Primary lateral sclerosis (PLS)

Diagnosis

No single test confirms a diagnosis of primary lateral sclerosis (PLS). PLS can have symptoms similar to those of other neurological diseases, such as multiple sclerosis and ALS. For this reason, you may need to have several tests to rule out other diseases.

A healthcare professional carefully reviews your medical and family history and performs a neurological exam. Then you may have one or more of the following tests:

• Blood work. Blood tests are done to check for infections or other possible causes of muscle weakness.
• MRI. An MRI or other imaging tests of your brain or spine might show signs that nerve cells have broken down. An MRI also can show other causes of symptoms, such as structural changes, multiple sclerosis or spinal cord tumors.

• Electromyogram (EMG). The test evaluates the electrical activity of muscles when they contract and are at rest. This test also measures the involvement of lower motor neurons. This can help tell the difference between PLS, an upper motor neuron disease, and ALS, which affects both upper and lower motor neurons.

  During an EMG, your healthcare professional inserts a needle electrode through your skin into different muscles.

• Nerve conduction study. This test can determine whether you have nerve damage. Low electrical current measures how well your nerves can send impulses to muscles in different areas of your body.
• Lumbar puncture, also known as a spinal tap. A spinal tap can help rule out multiple sclerosis, infections and other conditions. A thin, hollow needle inserted into your spinal canal removes small samples of cerebrospinal fluid. This is the fluid that surrounds your brain and spinal cord. The samples are then studied in a lab.

Sometimes it takes 3 to 4 years to get a diagnosis. This is because early ALS can look like PLS until other symptoms surface a few years later. You might have to return for repeat EMGs during those 3 to 4 years.

Genetic testing may be done when juvenile PLS is suspected. Genetic counseling also may be recommended.

Treatment

There are no treatments to prevent, stop or reverse primary lateral sclerosis. Treatment focuses on relieving symptoms and preserving function.

Medicine

You might take medicine to relieve these symptoms:

• Muscle spasms, known as spasticity. Muscle spasms may be relieved by several medicines that can be taken by mouth, such as:
  • Baclofen (Fleqsuvy, Ozobax, Lyvispah).
  • Tizanidine (Zanaflex).
  • Benzodiazepines:
    • Clonazepam (Klonopin).
    • Diazepam (Valium).
  • Gabapentin (Neurontin).
  • Pregabalin (Lyrica).
  • Dantrolene (Dantrium).

  If muscle spasms aren't controlled with medicine you take by mouth, your healthcare professional might recommend surgery to implant a medicine pump. The pump delivers baclofen directly to the spinal fluid.

• Emotional changes. You may be prescribed an antidepressant if you have frequent, rapid and intense shifts in emotions.
• Drooling. Drooling may be helped by the medicine onabotulinumtoxinA (Botox) or muscle relaxers. Medicines such as amitriptyline, glycopyrrolate and atropine also may be helpful.

Physical and occupational therapies

Stretching and strengthening exercises can help maintain muscle strength, flexibility and range of motion. The exercises also may help keep joints from becoming less mobile.

Speech and language therapy

Speech therapy might help with communication and swallowing if your facial muscles are affected by PLS.

Nutrition support

If you have trouble chewing and swallowing, a dietitian can offer diet tips, nutritional supplements or special feeding methods. These can help you maintain your body weight when symptoms make it hard to eat.

Assistive devices

As PLS symptoms get worse, you may need assistive devices. Physical or occupational therapists may evaluate you regularly to determine whether you need a brace, cane, walker or wheelchair. Assistive technology devices also may help with communication.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Coping and support

It's common to have a range of emotions when you have primary lateral sclerosis. To cope with the disease and its effects, consider these tips:

• Seek emotional support. Family and friends can be great sources of comfort and support. By joining a support group, you might learn how others cope with the condition. Because PLS is not common, it might be a challenge to find a local support group. But online discussion groups are available. Your healthcare team may have suggestions.
• Get help from a mental health professional if you need it. Living with a chronic illness can feel overwhelming at times. Seek counseling from a mental health professional for another point of view or if you have depression and need advice on treatment.
• Know and use resources available to you. If PLS limits your activities, ask a healthcare professional about devices designed to help you stay independent. Social services also help people with disabilities of all kinds. Try to learn all you can about the resources available to you. Sometimes, leaning on your community for help can strengthen ties in new ways.