Stiff-person syndrome (SPS) is a rare, progressive neurological disorder that causes muscle spasms and stiff muscles in the torso, arms, and legs. Although the exact cause is unknown, researchers suspect it may be an autoimmune condition in which the immune system attacks cells that control muscle movement.
UPMC neurology experts provide advanced care for SPS, including treatment with medication, immunotherapy, rehabilitation, supportive care, and mental health counseling.
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What Is SPS?
Stiff-person syndrome (SPS) is a rare, progressive neurological disorder that causes muscle spasms and stiff muscles in the torso, arms, and legs. Although the exact cause is unknown, researchers suspect it may be an autoimmune condition that occurs when your immune system attacks cells that control muscle movement.
Is SPS a form of multiple sclerosis (MS)?
No. Although MS and SPS are both neurological autoimmune disorders with overlapping symptoms, they are distinct conditions.
What are the types of SPS?
There are three types of SPS:
- Classic SPS — The most common form, it is associated with antibodies that attack glutamic acid decarboxylase (GAD), an enzyme that makes neurotransmitters that control muscle movement.
- Progressive encephalomyelitis with rigidity and myoclonus (PERM) — A more severe type of SPS that causes decreased consciousness, problems with eye movement, loss of muscle control, and problems with critical body functions.
- Stiff person syndrome variants — Involve specific parts of your body or more severe problems with coordination.
How common is SPS?
Stiff person syndrome is rare, affecting about 1 in 1 million people.
What causes SPS?
Researchers aren’t sure exactly what causes stiff person syndrome. However, some studies suggest it may be an autoimmune condition in which the immune system mistakenly attacks healthy cells. Several antibodies may be associated with SPS.
SPS risk factors
SPS is more common in females and people with other autoimmune disorders, such as:
- Autoimmune thyroid disease.
- Celiac disease.
- Pernicious anemia.
- Type 1 diabetes.
- Vitiligo.
Complications of SPS
Complications of SPS may include:
- Injuries from falls and other accidents.
- Loss of independence.
- Mobility problems.
- Shortness of breath caused by severe muscle spasms.
What Are the Signs and Symptoms of SPS?
Symptoms of SPS typically develop between the ages of 30 and 40, but they may start at any age. Symptoms worsen over time, but the rate of progression is different for everyone.
Symptoms of SPS include:
- Muscle stiffness or rigidity — Symptoms often start in your torso, causing pain and aching. Stiffness can come and go and spread to the arms and legs. Over time, you may develop an abnormal posture that causes problems with mobility.
- Painful muscle spasms — May occur in a specific body part or your entire body. In most cases, they last for a few minutes but may last for hours in severe cases.
What triggers SPS symptoms?
SPS may be triggered by:
- Stress.
- Temperature changes.
- Touch.
- Unexpected loud noises.
SPS can also cause mental health symptoms, such as anxiety and fear of going out in public due to exposure to triggers.
When should I see a doctor about my SPS symptoms?
If you have symptoms of SPS, you should schedule an appointment with your doctor right away. Early diagnosis and treatment can improve your quality of life.
How Do You Diagnose SPS?
To diagnose SPS, your doctor will perform physical and neurological examinations and review your symptoms and medical history. Your doctor may also order tests to confirm your diagnosis or rule out other problems.
What to expect during your visit
During your visit, your doctor will:
- Ask you about your symptoms.
- Order tests.
- Perform a physical and neurological exam.
- Review your medical history.
Tests to diagnose SPS
There's no conclusive test to diagnose SPS, and it can take time to receive an official diagnosis. Your doctor may order tests to gather information or rule out other conditions, including:
- Blood and urine tests — Checks for abnormalities and rules out other conditions. Blood tests can also look for antibodies that may be linked to SPS.
- Cerebral spinal fluid analysis (spinal tap or lumbar puncture) — Involves inserting a needle into your lower back to collect a sample of cerebrospinal fluid (CSF) for analysis in a lab.
- Electromyography (EMG) — Sometimes called an electromyogram, an EMG allows a doctor to record and study the electrical activity of your muscles.
- Neurological examination — A noninvasive test to check your reflexes, balance, movement, memory, and ability to think.
- Neuropsychological examination — Checks your ability to think, reason, and remember.
SPS prognosis
There is no cure for SPS and it is a lifelong condition. The rate at which symptoms progress varies from person to person, but early diagnosis and treatment may slow disease progression and reduce the risk of complications. As symptoms get worse, you may need to use a cane, walker, or wheelchair for mobility assistance.
What is the life expectancy of someone with SPS?
SPS doesn’t directly affect life expectancy, but may cause complications — such as accidents, infections, or respiratory problems — that eventually cause death. With treatment, many people live for years with good quality of life.
How Do You Treat SPS?
There is no cure for SPS. The goals of SPS treatment are to slow the progression of the disease, manage symptoms, and reduce your risk of complications.
SPS treatment options may include:
Medications
Your doctor may recommend medications to treat your symptoms, including:
- Benzodiazepines — A medication called diazepam is often one of the first treatments your doctor will recommend for muscle spasms.
- Muscle relaxants — A medication called baclofen can help to treat muscle spasms. For severe cases, your doctor may recommend a surgically implanted intrathecal baclofen pump to deliver medication directly into the spinal canal.
- Neuropathic pain medications — Treats nerve pain by reducing pain signals.
Intravenous immunoglobulin therapy (IVIG)
During IVIG, you will receive an intravenous injection of donor immunoglobulins. Immunoglobulins are a natural part of your immune system and protect your body by attacking foreign organisms. Immunoglobulins may prevent your immune system from further damaging your nerves.
Rehabilitation and supportive care
Rehabilitation therapy may help you maintain strength, mobility, and independence.
Rehabilitation treatment may include:
- Physical therapy — Improves strength, balance, and mobility using exercises, stretching, massage, electrical stimulation, and other techniques.
- Occupational therapy — Teaches techniques and strategies to help you perform everyday activities, such as bathing, dressing, cooking, and grooming, sometimes with the assistance of a cane, brace, walker, or wheelchair.
- Speech and swallowing therapy — Helps you regain the ability to swallow, chew, and speak.
Your doctor may recommend other therapies to help manage your symptoms, including:
- Alternative therapies, such as acupuncture or massage.
- Counseling for mental and emotional problems.
- Respiratory therapy for breathing problems.
Clinical trials
You may be eligible to participate in a clinical trial studying new treatments for SPS. Your doctor will let you know if you qualify for a clinical trial.
Why Choose UPMC for SPS Care?
When you choose UPMC for SPS care, you will receive:
- Multidisciplinary care — Our team of neurologists and autoimmune disease experts will work together to develop a customized treatment plan that reduces your risk of complications.
- Access to advanced clinical trials — Our team participates in national, multicenter clinical trials evaluating new treatment options, allowing you to contribute to research advancing care for autoimmune disorders.
- Seamless, ongoing treatment — If you are diagnosed with SPS, our team will develop a follow-up care plan that includes ongoing rehabilitation and symptom management as needed.
