From the Guidelines
Stiff Man Syndrome (SMS) is also known as Stiff Person Syndrome (SPS), a rare neurological disorder characterized by progressive stiffness and rigidity of the muscles.
Key Characteristics
- The condition is often associated with autoimmunity and antibody-mediated disorders 1.
- Patients with SPS may have a history of other antibody-mediated disorders or organ-specific autoimmunity 1.
- Glutamic acid decarboxylase (GAD) antibodies are often found in patients with SPS, suggesting an autoimmune component 1.
- Treatment options may include intravenous immunoglobulins (IVIG) and plasma exchange (PE) 1.
Diagnosis and Recognition
- The diagnosis of SPS can be challenging, and a thorough understanding of the clinical presentation and associated antibodies is essential 1.
- The recognition of SPS and other neuronal surface antibody-associated syndromes (NSAS) is crucial for timely and effective treatment 1.
From the Research
Definition and Characteristics of Stiff Man Syndrome (SMS)
- Stiff Man Syndrome (SMS) is a rare neurological disorder characterized by progressive rigidity of axial and limb muscles associated with painful spasms 2, 3, 4, 5, 6.
- The syndrome can be classified into different forms, including classic SMS, paraneoplastic SMS, and SMS variants such as stiff leg syndrome and progressive encephalomyelitis with rigidity and myoclonus 2, 3, 5, 6.
- The underlying pathogenesis of SMS is likely autoimmune, with most cases involving antibodies against glutamic acid decarboxylase (GAD) or other autoantibodies such as anti-amphiphysin antibodies 2, 3, 5, 6.
Clinical Features and Diagnosis
- SMS is characterized by symmetrical muscle stiffness and spasms that can lead to skeletal deformity, as well as other neurological symptoms such as eye movement disturbances, ataxia, and Babinski signs 3, 5.
- The condition is often misdiagnosed as a psychogenic movement disturbance, but electromyographic abnormalities and the presence of autoantibodies can help establish the correct diagnosis 3, 5.
- The clinical presentation of SMS can be highly variable, with different patients exhibiting different symptoms and severity of symptoms 2, 6.
Treatment and Management
- Treatment of SMS is based on drugs that enhance gamma-aminobutyric acid (GABA) transmission, such as benzodiazepines, as well as immunomodulatory agents such as intravenous immunoglobulin (IVIg) and corticosteroids 2, 3, 5, 6.
- Other treatment options, such as intrathecal baclofen, may be considered in certain cases 6.
- A personalized and multitask approach to treatment is often necessary due to the variability in clinical presentation and response to treatment 2.