What is Primary Lateral Sclerosis (PLS)

I’ve been writing a lot lately on the topic of pain and suffering and what this tells us about God. Some of my conclusions, I’m certain, are not popular, but I write from the perspective of one who has been suffering intensely since the fall of 2007 and not as a casual observer. Even so, I am sure that even those who share in my suffering will find much to disagree with. I only ask that you be considerate in your objections. The suffering that I write about is caused by a disease called Primary Lateral Sclerosis; or PLS for short. At least that’s what my neurologist is calling it.  The bare-bones basic explanation is that I am slowly becoming paralyzed. This is a process which will take decades and will eventually spread from my legs to my arms and possibly (although not garunteed) to my speech and swallowing muscles.

What does PLS look and feel like?

The primary symptoms are spasticity, weakness and a loss of balance. This causes a wide range of secondary symptoms including painful muscle cramps (in my calves, thighs, toes, feet, hands, fingers, arms, back, neck and face).  Other secondary symptoms include random burning pain and numbness (apparently caused by a degenerating disk in my spine…which is apparently caused by my body trying to compensate for muscle weakness caused by PLS and putting too much of a burden on my spine).

My primary symptom is spasticity of the legs, and this is what makes it so difficult for me to walk. Spasticity can be defined as an increase in the normal tension of a muscle, resulting in continuous resistance to movement. In other words, it is an involuntary and continuous muscle contraction. The best way to describe what is going on is that opposing muscles are pulling in opposite directions. When you flex your biceps, your triceps are supposed to relax, allowing your forearm to bend up toward your shoulder. With spasticity, instead of relaxing when you flex your biceps, your triceps engage and try to pull your arm back down. The simultaneous engagement of opposing muscles makes movement very difficult. I experience this mostly in my legs. Every step that I take feels like my leg is pegged to the ground with a giant rubber band. This constant resistance to movement results in painful cramps as my legs fights every step that I take.

PLS and ALS (Amyotrophic Lateral Sclerosis A.K.A. Lou Gehrig’s Disease)

PLS is a motor neuron disease in the same family as Amyotrophic Lateral Sclerosis (also known as ALS or Lou Gehrig’s disease). The difference between PLS and ALS can be complicated (it involves lower motor neurons vs. upper motor neurons) but the short explanation is that I get to live. Here is a useful diagram that illustrates the different nerve tracts affected in PLS and ALS:

 

 

So as you see from this chart, PLS affects the upper motor neurons and not the lower motor neurons. The differentiation between upper and lower motor neurons does not have anything to do with the upper/lower parts of the body, but rather, where the motor neuron is located within the motor system. The upper motor neurons send messages and signals to the limbs by passing through the corticospinal tracts (where my damage has occurred) down to the lower motor neurons. When the lower motor neurons are directly damaged, you have ALS.

 

What causes PLS?

The exact cause of PLS is unknown. The symptoms however, are caused by scarring (sclerosis) of the lateral tracts of the spinal cord.

PLS and life expectancy

Life expectancy is Normal in PLS since it does not affect the lower motor neurons like ALS does. However, life can be shortened by falls caused by weakness and loss of balance. While PLS is not life threatening, it is life altering.

Frequency of PLS

PLS is often misdiagnosed by neurologists who do not take the proper steps to accurately rule out other diseases (such as Multiple Sclerosis and ALS). As a result, the exact frequency is unknown, but most experts put the number of people living with PLS in the United States at about 500.