Poliomyelitis is an ancient disease and has been one of the most dreaded since pre-biblical times. 4000 year-old Egyptian carvings show a typical polio withered leg.
Before the 1900's, polio was endemic and most polio occurred in infants, hence the name "infantile paralysis". Few developed paralysis and poor hygiene meant that most people were exposed to the virus early in life, thus building active immunity. In fact, everyone had polio, just as we all had measles, mumps and chicken pox.
Polio is a gastro virus ie "a tummy wog". 95% of people were not even aware that they had had polio, having no symptoms or just a 'flu-like illness. The other 5% had either weakness or some paralysis. Only 2.5% were left with any visible effects from polio. The mortality rate is 3% of known polio cases ie 15 in 10,000 pop.
The first recorded "epidemics" were around 1916. Fear swept communities. Hospitals ran out of room. In NZ, patients were nursed in tents in the hospital grounds. Probably in other parts of the world too. Sporadic isolated cases were the norm until 1937-38 when again there was a major outbreak. In post-World War 2 years, epidemics escalated until the Salk vaccine was available in 1956. By the 1950's equal numbers of adults as children were contracting polio. Polio had become a disease of cleanliness. It affected the more affluent people and at an older age was more severe in its paralysis.
Polio is a picornavirus (pico = small; rna = RNA, part of cell nucleus). Rhinovirus belongs to the same family and causes colds. It replicates best at temperatures of 33O as found in the nose. Enteroviruses, which include Hepatitis A, echovirus, coxsackie and polio, replicate better at 37O - body temperature. Enteroviruses are resistant to gastric acidity and bile. There are 3 strains of polio. Most epidemics are caused by Type 1. Some people have had polio twice, having the misfortune to catch different strains in different epidemics.
COURSE OF DISEASE
Polio enters through the mouth and divides in the lymphoid tissue of the pharynx or intestine. If the body cannot stop the virus at this stage, it enters the bloodstream and may cause flu'-like symptoms. If the disease is able to progress further, (ie with poor immune function), the virus enters the anterior horn cells of the spinal column resulting in weakness and paralysis, which is then recognised as polio.
The polio virus uses the RNA of the host cell to enable it to divide. It continues to divide until it explodes the host cell destroying it. Roughly 1,000 new poliovirus can be released from one host cell to seek their own host cell and repeat the process. Each cycle takes about 10 hours. Polio may continue to replicate in the gut and faeces may still be infectious for months after all symptoms have gone.
Polio can affect any and many parts of the body. Some people have an arm or a leg weakened or paralysed. There may be any combination, opposite arms and legs, the same side, both legs, face, eye, hearing, swallowing only, voice, breathing, scoliosis (curvature of spine) etc. If bulbar polio occurred, involving swallowing or breathing, patients may need tube feeding or an iron lung. Death was possible.
The extent of damage depends on how many cells
are destroyed completely and where they are. Most polio survivors
have scattered unapparent damage in many parts of the body that can only
be determined by EMG testing. If there is extensive destruction
in an area, permanent paralysis will result. Some nerve cells may
survive in a weakened state and improve over time. Other surviving
nerves may send out sprouts to re-activate muscles that have lost their
nerves supply, resulting in further recovery years later.
A few people were left requiring help breathing. Some are still using iron lungs. Many had calipers initially but over time were able to walk without them. Some were left using calipers, crutches, sticks or wheelchairs. Most people recovered to lead normal lives - many with no visible effects from polio, others with a variety of limps. Some had surgery to improve muscle and joint function. There was pride that their efforts to recover were rewarded. Polio was gone.However, around 1980 it was realised that polio had another round to go. Although polio people from previous eras had had some deterioration later in life,
it wasn't until the huge numbers of polio survivors from the post war years began having problems and talking about this, that it was realised there are "Late Effects" of polio that needed to be investigated further.
Symptoms that are occurring can be generalised and non-specific. They may include some or all.
ø Undue fatigue
ø New muscle weakness
ø Pain - muscular and / or joint
ø Lack of endurability
ø Breathing difficulties
ø Sleeping problems
ø Swallowing difficulties
ø Reduced ability in daily activities
Diagnosis is one of exclusion. There is no definite test available for the late effects of polio.
The Late Effects of Polio (LEP) is a general term covering new health problems resulting from polio-caused impairment including arthritis, tendinitis, bursitis and other repetitive motion problems.
Post Polio Syndrome (PPS) is a sub-category that includes a symptom cluster of new weakness, fatigue and pain, resulting in declining ability and/or new disability.
Post Polio Progressive Muscular Atrophy (PPMA) is a sub-group of PPS defined as progressive new weakness and atrophy in muscles and this can be demonstrated on EMG.
AN INTERNATIONAL CAUTION -
The following drugs may worsen the symptoms of polio survivors and should be avoided or used with caution: Alert your doctor to these.
|POLIO MEDICAL ALERT CARD
betaloc, inderal, tenormin
Alcohol may increase likelihood of falls
Treatment has mainly been to advise people to
reduce activity levels, building frequent rest periods into the day.
Exercise to maintain and improve muscle function advises exercising at
20% of your capacity only, to reduce further deterioration. Local
research by polio people in WA has improved on this advice, enabling many
in WA to return to previous activities again without the pain and fatigue
encountered previously. We can continue to be independent and in
control of our lives.
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