Polio commonly occurs in children. Most infections are acquired from cases that are sub–clinical, i.e. they do not manifest the full blown symptoms. Such cases shed the virus in the feces. The cases are most infectious about one week to 10 days before and after the onset of symptoms. In the feces, the virus is excreted commonly for about two to three weeks, and sometimes as long as about three to four months. The infection may spread directly through contaminated fingers where hygiene is poor, or indirectly through contaminated water, milk, foods, flies and articles of daily use.
Clinical Features of Poliomyelitis
As mentioned earlier, many cases are sub–clinical. Almost 95% of infections are sub–clinical. The patients have minimum or no symptoms at all. The cases can either present as paralytic or non–paralytic polio. In non–paralytic polio, the child usually presents with low grade fever, diarrhea, and this is followed by stiffness and pain in the neck and back. The disease lasts for about two to 10 days. Recovery is rapid. It occurs in approximately 1% of all infections.
The presenting features are stiffness and pain in the neck and back. The disease is synonymous with aseptic meningitis.
ProsthesisThe virus in paralytic polio invades the nervous system such that eventually results in paralysis. The infection starts with a low grade fever and associated non–specific symptoms such as nausea, abdominal pain, headache etc. This is followed by paralysis which usually involves the lower extremity, starting at the hip and spreading downwards. The paralysis is asymmetrical.
This occurs in less than 1% of the infections. The virus invades the CNS (central nervous system) and causes varying degrees of paralysis. Other associated symptoms are malaise, anorexia, nausea, vomiting, headache, sore throat, constipation and abdominal pain. The paralysis is characterized as descending, i.e. starting at the hip and then moving down to the distal parts of the extremity.
There is no specific treatment for polio. Good nursing care from the beginning of illness can minimize or even prevent crippling. Physiotherapy is of vital importance. It can be initiated in the affected limb immediately. It helps the weakened muscles to regain strength. Very probably, the child may have to put on metal calipers.