FAMILY MEDICINE® COLUMN

By Martha A. Simpson, D.O., M.B.A.
Associate Professor of Family Medicine
Ohio University College of Osteopathic Medicine

POST-POLIO SYNDROME CAN STRIKE YEARS AFTER ORIGINAL INFECTION

Question: I am 82 years young and have begun having some weakness in my legs. I am blessed with robust health, no diabetes, high blood pressure, etc. I did have polio as a child, and a friend was telling me that polio could cause problems when people get older. Is that true? If so, what types of problems are we talking about?

Answer: Your friend is talking about post-polio syndrome (PPS). Some people who had polio at a young age develop effects from the disease many years later. No one knows why this happens, but it is believed that up to 50 percent of polio survivors are affected by PPS. Research is ongoing.

The number of people who are at risk for PPS has been estimated to be more than 440,000 by the National Center for Health Statistics. This isn’t surprising since during the height of the polio epidemic in the 1940s and 1950s, nearly 20-thousand Americans contracted the disease each year. The introduction of the Salk vaccine in 1955 stopped this deadly killer in its tracks. Fortunately PPS, while aggravating, is rarely life-threatening like polio itself.

Your original polio infection caused problems with motor neurons, a type of nerve cell that carries electrical impulses between your brain and your muscles. Some of these motor neurons were damaged by the polio. During recovery, surviving motor neurons in the affected area are often able to sprout new nerve terminals to “orphaned” muscle fibers. Over time, this can result in various degrees of recovery of whatever movement was lost.

According to some experts, PPS involves degeneration of individual nerve terminals in the motor neurons that survived the original polio attack. Since these surviving motor neurons have to do more work to compensate for the lost neurons, they eventually begin to “wear out” and produce new weakness in the affected area. This weakness may be temporary or permanent. This is one of several hypotheses around the cause of PPS, but to be frank, no one is completely sure why PPS develops.

The symptoms of PPS include new onset of weakness in the limbs, especially those that were affected by the original polio infection, fatigue, muscle and joint pain, breathing problems, swallowing problems, sleep disorders and cold intolerance. You may also experience exhaustion from minimal activity. These symptoms come and go, with symptom-free periods between times when symptoms are exacerbated. The symptoms tend to get worse with time, but their course is unpredictable.

Some risk factors for developing PPS relate to the severity of your original polio infection and your age at the time you were infected. Unfortunately, people who had a strong recovery from the most severe cases of polio are likely to have the greatest loss of function and more fatigue with PPS. However, in cases where the original polio produced fairly minimal symptoms, PPS usually produces only minor symptoms.

To determine if you are suffering from PPS, your doctor may do nerve conduction and muscle conduction studies, CT scanning and MRI imaging. He or she may need to rule out other conditions like Lou Gehrig’s disease. The treatment is aimed at relieving symptoms and includes physical and occupational therapy as well as energy conservation measures.

Family Medicine® is a weekly column. To submit questions, write to Martha A. Simpson, D.O., M.B.A., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701, or via e-mail to readerquestions@familymedicinenews.org. Medical information in this column is provided as an educational service only. It does not replace the judgment of your personal physician, who should be relied on to diagnose and recommend treatment for any medical conditions. Past columns are available online at www.familymedicinenews.org.