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.
- The syndrome can be classified into different forms, including classic SMS, paraneoplastic SMS, and SMS variants, such as stiff limb syndrome 2, 3.
- The underlying pathogenesis of SMS is likely autoimmune, with most cases involving antibodies against glutamic acid decarboxylase (GAD) or anti-amphiphysin antibodies 2, 3, 5, 6.
Clinical Manifestations and Diagnosis
- Symptoms of SMS include symmetrical muscle stiffness and spasms, often leading to skeletal deformity, as well as unusual features such as recurrent vomiting and progressive dysarthria 2, 3.
- Electromyographic abnormalities and the presence of autoantibodies against GAD in serum and cerebrospinal fluid can help establish the correct diagnosis 3, 5.
- SMS is frequently misinterpreted as a psychogenic movement disturbance, but a correct diagnosis is essential for effective treatment 3, 5.
Treatment and Management
- Treatment of SMS is based on drugs that enhance gamma-aminobutyric acid (GABA) transmission and immunomodulatory agents, such as benzodiazepines, intravenous immunoglobulins (IVIg), and corticosteroids 2, 3, 5, 6.
- A multitask and personalized treatment approach is indicated due to the extensive clinical variability of SMS 2.
- Symptomatic treatment with benzodiazepines is often effective, while alternative treatments like intrathecal baclofen may be considered in some cases 3, 6.