It's been over 40 years since the last major Polio epidemic in North America. With the advent of the Sabin & Salk vaccines most physicians will never see an acute case of poliomyelitis. In fact in North America the Polio virus has gone the way of the Small Pox virus and is found only in the laboratory setting. So for most physicians our role in this once devastating disease has changed. Now, we will only be dealing with patients who have had the acute infection some 40 to 50 years ago. What we as modern physicians need to recognize now however, is one of the common aftermaths of poliomyelitis - the post polio syndrome.
The term, post polio syndrome, was coined because a growing number of polio patients, who had long since recovered from the acute infection with variable degree of residual disability, began reporting increasing disability once again. Post polio victims began complaining of weakness, muscle atrophy and dysfunction and increasing gait disturbances. As primary care physicians we need to recognize this syndrome and have a higher index of suspicion when faced with a patient who fits this profile.
The syndrome is characterized by a number of signs and symptoms including musculoskeletal pain, weakness, wasting, gait disturbance, fatigue and even insomnia & depression. A patient may present to his or her physician with problems at the work place related to their reduced capabilities; or perhaps even family and marital stress as the result of reduced earning power. Due to diminishing stamina, the afflicted may have to experience role changes at home. Although necessary, such changes are threatening to ones self-esteem and their frustrations may be taken out on family members or friends. The threat of lost independence may present with depression, mood swings and anger. These feelings need to be explored before some of the physical problems can be addressed.
Before the possibility of post polio syndrome can be considered other causes of such physical deterioration should also be kept in mind. The differential should include multiple sclerosis, peripheral neuropathies, myopathies, degenerative arthritis and various nerve root compression disorders. Screening laboratory investigations may include C.B.C., electrolytes, urea, creatinine, TSH, serum glucose, calcium, ck, liver function test, B12 & folic acid. E.M.G. and NCT are also indicated both to rule out other neuromuscular disorders as well as being diagnostic in many cases of post polio syndrome. CT scan or MRI may be necessary in cases in which demyelinating disorders or nerve root entrapment are suspected. If other conditions have been ruled out it may be appropriate to refer such patients to a neurologist or physiatrist who has a special interest in this condition. There are a number of tertiary centres which have programs suited particularly to the diagnosis, education and rehabilitation of such patients.
The actual pathophysiology of post polio syndrome is unknown. A number of theories are abound. The most likely explanation is that motorneuron, undamaged by the initial viral insult, compensated for the loss of the thousands of these cells in the anterior horn by sprouting multiple nerve endings in the affected muscles. However these compensatory sprouts and perhaps even the overload axons supplying excessive motor impulses, eventually burn out years later. This is probably why patients who try to over come increasing weakness and disability by vigorous exercise only get worse. The overload axons only fail at an even faster rate.
Appropriate isometric exercises and physiotherapy are the mainstay of treatment but orthotics and functional braces also maybe necessary in some cases. Patient must be informed as to the need to carefully budget ones physical activity and to avoid getting exhausted physically both at work and with exercising. The role of the family physician in monitoring and reinforcing this concept is very important.
There are a number of drugs that have been tried which may have theoretical benefits but few have proven of any great benefit yet. Pyridostigmine is one such drug and studies are currently under way to see if fatigue symptoms respond to it. The appropriate use of analgesics and NSAIDs may be useful for those experiencing enough musculoskeletal pain to interfere with even moderate activity. Antidepressants at low doses for chronic pain situations or at high doses for depression should also be kept in mind. The judicious use of muscle relaxants for the treatment of severe muscle spasms may also be necessary. Other measures such as weight loss and balanced nutrition are important in maintaining overall health and this is even more important in post polio patients. Lifestyle issues such as excessive alcohol consumption and smoking need to be addressed as these substances only potentiate the problems your patient faces.
In summary, post polio syndrome is somewhat of a new concept but as family physicians, it is probably more important to recognize this disorder than acute poliomyelitis because the latter we will probably never see in this country. With an appropriate screening work up physicians can make the best referral choices for our patients and support them in their need to maintain a practical lifestyle and functional level.
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