According to data from the specialist journal The Neurologist, two out of three people with stiff man syndrome are women. This very rare neurological condition is mainly characterized by progressive and irremediable muscular stiffness, accompanied by spasms. Very disabling, it shortens life expectancy.
What are the symptoms of stiff man syndrome?
Muscle rigidity is the main characteristic of HRS. The muscles lose their elasticity and find it more and more difficult to stretch. In most cases, this muscle stiffness is first observed in the back and trunk. The spine becomes less flexible. The patient has difficulty bending forward or performing thoracic rotations. This stiffness then extends to other parts of the body, especially to the lower limbs (feet and legs). Muscles sometimes have involuntary reactions. They contract. Spasms affect several muscles or groups of muscles at the same time:
- agonist* muscles which contract during a movement;
- the antagonistic muscles that stretch during the same movement.
Patients also complain of joint pain in the knees, ankles, hands, wrists, shoulders and cervical spine. Some people have skin lesions, small sores and/or scabs on different parts of the body.
* When we bend our knees, the hamstring muscles are the agonist muscles. Their contraction is only possible if the antagonist muscles, the quadriceps, stretch simultaneously.
What causes stiff person syndrome?
This syndrome is sometimes called Moersch and Woltman syndrome, in homage to the American neurologists who first described the disease in 1956. It can be of origin:
- autoimmune: feeling threatened, the body produces antibodies which attack the nerve cells of the spinal cord;
- paraneoplastic: muscle rigidity is caused by a cancerous tumor;
- unknown (idiopathic origin).
RPS can be detected in a patient who already has one of the following diseases:
How to diagnose the disease?
The diagnosis is often made several years after the first symptoms appear. Electromyography (EMG) is a test that studies the peripheral nervous system, responsible for transmitting information between the central nervous system and the muscles. It makes it possible to observe muscular activity at rest and to confirm spasms. HRS is difficult to diagnose, because it can be confused with other diseases:
How to treat stiff man syndrome?
The management of stiff person syndrome essentially relies on the administration of medications, particularly diazepam. This molecule is known for its muscle relaxant effects. It causes muscles to relax, reducing the risk of spasms. This medication belongs to the benzodiazepine family. It is also used to prevent epileptic seizures and to combat anxiety. Baclofen also has interesting muscle relaxant properties. If these two substances do not relieve the symptoms, other medications may be indicated: immunoglobulins, rituximab, steroids.
What life expectancy for people with HRS?
HRS affects one or two people per million inhabitants, according to data from PubMed, the database of the National Library of Medicine, attached to the United States Department of Health. Life expectancy is shorter in these people. It depends on the origin of the disease, the severity of the symptoms and their evolution. Without any treatment, stiff man syndrome can lead to serious orthopedic problems and real disability. Life expectancy also depends on the effectiveness of treatments and the cause of the syndrome. The physiotherapist, the orthopedic surgeon and the psychiatrist play a major role in this multidisciplinary care.
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