Post-Polio Syndrome: A Diagnosis of Exclusion
Updated from the original, published in The Polio Paradox
Before treating new symptoms, you have to make sure that the symptoms are in fact Post-Polio Sequelae. Thus this essential Post-Polio Precept:
‘All PPS are diagnosed by exclusion.’
Post-Polio Sequalae (PPS) encompasses many symptoms. All are ‘diagnosed by exclusion’ meaning that your doctor has to perform tests to exclude all other possible causes for muscle weakness -- for all new symptoms that you think might be PPS -- before concluding by a process of elimination that your symptoms indeed are PPS. A process of elimination is needed because, in spite of more than 40 years of research, there still is not one test that can prove new muscle weakness or any new symptom is PPS. Even polio related problems, e.g., sleep disorders, must be ruled out before a diagnosis of post-polio fatigue can be made.
It had been hoped in the 1980s that the EMG would become the one tool for diagnosing PPS. There have been dozens of studies using EMG to test polio survivors with and without new muscle weakness. Not one has found that the regular EMG your doctor can do in the office diagnoses PPS. So watch out for a detrimental Post-Polio Fiction:
‘You can't have PPS because your EMG doesn't prove it.’
There are studies using special EMG techniques performed at university medical centers, but not at your local doctor’s office, showing that polio survivors’ motor neurons are dying and breaking up. Your local doctor doesn't do these special EMGs. What's more, the special EMG studies showing the death and disintegration of motor neurons were conducted in subjects over the course of years. Even if you went to a medical center today where a special EMG could be done, you wouldn't know for a year whether your neurons were dying or sprouts shrinking. However, your doctor may legitimately want a regular EMG to rule out another cause for your muscle weakness, such as a herniated disc pressing on the spinal cord or a neurological disease like ALS. EMGs are both expensive and painful. So before you agree to one, ask what the doctor is looking for and make sure that he isn't doing an EMG to “prove” you have PPS. What's more, you shouldn't be denied long-term disability or Social Security Disability because an EMG didn't “prove” you have PPS.
If you have new weakness is there a chance that you have something other than PPS? Yes, but the chance is very small. In our 30 plus years of treating polio survivors, we never saw a patient that had a herniated disc or a rare muscle disease that caused weakness. We did see six patients who had PPS plus another neurological disease (four with Parkinson’s, one with Alzheimer's and one with ALS). But the additional diagnosis was apparent as the patient came through the door. Again, you must be fully evaluated to exclude all other conditions, neurological and medical, before the diagnosis of PPS is accepted. But there’s an old medical adage: “If you hear hoof beats expect horses, not zebras.” The good news is, if you hear the “hoof beats“ of new muscle weakness, expect PPS.
‘EMG and Exercise’
If an EMG can’t diagnose PPS, is it of any use in guiding treatment for muscle weakness? A regular EMG can identify muscles that have lost motor neurons to the poliovirus. But, physiatrist Mark Bromberg found that almost 10% of patients who had a clear history of muscle weakness with their acute polio, and who were reporting new pain, fatigue or weakness, had normal regular EMGs, meaning that there was no EMG evidence that they’d ever had polio!
But, in spite of the finding that an EMG can actually miss damage done by the poliovirus, it has been suggested that every polio survivor get a regular EMG to identify muscles that were not affected by the poliovirus and identify which limbs can be exercised without worrying that they will become weaker. One study using regular EMG found that almost a quarter of paralytic polio survivors' limbs had no evidence of motor neurons having been killed. Those limbs were classified as having "no clinical polio" and therefore could be exercised like anyone else's muscles. However, neurologist Carlos Luciano used that special EMG and found over-sprouted motor neurons in 85% of muscles that were thought to have had “no clinical polio.” This finding highlights research by Dr. David Bodian in the 1940s and Dr. Alan McComas in the 1990s showing that seemingly unaffected muscles had lost an average of 40% of their motor neurons to polio. Dr. McComas' study of polio survivors was clinical confirmation of David Bodian's findings from autopsies of more than 100 polio-infected individuals, plus hundreds of monkeys infected with polio, that polio survivors had to lose more than 60% of motor neurons for weakness to be apparent with the acute polio.
The danger of using a regular EMG to diagnose polio or identify “unaffected” muscles comes through loud and clear in the experience of one of our patients, whose legs had been severely weakened by polio and were getting weaker, causing him to walk with crutches. He believed that polio had not affected his arms and he wanted to go on a “‘walking tour” of Europe. He asked for a regular EMG of all of the muscles of his arms, which showed no evidence of polio. Off he went on his crutches to Europe, where his arms started to become weak. He returned to the Post-Polio Institute a month later, barely able to lift his arms.
The moral is that an expensive and painful EMG is neither reliable nor desirable if you're trying to decide how you should preserve your remaining overworked, poliovirus-damaged motor neurons and your muscle strength. The safest thing to do is assume that every muscle was affected by polio, and follow this Post-Polio Precept, the fundamental tenet that underlies all PPS treatment. We call it ”The Golden Rule”.
"If anything causes fatigue, weakness or pain DON'T DO IT! (Or do much less of it.)”
Text originally published in The Polio Paradox. Updated from the original by Richard L. Bruno, HD, PhD., 2022