Enteroviruses Follow-up

Updated: Mar 01, 2018
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Michael Stuart Bronze, MD  more...
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Follow-up

Inpatient & Outpatient Medications

Pleconaril interferes with enterovirus attachment and uncoating by binding to the virus protein capsid. It was once the most promising candidate for the treatment of enterovirus infections because of its oral bioavailability, penetration into the CNS, and efficacy in reducing the duration of symptoms and morbidity in neonatal sepsis, adult meningitis, and perimyocarditis; however, efficacy has not been definitively established. [67, 65] Until 2003, when the US Food and Drug Administration (FDA) declined its approval, pleconaril had been used on a compassionate basis for treatment of myocarditis and aseptic meningitis in infants. Pleconaril in an intranasal form is currently awaiting FDA approval for the treatment of rhinoviral infections, which although usually self-limited, may persist untreated, particularly in immunosuppressed individuals. [68]

Immunoglobulins have been used therapeutically and prophylactically for enteroviral CNS infections in neonates and immunocompromised hosts, with mixed results. [8] Pre-exposure prophylaxis with immunoglobulins is known to reduce the risk of paralysis in patients with poliovirus infections.

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Deterrence/Prevention

Hygienic measures such as hand washing and adequate disposal of infected secretions help prevent the spread of enteroviral infections.

Poliovirus vaccines have been instrumental in the effort to eradicate polio; the vaccine is available in 2 forms. Considerations are as follows:

  • The OPV is a live attenuated vaccine that contains all 3 serotypes. It was developed by Sabin. OPV administration decreases replication of the virus in the small intestine and increases production of high titers of IgA in the mucosa. The advantages of OPV include easy administration, stimulation of local and generalized immunity, and herd immunity. Adverse effects include vaccine-associated paralytic poliomyelitis [69] and seroconversion rates lower than those achieved with IPV. OPV should not be administered to immunocompromised patients or to household contacts of these patients.

  • OPV is used in developing nations because of it lower cost, ease of administration, and superior secretory immunity in the GI tract in comparison to IPV.

  • IPV was originally developed by Salk in 1955. Current formulations of IPV are more immunogenic than those available before 1987. This vaccine elicits higher IgG antibody titers and has few adverse effects but is inferior to OPV in providing secretory immunity in the GI tract. It is the recommended polio vaccine in United States when the risk of vaccine-associated paralytic polio disease due to OPV exceeds that of wild-type polio disease. Higher costs for production and supply and the delivery route, along with the lack of herd immunity, makes its use less desirable in developing countries.

  • Combined immunization with OPV and IPV provides the highest serum level of antibody response, with equivalent mucosal immunity to that produced by OPV alone. [70]

The spread of AHC is prevented by hand washing and using separate towels.

Intensified efforts to eradicate polio have led to the introduction of new monovalent OPV type 1 (mOPV1) and type 3 (mOPV3) vaccines to more rapidly eliminate the final strains of poliovirus in circulation.

Further efforts to simplify administration of the two monovalent vaccines have resulted in the development of a bivalent oral polio vaccine (bOPV). This vaccine consists of live-attenuated (weakened) poliovirus strains of type 1 and type 3, which simultaneously target the two remaining types of wild poliovirus (type 1 and type 3).

Recent trials demonstrated the superiority of bOPV over tOPV and noninferiority to the respective mOPVs in achieving seroconversion. [71]

As of 2009, the use of bOPV or mOPVs as supplementary immunization activity to complement tOPV is recommended. [30]

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Complications

Polio

Respiratory failure secondary to paralysis of respiratory muscles or to lesions of the respiratory center is a life-threatening complication of paralytic polio.

Pharyngeal paralysis may occur.

Myocarditis is rarely diagnosed clinically.

Gastrointestinal hemorrhage results from intestinal erosions and may require transfusion. Gastric dilation is abrupt in onset, and immediate gastric aspiration should be performed.

Hypertension is a common complication and may progress to hypertensive encephalopathy.

Postpolio syndrome occurs 3-4 decades after acute paralytic polio. It is characterized by muscle pain, worsening of prior weakness, or new paralysis. This is more common in women than in men.

Vaccine-associated poliomyelitis occurs in approximately 1 per 2.6 million people overall and in 1 per 750,000 people who receive the OPV.

Aseptic meningitis

Complications include lethargy, febrile seizures, and coma.

Nonpoliovirus paralytic disease

This is usually less severe than polio-associated paralysis.

Myopericarditis

Chronic dilated cardiomyopathy may result from past enteroviral infections, and cardiac transplantation may be required in severe cases.

In rare cases, chronic constrictive pericarditis develops 5 weeks to 1 year after resolution.

Acute hemorrhagic conjunctivitis

Secondary bacterial conjunctivitis may occur.

In severe cases, keratitis may occur and may last several weeks but is rarely permanent.

Paralysis (motor and/or sensory) may follow AHC by 2-5 weeks. It is clinically indistinguishable from polio, although it occurs exclusively in patients older than 20 years. Males are affected more frequently than females. [72]

Neurological complications of AHC occur in epidemics caused by enterovirus 70 but not by coxsackievirus A24.

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Prognosis

Polio: Paralytic polio leads to permanent weakness in the affected limb. Permanent weakness occurs in approximately two thirds of patients. Postpolio syndrome is slowly progressive. In the epidemic era, poliomyelitis carried an overall mortality rate of 5%-10%.

Aseptic meningitis: Fever and signs of meningeal irritation usually resolve within 1-2 weeks in infants; some adults are ill for 2-3 weeks. Long-term prognosis is excellent.

Pleurodynia: Patients with epidemic pleurodynia completely recover.

Myopericarditis: The prognosis is good, and mortality rates in acute infection are low. Severe cases can result in dilated or restrictive cardiomyopathy, persistent electrocardiographic abnormalities, or congestive heart failure. Twenty percent of patients may have recurrent myopericarditis and develop chronic dilated cardiomyopathy. Infants are at a higher risk of developing long-term sequelae.

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Patient Education

HFMD is very contagious, especially during the first week of the illness. The virus can still be spread weeks after symptoms have resolved. As a preventive measure, close contact with affected individuals should be avoided.

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