Primary Care Corner with Geoffrey Modest MD: Zika and Neurologic Problems in Brazil

By Dr. Geoffrey Modest

STAT (see statnew.com) has frequent updates on Zika, noting the following:

  • Puerto Rico reported the biggest weekly rise in Zika cases yet, with 1,336 new cases for the week ending June 30, including 533 pregnant women diagnosed with the virus
  • Two patients who were infected with the Zika virus have developed severe thrombocytopenia
  • Brazilian researchers have observed a sharp increase in cases of Guillain-Barré syndrome

For this last point, there was a recent release of an article in Neurology (see doi:10.1212/WNL.0000000000003024) from Brazilian neurologists who started a study group in Rio to further understand the Zika-related neurologic disorders (Guillain-Barré syndrome –GBS, meningoencephalitis, transverse myelitis), finding that in the period Dec 5, 2015 to <arch 18, 2016, there were:

  • 20 confirmed cases of GBS (there had previously been 15 case in 24 months prior to Zika: so average GBS cases increased from 0.67/month to 5.4/month)
  • 17 were associated with a viral prodrome consistent with Zika (pruritic rash, fever, arthralgias).
  • But there is an issue with associating all cases with Zika, since Zika is so prevalent there and 80% of cases are asymptomatic, making the causal link difficult especially in those without a clear prodrome
  • They have also seen Zika-related AMAN (acute motor axonal neuropathy), acute motor sensory polyneuropathy, acute inflammatory demyelinating polyradiculoneuropathy, chronic inflammatory demyelinating polyradiculoneuropathy, and Miller Fisher variant along with encephalitis, transverse myelitis and acute disseminated encephalomyelitis following a Zika prodrome.
  • The neurological associations are not limited to Brazil’s outbreak/variant: there were cases of Zika-related GBS and AMAN in French Polynesia, which is genetically distinct from Brazil.
  • Also a couple of recent new transmissions: from an infected woman to her male sexual partner, and a possible case of a domestic worker getting infected.
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