Stiff person syndrome (SPS) is a rare autoimmune neurological disorder that most commonly causes symptoms of muscle stiffness in your trunk and abdomen, with stiffness and painful spasms in the legs and other muscles developing over time.  

Symptoms of stiff person syndrome can develop at any age, but it most often begins in your 30s and 40s. Scientists believe stiff person syndrome can range from just one area of a person’s body to a widespread syndrome that affects multiple parts of the body, and involves the brain, brain stem, and spinal cord. Stiff person syndrome is a progressive disorder, which means symptoms can get worse over time, and can take several months to a few years to develop.  

In most cases of stiff person syndrome, muscle stiffness in the abdomen, chest, or back muscles is the first symptom experienced. This rigidity causes pain and an aching discomfort that can fluctuate in severity without a clear trigger or reason. These symptoms can also affect the arms and legs. As stiffness increases, some people may develop an abnormal posture that can make it difficult to walk or move. Individuals may also experience painful muscle spasms that can involve the entire body, or only a specific area. These spasms can last a few seconds, minutes, or occasionally, a few hours. 

Symptoms of stiff person syndrome, such as muscle spasms, can be triggered after: 

• Physical touch or stimulation 

• Unexpected or loud noises 

• Changes in temperature, including cold environments 

• Stressful events 

The triggers of stiff person syndrome-related muscle spasms can be unpredictable. This can cause some people with stiff person syndrome to develop anxiety and agoraphobia because it is more difficult to avoid the triggers of muscle spasms in public.  

Researchers don’t know the exact cause of stiff person syndrome, but they believe it is an autoimmune condition. Some studies suggest antibodies may play a role in stiff person syndrome, as many people with the condition make antibodies against glutamic acid decarboxylase (GAD). GAD makes a neurotransmitter called gamma-aminobutyric acid (GABA), which helps control muscle movement. 

Unfortunately, researchers don’t yet understand the exact role that GAD plays in the development and worsening of stiff person syndrome. However, it is important to note that having GAD antibodies doesn’t mean that you have stiff person syndrome. A small portion of the general population has GAD antibodies without any adverse effects. There are other antibodies associated with stiff person syndrome, including: 

• Glycine receptor 

• Amphiphysin  

• Dipeptidyl peptidase-like protein 6 (DPPX) 

Additionally, some people with this condition don’t have any detectable antibodies, but ongoing research is investigating whether other potential antibodies may also cause symptoms.  

Stiff person syndrome is very rare, as about one out of every one million people has this condition. What’s more, it is twice as common in females, and may also occur with other autoimmune conditions, such as: 

• Type 1 diabetes 

• Autoimmune thyroid disease 

• Celiac disease 

• Vitiligo 

• Pernicious anemia 

A healthcare provider can diagnose stiff person syndrome by looking for specific signs of the condition through exams and tests. They will ask questions about symptoms during physical and neurological exams. If the healthcare provider suspects stiff person syndrome, they may recommend other tests, including: 

• Antibody blood test 

• Lumbar puncture 

• Electromyography (EMG) 

Stiff person syndrome can be difficult to diagnose, as it is rare and has similar symptoms to other conditions, such as ankylosing spondylitis, multiple sclerosis (MS), or other autoimmune conditions. 

Unfortunately, there isn’t a treatment that cures stiff person syndrome. However, working with a specialist and maintaining symptom control can make it easier to live with the condition. Specialists include: 

• Neurologists, specifically neuroimmunologists 

• Physical medicine and rehabilitation specialists 

• Occupational and physical therapists 

• Mental health specialists, such as psychologists 

• Speech therapists 

To treat stiff person syndrome, two main treatment strategies can be used, such as: 

• Medications and therapies for symptom management 

• Immunotherapy or disease-modifying treatment 

Treatment for stiff person syndrome varies based on your symptoms. The goal of treatment is to manage how symptoms affect you and improve your mobility and comfort.  

If you or a loved one is experiencing symptoms of stiff person syndrome, you can receive treatment at Flushing Hospital Medical Center’s Ambulatory Care Center. To schedule an appointment, please call (718) 670-5486. 

All content of this newsletter is intended for general information purposes only and is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. Please consult a medical professional before adopting any of the suggestions on this page. You must never disregard professional medical advice or delay seeking medical treatment based upon any content of this newsletter. PROMPTLY CONSULT YOUR PHYSICIAN OR CALL 911 IF YOU BELIEVE YOU HAVE A MEDICAL EMERGENCY.