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Stiff-Person Syndrome

(Stiff-Man Syndrome)


Michael Rubin

, MDCM, New York Presbyterian Hospital-Cornell Medical Center

Reviewed/Revised Mar 2024

Stiff-person syndrome is a CNS disorder that causes progressive muscle stiffness and spasms.

Stiff-person syndrome (formerly called stiff-man syndrome) affects the central nervous system (CNS) but has neuromuscular manifestations.

Most patients with stiff-person syndrome have antibodies against glutamic acid decarboxylase (GAD), the enzyme involved in the production of the inhibitory neurotransmitter GABA (gamma-aminobutyric acid). However, stiff-person syndrome may be

  • Autoimmune

  • Paraneoplastic

  • Idiopathic

Symptoms and Signs of Stiff-Person Syndrome

Clinical manifestations of stiff-person syndrome are similar in all types. Muscle stiffness, rigidity, and spasms progress insidiously in the trunk and abdomen and, to a lesser degree, in the legs and arms. Patients are otherwise normal, and examination detects only muscle hypertrophy and stiffness. Stiff-person syndrome typically progresses, leading to disability and stiffness throughout the body.

Diagnosis of Stiff-Person Syndrome

Diagnosis of stiff person syndrome is based on recognizing the symptoms and is supported by antibody testing, response to diazepam, and results of electromyography (EMG) studies, which show the electrical activity of apparent normal contraction.

Treatment of Stiff-Person Syndrome

  • Diazepam or baclofen

  • IV immune globulin (IVIG)

  • Sometimes rituximab or plasma exchange.

Symptomatic therapy is available for stiff-person syndrome. Diazepam is the medication of choice; it most consistently relieves muscle stiffness. If diazepam is ineffective, baclofen, given orally or intrathecally, can be considered. However, these recommendations are not supported by randomized trials.

Corticosteroids are now avoided because adverse effects are associated with prolonged use of the high doses needed to control symptoms. Azathioprine, methotrexate, and mycophenolate mofetil are no longer used.

Treatment references

  • 1. Dalakas MC, Fujii M, Li M, et al: High-dose intravenous immune globulin for stiff-person syndrome. N Engl J Med 27;345 (26):1870–1876, 2001. doi: 10.1056/NEJMoa01167

  • 2. Ortiz JF, Ghani MR, Cox AM, et al: Stiff-person syndrome: A treatment update and new directions. Cureus 12 (12):e11995, 2020. doi: 10.7759/cureus.11995

Key Points

  • There are 3 types of stiff-person syndrome: autoimmune, paraneoplastic, and idiopathic.

  • Stiff-person syndrome affects the CNS but causes progressive muscle stiffness, rigidity, and spasms, mainly in the trunk and abdomen.

  • Diagnose based on symptoms, response to diazepam, and results of antibody testing and EMG studies.

  • Treat with diazepam or, if it is ineffective, baclofen; other options include IVIG, rituximab, and plasma exchange.

Drugs Mentioned In This Article

Drug Name Select Trade
Diastat, Dizac, Valium, VALTOCO
ED Baclofen, FLEQSUVY, Gablofen, Lioresal, Lioresal Intrathecal, LYVISPAH, OZOBAX, OZOBAX DS
RIABNI, Rituxan, RUXIENCE, truxima
Azasan, Imuran
Jylamvo, Otrexup, Rasuvo, RediTrex, Rheumatrex, Trexall, Xatmep
CellCept, Myfortic
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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