Postmortem examination results of a patient with Guillain-Barré syndrome and confirmed Zika virus infection revealed demyelination of the sciatic and cranial IV nerves, providing evidence of the acute demyelinating inflammatory polyneuropathy Guillain-Barré syndrome variant. Lack of evidence of Zika virus in nervous tissue suggests that pathophysiology was antibody mediated without neurotropism.
Guillain-Barré syndrome (GBS) is an uncommon autoimmune disorder characterized by progressive, bilateral weakness and diminished deep tendon reflexes due to peripheral nerve damage. GBS is typically triggered by an acute infection and, less frequently, by vaccination. GBS has been associated with infection by Zika virus, a flavivirus transmitted primarily by Aedes species mosquitoes, and countries have reported increased GBS incidence during Zika virus outbreaks.[3–5] Reports suggest Zika virus may result in a hyperacute immune response or have a direct viral neuropathic effect contributing to GBS. Further, case reports and series have noted higher rates of cranial neuropathy, such as facial palsy and paresthesia, among GBS patients with evidence of Zika virus infection, suggesting that the cranial nerves may be targeted by either virus or antibody.[3,6–9]
Mortality rates among GBS patients in North America and Europe vary from 3% to 7%, and death often results from respiratory failure, autonomic dysfunction, or deep vein thrombosis. In Puerto Rico, the GBS in-hospital mortality rate before the introduction of Zika virus was estimated at 4%. Postmortem investigations of GBS are rare, but results may indicate underlying pathophysiologic mechanisms.
During a Zika virus epidemic in Puerto Rico in February 2016, an islandwide surveillance system was implemented to identify GBS cases and provide Zika virus diagnostic testing. Fatal GBS cases could be reported, and postmortem investigations were incorporated into an established fatal case surveillance system. Such investigations were implemented to clarify the pathophysiology of GBS patients with Zika virus infection.
Source : https://www.medscape.com/viewarticle/892528371