SUPERSTAR SINGER CELINE DION recently announced that he is postponing her European tour, given her development of a rare neurological condition. She has stiff-person syndrome, a rare condition that causes progressive muscle stiffness and spasms.

Dion has long struggled with muscle spasms, as she explains in her Instagram video:

“While we’re still learning about this rare condition, we now know this is what’s been causing all of the spasms that I’ve been having. Unfortunately, these spasms affect every aspect of my daily life, sometimes causing difficulties when I walk and not allowing me to use my vocal cords to sing the way I’m used to.”

Today, we explore stiff-person syndrome, a rare neurological condition that strikes approximately one in a million individuals, according to the US National Organization for Rare Disorders (NORD).

Stiff-person syndrome

Stiff-person syndrome (SPS) is a rare acquired neurological problem marked by progressively worsening rigidity and repetitive painful muscle spasms. SPS affects twice as many women as men.

Symptoms

Common symptoms associated with the disorder include the following:

• Stiff muscles, including the trunk, arms, and legs
• Sensitivity to noise, touch, and emotional distress (which can precipitate muscle spasms)

Stiff-person syndrome is considered a spectrum of diseases ranging from the involvement of one body area to a widespread, rapidly progressive form that includes the involvement of the brain stem and spinal cord (progressive encephalomyelitis with rigidity and myoclonus (PERM)).

Over time, those with stiff-person syndrome may develop abnormal postures, appearing hunched over. Some individuals may become unable to walk or move. Lacking normal reflexes to catch themselves is particularly problematic as serious injury risk rises.

Putting it all together, you can imagine that many people with SPS can become fearful of leaving their homes because of street noise (for example, a car horn) that can trigger muscle spasms and falls.

Causes

The cause of the stiff-person syndrome remains unknown, but researchers believe it is an autoimmune response gone awry in the spinal cord and brain.

Here is the take of Dr. Richard Nowak, an assistant neurology professor at the Yale School of Medicine: “Stiff-person syndrome overall disrupts the normal communication pathways between the brain and the muscles. He adds:

“There’s a massive firing occurring from the central nervous system, down through the spinal cord, down through the nerves as they plug into the muscles, and it’s causing them to become rigid or go into spasm, which equals the stiffness.”

SPS is frequently associated with other autoimmune diseases, including type-1 diabetes and vitiligo (a disease that causes loss of skin color in patches). SPS may also be associated with thyroiditis and pernicious anemia (a condition in which the body does not have enough healthy red blood cells).

Most (but not all) individuals with SPS have elevated antibodies targeting a protein involved in muscle function control.

Dr. Simon Helfgott, a rheumatologist at Harvard Medical School, explains that about two-thirds of stiff-person patients have these antibodies, detectable by a blood test. For the 30 percent that don’t, researchers do not fully comprehend what is driving the condition.

Dr. Helfogott adds that a small proportion of those with cancer produce antibodies attacking the nervous system and triggering SPS. This phenomenon is a paraneoplastic-related stiff-person syndrome.

Treatment and prognosis

Symptoms can improve with an oral anti-anxiety drug (diazepam; Valium). This medicine works by calming the brain and nerves. Diazepam belongs to a class of drugs known as benzodiazepines.

For those with SPS, other medication types that should be avoided include serotonin-norepinephrine reuptake inhibitors (SNRIs; selected examples include tricyclic antidepressants and duloxetine).

Opioids are not recommended for pain because most people with SPS are on benzodiazepines. Mixing these two medication classes can lead to severe respiratory depression and death.

Drugs that may target muscle spasms may be added. Examples of such medicines include baclofen or gabapentin (Neurontin). Botox injections may be palliative for those with milder symptoms, including spasms.

Patients with more severe symptoms are often given immunoglobulin (by vein). Such infusions can reduce stiffness and noise, touch, and stress sensitivity.

Appropriate management may keep symptoms under control. Still, the natural history of SPS is unpredictable. Some remain stable for a decade, while others slowly decline over several months or a few years.

“I have a great team of doctors working alongside me to help me get better,” Dion volunteered on Instagram.

Thank you for joining me for this brief look at stiff-person syndrome (SPS). I wish Celine Dion all the best.