Reviewed by: HU Medical Review Board | Last reviewed: May 2015. | Last updated: January 2022

Spasticity is a stiffness of the limbs resulting from increased muscle tone and is common in people with MS. Spasticity results from demyelination that occurs in nerves that regulate muscle tone. It most frequently affects the group of muscles known as the antigravity or postural muscles, which include the calf muscles, thigh, buttock, groin, and back. Spasticity is often mild; however, in some cases it can be severe and painful, making normal daily activities difficult.

In some instances, people with MS who are affected by weakness in the leg muscles, may find mild stiffness helpful in standing and moving. People often experience a worsening of stiffness the more quickly they move their limbs. So, one rule of thumb with spasticity is to move slowly and steadily.

People with MS-related spasticity may occasionally develop a type of muscle spasm, called flexor spasm or extensor spasm, which are reflexes in response to the slightest of stimuli, such as when your foot rubs against a sheet during sleep. With flexor spasms, both legs pull up in a clinched position. With extensor spasms, the opposite occurs, legs extend straight and stiff. These spasms are uncontrollable and can happen so suddenly and intensely that they are capable of forcing a person out of a chair.

How is spasticity treated?

If spasticity is mild, treatment may not be necessary. However, if spasticity presents a problem, a variety of treatment options are available, including physical therapy and medication. The first approach to managing spasticity is to treat the problems that are known to increase risk for developing spasticity. These include pain of any kind, urinary tract infection and other types of infections, distended bladder or bowel, and pressure sores.

A physical therapist can recommend and offer instruction on stretching routines that involve active stretching (stretches you do on your own) and passive stretching (stretches that someone helps you to do).

Medications that may be effective in treating spasticity include Lioresal (baclofen), Zanaflex (tizanidine), Klonopin (clonazepam), Valium (diazepam), Dantrium (dantrolene), and Neurontin (gabapentin). The drug most commonly used to treat spasticity, Lioresal (baclofen), can cause you to feel weak or fatigued. The challenge with Lioresal is finding a dosage that relieves spasticity without causing excessive weakness. Another treatment option is involves injection of the drug Botox (botulinum toxin) to block nerve signaling to muscles. In some people whose spasticity is severe and does not respond to oral medication, a pump can be surgically implanted in the abdomen to deliver low doses of baclofen into the spinal canal. Intrathecal baclofen can be an effective treatment in cases of severe spasticity and the low doses of baclofen utilized limit the side effects of weakness and fatigue.

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