Discussion
The clinical presentation of the reported case, and CSF analysis showing a picture of albumin-cytological dissociation, suggested the diagnosis of MFS as previously described in the literature (Wakerley et al. 2014). The novelty of this case is represented by the diagnosis of MFS in a COVID-19 patient and by the clinical suggestion of treating neurological complications with intravenous immunoglobulin therapy. Such neurological complications are common in respiratory infections (Sellers et al. 2017); therefore, a cross-reactivity also for the new SARS-CoV-2 was speculated and reported (Zhao et al. 2020) as for SARS-CoV affected patients (Baig et al. 2020). We did not find any presence of anti-GQ1b, usually explaining the symptoms of the disease (Wakerley et al. 2014). However, negative results for anti-GQ1b tests have been previously reported (Wattanasit and Sathirapanya 2020). The particular cranial polyradiculoneuritis with the involvement of the facial and trigeminal nerve is well-known in MFS and MFS variants (Polo et al. 1992; Wakerley et al. 2014), and in the reported case, it was found being associated to an altered sense of taste, which is an uncommon feature of MFS but well-reported in COVID-19. IVIG was found to be effective and safe to treat the reported neurological symptoms, showing complete recovery after 7 days. In conclusion, this case report describes the characteristics of a MFS/cranial polyneuritis in a patient with COVID-19, and the clinical responses to intravenous immunoglobulin therapy, suggesting possible diagnosis and treatment options in this peculiar condition.