Bulletin of the World Health Organization

Poliomyelitis in the terminal stages

Polio theme issue 82(1)

To the Editor: Your Theme issue on the end stage challenges linked with polio eradication [1] would appear to be a fairly comprehensive one though it does not address the impending diagnostic challenges. A specific diagnosis of poliomyelitis continues to be based on virological investigations employing cell cultures. With an almost extinct number of poliomyelitis cases, wild-virus induced, vaccine-associated, or following prolonged viral excretion among those with immune disorders, there is going to be a reduction in laboratories available for an early diagnosis. Furthermore, there would be several unknown and atypical presentations linked with polioviruses.

Prospective global plans should incorporate the important role of imaging techniques to obtain an earlier indication of viral replication in the central nervous system. Both magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) have contributed significantly to ascertain pathogenesis of replication of poliovirus and measles virus in the central nervous system. MRI of the cervical spine of a 27-year-old man who developed acute flaccid paralysis three weeks after his 20-month-old infant was immunized with live poliovirus vaccine revealed smooth hyperintense bands. Sagittal proton-density T2-weighted images revealed involvement of the regions corresponding to the anatomic locations of ventral horns [2]. Type 2 poliovirus multiplication in a patient spared target neurons. Instead the virus-associated lesions were found during T2-weighted MRI in the spinal cord. These high-intensity lesions were confined to C1-2, C4-5, and T1-2 on the sagittal section and at the right side of the cervical cord on axial section [3]. such lesions would have never been described without MRI of the patients.

The role of MRS has been important. For example, examination of a 13-year-old girl with subacute sclerosing panencephalitis during a MRS to establish any in-vivo pathophysiological abnormalities was intriguing. Both inflammatory processes and glial proliferation were evident prior to neuronal loss visible in MRI-negative as well as MRI-positive regions [4]

Prospective plans against poliomyelitis, international and national, should mandate efforts to procure an earlier indication about replication of polioviruses in the central nervous system. The conventional tissue culture apart, only imaging technology would assist the clinicians with an effective antiviral recipe. Therapeutic recipe of pleconaril in three patients with acute poliovirus infection, two vaccine-associated and one wild-type poliovirus, was associated with a definite clinical and virological response. Neurological improvement was evident in two cases while in one case, there was better respiratory status and muscle strength. In one patient, the initial positive viral CSF culture and PCR were followed by negative results [5].

In conclusion, recommendations to address any episode of poliomyelitis, irrespective of the virus type or any accompanying host factors by both the imaging techniques and an antiviral recipe would be incorporated in prospective policy statements. That would indeed ensure that all those afflicted with acute flaccid paralysis would not end up with any permanent residual disability.

Subhash C. Arya & Nirmala Agarwal, Sant Parmanand Hospital, 18 Alipore Road, Delhi- 110054, India. Email: subhashji@hotmail.com

REFERENCES:

  • Polio eradication-end-stage challenges. the Bulletin of the World Health Organization 2004; 82:1-70
  • Malzberg MS, Rogg JM, Teta CA, et al. Poliomyelitis: hyperintensity of the anterior horn cells on MRI imaging of the spinal cord. American Journal of Roentgenology 1993;161:563-565
  • Ozawa H, Noma S, Yoshikda Y, Sekine H, Hashimoto T. Acute disseminated encephalomyelitis associated with poliomyelitis vaccine. Pediatric Neurology 2000,23:177-179
  • Kato Z, Saito K, Yamada M, Asano T, Kondo N. Proton magnetic resonance spectroscopy in a case of subacute sclerosing panencephalitis. Journal of child neurology 2002; 17: 788-790
  • Robert HA, Webster AD. Treatment of potentially life-threatening enterovirus infections with pleconaril. Clinical Infectious Diseases 2001;32:228-235
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