AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Poliomyelitis is an enteroviral infection that can manifest in 4 different forms: inapparent infection, abortive disease, nonparalytic poliomyelitis, and paralytic disease. Before the 19th century, poliomyelitis occurred sporadically. During the 19th and 20th centuries, epidemic poliomyelitis was more frequently observed, reaching its peak in the mid 1950s. The worldwide prevalence of this infection has decreased significantly since then because of aggressive immunization programs. Eradication of this disease during the present decade is a top priority for the World Health Organization (WHO).

Pathophysiology

Poliovirus is an RNA virus that is transmitted through the oral-fecal route or by ingestion of contaminated water. Three serotypes are able to cause human infection. The incubation period for poliovirus is 5-35 days. The viral particles initially replicate in the nasopharynx and gastrointestinal tract and then invade lymphoid tissues, with subsequent hematologic spread. After a period of viremia, the virus becomes neurotropic and produces destruction of the motor neurons in the anterior horn and brainstem. The destruction of motor neurons leads to the development of flaccid paralysis, which may be bulbar or spinal in distribution.

Frequency

United States

No cases of wild-type poliovirus infection have been reported in the United States since 1979. Until 1998, an average of 8-10 cases associated with the vaccine virus were reported every year. Since the institution of an all-inactivated poliovirus vaccine (IPV) policy in the routine immunization schedule, the number of vaccine-associated cases has significantly decreased. Four cases of vaccine-derived poliovirus were identified in 2005 among unvaccinated children in an Amish community in Minnesota.

International

The global incidence of poliovirus infection has decreased by more than 99% since 1988. Although no outbreaks had been reported in the western hemisphere since 1991, the Pan American Health Organization reported an outbreak in Haiti and the Dominican Republic in 2001. Since 2001, no additional outbreaks of disease caused by wild poliovirus have been reported in the Americas. Clusters of wild-type disease are still found in some areas in Africa and Southeast Asia. By 2004, the only 6 countries in which wild poliovirus transmission had not been interrupted were India, Egypt, Nigeria, Niger, Pakistan, and Afghanistan. Although significant progress has been made towards eradication of this infection in these countries, an increase in the number of cases was observed in 2006.

Mortality/Morbidity

Mortality is more frequently observed in cases of paralytic poliomyelitis and is associated with complications such as respiratory failure. No deaths due to wild-type poliovirus have been reported in the United States since 1979.

Although most cases of poliomyelitis (90-95%) are inapparent, 5-10% of patients who acquire this infection develop symptoms.

Sex

Males and females of pediatric age are affected with equal frequency.

Age

Poliovirus affects mainly children. However, individuals of any age (especially those who are immunocompromised) may also develop the disease.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Most patients infected with poliovirus develop inapparent infections and are frequently asymptomatic.
• In cases of abortive poliomyelitis (5-10%), a history of the following is found with normal neurologic examination findings:
• • Anorexia
  • Vomiting
  • Abdominal pain
  • Duration of illness usually less than 5 days
• When nonparalytic poliomyelitis develops, symptoms usually are those observed in abortive disease in addition to meningeal irritation.
• Paralytic poliomyelitis involves systemic manifestation, such as respiratory failure, in addition to symptoms observed in nonparalytic poliomyelitis.
• Patients who have recovered from poliomyelitis occasionally develop a postpoliomyelitis syndrome, in which recurrences of weakness or fatigue are observed and which usually involve groups of muscles that were initially affected. This postpolio syndrome may develop 20-40 years after infection with poliovirus.

Physical

The spectrum of disease varies from inapparent infection to paralytic disease.

• In mild cases, the following nonspecific signs and symptoms are observed and usually resolve within a few days:
• • Fever
  • Headache
  • Nausea
  • Vomiting
  • Abdominal pain
  • Oropharyngeal hyperemia
• Nonparalytic poliomyelitis is characterized by the symptoms described above in addition to the following:
• • Nuchal rigidity
  • More severe headache
  • Back and lower extremity pain
  • Meningitis with lymphocytic pleocytosis (usually)
• Paralytic poliomyelitis occurs in fewer than 5% of affected patients and is characterized by the following:
• • Compromise of the motor neurons may be localized or widespread.
  • More frequently, asymmetric loss of muscle function is observed with involvement of major muscle groups.
  • Muscle atrophy is generally observed several weeks after the beginning of symptoms.
  • Recovery may be complete, partial, or absent.

