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Jun 15, 2006
Polio or Poliomyelitis: Viral Paralytic Disease
by SirGan
 Poliomyelitis is a highly contagious infectious disease caused by three types of poliovirus. The poliovirus is a virus most recognized for its destruction to the nervous system causing paralysis. Paralytic polio can lead to temporary or permanent muscle paralysis, disability and deformities of the hips, ankles and feet. Since polio immunization has become widespread, cases of polio are very rare. An ancient disease, it was first recognized as a medical entity by Jakob Heine in 1840.Incidence of the conditionNearly 50 years ago in 1952, there were nearly 58,000 known cases of polio in the United States but currently in the US, about 8 cases of polio are reported yearly. Over 1/3 of these individuals developed paralytic polio. Of the 1/3 infected with paralytic polio, 3000 died. These cases are usually in children and the cause has been traced to the oral poliovirus vaccine in most cases. Infants and young children are at greatest risk and infections are more common during the summer and autumn seasons.
Signs and symptoms of poliomyelitisThe fact is that there are three basic patterns of polio infection:
Every stadium has its own recognizable symptoms!
Subclinical infection
Nonparalytic poliomyelitis
Paralytic poliomyelitis
Post-polio syndrome
Affecting people who have recovered from polio, post-polio syndrome is a cluster of disabling signs and symptoms that appear decades — between 10 and 40 years — after the initial illness.
Virus target tissuesPolio has also been divided into several types, depending on which part of the body is affected.
This, most common form, attacks nerve cells in spinal cord and may cause paralysis of the muscles in your arms and legs, and respiratory muscles. Children younger than age 5 are most likely to become paralyzed in a single leg, whereas paralysis of both arms and legs is more common in adults. An affected limb becomes floppy and poorly controlled — the condition of acute flaccid paralysis (AFP).
During this type of infection -the virus affects the motor neurons in your brain, where the centers of certain nerves, called the cranial nerves, are located. These nerves are involved in your ability to see, hear, smell, taste and swallow.
This is a combination of both bulbar and spinal paralytic polio. It usually leads to paralysis of arms and legs and may also affect breathing, swallowing and heart function.
The cause of poliomyelitis, ways of transmissionThe cause of poliomyelitis is one virus called Poliovirus! What is so important about this virus? Poliovirus resides only in humans and enters the environment in the feces of someone who is infected. How it is being transmitted?
The virus spreads primarily through the fecal-oral path of infection, especially in areas where ventilation and sanitation systems are inadequate. Several researches done in the past have proven that it also can be transmitted through contaminated water and food. Important and very dangerous thing is that, although people carrying the virus are most contagious seven to 10 days before and after signs and symptoms appear, they can spread the virus for weeks in their feces.
Pathogenesis of poliomyelitisWhat happens after the infection? Well, once the poliovirus invades a patient’s body, it multiplies in throat lining and intestinal tract and then travels to central nervous system through blood and lymph. The most important thing is that, while the virus moves along nerve fibers, it damages the motor neurons that normally carry messages between patient’s brain and muscles.
So, what happens after this damage? Well, the mechanism is well studied: in order to compensate the missing neurons, the remaining nerve cells spread new fibers. This process places added stress on the nerve cell body, which has to nourish the additional fibers. Over time, this stress may be more than the neuron can handle.
Risk factors for developing poliomyelitisMost common risk factors for developing this serious infection are:
Diagnosis of poliomyelitisThere are several very effective diagnostic tools for the accurate diagnosis of poliomyelitis! Some of the most common are:
These should be the first step of poliomyelitis diagnosis
These specimens are grown on a special medium and checked for the presence of the poliovirus.
This diagnostic tool has become a routine! A special needle is placed into the lower back, into the spinal canal and a small amount of cerebral spinal fluid can be removed and sent for testing to determine if there is an infection or other problems.
Possible complications of poliomyelitisBesides the temporary or permanent muscle paralysis, polio virus can cause several other complications such as:
This potentially life-threatening condition occurs when increased pressure in the blood vessels in lungs forces fluid into the air sacs, filling lungs with fluid.
This inflammation results when someone inhale foreign material into lungs.
These infections usually begin when bacteria enter the bladder through the urinary tract.
This is a partial or complete blockage of bowel that prevents food from moving through the intestinal tract.
This is one infection in which the muscular layer of heart becomes inflamed, leading to chest pain, an abnormal heartbeat or congestive heart failure
This condition occurs when the right side of heart can't pump hard enough to compete with the lungs' increased blood pressure.
Treatment of poliomyelitisUnfortunately, there is no cure for the poliovirus infection! Because no cure for polio exists, the focus is on increasing comfort, speeding recovery and preventing complications. Supportive treatments include:
Moist heat, heating pads, warm towels, may reduce muscle pain and spasm. Physical therapy combined with braces or corrective shoes, orthopedic surgery, or similar interventions may eventually be necessary to maximize recovery of muscle strength and function.
Prevention and immunizationThere are several prevention measures of poliomyelitis and some of those are:
Two versions of the vaccine may be administered:
It is administered by injection. This vaccine is administered at all four immunization visits. Administration of the IPV cannot cause polio and is safe to use for individuals with weakened immune systems.
It is administered by mouth. In rare cases, OPV has been known to cause vaccine-associated paralytic poliomyelitis (VAPP).
Oral Polio Vaccine should not be given to a child if they have any of the following:
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