Stiff Person Syndrome

Stiff Person Syndrome

Overview

Stiff person syndrome (SPS) is a rare autoimmune neurological disorder that causes muscle stiffness in your trunk and abdomen (the middle part of your body). Over time, you may also develop stiffness (rigidity) and spasms in your legs and other muscles. Walking may be difficult, and you may become more prone to falls and injury.

Understanding and managing your stiff person syndrome diagnosis can be overwhelming. Your healthcare team will create a treatment plan that’s unique to you and your symptoms, as they vary from person to person. It’s important to make sure you’re getting the support you need to stay healthy by scheduling regular visits with your providers throughout your life.

Stiff person syndrome used to be called “stiff man syndrome,” but the name was updated to reflect that it can affect anyone, regardless of age or sex.

Symptoms

The two main symptoms of stiff person syndrome are:

Muscle stiffness or rigidity.

Painful muscle spasms.

Symptoms can develop at any age, but they most often begin in your 30s and 40s.

Stiff person syndrome symptoms can spread to other areas of your body and/or get worse over time. Symptoms can take several months to a few years to develop. Some people’s symptoms remain the same for years. Others experience slowly worsening symptoms, including more severe spasticity/rigidity, which can limit their ability to perform activities of daily living.

Muscle stiffness

In most cases of stiff person syndrome, the first symptom you’ll experience is muscle stiffness in your trunk (abdomen, chest and back muscles). The rigidity causes pain and an aching discomfort. These symptoms can fluctuate (swing) in severity without a clear reason or trigger. They can also affect your arms and legs. As stiffness increases, some people develop an abnormal posture that can make it difficult to walk or move.

Muscle spasms

Painful muscle spasms are another symptom of stiff person syndrome. They can involve your entire body or only a specific area. These spasms can last a few seconds, minutes or, occasionally, a few hours.

Causes

Researchers don’t know the exact cause of stiff person syndrome. But they think it’s an autoimmune condition. This is a condition in which your immune system attacks healthy cells for unknown reasons.

Studies suggest antibodies may play a role in SPS. Many people with stiff person syndrome make antibodies against glutamic acid decarboxylase (GAD). GAD makes a neurotransmitter called gamma-aminobutyric acid (GABA), which helps control muscle movement.

Researchers don’t yet understand the exact role that GAD plays in the development and worsening of stiff person syndrome. It’s important to note that the presence of GAD antibodies doesn’t mean that you have stiff person syndrome. In fact, 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 and DPPX (dipeptidyl peptidase-like protein 6) antibodies. There are also some people with this condition who have no detectable known antibodies. Research is ongoing to discover if other potential antibodies may also cause symptoms.

Risk factors

Stiff person syndrome is twice as common in females. It may also happen with other autoimmune conditions, like:

Type 1 diabetes.

Autoimmune thyroid disease.

Vitiligo.

Pernicious anemia.

Celiac disease.

Diagnosis

A healthcare provider will diagnose stiff person syndrome by looking for specific signs of the condition with exams and testing. They’ll ask you questions about your symptoms during a physical exam

Stiff person syndrome is very rare and complex, and its many symptoms can be caused by other, more common conditions. It may take time and several tests to diagnose SPS. If your doctor suspects that your symptoms are due to stiff person syndrome, he or she will review your detailed medical history and perform a physical exam followed by a diagnostic workup. A doctor may make a diagnosis of SPS when there is no better explanation for the symptoms and exam findings.

The following tests can help confirm an SPS diagnosis:

Blood tests are performed to look at several factors, including the anti-GAD65 antibody. This antibody is present in up to 80% of patients who have classic SPS, and very high levels of the antibody are strong indicators of the condition. Other antibody tests associated with SPS include those to detect the glycine receptor antibody and the amphiphysin antibody. Blood work can also check for non-SPS related antibodies, hemoglobin A1c and vitamin deficiencies.

Electromyography (EMG) evaluates the body’s nerve and muscle function. If you are taking medications to manage symptoms, such as muscle relaxers, it is important to hold off taking them before this test. This will make your symptoms worse for a short amount of time, but signs of SPS may be easier to see on the EMG.

A lumbar puncture can help the doctor rule out other causes of your symptoms, as well as help look for SPS markers such as anti-GAD65 antibodies.

Imaging studies can help your doctor visualize your brain, spinal cord, nerves and other body structures. Usually, imaging studies are performed to rule out other conditions that can seem like SPS. These tests may include MRI of the brain and spine and whole-body fluorodeoxyglucose-positron emission tomography (FDG-PET) with a computerized tomography (CT) scan. FDG-PET with a CT scan and mammogram are also done when there is concern about an underlying cancer.

After the diagnostic workup, your doctor will review the test results with you. If the SPS diagnosis is confirmed, the next priority is creating a custom treatment plan to address your symptoms and prevent them from worsening. Most people with SPS do not need hospitalization as part of treatment. Once the doctor has tailored a plan, you should have regular follow-up visits.

Treatment

Stiff person syndrome is a complex condition that affects people in different ways. Also, different types of SPS may require different treatment approaches. A personalized SPS treatment plan typically addresses the syndrome’s autoimmune, neurologic, visual, mobility and pain aspects.

Although currently, no therapy makes stiff person syndrome go away, treatment can help minimize the severity of symptoms and improve quality of life.

Medications to Manage Symptoms

Some medications help reduce spasms, stiffness and pain for people with stiff person syndrome:

Oral muscle relaxers, such as diazepam, clonazepam, baclofen or tizanidine

Oral medications that are not muscle relaxers but that have some effect on the GABA neurotransmitter, including gabapentin, pregabalin and tiagabine

Botulinum toxin, which is sometimes used when there are distinct areas of muscle spasm/tightness

Other medications, such as serotonin reuptake inhibitors (SSRIs), can be added to address physical symptoms triggered by anxiety.

Medications to Target the Immune System

Immune therapies aim to modify or suppress the immune system. Immune-based therapies for stiff person syndrome include:

Intravenous (injected into a vein) or subcutaneous (given as an infusion under the skin) immunoglobulin

Plasma exchange

Intravenous immunosuppressant therapy (e.g., rituximab)

Oral immunosuppressant therapy (e.g., mycophenolate mofetil, azathioprine)

Other Treatments

Together with medications, nonmedication therapies can make stiff person syndrome symptoms more manageable. Examples include:

Physical therapy that focuses on stretching, deep tissue myofascial techniques, balance/gait, ultrasound therapy and heat therapy

Aquatic therapy (very warm temperature)

Heating pads

Transcutaneous electrical nerve stimulation

Stretching

Osteopathic manipulation

Qi gong

Chiropractic treatments

Massage

Yoga

Acupuncture

Acupressure

Pilates training

Cognitive behavioral therapy

These treatments may have different effects for each person with SPS and are worth trying. A combination of medication and nonmedication treatments seems to be the most effective in minimizing the severity and intensity of symptoms over time, but it takes a while to figure out the combination that works best.

Type of Doctor Department : A Neurologist