Stiff Person Syndrome: Symptoms, Causes & Treatment

Stiff person syndrome is an autoimmune disease that affects your ability to relax the muscle. It is associated with symptoms like rigidity and  sudden muscle contractions and spasms which can be triggered by palpation, intense emotions or stress. 

This syndrome is caused by an abnormal production of antibodies in the body that attack the nervous system. It is most common in people with diabetes or celiac disease, and is more frequently diagnosed in adults over 30. 

If you suspect you may have stiff person syndrome, you should consult a neurologist for assessment and treatment. Treatment may include medications like benzodiazepines, muscle relaxants and immunomodulators. 

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Common symptoms

The most common symptoms of stiff person syndrome are: 

  • Stiffness when trying to move the torso, arms and legs
  • Difficulty walking
  • Frequent falls
  • Muscle contractions triggered by intense emotions and visual or auditive stimulations 
  • Joint and spine deformity 

Normally, symptoms of stiff person syndrome progress slowly, and it can take several months until they are noticeable, Initially, the muscles in the torso are most affected, and many people present with difficulty bending over or turning at the waist. 

These symptoms tend to worsen throughout the day at times of stress or changes in temperature. Infections can also worsen symptoms. Because the muscle spasms can be sudden, some patients may develop anxiety, depression, fear or leaving the home or hesitation performing certain activities.

Different types

There are different types of variants of stiff person syndrome, which are more rare but may affect ja specific part of the body (like the arms, legs or neck). In addition, some other symptoms associated with these variants include weakness, drowsiness and loss of motor control. 

Possible causes 

Stiff person syndrome is normally caused by the abnormal production of antibodies that attack the nervous system and affect muscle contractions and relaxation. It is not known what triggers this abnormal production, but some cases are related to the development of a cancerous tumor, as seen with breast cancer or colon cancer. 

Stiff person syndrome is more common in adults over 30 and in patients with a positive family history and/or a history of another autoimmune disease, like type 1 diabetes, celiac disease, pernicious anemia and vitiligo. 

Confirming a diagnosis

Stiff person syndrome is normally diagnosed by a neurologist, who will evaluate the presenting symptoms, test results (which may include an EMG report), specific antibody testing in the blood and the response to medications, like benzodiazepines. 

Other tests, like an MRI, blood sugar levels, and thyroid levels, may also be ordered by the doctor to rule out other conditions that may present similarly, like diabetes, hypothyroidism or tumors. 

Treatment options

Treatment for stiff person syndrome usually involves the use of medications like diazepam, baclofen, pregabalin or levetiracetam. These help to relieve symptoms like rigidity, muscle spasms and pain. 

Depending on the patient's initial response to treatment, the doctor may also prescribe IV immunoglobulin or immunomodulators (like rituximab or azathioprine), as these can help to reduce the amount of abnormal antibodies in the body. 

Is there a cure?

There is no cure for stiff syndrome person, however symptoms can be well managed with appropriate treatment, especially if this condition is diagnosed in its early phases.