Neuralgic amyotrophy triggered by hepatitis E virus: a particular phenotype

The neuralgic amyotrophy may be of difficult diagnosis, due to phenotypic variability, with different initial presentations (upper plexus multiple mononeuropathy, lumbosacral involvement, distal reached, phrenic involvement). To date, there is little guidance on these patients' therapeutic management, especially those for which neuralgic amyotrophy is triggered by hepatitis E virus (HEV-NA). The study aims to identify specific features that characterize patients bearing the neuralgic amyotrophy triggered by HEV. We first describe a new case report of HEV-neuralgic amyotrophy, with delayed diaphragmatic reach. Then, the literature was searched for reports of HEV-NA (n = 39), and neuralgic amyotrophy with phrenic paresis (n = 42) from 1999 to June 2016. Relevant data were retrieved, analyzed and compared with the parameters of idiopathic neuralgic amyotrophy (n = 199) of the largest cohort, described by Van Alfen and Van Engelen in 2006. Compared to the published cohort, HEV-NA patients were more likely to be men (M/F 34/5 vs. 136/63, p = 0.017), with more frequent bilateral symptoms (86.8% cases vs. 28.5%, p < 0.0001) as well as phrenic paresis (18.0 vs. 6.6%, p = 0.028). The clinical improvement is poor, with 15.6% of cases with remission only. A particular phenotype characteristic of the HEV-induced neuralgic amyotrophy has arisen. Our findings call for action in validating the above-mentioned features that illustrate the HEV-NA cases as an early diagnosis would prevent complications, especially the phrenic damage often associated with a worse functional outcome.