Clinical neurophysiology and cerebrospinal liquor analysis to detect Guillain-Barré syndrome and polyneuritis cranialis in COVID-19 patients: A case series.

We report a case series of five patients affected by SARS-CoV-2 who developed neurological symptoms, mainly expressing as polyradiculoneuritis and cranial polyneuritis in the 2 months of COVID-19 pandemic in a city in the northeast of Italy. A diagnosis of Guillain-Barré syndrome was made on the basis of clinical presentation, cerebrospinal fluid analysis, and electroneurography. In four of them, the therapeutic approach included the administration of intravenous immunoglobulin (0.4 g/kg for 5 days), which resulted in the improvement of neurological symptoms. Clinical neurophysiology revealed the presence of conduction block, absence of F waves, and in two cases a significant decrease in amplitude of compound motor action potential compound muscle action potential (cMAP). Four patients presented a mild facial nerve involvement limited to the muscles of the lower face, with sparing of the forehead muscles associated to ageusia. In one patient, taste assessment showed right-sided ageusia of the tongue, ipsilateral to the mild facial palsy. In three patients we observed albuminocytological dissociation in the cerebrospinal fluid, and notably, we found an increase of inflammatory mediators such as the interleukin-8. Peripheral nervous system involvement after infection with COVID-19 is possible and may include several signs that may be successfully treated with immunoglobulin therapy.

Cerebrospinal fluid and serum interleukins 6 and 8 during the acute and recovery phase in COVID-19 neuropathy patients.

This case series describes three patients affected by severe acute respiratory syndrome coronavirus 2, who developed polyradiculoneuritis as a probable neurological complication of coronavirus disease 2019 (COVID-19). A diagnosis of Guillain Barré syndrome was made on the basis of clinical symptoms, cerebrospinal fluid analysis, and electroneurography. In all of them, the therapeutic approach included the administration of intravenous immunoglobulin (0.4 gr/kg for 5 days), which resulted in the improvement of neurological symptoms. Clinical neurophysiology revealed the presence of conduction block, absence of F waves, and in two cases, a significant decrease in amplitude of compound motor action potential cMAP. Due to the potential role of inflammation on symptoms development and prognosis, interleukin-6 (IL-6) and IL-8 levels were measured in serum and cerebrospinal fluid during the acute phase, while only serum was tested after recovery. Both IL-6 and IL-8 were found increased during the acute phase, both in the serum and cerebrospinal fluid, whereas 4 months after admission (at complete recovery), only IL-8 remained elevated in the serum. These results confirm the inflammatory response that might be linked to peripheral nervous system complications and encourage the use of IL-6 and IL-8 as prognostic biomarkers in COVID-19.

Olfactory swab sampling optimization for α-synuclein aggregate detection in patients with Parkinson's disease.

BACKGROUND: In patients with Parkinson's disease (PD), real-time quaking-induced conversion (RT-QuIC) detection of pathological α-synuclein (α-syn) in olfactory mucosa (OM) is not as accurate as in other α-synucleinopathies. It is unknown whether these variable results might be related to a different distribution of pathological α-syn in OM. Thus, we investigated whether nasal swab (NS) performed in areas with a different coverage by olfactory neuroepithelium, such as agger nasi (AN) and middle turbinate (MT), might affect the detection of pathological α-syn. METHODS: NS was performed in 66 patients with PD and 29 non-PD between September 2018 and April 2021. In 43 patients, cerebrospinal fluid (CSF) was also obtained and all samples were analyzed by RT-QuIC for α-syn. RESULTS: In the first round, 72 OM samples were collected by NS, from AN (NSAN) or from MT (NSMT), and 35 resulted positive for α-syn RT-QuIC, including 27/32 (84%) from AN, 5/11 (45%) from MT, and 3/29 (10%) belonging to the non-PD patients. Furthermore, 23 additional PD patients underwent NS at both AN and MT, and RT-QuIC revealed α-syn positive in 18/23 (78%) NSAN samples and in 10/23 (44%) NSMT samples. Immunocytochemistry of NS preparations showed a higher representation of olfactory neural cells in NSAN compared to NSMT. We also observed α-syn and phospho-α-syn deposits in NS from PD patients but not in controls. Finally, RT-QuIC was positive in 22/24 CSF samples from PD patients (92%) and in 1/19 non-PD. CONCLUSION: In PD patients, RT-QuIC sensitivity is significantly increased (from 45% to 84%) when NS is performed at AN, indicating that α-syn aggregates are preferentially detected in olfactory areas with higher concentration of olfactory neurons. Although RT-QuIC analysis of CSF showed a higher diagnostic accuracy compared to NS, due to the non-invasiveness, NS might be considered as an ancillary procedure for PD diagnosis.

Efficacy of rituximab on seizure control and cognitive symptoms in leucine-rich, glioma-inactivated 1 (LGI1) limbic encephalitis: a high-density electroencephalography case study.

LGI1 encephalitis is an autoimmune disorder characterized by cognitive symptoms and seizures, which rarely respond to common antiepileptic drugs (AEDs). Rituximab (RTX) is a CD-20-depleting monoclonal antibody which has been used for the treatment of LGI1 encephalitis, however, its efficacy remains controversial. A 54-year-old woman came to our attention due to memory loss and gambling. Brain MRI revealed areas of bilateral hippocampal hyperintensity and LGI1 antibodies were found in both serum and cerebrospinal fluid. Immunotherapy with steroids was started, followed by intravenous immunoglobulins with partial improvement. The patient developed multiple generalized tonic-clonic seizures. She was then administered intravenous rituximab with significant improvement for both cognitive symptoms and seizure control. High-density EEG was recorded before treatment, seven days after the first dose and seven days after the second dose. Topoplot and power spectrum analysis were performed for each recording. Interictal epileptiform discharges, as well as theta power bands, were significantly reduced after each dose, while topoplot analysis showed reduced spreading over posterior and frontal electrodes for interictal epileptiform discharges of temporal origin. Our experience indicates that rituximab is a valid treatment for LGI1 encephalitis, demonstrating efficacy for both cognitive symptoms and seizure control. High-density EEG could represent a novel, safe and reproducible method to study epileptogenesis in autoimmune limbic encephalitis.