Stiff Person Syndrome

Definition[edit | edit source]

Stiff person syndrome (SPS) is a rare acquired neurological disorder characterized by fluctuating muscle rigidity and stiffness, painful spasms, and continuous motor unit activity.[1][2][3]

Epidemiology[edit | edit source]

  • Mostly reported in women, with 2 women affected per every one man.[1][4]
  • Onset is usually between 30 and 50 years of age.
  • An association with autoimmune disease and various malignancies is described and these are thought to play a role in the pathophysiology.

Pathophysiology[edit | edit source]

SPS is part of the spectrum of autoimmune encephalitides (an antibody-mediated brain inflammatory process, typically involving the limbic system, however all parts of the brain can be involved).

  • Anti-GAD antibodies may attach to and lead to the ongoing destruction of GABAergic neurones involved in motor pathways.
  • Also, a paraneoplastic syndrome causing anti-amphiphysin antibodies has been reported.[5]

Clinical Presentation[edit | edit source]

SPS is characterised by progressive stiffening of the muscles in the trunk and limbs.[6] Fluctuating levels of pain and muscle rigidity spread slowly throughout the body and become progressively worse until it becomes difficult to perform activities of daily living independently. As a result of stiffening, a fixed hyperlordosis develops in the lumbar spine that remains evident in supine lying but relaxes during sleep.[2]

Clinical features of SPS

  • Progressive muscle stiffness predominantly affecting the axial muscles (especially the abdominal and thoracolumbar paraspinal musculature) and lower limbs
  • Muscle spasms triggered by external stimuli or emotional stress
  • Symptoms typically relieved by benzodiazepines[5]

Pain is a chronic symptom of SPS, but it can flare up acutely in response to muscle spasms.[2]

Diagnostic Procedures[edit | edit source]

The wide variation in the clinical presentation of SPS makes it difficult to diagnose, and diagnosis is often delayed considerably with an average of a 6.2-year delay.[2] The diagnosis is usually confirmed with EMG and serology (anti-GAD and anti-amphiphysin antibodies). These are specific, however they are only present in 60% of cases.[5]

Treatment and Prognosis[edit | edit source]

In addition to benzodiazepines, baclofen has been used for treatment. More recently, intravenous immunoglobulins (IVIG) have been used in combination with other drugs.[5]

The progression of SPS can vary depending on the individual and how it initially presents. From symptom onset to death, the course of SPS can range from 6-28 years.[2] The rate at which SPS progresses depends on several factors:

  1. Whether symptoms initially presented as classic SPS (prognosis is more favourable)[7]
  2. If symptoms belong to the ‘stiff man plus’ category, a more complicated form of non-classic SPS (poorer treatment response)[7]
  3. Accompanied by diabetes mellitus or malignancy (prognosis is less predictable)[8]

Patients with classic SPS usually respond well to treatment[7] and their condition usually stabilizes over time with intermittent relapses and remissions.[9] Early detection and neurological treatment is important to limit progression of SPS.[2] Even with treatment, the quality of life of individuals with SPS usually declines as stiffness limits many activities of daily living.[2][7]

Physical Therapy Management[edit | edit source]

It is important to note that physical therapy could worsen symptoms of SPS during certain phases of the disease; the efficacy of physical therapy is highly variable, and certain precautions should be taken before proceeding with treatments.

Scott Newsome, DO, Department of Neurology at Johns Hopkins Medical[10] recommends that physical therapy involve:

  • Deep tissue myofacial techniques
  • Ultrasound
  • Passive range of motion (any type of contractile exercise can reproduce or worsen symptoms), and
  • Heat therapy or possibly hydrotherapy, as any type of cold therapy can exacerbate symptoms

Ultimately, physical therapy should be tailored to the individual with SPS, as patients may present in different ways. It is important to comply with patient goals, understand symptom triggers, and help in the best way possible in order to reduce pain and increase the quality of life in those living with SPS.

