Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder that causes muscle weakness and degeneration over time. SMA can also cause uncontrolled muscle spasms or contractions, a symptom known as spasticity.

Spasticity can be painful, and getting a spasming muscle to relax can be difficult. As a result, spasticity can cause difficulties in all parts of life. However, there are a few approaches for working through muscle weakness and spasticity caused by SMA.

What Does SMA Spasticity Feel and Look Like?

In people with spasticity, the muscles remain contracted and resist being stretched, which often leads to pain or discomfort. The exact symptoms of spasticity can vary. In some people, spasticity may cause only mild stiffness or muscle tightness. In others, it may cause uncontrollable muscle spasms.

Spasticity mostly frequently occurs in the legs, sometimes causing them to cross involuntarily. Spasticity can also affect the arms, leading to:

• Bent wrists
• Pronated (turned) arms
• Clenched fists
• Fixed elbow positions
• Thumbs held in the palm

Spasticity may also cause the muscles to twitch or cramp. These involuntary movements can take two forms: spasms (quick or sustained muscle contractions) or clonus (a series of fast contractions). Muscle spasming and twitching can be painful and lead to increased muscle tone, as well as abnormal posture and deformities of the bone and joints.

Cramping and stiffness can also cause your movements to be less precise, and it can affect speech and gait (way of walking), reducing mobility and physical functioning.

Potential Complications of Spasticity

Over time, severe stiffness and muscle spasming can lead to contracture: a permanent contraction of the muscles and tendons. Spasticity can also result in other complications, including:

• Urinary tract infections (or UTIs)
• Chronic constipation
• Pressure sores (areas of skin that break down due to continuous friction or pressure)
• Frozen (painful and stiff) joints
• Fever
• Other systemic illnesses

What Causes Spasticity in SMA?

The genes impacted by SMA decrease the health and functioning of motor neurons, which help control muscles throughout the body and keep them healthy and strong. As SMA can cause a person to have fewer motor neurons in their spinal cords, the spasticity that some people with SMA experience occurs when the muscles are not well-controlled by motor neurons.

For the same reason, spasticity can occur in several other conditions that affect the brain or spinal cord, including:

• Cerebral palsy
• Multiple sclerosis
• Traumatic brain injury
• Severe spinal cord injury

Managing Spasticity With SMA

People with SMA have several options for addressing muscle spasticity. Because spasticity varies so much from person to person, it is generally managed according to your unique symptoms and needs.

It’s important to talk to your doctor to determine which treatment might be best for you and to follow through with any treatment you decide to pursue. Oftentimes, people with SMA work with a care team of professionals with different specialties — including physicians, nurses, and physical therapists — to manage spasticity.

Stretching

If you’re able, performing daily stretching exercises can lengthen the muscles, helping to prevent contracture and decrease spasticity.

Support Devices

Devices such as splints, casts, and braces can help maintain range of motion and flexibility with spasticity.

Muscle Relaxants

Taking medication to relax spasmed muscles is another option for managing spasticity in SMA.

Normally, the body’s muscles function as a result of signals passing from nerve cells to muscle cells. Muscle relaxants work by targeting this signaling pathway and making the signals less powerful. The decreased signal strength and speed, in turn, reduces the action of the muscle, ultimately reducing spasms and the associated muscle tension and pain.

Muscle relaxants for spasticity in SMA may include:

• Baclofen, sold under brand names including Gablofen and Lioresal
• Tizanidine, found in medications such as Comfort Pac-tizanidine and Zanaflex
• Benzodiazepines, which include include Valium (diazepam), Xanax (alprazolam), and Klonopin (clonazepam)

Physical Therapy

Physical therapists who specialize in working with people diagnosed with spinal muscular atrophy know how to help you lengthen and strengthen your muscles to keep them working as well as possible and to avoid or counteract any spasticity that you might experience.

Many mySMAteam members have found physical therapy (PT) to be helpful. One member shared their experience during physical therapy: “I used an antigravity treadmill today in PT. It allows me to walk and exercise without the fear of falling.”

Another member advised that “PT plus a medication or treatment is supposed to work best.”

Occupational Therapy

Occupational therapists can help people with muscle spasticity figure out how to perform certain actions or tasks without triggering or worsening spasticity. They offer a variety of tools, tricks, and techniques that will help you get through your daily routine with fewer problems from your spasticity and SMA.

Injections

Your doctor may recommend local injections to help reduce muscle tone in the muscles most affected by spasticity. These injections, which may involve Botox (botulinum toxin type A) or phenol, weaken muscles and may improve muscle positioning and function.

The effects of local injections usually take between seven and 10 days to become noticeable and last from three to six months.

Surgical Treatments

In some cases, your health care team may recommend surgery for spasticity. Several surgical procedures used to treat spasticity include the following:

Intrathecal Baclofen Therapy

ITB is used to treat severe spasticity. The treatment involves delivering baclofen directly into the spinal cord using a pump and catheter. Therefore, it requires much less of the drug, resulting in fewer side effects than if it were taken orally.

Orthopedic Surgery

Orthopedic surgery helps treat spasticity-related problems in the muscles, bones, and connective tissues.

Neurosurgery

Neurosurgery, or neurological surgery, may be used to treat disorders that affect any portion of the nervous system, including the brain, spinal cord, and nerves.

Rhizotomy

Rhizotomy is a surgical procedure that involves cutting out abnormal sensory nerves along the spine. Removing these abnormalities may help relieve spasticity while preserving other motor and sensory functions.

Get Support

The social network mySMAteam is for people with spinal muscular atrophy and their loved ones. Here, you can ask questions, get the answers you need, and make connections with people around the world who understand life with SMA.

Have you experienced spasticity with SMA? What treatments, if any, have you tried? Share your story in the comments below, or start a conversation by posting on mySMAteam.