RESUMO
BACKGROUND AND PURPOSE: Infections and vaccinations have been identified as potential immunological triggers of neuralgic amyotrophy (NA), but the exact type and frequency of the preceding agents is unknown. METHODS: This was a multicentre, prospective, observational, matched case-control study. NA was diagnosed by neuromuscular experts according to validated clinical criteria and electrodiagnostic studies. Clinical data and biological samples of NA patients were collected within 90 days from disease onset between June 2018 and December 2023. All NA patients were asked about prior infection and vaccination in the month before disease onset. Serological tests for hepatitis E virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, cytomegalovirus, parvovirus B19, varicella-zoster virus, Borrelia burgdorferi, Mycoplasma pneumoniae and Bartonella henselae were performed in a central laboratory. Each case was matched with a healthy control for age, sex, place of residence and time of blood collection. RESULTS: Fifty-seven patients and corresponding controls were included. The mean age was 45 years for both groups. NA onset was preceded by a symptomatic infectious trigger confirmed by microbiological tests in 15/57 (26.3%) patients. Coronavirus disease 2019 vaccination was considered a potential trigger in 7/57 (12.3%) subjects. An acute viral infection was associated with a bilateral involvement of the brachial plexus (p = 0.003, Cramèr's V = 0.43). CONCLUSIONS: Confirmed immune triggers (infection or vaccination) preceded disease onset in 22/57 (38.6%) NA cases. We suggest to test NA patients in the acute phase for intracellular antigens, especially in the case of concomitant bilateral involvement and hepatitis.
RESUMO
BACKGROUND: Acute hepatitis E virus (HEV) infection has recently emerged as a potential trigger for acute dysimmune neuropathies, but prospective controlled studies are lacking. AIMS: To compare the frequency of concomitant acute HEV infection in patients with neuralgic amyotrophy (NA), Guillain-Barré syndrome (GBS), and Bell's palsy with a matched control population. METHODS: Swiss multicenter, prospective, observational, matched case-control study over 3 years (September 2019-October 2022). Neurological cases with NA, GBS, or Bell's palsy were recruited within 1 month of disease onset. Healthy controls were matched for age, sex, geographical location, and timing of blood collection. Diagnostic criteria for acute hepatitis E were reactive serum anti-HEV IgM and IgG assays (ELISA test) and/or HEV RNA detection in serum by real-time polymerase chain reaction (RT-PCR). RT-PCR was performed on sera to confirm IgM positivity. RESULTS: We included 180 patients (59 GBS, 51 NA, 70 Bell's palsy cases) and corresponding matched controls (blood donors) with median age 51 years for both groups and equal gender distribution. Six IgM+ cases were detected in the NA, two in the GBS, and none in the Bell's palsy group. Two controls were anti-HEV IgM-positive. At disease onset, most cases with acute HEV infection had increased liver enzymes. A moderate association (p = 0.027, Fisher's exact test; Cramér's V = -0.25) was observed only between acute HEV infection and NA. CONCLUSION: This prospective observational study suggests an association between concomitant acute HEV infection and NA, but not with GBS or Bell's palsy.