Diagnosing and Treating Stiff Person Syndrome

Stiff person syndrome (SPS) is a rare autoimmune neurological condition of the central nervous system. It was previously named stiff-man syndrome but was updated over the years because SPS can affect either sex, and in fact, it affects women more than men. It can begin at any age but symptoms typically emerge between 30 and 40 years. It is also known as Moersch-Woltman syndrome, since it was first described in 1956 by Frederick Moersch, MD, and Henry Woltman, MD.

Types of SPS

There are three types of SPS: classic, variants and progressive encephalomyelitis with rigidity and myoclonus (PERM).

Classic: Classic SPS is the most common clinical form, present in 70 to 80 percent of SPS patients. It is associated with anti-glutamic acid decarboxylase (anti-GAD) antibodies.¹ GAD is the enzyme that catalyzes the production of GABA, a major neurotransmitter of the central nervous system.² Antibodies against GAD can interfere with the signal for the body and muscles to relax. GAD is found in the nervous system and the pancreas; as such, these antibodies are also found in other neurological and autoimmune conditions, particularly type 1 diabetes, as well as pernicious anemia, vitiligo and autoimmune thyroid disease.

Variants: Several clinical variants of SPS have been described and include stiff limb syndrome, jerky SPS, cerebellar variant, SPS with epilepsy and dystonia.¹ There is also a variant that is associated with various forms of cancer in which the SPS manifests prior to the cancer diagnosis.

PERM: This is the most severe and rare form of SPS. It can involve the brain stem, spinal cord and the autonomic nervous system, and therefore, it can result in breathing problems, trouble with gait and vertigo. Antibodies against glycine receptors have been noted. Glycine receptors play a role in neurotransmission, motor control and pain control.

SPS Symptoms

The primary symptoms of SPS are muscle rigidity and spasms that can be achy or painful. Symptoms can begin as mild and be as common as a sore back. The main area for muscle rigidity and spasms are the trunk and abdominal region; however the legs and arms can also be affected. The rigidity can fluctuate without a clear cause. Over time, it can affect posture, and depending on the type of SPS, it can affect gait and balance. Spasms can occur anywhere and last minutes or hours. They can be triggered by a loud or sudden noise such as a door slamming or thunder, as well as changes in temperature or some sort of physical stimulus. Stress can also be a trigger.

Because symptoms are somewhat unpredictable, people with SPS frequently have anxiety and fear about being out and about because symptoms might be triggered in a public environment where they don’t have as much control over sensation, noise and stress.

Like other rare autoimmune neurological conditions, SPS is challenging to diagnose because of the rare incidence and insidious symptoms that can be indicative of many conditions.

Diagnosing SPS

Like other rare autoimmune neurological conditions, SPS is challenging to diagnose because of the rare incidence and insidious symptoms that can be indicative of many conditions. Typically, a neurologist would be the specialist to perform a full neurological assessment, as well as an EMG to measure muscle activity. If SPS is suspected, blood work might be done to look for the presence of anti-GAD. A lumbar puncture might also show anti-GAD, as well as protein in the cerebral spinal fluid, which may be indicative of an immune response. Much of the workup involved in neurological conditions can be as much to rule out other conditions as it is to confirm a diagnosis.

Treating SPS

Once a diagnosis of SPS is confirmed, a treatment plan is determined. A neurologist, preferably one who specializes in immune-mediated neuromuscular conditions, should be managing the treatment plan. Because of the nature of the condition, the treatment plan might consist of medications, physical therapy and/or psychological care through therapy and counseling. There is no cure for SPS. Treatment is aimed at symptom management and promoting optimal functioning.

Medications can include benzo- diazipines, baclofen, pain relief/GABA, analogue/immunosuppressants and intravenous immune globulin (Table).

Physical therapy may be required depending on the extent of the impact on muscle function and mobility. In addition to traditional physical therapy, activities such as yoga, stretching, water aerobics and chiropractic treatments can help manage symptoms and improve pain and function. Additional interventions such as acupuncture and acupressure may help. Meditation and breathwork can also assist with relaxation.

Since SPS can lead to anxiety, and anxiety can be a trigger for onset of or an increase in SPS symptoms, it’s important to manage anxiety. In addition to some of the medicines used to manage the symptoms of SPS, it’s important to implement nonmedicinal interventions. Counseling and therapy can help manage stress and anxiety, as well as meditation, prayer and breathwork. Some newer activities include qigong, a form of exercise that uses a combination of gentle movement, calm breathing and meditation that together can reduce stress and anxiety.

Table. Medications That Treat SPS

Opt for the Best Healthcare Team

As with any chronic condition, understanding, managing and living with SPS can be frustrating and overwhelming. It’s important to get the best healthcare team and get on top of the symptoms to enhance function and control pain and anxiety.

References

1. Muranova, A, and Shanina, E. Stiff Person Syndrome. StatPearls, Jul. 10, 2023. Accessed at pubmed.ncbi.nlm.nih.gov/34424651.
2. Vianello, M, Tavolato, B, and Giometto, B. Glutamic Acid Decarboxylase Autoantibodies and Neurological Disorders. Neurological Sciences, 2002 Oct;23(4):145-51. Accessed at pubmed.ncbi.nlm.nih.gov/12536283.