregnancy in February 2015 which made it difficult for her to go up and down stairs, but doctors at the time put it down to her pregnancy.
The niggling pain and other symptoms persisted after the birth of her son, which she chalked up to having had a caesarean section and epidural. After her maternity leave, Mpandanyama returned to work as an intensive care unit nurse, but fell on her commute home one day while crossing Flemington Road in Melbourne.
She ended up in hospital a day later with spasms and a loss of bladder control. Doctors diagnosed acute chronic back pain.
As she continued to be hospitalised after falls, doctors gave her a muscle relaxant, and while her symptoms temporarily went away they would always return. It was only when a pain specialist advised her to stop taking muscle relaxants and doctors saw her unaffected by the drugs that she received a diagnosis of stiff person syndrome in 2017.
Juliet Hall, a physiotherapist at Bodyfit Physio, is used to helping the mobility of people with neurological conditions, but had never heard of stiff person syndrome before Mpandanyama came to her. She says stiff person syndrome is “a different type of stiffness than happens with other neurological disorders”.
“With cerebral palsy, if you pull against the muscle it tightens more, whereas this stiffness is more rigid but it can also be more violent.”
Because the diagnosis “doesn’t sound like a real condition” and it’s so unusual, Hall says there can be a lot of stigma.
Mpandanyama describes the feeling during a seizure, “as if something is trying to tear you apart”.
“Every muscle is so taut you feel as if something is going to break.”
She tried all the standard treatments , but said only an experimental stem cell treatment she started in 2021 has provided more lasting relief.
The stem cell therapy – reintroducing her own immature cells to replace the white blood cells which cause the autoimmune reaction – has taken her functionality “from zero to about 50% of where I had been”.
“I’ve improved heaps – not that I could go back to be a bedside nurse any more or even work a full day at work,” Mpandanyama said. “If I try to stay on my feet at home, if I do the wrong thing, my back will tell me. But it’s not as bad as before.
“You have to be grateful for what you have, because there are always people that are worse than you, and take one day at a time.”
