UMN-predominant presentation of ALS
This is off the MDA site. From what I have read in different areas PLS is an ALS Variation.
I would definetly persue MDA about this.
When It's 'Almost ALS,'
Will the Disease Progress?
by Margaret Wahl
The hallmark of ALS is the degeneration of two kinds of motor neurons — upper, which are in the brain, and lower, which are in the anterior horn (front section) of the spinal cord and in the brainstem. These two sets of motor neurons work together to drive movement and locomotion, but have separate, important functions as well.
Sometimes people come to a neuromuscular disease clinic who have only upper motor neuron (UMN) or only lower motor neuron (LMN) involvement. There’s usually an important question on everyone’s mind: Is this disorder likely to progress to ALS, or not?
The answer, unfortunately, usually requires waiting a few years to find out.
Stop, Go Or Modify
LMNs provide “go” signals directly to muscles. When they’re lost, muscles become weak and eventually unable to contract effectively, although they may twitch (fasciculate) involuntarily.
UMNs are different. They don’t go directly to muscles; they go to the LMNs, and they refine muscle movement from the raw “go” signal of these spinal nerve cells into the highly specialized movements needed for walking, running, typing, talking and hundreds of other motor activities. Without UMN control, muscles become tight (spastic) as well as weak, and reflexes may be accentuated. Muscles generally don’t atrophy or fasciculate (twitch) if only UMN loss occurs.
After Five Years, ALS Diagnosis Unlikely If Only UMNs Involved
Michael Singer at the University of Texas Southwestern Medical Center in Dallas, and colleagues, reviewed in the March issue of Muscle & Nerve the likely outcomes for people with only UMN damage. Gil Wolfe, co-director of the MDA clinic at UT Southwestern, was also an author.
“For patients with exclusive upper motor neuron symptoms acquired in middle age or later, the two main diseases to consider are ALS and primary lateral sclerosis,” the review says. “ALS [with UMN and LMN symptoms] is more common, and is usually the ultimate diagnosis.” However, they refer to studies that suggest that if LMN symptoms haven’t appeared after three years (one study) or five years (another study), it’s likely they won’t occur.
A third study found that when people developed LMN loss after having only UMN deficits, 77 percent did so within four years of symptom onset.
Better Prognosis, Slower Progression
The prognosis in these UMN-only cases, which are referred to as “primary lateral sclerosis” (PLS), is better than it is for ALS, and the progression of the disease is generally slow.
Drugs that combat spasticity, such as baclofen (Lioresal), are often prescribed, with a variety of supportive care measures.
“As difficult as it is to wait, the benefit of PLS as the diagnosis is undeniable,” Singer says. “Studies of PLS patients show them surviving nearly eight years or longer after diagnosis. In cases where deaths were discussed in medical journals, survival ranged from one to 15 years, and notably, none of the deaths were directly attributable to PLS.”
Wolfe concurs. “Compared to ALS, patients with PLS display more muscle stiffness, but they have less weakness and less respiratory compromise, and their prognosis as a result is much more favorable. The dilemma is separating PLS from ALS early on in the disease course so that we can provide some degree of reassurance to patients.
“This can be challenging, but if several years pass without clinical evidence of LMN involvement, one can be reasonably confident in making the diagnosis of PLS. Even having a UMN-predominant presentation of ALS casts a more favorable light on the situation.”