Health Encyclopedia

Poliomyelitis

Definition

Poliomyelitis is a viral disease that can affect nerves and lead to paralysis.

Alternative Names

Polio; Infantile paralysis

Causes, incidence, and risk factors

Poliomyelitis is a disease caused by infection with the poliovirus. The virus spreads by direct person-to-person contact, by contact with infected mucus or phlegm from the nose or mouth, or by contact with infected feces.

The virus enters through the mouth and nose, multiplies in the throat and intestinal tract, and then is absorbed and spread through the blood and lymph system. The time from being infected with the virus to developing symptoms of disease (incubation) ranges from 5 - 35 days (average 7 - 14 days).

Risks include:

Lack of immunization against polio and then exposure to polio
Travel to an area that has experienced a polio outbreak

In areas where there is an outbreak, those most likely to get the disease include children, pregnant women, and the elderly. The disease is more common in the summer and fall.

Between 1840 and the 1950s, polio was a worldwide epidemic. Since the development of polio vaccines, the incidence of the disease has been greatly reduced. Polio has been wiped out in a number of countries. There have been very few cases of polio in the Western hemisphere since the late 1970s. Children in the United States are now routinely vaccinated against the disease.

Outbreaks still occur in the developed world, usually in groups of people who have not been vaccinated. Polio often occurs after someone travels to a region where the disease is common. Thanks to a massive global campaign over the past 20 years, polio exists only in a few countries in Africa and Asia.

Symptoms

There are three basic patterns of polio infection: subclinical infections, nonparalytic, and paralytic. Approximately 95% of infections are subclinical infections, which may not have symptoms.

SUBCLINICAL INFECTION

General discomfort or uneasiness (malaise)
Headache
Red throat
Slight fever
Sore throat
Vomiting

People with subclinical polio infection might not have symptoms, or their symptoms may last 72 hours or less.

Clinical poliomyelitis affects the central nervous system (brain and spinal cord), and is divided into nonparalytic and paralytic forms. It may occur after recovery from a subclinical infection.

NONPARALYTIC POLIOMYELITIS

Back pain or backache
Diarrhea
Excessive tiredness, fatigue
Headache
Irritability
Leg pain (calf muscles)
Moderate fever
Muscle stiffness
Muscle tenderness and spasm in any area of the body
Neck pain and stiffness
Pain in front part of neck
Pain or stiffness of the back, arms, legs, abdomen
Skin rash or lesion with pain
Vomiting

Symptoms usually last 1 - 2 weeks.

PARALYTIC POLIOMYELITIS

Abnormal sensations (but not loss of sensation) in an area
Bloated feeling in abdomen
Breathing difficulty
Constipation
Difficulty beginning to urinate
Drooling
Fever 5 - 7 days before other symptoms
Headache
Irritability or poor temper control
Muscle contractions or muscle spasms in the calf, neck, or back
Muscle pain
Muscle weakness, asymmetrical (only on one side or worse on one side)
- Location depends on where the spinal cord is affected
- Progresses to paralysis
- Rapid onset
Sensitivity to touch; mild touch may be painful
Stiff neck and back
Swallowing difficulty

Signs and tests

The health care provider may find signs of meningeal irritation (similar to meningitis), such as stiff neck or back stiffness with difficulty bending the neck. The person also might have difficulty lifting the head or lifting the legs when lying flat on the back, and abnormal reflexes.

Tests include:

Routine CSF examination
Test for levels of antibodies to the polio virus
Viral cultures of throat washings, stools, or cerebrospinal fluid (CSF)

Treatment

The goal of treatment is to control symptoms while the infection runs its course.

People with severe cases may need lifesaving measures, especially breathing help.

Symptoms are treated based on how severe they are. Treatments include:

Antibiotics for urinary tract infections
Medications (such as bethanechol) for urinary retention
Moist heat (heating pads, warm towels) to reduce muscle pain and spasms
Pain killers to reduce headache, muscle pain, and spasms (narcotics are not usually given because they increase the risk of breathing difficulty)
Physical therapy, braces or corrective shoes, or orthopedic surgery to help recover muscle strength and function

Expectations (prognosis)

The outcome of the disease depends on the form (subclinical, nonparalytic, or paralytic) and the site affected. If the spinal cord and brain are not affected, which is the case more than 90% of the time, complete recovery is likely.

Brain or spinal cord involvement is a medical emergency that may result in paralysis or death (usually from respiratory difficulties).

Disability is more common than death. Infection high in the spinal cord or in the brain increases the risk of breathing problems.

Complications

Aspiration pneumonia
Cor pulmonale
High blood pressure
Kidney stones
Lack of movement
Lung problems
Myocarditis
Paralytic ileus (loss of intestinal function)
Permanent muscle paralysis, disability, deformity
Pulmonary edema
Shock
Urinary tract infections

Calling your health care provider

Call your health care provider if:

Someone close to you has developed poliomyelitis and you haven't been vaccinated
You develop symptoms of poliomyelitis
Your child's polio immunization (vaccine) is not up to date

Prevention

Polio immunization (vaccine) effectively prevents poliomyelitis in most people (immunization is over 90% effective).

Review Date:1/22/2008
Reviewed By:Kenneth M. Wener, MD, Department of Infectious Diseases, Lahey Clinic, Burlington, MA. Review provided by VeriMed Healthcare Network.

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