Acute Flaccid Paralysis as an Unusual Presenting Symptom of Japanese Encephalitis: A Case Report and Review of the Literature

Abstract

Japanese encephalitis (JE) is an endemic disease in Taiwan. Acute JE virus infection characterized by acute flaccid paralysis in an adult has never been reported in Taiwan. We report a young adult man who received four doses of JEV (Nakayama strain) vaccination in childhood, but still developed acute JE virus infection, characterized with acute flaccid paralysis.He presented with fever, headache, progressive muscle weakness, and respiratory paralysis requiring mechanical ventilator. Deep tendon reflexes were decreased except for the Achilles reflex. After supportive care, he was weaned from the mechanical ventilator and at discharge 1 month later, his muscle power level and deep tendon reflexes recovered partially. The diagnosis of JE was based on the presence of anti-JE virus IgM in the CSF and seroconversion of IgM and IgG by the ELISA method. Electrophysiological findings were described. From the experience of this case, we caution that a history of vaccination for JE with the Nakayama strain may not provide a complete protection against natural infection in the community; and in Taiwan or any area where JE remains an endemic disease, Japanese virus encephalitis infection should be considered as a differential diagnosis in any adult presenting with acute flaccid paralysis.

The role of chemokines in the pathogenesis of neurotropic flaviviruses

“…Unlike WNV, where monocytosis is observed, JEV induces a neutrophil leukocytosis in mice infected intraperitoneally; this has also been observed in human infections as well [78][79][80][81]. Although not well studied in mice, significant induction of CXCL8 was observed in patient serum and CSF, which corresponded with the presence of neutrophils in the CSF [72,79,82].…”

“…Although not well studied in mice, significant induction of CXCL8 was observed in patient serum and CSF, which corresponded with the presence of neutrophils in the CSF [72,79,82]. Notably, significantly higher levels of CXCL8 were associated with patient mortality [82,83].…”

Flavivirus Encephalitis

“…25,27,128 Conscious patients with polio-like acute flaccid paralysis have been reported. 16,111,112 Histological findings of the brain lesions in JEV-infected mice include neuronal degeneration and necrosis, neuronophagia, microglial proliferation forming glial nodules, mild perivascular hemorrhage, and perivascular cuffing. 33,40 Although the severity of the inflammation and the distribution of viral antigens are influenced by the phenotype of the inoculated viruses and by the route of inoculation, respectively, the histological changes occur mostly in the gray matter and are predominantly found in the cerebral cortex and hippocampus; 30,33,42 however, they are also frequently found in basal ganglia, thalamus, brainstem, and other regions.…”

Acute transverse myelitis following Japanese encephalitis viral infection: an uncommon complication of a common disease: Figure 1

“…Misra et al 5 reported that patients with JE present with altered sensorium, anterior horn cell involvement and hyperkinetic movement disorders. Unusual features of JE described in the literature include respiratory paralysis,6 oromandibular dystonia,7 acute flaccid paralysis8 and hemiplegia with dysarthria 9. However, there are no previous case reports of immune-mediated demyelinating neurological syndrome as ATM following JE.…”