Stiff Person Syndrome
What is stiff person syndrome?
Stiff person syndrome is a rare autoimmune movement disorder that affects the central nervous system (the brain and spinal cord). People with this condition first experience a stiffening of the muscles of their trunk followed, over time, by the development of stiffness and rigidity in the legs and other muscles in the body.
Stiff person syndrome, also called Moersch-Woltman syndrome and formerly stiff man syndrome, can also cause painful muscle spasms. The muscle spasms occur randomly or can be triggered by noise, emotional distress and light physical touch.
Over time, stiff person syndrome can lead to an altered posture. Severe cases can limit your ability to walk or move. Some people with this disorder need ongoing treatment for years to manage symptoms and maintain quality of life.
Stiff person syndrome is thought to be part of a wide range of similar diseases that involve one area of the body and then spread throughout the body.
Who might get stiff person syndrome?
Stiff person syndrome is extremely rare. Only about one out of every one million people have been diagnosed this syndrome. Twice as many women have stiff person syndrome as men. Symptoms can occur at any age but usually develop between ages 30 and 60.
Stiff person syndrome is more likely seen in people with certain types of diseases including:
Symptoms and Causes
What causes stiff person syndrome?
Researchers are not sure of the exact cause stiff person syndrome. However, they believe it to be an autoimmune disorder, a condition where your immune system attacks healthy cells. Many people with this disorder make antibodies that attack an enzyme called glutamic acid decarboxylase (GAD). GAD plays a role in making a neurotransmitter called gamma-aminobutyric acid (GABA), which helps control muscle movement. It is thought that the immune system in people with stiff person syndrome mistakenly attacks GAD enzyme, which decreases the amount of GABA in the body.
Antibodies to another protein called amphiphysin is a less common finding in people with this syndrome. This protein is found in nerve terminals and is involved in helping nerve cells communicate with each other.
The exact role that GAD plays in the development and worsening of stiff person syndrome is not totally understood. In fact, there are people with the syndrome that do not have detectable antibodies to GAD.
What are the symptoms of stiff person syndrome?
Symptoms of stiff person syndrome can take several months to a few years to develop. Some patients remain stable for years; other slowly worsen.
In most people with stiff person syndrome, the trunk and abdomen muscles are the first to become stiff and enlarged. Symptoms include pain, muscle stiffness and aching discomfort. Early on, stiffness may come and go but eventually the stiffness remains constant. Over time, leg muscles become stiff and more muscles throughout your body become stiff including the arms and even the face. As stiffness increases, some people developed a hunched posture. In severe cases, this stiffness can make it hard to walk or move.
Painful muscle spasms also occur. These spasms can last a few seconds, minutes or occasionally a few hours. Sometimes, the spasms can be severe enough to dislocate a limb, break a bone or cause uncontrolled falls. The spasms usually worsen the muscle stiffness. Spasms can occur for no reason or can be triggered when you’re exposed to an unexpected or loud noise, physical touch, cold environment or stressful event that causes an emotional response. The muscle spasms can involve the entire body or only a specific area. Sleep usually reduces the number of spasms.
Diagnosis and Tests
How is stiff person syndrome diagnosed?
Symptoms of stiff person syndrome are similar to other conditions such as tetanus, multiple sclerosis and muscular dystrophies. Your healthcare provider may use several tests to rule out these conditions and look for signs of stiff person syndrome.
If your healthcare provider suspects stiff person syndrome, tests to confirm the diagnosis may include:
- Blood test: Your blood is checked for the presence of antibodies to GAD or amphiphysin and for other signs that might indicate or rule out other diseases. Between 60 and 80% of people with stiff person syndrome have antibodies against GAD.
- Electromyography (EMG): A machine measures electrical activity in your muscles to look for continuous motor activity in the muscles.
- Lumbar puncture (spinal tap): During a lumbar puncture, a doctor uses a needle to draw fluid from your spinal canal to check for the presence of antibodies to GAD and for other signs that might indicate or rule out other diseases.
Management and Treatment
How is stiff person syndrome managed or treated?
Treatment for stiff person syndrome is based on your symptoms. The goal of treatment is to manage symptoms and improve your mobility and comfort.
Therapies your healthcare provider may try include benzodiazepines (such as diazepam and clonazepam) or baclofen to treat muscle stiffness and spasms. Anti-seizure drugs may lessen pain. Occasional use of anti-inflammatories and corticosteroids may be useful in some cases for pain flares.
Other treatment options include intravenous immunoglobulin (IVIG), plasmapheresis, rituximab and autologous stem cell transplant. Your healthcare provider will work with you to provide the best options and order of treatment options to manage your specific symptoms.
Effective non-medication options (given along with medication) include physical therapy, massage, water therapy, heat therapy, acupuncture and others.
What are the complications of stiff person syndrome or its treatment?
Stiff person syndrome causes limited movement and muscle spasms. These issues can lead to complications including:
- Anxiety and depression.
- Dislocated or broken bones from severe muscle spasms.
- Frequent falls.
- Excessive sweating (hyperhidrosis).
How can I prevent stiff person syndrome?
Scientists do not know what causes stiff person syndrome. There is no known way to prevent it.
Outlook / Prognosis
What is the prognosis (outlook) for people with stiff person syndrome?
The prognosis for stiff person syndrome varies depending on a person’s symptoms. The severity of the syndrome and speed of decline varies from person to person.
Over time, walking can become more and more difficult. In addition, a person’s ability to perform daily, routine tasks may also decline over time. Various treatments may be helpful in reducing the symptoms in some patients. The increased risk of falls becomes a growing concern as the disorder worsens. Some people may need to use a cane, walker or wheelchair for assistance.
When should I call the doctor?
Contact your healthcare provider if you experience muscle spasms or stiffening of the muscles in your trunk, arms or legs. If you have any of the risk factors, especially an autoimmune condition, ask your doctor specifically about stiff person syndrome.
What questions should I ask my doctor?
If you have stiff person syndrome, you may want to ask your doctor:
- What drugs should may work best based on my symptoms?
- What signs of complications should I look out for?
- What should I expect to happen to my health in the future?
To look for clinical trials, go to Clinical Trials.gov .
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