Central and Peripheral Nervous System Complications of Vasculitis Syndromes from Pathology to Bedside: Part 2—Peripheral Nervous System

Abstract

Purpose of Review Peripheral nervous system vasculitides (PNSV) are a heterogeneous group of disorders with a clinical subset that may differ in prognosis and therapy. We provide a comprehensive update on the clinical assessment, diagnosis, complications, treatment, and follow-up of PNSV. Recent Findings Progress in neuroimaging, molecular testing, and peripheral nerve biopsy has improved clinical assessment and decision-making of PNSV, also providing novel insights on how to prevent misdiagnosis and increase diagnostic certainty. Advances in imaging techniques, allowing to clearly display the vessel walls, have also enhanced the possibility to differentiate inflammatory from non-inflammatory vascular lesions, while recent histopathology data have identified the main morphological criteria for more accurate diagnosis and differential diagnoses. Overall, the identification of peculiar morphological findings tends to improve diagnostic accuracy by defining a clearer boundary between systemic and non-systemic neuropathies. Therefore, the definition of epineurium vessel wall damage, type of vascular lesion, characterization of lymphocyte populations, antibodies, and inflammatory factors, as well as the identification of direct nerve damage or degeneration, are the common goals for pathologists and clinicians, who will both benefit for data integration and findings translation. Nevertheless, to date, treatment is still largely empiric and, in some cases, unsatisfactory, thus often precluding precise prognostic prediction. In this context, new diagnostic techniques and multidisciplinary management will be essential in the proper diagnosis and prompt management of PNSV, as highlighted in the present review. Summary Thirty to fifty percent of all patients with vasculitis have signs of polyneuropathy. Neuropathies associated with systemic vasculitis are best managed according to the guidelines of the underlying disease because appropriate workup and initiation of treatment can reduce morbidity. Steroids, or in severe or progressive cases, cyclophosphamide pulse therapy is the standard therapy in non-systemic vasculitic neuropathies. Some patients need long-term immunosuppression. The use of novel technologies for high-throughput genotyping will permit to determine the genetic influence of related phenotypes in patients with PNSV. Supplementary Information The online version contains supplementary material available at 10.1007/s11910-023-01249-3.

A Rare Presentation of Non-systemic Vasculitic Neuropathy Mimicking Guillain-Barré Syndrome: A Case Report

“…Non-systemic vasculitic neuropathy is caused by mononuclear inflammatory infiltrate, with or without necrosis, resulting in ischemic axonal degeneration [ 11 ]. Ischemic injury from the microvasculitic nerve appears to be the main etiopathogenetic event, along with immune-mediated mechanisms by complements, immunoglobulins, and significant immuno-expression of adhesion molecules (ICAM-1) in the neovascularization and endoneural microvessels, as well as tumor necrosis factor alpha (TNF-α) in the macrophages and Schwann cells, whereas interleukins are less significantly expressed [ 12 ].…”

“…Regardless of the categorization into subtypes, the damage caused during a vasculitic process determines the degeneration and subsequent necrosis of peripheral nervous structures, which are responsible for clinical symptoms [ 11 ]. In the specific case of NSVN, the presence of parietal damage to the vessels is needed, together with perivascular inflammation, to make the diagnosis of definite vasculitic neuropathy.…”

“…It should be considered 'probable' as the involvement could be patchy otherwise. [11,12] Vasculitic neuropathy can be a devastating condition if treatment is not initiated early and the diagnosis is missed. Our patient was treated for vasculitic neuropathy early, for which she achieved a near-complete recovery.…”