Spasticity

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

• 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

Medications

• 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

Surgery

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

• Severe contractures may be treated by surgical tendon release

Prevention

• Physical therapy with appropriate stretching programs is important during rehabilitation after the development of an upper motor neuron lesion and in subsequent management of the patient

  • The aim is to prevent joint and muscle contractures and perhaps to modulate spasticity

When to Refer

• Refer early to a physical therapist