AUTHOR=Kolb Ninja , Matiasek Kaspar , van Renen Jana , Fischer Andrea , Zablotski Yury , Wieländer Franziska , Nessler Jasmin , Tipold Andrea , Cappello Rodolfo , Flegel Thomas , Loderstedt Shenja , Dietzel Josephine , Gnirs Kirsten , Rentmeister Kai , Rupp Stephan , von Klopmann Thilo , Steffen Frank , Jurina Konrad , Del Vecchio Omar V. , Deutschland Martin , König Florian , Gandini Gualtiero , Harcourt-Brown Tom , Kornberg Marion , Bianchi Ezio , Gagliardo Teresa , Menchetti Marika , Schenk Henning , Tabanez Joana , Rosati Marco TITLE=Biopsy Characteristics, Subtypes, and Prognostic Features in 107 Cases of Feline Presumed Immune-Mediated Polyneuropathy JOURNAL=Frontiers in Veterinary Science VOLUME=9 YEAR=2022 URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.928309 DOI=10.3389/fvets.2022.928309 ISSN=2297-1769 ABSTRACT=

Inflammatory polyradiculoneuropathy (IMPN) is one of the causes of sudden onset of neuromuscular signs such as para-/tetraparesis in young cats. Even though most cases have a favorable outcome, persistent deficits, relapses, and progressive courses are occasionally seen. As clinical presentation does not always appear to predict outcome and risk of recurrence, this study was initiated to screen for prognostic biopsy findings in a large cohort of histologically confirmed IMPN cases with clinical follow-up. In total, nerve and muscle specimens of 107 cats with biopsy diagnosis of presumed autoreactive inflammatory polyneuropathy and 22 control cases were reviewed by two blinded raters for a set of 36 histological parameters. To identify patterns and subtypes of IMPN, hierarchical k-means clustering of 33 histologic variables was performed. Then, the impact of histological parameters on IMPN outcome was evaluated via an univariate analysis to identify variables for the final multivariate model. The data on immediate outcome and follow-up were collected from submitting neurologists using a purpose-designed questionnaire. Hierarchical k-means clustering sorted the tissues into 4 main categories: cluster 1 (44/129) represents a purely inflammatory IMPN picture, whereas cluster 2 (47/129) was accompanied by demyelinating features and cluster 3 (16/129) by Wallerian degeneration. Cluster 4 (22/129) reflects normal tissues from non-neuropathic control cats. Returned questionnaires provided detailed information on outcome in 63 animals. They were categorized into recovered and non-recovered. Thereby, fiber-invasive infiltrates by mononuclear cells and mild fiber loss in intramuscular nerve branches correlated with higher probabilities of recovery. Remyelination in semithin sections, on the other hand, is correlated with a less favorable outcome. Animals grouping in cluster 1 had a tendency to a higher probability of recovery compared to other clusters. In conclusion, diagnosis of feline IMPN from nerve and muscle biopsies allowed for the identification of histologic features that were positively or negatively correlated with outcome.