For the last couple of decades before his death in 2008, science fiction writer Arthur C. Clarke struggled with limited mobility due to postpolio syndrome. He’d been symptomatic since 1984 after having had acute poliomyelitis in 1962. Postpolio syndrome generally begins 15-30 years after the initial illness. After decades of stable deficits, patients present with progressive weakness, atrophy, fatigue and pain. Decline is often stepwise with intermissions of stability.

The mechanism of postpolio syndrome isn’t known with certainty, but the explanation that’s always made the most sense to me is the progressive loss of motor neurons over time. Polio destroys lower motor neurons during the initial illness. Remaining motor neurons then sprout to re-innervate muscle fibres that have been denervated. With aging, we all lose some motor neurons but, in most of us, there is a considerable safety factor so that we never become symptomatic. In those with polio, the loss of those remaining neurons that are doing more than they were meant to do leads to weakness. Also, those neurons may be more likely to die because of the metabolic exhaustion of individual neurons supplying so many extra muscle fibres.

There’s no specific treatment to reverse the underlying process. I’d strongly recommend, however, referral of patients with postpolio syndrome to a rehabilitation and physical medicine specialist to help maintain function with orthotics and other devices and to prevent orthopedic complications. There is some evidence that exercise is beneficial in maintaining strength. The best prevention is population immunization for polio. Since West Nile virus can also cause a polio-like illness, it’s possible that a few decades from now we’ll be seeing post-West Nile syndrome.

Although postpolio syndrome presumably shortened Sir Arthur’s life, he still made it to 90 and got to see what really happened in 2001.

Reference

1. Howard RS. Poliomyelitis and the postpolio syndrome. BMJ 2005;330:1318-9.

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