Causes

Polioviruses are enteroviruses within the Picornaviridae family. These viruses are resistant to ether and chloroform but can be inactivated by formaldehyde. They multiply in the gastrointestinal tract but are particularly neurotropic.

Documentation suggests that infections with polioviruses can be potentiated by factors such as exercise and tonsillectomy. Additionally, patients who are immunocompromised, such as those with human immunodeficiency virus (HIV) infection, B-cell disfunction, immunoglobulin A (IgA) deficiency, or severe combined immunodeficiency, are particularly at high risk of developing poliomyelitis when exposed to both wild-type polioviruses and vaccine-attenuated viruses present in the oral poliovirus vaccine.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Guillain-Barré syndrome
Aseptic meningitis
California encephalitis
Nonpoliovirus enteroviral encephalitis

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Obtain specimens from the CSF, stool, and throat for viral cultures.
• Obtain acute and convalescent serum for antibody concentrations against the 3 polioviruses.
• A 4-fold increase in the immunoglobulin G (IgG) antibody titers or a positive anti-immunoglobulin M (IgM) titer during the acute stage is diagnostic.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

No antivirals are effective against polioviruses. The treatment of poliomyelitis is mainly supportive.

• Analgesia is indicated in cases of myalgias or headache.
• Mechanical ventilation is often needed in patients with bulbar paralysis.
• Tracheostomy care is often needed in patients who require long-term ventilatory support.
• Physical therapy is indicated in cases of paralytic disease.
• • In paralytic disease, provide frequent mobilization to avoid development of chronic decubitus ulcerations.
  • Active and passive motion exercises are indicated during the convalescent stage.
• Fecal impaction is frequent in cases of paralytic disease and can be treated with laxatives as soon as it develops.

Consultations

• Physical therapist and rehabilitation therapist
• Pulmonologist
• Neurologist
• Immunologist
• Infectious diseases specialist

Diet

Because patients with poliomyelitis are prone to develop constipation, a diet rich in fiber is usually indicated.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

No antiviral agents are effective against poliovirus.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• Patients with poliomyelitis may develop bladder dysfunction for which catheterization is frequently required.

Deterrence/Prevention

• Two types of vaccines used in the prevention of poliomyelitis are IPV administered parenterally and oral attenuated poliovirus vaccine (OPV).
• • Inactivated poliovirus vaccine
  • • IPV was the first polio vaccine available on the market, and its widespread administration began in the 1950s. An enhanced inactivated poliovirus vaccine (eIPV) formulation is now available. Nonenhanced early formulations had the disadvantages of not being as immunogenic as OPV, not being able to induce mucosal immunity, and having to be administered parenterally, which increased costs and decreased compliance.
    • One of the major advantages of IPV is that it contains an inactivated virus; for that reason, IPV is not associated with the development of vaccine-associated poliomyelitis. Although they do not induce mucosal immunity, new eIPV formulations have been proven to be as immunogenic as OPV. For that reason, countries in which no cases of wild-type disease have been reported during the last several years (eg, the United States) have now adopted eIPV immunization schedules. This new prophylactic approach has the advantage of eliminating vaccine-associated cases.
    • This vaccine is administered when individuals are aged 2 months, 4 months, and 6-12 months and before school entry, which is usually at age 4 years.
  • Oral attenuated poliovirus vaccine
  • • Trivalent OPV has been used since the early 1960s. Immunization with this formulation was responsible for the significant decrease in the prevalence of disease throughout the world. This formulation has the advantages of inducing mucosal immunity, providing appropriate herd immunity, and increasing vaccine uptake because of oral administration. Additionally, it is cost-effective, especially in countries in the developing world.
    • The major disadvantage of trivalent OPV is its association with vaccine-associated paralytic poliomyelitis (VAPP). Although the virus contained in this formulation is attenuated, it may occasionally become neurotropic and be able to produce disease similar to wild-type virus.
    • Trivalent OPV is being administered in developing countries when individuals are aged 2 months, 4 months, and 6 months and with a booster at age 4 years. VAPP occurs most frequently after the first dose of OPV but may also occur after administration of the second or third doses.
    • A new high-potency monovalent oral poliovirus type 1 vaccine (mOPV1) was introduced in India in April 2005. This vaccine is targeted to eliminate some of the last poliovirus reservoirs. This product constitutes part of an international effort to eradicate wild poliovirus. Studies have revealed that mOPV1 is 3 times more effective against type 1 poliomyelitis than trivalent OPV. In addition, it has been demonstrated to be particularly efficacious in areas in which the efficacy of trivalent OPV may be compromised by the high prevalence of diarrhea and other infectious processes. mOPV1 may be the preferred option to control a poliovirus outbreak in areas that have already been declared free of wild poliovirus transmission.

