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For further information, see CMDT Part 24-21: Spasticity

Key Features

Essentials of Diagnosis

  • The term "spasticity" is commonly used for an upper motor neuron deficit, but it properly refers to an increase in resistance to passive movement that affects different muscles to a different extent

General Considerations

  • Spasticity is often a major complication of stroke, cerebral or spinal injury, static perinatal encephalopathy, and multiple sclerosis

  • It may be exacerbated by pressure injuries (formerly pressure ulcers), urinary or other infections, and nociceptive stimuli

Clinical Findings

  • A velocity-dependent increase in resistance to passive movement that affects different muscles to a different extent

  • Not uniform in degree throughout the range of a particular movement

  • Commonly associated with other features of pyramidal deficit


  • Clinical



  • Drug therapy is important, but it may increase functional disability when increased extensor tone is providing additional support for patients with weak legs

  • Dantrolene

    • Weakens muscle contraction by interfering with the role of calcium

    • Best avoided in patients with poor respiratory function or severe myocardial disease

    • Begin with 25 mg once daily orally, and increase by 25-mg increments every 3 days, depending on tolerance, to a maximum of 100 mg four times daily orally

    • Side effects: diarrhea, nausea, weakness, hepatic dysfunction (which may rarely be fatal, especially in women older than age 35), drowsiness, light-headedness, hallucinations

  • Baclofen

    • An effective drug for treating spasticity of spinal origin and painful flexor (or extensor) spasms

    • Initial dose is 5 or 10 mg twice daily orally and then built up gradually

    • The maximum recommended dose is 80 mg once daily orally

    • Side effects: gastrointestinal disturbances, lassitude, fatigue, sedation, unsteadiness, confusion, hallucinations

  • Diazepam

    • May modify spasticity by its action on spinal interneurons and perhaps also by influencing supraspinal centers

    • Effective doses (2–10 mg three to four times daily orally) often cause intolerable drowsiness and vary with different patients

  • Tizanidine is a centrally acting α2-adrenergic agonist

    • As effective as these other agents but is probably better tolerated

    • The daily dose is built up gradually from 4 mg once daily orally, usually to 8 mg three times daily orally

    • Side effects: sedation, lassitude, hypotension, dryness of the mouth

  • Cannabinoids are effective in reducing spasticity but are associated with side effects, including dizziness, drowsiness, and fatigue

  • Intramuscular administration of botulinum toxin has been used to relax targeted muscles

  • Intrathecal injection of phenol or alcohol may be helpful in severe cases


  • Options include implantation of an intrathecal baclofen pump, rhizotomy, or neurectomy

  • Severe contractures may be treated by surgical tendon release



  • Physical therapy with appropriate stretching programs ...

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