What Is Stiff Person Syndrome?

Stiff person syndrome (SPS), also called Moersch-Woltmann syndrome, is a rare nervous system disorder in which muscle stiffness comes and goes. Research suggests that SPS is also an autoimmune disorder, and people with it often have other autoimmune disorders such as type 1 diabetes or thyroiditis as well.

Stiff person syndrome affects both males and females and may begin at any age, although diagnosis during childhood is rare. It is not known exactly how many people have it.

Symptoms of Stiff Person Syndrome

Symptoms of SPS may include:

• Muscle stiffness in the trunk and limbs that comes and goes: This causes back stiffness or pain, an exaggerated upright posture, and stiff-legged walk.
• Severe muscle spasms in the arms and legs when a person is startled, touched, upset, or anxious
• Curved lower back (lordosis) and deformed joints in the body (over time)
• Falling during sudden muscle spasms (may cause additional related problems)

Diagnosis

The symptoms suggest the diagnosis. However, because it is a rare disorder, it may be misdiagnosed as multiple sclerosis, fibromyalgia, or a psychological disorder.

The diagnosis can often be confirmed by the presence of anti-GAD antibodies, which are present in 60% to 80% of those with SPS. Some people with SPS have antibodies to amphiphysin, a protein involved in the transmission of signals between neurons. Having these antibodies increases the risk of breast, lung, and colon cancer in these patients.

Other tests may be done, such as hemoglobin A1C to check for diabetes or thyroid-stimulating hormone (TSH) to check for thyroiditis. Muscle testing (electromyography, or EMG) may also be performed.

Treatment

Although there is no cure for SPS, there are treatments available. Drugs such as Azasan (azathioprine), Valium (diazepam), Neurontin (gabapentin), Gabitril (tiagabine ), or Lioresal (baclofen) may be used.

Plasma exchange (plasmapheresis) helps reduce symptoms in some individuals, but this treatment is typically reserved for those with life-threatening respiratory decline. For others, intravenous immunoglobulin (IVIg) is helpful.

Physical therapy may help relieve symptoms related to prolonged muscle tension, but it may also trigger muscle spasms. Corticosteroids may help as well, though they must be carefully given to those with diabetes.