Overview of 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 the syndrome often have other autoimmune disorders such as type 1 diabetes or thyroiditis.

SPS 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 suffer from it.

Man clutching thigh in pain

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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 the 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)


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

The diagnosis can sometimes be confirmed by the presence of anti-GAD antibodies, or other types of antibodies when the syndrome is associated with certain cancers. However, 35 percent of patients with SPS have no antibodies and no associated cancers.

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.


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

Symptoms in those with associated cancers can improve after the tumor is removed and steroid treatment is given.

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.

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