Ask the Doc: Q & A with Edward Kasarskis, MD, PhD 

Dr. Kasarskis

Edward Kasarskis, MD, PhD is Director of the University of Kentucky ALS Multidisciplinary Clinic at Cardinal Hill Rehabilitation Hospital in Lexington, Kentucky, professor in the Department of Neurology at the University of Kentucky, and Chief of Neurology at the VA Medical Center in Lexington KY. 

Q: I was diagnosed with ALS five years ago, but my doctor says it “hasn’t fully developed.” He said I could have primary lateral sclerosis (PLS). What does this mean?

Dr. Kasarskis:  While both ALS and PLS are rare neurodegenerative disorders, there is a big distinction between the two. PLS is caused primarily by degeneration of the so-called "upper motor neurons" in the brain, causing increasing spasticity and weakness of voluntary muscles. Unlike ALS, the spinal motor neurons or "lower motor neurons" stay intact, so muscle wasting is not a prominent early feature of PLS.  Although both types of neurons are motor neurons, the distinction is important because people with PLS will most likely live for decades. But because there are some slowly progressing forms of otherwise classic ALS, the distinction can be difficult to make. Up to about 10% of ALS patients live for 10 years after they are diagnosed.

Therefore, PLS is difficult to diagnose, especially on the first visit to your ALS specialist. Out of 100 to 150 cases of ALS, there might be one case of PLS. Physicians will do a detailed clinical examination, exclude other disorders that can cause progressive spasticity and weakness, and almost certainly will need to re-evaluate you over time. Other conditions, such as vitamin B12 deficiency, multiple sclerosis and many other conditions, have to be ruled out. Physicians often use imaging and genetic testing to help determine the diagnosis. You can count on needing additional EMG studies over time to be as sure as possible that PLS is the correct diagnosis.

Treatment for PLS is focused on relieving symptoms, such as spasticity; offering physical therapy and exercise to maintain range of motion and strength; and prescribing assistive devices, and mobility and communications aids.

In an effort to better understand PLS, an International Registry was created at Northwestern University with funding by the PLS Foundation and the Spastic Paraplegia Foundation. Because there are only about 1,000 cases of PLS in the US, it should be possible to collect data from virtually the entire patient population, which is the goal of the registry. The data may help researchers better understand the cause of the disease and guide treatment. For more information or to participate in the study, contact Nailah Siddique, at (312) 503-2712, or email her at nsiddique@northwestern.edu.

Each issue we feature a leading neurologist specializing in ALS responding to a question. If you would like to submit questions for a future Q & A, please send your questions to Amber Walters. Please understand that we won’t be able to address all questions and we won’t be able to respond to individuals personally.