Although no formal measurement tools exist for stiff person syndrome, both the Functional Independence Measure (FIM) and the Timed up and Go (TUG)  assessment tools have been used as objective measures in the assessment of SPS symptoms.[11]

Differential Diagnoses[edit | edit source]

SPS is often misdiagnosed as a more common neurological or psychological condition, including but not limited to the following[12]:

Physical Therapy Research[edit | edit source]

One of the more notable case studies to be published about SPS and physical therapy was by Kristen Potter in 2006. She found that inpatient rehabilitation twice daily for 30 minute sessions, and one 30 minute session on weekends focusing on exercise (stretching and relaxation) and functional retraining (transfers, stairs, sit to stand, etc.) improved range of motion, posture, and gait in a male patient with SPS, despite his continued spasms, pain, and stiffness.[11]

Recently, a case study by Christopher Hegyi[13], found that physical therapy treatments including: ultrasound, soft tissue mobilization, passive stretching, education, and exercise were most beneficial for a 24 year old woman with SPS. Over the course of 15 weeks (one treatment per week) the woman’s spasms and stiffness significantly reduced. Near the end of treatment, she could achieve full range of motion and flexibility, however these achievements were only seen seated or lying down. Since her symptoms were worse when standing, they issued an ankle foot orthosis (AFO) which greatly improved her gait by allowing her foot to be placed flat on the floor.

References[edit | edit source]

  1. 1.0 1.1 Bhatti AB, Gazali ZA. Recent advances and review on treatment of stiff person syndrome in adults and pediatric patients. Cureus. 2015 Dec;7(12). DOI: 10.7759/cureus.427
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Hadavi S, Noyce AJ, Leslie RD, Giovannoni G. Stiff person syndrome. Practical neurology. 2011 Oct 1;11(5):272-82. DOI: 10.1136/practneurol-2011-000071
  3. Meinck HM, Thompson PD. Stiff man syndrome and related conditions. Movement Disor-ders. 2002 Sep 1;17(5):853-66. DOI: 10.1002/mds.10279
  4. Division of Neuroimmunology and Neurological Infections, Johns Hopkins Hospital. Stiff Person Syndrome. Available from https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/neuroimmunology_and_neurological_infections/conditions/stiff_person_syndrome.html (accessed May 4, 2017).
  5. 5.0 5.1 5.2 5.3 Radiopedia SPS Available:https://radiopaedia.org/articles/stiff-person-syndrome-1 (accessed 16.12.2022)
  6. Yale School of Medicine. Stiff-Man Syndrome. https://medicine.yale.edu/neurology/patients/neuromuscular/sms.aspx# (accessed May 4 2017).
  7. 7.0 7.1 7.2 7.3 Brown P, Marsden CD. The stiff man and stiff man plus syndromes. Journal of neurology. 1999 Aug 1;246(8):648-52. DOI: doi:10.1007/s004150050425
  8. Jung YJ, Jeong HG, Kim R, Kim HJ, Jeon BS. Stiff-person syndrome: Case series. Journal of movement disorders. 2014 Apr 30;7(1):19-21. DOI: https://doi.org/10.14802/jmd.14004
  9. Duddy ME, Baker MR. Stiff person syndrome. InImmune-Mediated Neuromuscular Diseases 2009 (Vol. 26, pp. 147-165). Karger Publishers. DOI: doi: 10.1159/000212375
  10. Newsome S. Management of Stiff Person Syndrome [Internet]. Raredr.com. 2017 [cited 2 May 2017]. Available from: http://www.raredr.com/videos/Management-Stiff-Person-Syndrome
  11. 11.0 11.1 Potter K. Physical Therapy During In‐Patient Rehabilitation for a Patient with Stiff‐Person Syn-drome. Journal of Neurologic Physical Therapy. 2006 Mar 1;30(1):28-38. DOI: 10.2522/ptj.20100303
  12. National Institute of Neurological Disorders and Stroke. Stiff-Person Syndrome Information Page. https://www.ninds.nih.gov/Disorders/All-Disorders/Stiff-Person-Syndrome-Information-Page (accessed May 4 2017).
  13. Hegyi CA. Physical therapist management of stiff person syndrome in a 24-year-old woman. Physical therapy. 2011 Sep 1;91(9):1403. DOI: 10.1097/01.NPT.0000282147.18446.b8