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Stiff person syndrome
Other Resources UpToDate PubMed

Stiff person syndrome

Contributors: Andrea Wasilewski MD, Jamie Adams MD, Richard L. Barbano MD, PhD
Other Resources UpToDate PubMed


Stiff person syndrome is a rare autoimmune or paraneoplastic disorder characterized by progressive muscle stiffness and spasms. It can be associated with significantly elevated levels of anti-glutamic acid decarboxylase (anti-GAD) antibodies. Average age of onset is between 20 and 50 years old. Onset in childhood is rare. Women are affected 2-3 times more often than men.

Patients present with nonspecific back pain or axial stiffness with or without episodes of severe spasms that resolve over hours to days. Some patients may only present with stiffness in the extremities or facial muscles. Spasms can be precipitated by stress, anxiety, startle responses, stimulation, or emotion. There can be abdominal contractions as well as significant lumbar lordosis. The disorder is associated with diabetes mellitus type 1 and thyroid disease; it rarely occurs as a paraneoplastic syndrome. Prognosis is variable.


G25.82 – Stiff-man syndrome

5217008 – Stiff-man syndrome

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Tetanus – look for trismus and facial spasms early and lack of response to benzodiazepines
  • Neuromyotonia
  • Hypocalcemia or other electrolyte abnormalities
  • Hyperekplexia
  • Multiple sclerosis
  • Torsion dystonia
  • Parkinson disease
  • Myoclonic seizures
  • Metabolic or congenital myopathies
  • Progressive encephalomyelitis with rigidity and myoclonus (PERM)
  • Spinocerebellar degeneration
  • Neuroleptic malignant syndrome
  • Somatic symptom and related disorders

Best Tests

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Management Pearls

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Last Reviewed:02/24/2019
Last Updated:01/24/2022
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Stiff person syndrome
A medical illustration showing key findings of Stiff person syndrome : Gait disturbance, Lumbar lordosis, Muscle spasm, Limb pain, Myalgia, Axial rigidity
Copyright © 2024 VisualDx®. All rights reserved.