Development of a Composite Clinicopathological Scoring System for Enhancing Diagnostic Accuracy of Vasculitic...

Nerve biopsy remains the gold standard for diagnosing vasculitic neuropathy. However, when a biopsy lacks features of "definite" vasculitis, distinguishing it from other inflammatory neuropathies, particularly chronic inflammatory demyelinating polyneuropathy (CIDP) is difficult. Precise differentiation is critical for appropriate management. We aimed to develop an objective scoring system integrating clinical, electrophysiological, histopathological, and ancillary findings to differentiate vasculitis from CIDP.

Two sets of cases were used. The test set comprised 20 clinically diagnosed vasculitis and 10 cases of CIDP. Based on nerve biopsy findings, these were categorized as definite vasculitis ( n = 10), probable vasculitis ( n = 10), definite CIDP ( n = 5), and probable CIDP ( n = 5). Receiver operating characteristic analysis was used to derive cut-off scores. Validation was performed on 10 patients each of suspected vasculitis and CIDP. Assessment was performed using histopathology alone (HP-score) and a composite of clinical, electrophysiological, and histopathology parameters (C-score).

Cut-offs derived in the test set were: definite vasculitis >20, probable vasculitis 11-20, definite CIDP ≤2, and probable CIDP 3-10. In the validation set, the HP-score showed poor discrimination, with overlapping ranges between probable vasculitis (2-9) and probable CIDP (1-5). In contrast, the C-score could distinguish probable vasculitis from probable CIDP on employing a cut-off of 11.

Our observations suggest that the C-score could serve as a practical and objective diagnostic tool. Given the pilot nature of this study, larger prospective multicentric studies are needed to validate its utility in clinical practice.