What Is Stiff Person Syndrome?

Stiff person syndrome is an extremely rare neurological disorder that causes severe muscle spasms and stiffening of the body. 

Singer Celine Dion recently revealed that she has been diagnosed with the incurable disease, which affects the brain and spinal cord. The performer announced that she is rescheduling dozens of performances that were planned for 2023 while she works with doctors.

Stiff person syndrome affects about one in a million people, and women are twice as likely to get the disease. Symptoms usually appear between the ages of 20 and 50.

Unfortunately, the exact cause remains unknown. It is thought to be an autoimmune disorder, in which the body’s immune system attacks healthy cells. Researchers suspect that the disorder might cause the immune system to target an enzyme – glutamic acid decarboxylase (GAD) – involved in the production of a neurotransmitter that helps control and inhibit muscle movement.

Symptoms of Stiff Person Syndrome

The syndrome commonly starts with stiffness of muscles in the trunk and abdomen. In the early stages, there may only be periods of temporary stiffness. But as the disease progresses, the stiffness becomes constant and may spread to your legs, arms and even your face.

The disorder can cause significant pain and aching discomfort. As the stiffness spreads, it can cause a hunched posture. And in extreme cases, it can be difficult to walk or move, leaving you with a “Frankenstein gait.”

Muscle spasms also can be quite severe, lasting for seconds, minutes or hours when you attempt to make a sudden movement. They can be powerful enough to dislocate limbs, break bones or cause falls. These spasms, which may affect the entire body or a specific area, can occur without warning. They also happen in response to unexpected sounds, physical touch, cold and stressful situations.

Diagnosis

Diagnosing stiff person syndrome can be tricky, since it shares symptoms with other, more common, conditions such as spinal cord pathologies, tetanus, and hereditary hyperexcitable and spastic disorders. Doctors are likely to rule out those disorders before considering this rare disease. Once it is suspected, there are several tests that might be used. But even then, diagnosis can be complicated and should only be done by specialists. Among the testing options:

Blood test: A large segment of people (60 percent to 80 percent) with stiff person syndrome have antibodies against the GAD enzyme in very high titers in their blood. There are large false positive GAD-positive (low titer) people without this disease or any other diseases. Proper cancer workup is necessary in patient with GAD-positive results.

Spinal tap (lumbar puncture): The test takes a small sample of cerebrospinal fluid to look for antibodies to GAD if the blood workup is questionable. This procedure is rarely used for confirmation of diagnosis.

Response to treatment with Benzodiazepine is one of the main criteria of diagnosis.

Treatment

There is no cure for stiff person syndrome. Treatment is focused on managing symptoms to improve mobility, and reduce discomfort and pain. Benzodiazepine and Baclofen are the mainstream treatment. In rare cases with a lack of response to mainstream treatment, intravenous immunoglobulin has been used with variable responses.

Other treatments include:

• Physical therapy
• Massage
• Water therapy
• Heat therapy
• Acupuncture
• Stretching
• Ultrasound therapy

Long-Term Outlook

The long-term outlook for stiff person syndrome can vary widely from person to person, based on the severity of symptoms and the speed of the decline. In some instances, medication and other treatments can keep symptoms largely under control. But some patients may find the symptoms more disabling, with the disorder interfering with walking and the ability to do routine tasks. If this happens, the risk of falling can rise substantially, forcing some people to use a cane, walker or wheelchair.

The disease can also lead to bouts of anxiety and depression. As with most neurological disorders, there can be a significant psychological burden that accompanies the loss of previous abilities. But there’s also the fear that comes with not knowing when the next spasm might occur.

Even a trip outside the house can be a source of stress since unexpected noises (honking horns, for example) can trigger spasms. This can lead to phobias and severe anxiety disorders related to fears of spasms involving the diaphragm muscle, which plays a major role in breathing. A severe diaphragm muscle spasm could lead to stopping of breathing and sudden death.

Still, in a best-case scenario, people with the disorder can live an enjoyable life, with some compromises in terms of what they can do, and the intensity with which they can do it.