Prognosis

• Bulbar paralytic poliomyelitis has been associated with the highest rate of complications and a mortality rate as high as 60%; spinal poliomyelitis follows. Patients with inapparent or abortive poliomyelitis recover without significant sequelae.

Patient Education

• For excellent patient education resources, visit eMedicine's Children's Health Center and Brain and Nervous System Center. Also, see eMedicine's patient education articles Immunization Schedule, Children and Brain Infection.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Administration of OPV is contraindicated in children who are immunocompromised and in children whose caretakers are immunocompromised. A risk for development of poliomyelitis is present in those individuals who receive this vaccine and are immunocompromised. Although OPV is no longer included in the routine vaccination schedule in the United States, its administration remains a common practice in other countries.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• AAP. Prevention of poliomyelitis: recommendations for use of only inactivated poliovirus vaccine for routine immunization. Committee on Infectious Diseases. American Academy of Pediatrics. Pediatrics. Dec 1999;104(6):1404-6. [Medline].
• Aylward RB, Sutter RW, Heymann DL. Policy. OPV cessation--the final step to a "polio-free" world. Science. Oct 28 2005;310(5748):625-6. [Medline].
• Bernier RH. Improved inactivated poliovirus vaccine: an update. Pediatr Infect Dis. May-Jun 1986;5(3):289-92. [Medline].
• Cashman NR, Maselli R, Wollmann RL. Late denervation in patients with antecedent paralytic poliomyelitis. N Engl J Med. Jul 2 1987;317(1):7-12. [Medline].
• CDC. From the Centers for Disease Control and Prevention. Progress toward poliomyelitis eradication--African Region, 1999-March 2000. JAMA. Oct 11 2000;284(14):1781-2. [Medline].
• CDC. From the Centers for Disease Control and Prevention. Progress toward poliomyelitis eradication--Eastern Mediterranean Region, 1998-October 1999. JAMA. Jan 12 2000;283(2):195-6. [Medline].
• CDC. Poliovirus infections in four unvaccinated children--Minnesota, August-October 2005. MMWR Morb Mortal Wkly Rep. Oct 21 2005;54(41):1053-5. [Medline]. [Full Text].
• CDC. Progress toward poliomyelitis eradication--India, January 2004-May 2005. MMWR Morb Mortal Wkly Rep. Jul 8 2005;54(26):655-9. [Medline].
• Grassly NC, Wenger J, Durrani S, et al. Protective efficacy of a monovalent oral type 1 poliovirus vaccine: a case-control study. Lancet. Apr 21 2007;369(9570):1356-62. [Medline].
• Heymann D, Aylward B. Polio will soon be history. Bull World Health Organ. Jan 2007;85(1):7-8. [Medline].
• Jenkins PC, Modlin JF. Decision analysis in planning for a polio outbreak in the United States. Pediatrics. Aug 2006;118(2):611-8. [Medline].
• Kew OM, Sutter RW, de Gourville EM, Dowdle WR, Pallansch MA. Vaccine-derived polioviruses and the endgame strategy for global polio eradication. Annu Rev Microbiol. 2005;59:587-635. [Medline].
• Lahariya C, Pradhan SK. Prospects of eradicating poliomyelitis by 2007: compulsory vaccination may be a strategy. Indian J Pediatr. Jan 2007;74(1):61-3. [Medline].
• McBean AM, Thoms ML, Albrecht P. Serologic response to oral polio vaccine and enhanced-potency inactivated polio vaccines. Am J Epidemiol. Sep 1988;128(3):615-28. [Medline].
• Prevots DR, Strebel PM. Poliomyelitis prevention in the United States: new recommendations for routine childhood vaccination place greater reliance on inactivated poliovirus vaccine. Pediatr Ann. Jun 1997;26(6):378-83. [Medline].
• Sutter RW, Prevots DR, Cochi SL. Poliovirus vaccines. Progress toward global poliomyelitis eradication and changing routine immunization recommendations in the United States. Pediatr Clin North Am. Apr 2000;47(2):287-308. [Medline].

Article Last Updated: Aug 15, 2007