Poliomyelitis

Dr. Parang Mehta, MD.

Polio changes lives -- for the worse.  Before the vaccines became available, it was a much feared disease around the world, and caused thousands of deaths and disabilities each year.

Polio is a viral disease.  The virus enters the body throught the mouth, and infects the rest of the body by spreading through the bloodstream.  The viral illness lasts only a few days, but leaves damaged nerve cells which cause lifelong weakness of various muscles of the body.

Though we associate polio with a limp, the disease affects upper limbs, neck, and trunk muscles also.  When it affects the muscles of respiration, or the nerves from the brain, it sometimes causes death.  After recovery from the immediate illness, physiotherapy can help regain some strength in the partially affected muscles.  Severe weakness is permanent.

There are three types of poliomyelitis viruses, and any one of them causes poliomyelitis.  Type 2 poliovirus has now been eradicated all around the world.  The infection is usually through contaminated water, hands, or other objects.  The infection localises in the gut, and spreads to the nervous system to do its terrible job.

The Disease

Most children who are infected with the polio viruses do not get the disease. More than 90% of polio virus infections are asymptomatic. A few children get mildly ill, with fever, sore throat, loose motions, vomiting, abdominal pain, etc. This is known as abortive poliomyelitis, and the children recover completely with no nervous system involvement or paralysis. About one percent of children with polio virus infections get the paralytic disease.

Paralytic illness also starts with fever, loose motions, and other symptoms of a viral fever.  The true diagnosis is difficult to make in the early days.  Weakness of various body parts appears as the disease progresses.  The paralysis progresses for 2-3 days after it appears, and then becomes stable. Once the fever has subsided, the paralysis does not progress.

Admission to hospital, immobilisation of the affected limbs in an attempt to prevent further damage, and supportive treatment is all we have to offer these children.  There is no curative treatment for this viral infection, but a large proportion of affected persons will recover spontaneously in the months after recover. The muscle power return is variable, from complete recovery to no recovery at all and lifelong flaccid paralysis.

Polio Prevention

There is no drug for the polio virus, and the paralysis left by this disease is permanent. Prevention is thus very important.

Polio vaccines became available in the 1950s, and most countries have now got rid of the disease completely.   The eradication of this disease from almost the entire world is one of the triumphs of science and international cooperation.

There are two types of vaccines available, the oral and the injectable.
Polio vaccines
 

Last Revision: May 22, 2020