Sural nerve biopsy improves diagnosis of vasculitis

Patients who undergo sural nerve biopsy (SNB) have a better diagnostic yield for vasculitis, results of a study have shown.

This study sought to verify relevant characteristics of patients undergoing SNB in the investigation of vasculitis; determine the diagnostic yield; relate positive biopsy findings to patient demographic, laboratory, and clinical variables; and calculate the rate of surgical complications.

Researchers accessed local pathology databases and clinic registers to identify patients with suspected vasculitis who underwent SNB as part of diagnostic evaluation at academic medical centres in Sweden and the UK. They also conducted a structured review of medical case records and pathology reports.

Histological findings were classified as definite, probably, or no vasculitis using the 2015 Brighton Collaboration reinterpretation and update of the Peripheral Nerve Society guidelines for vasculitis neuropathy. Researchers considered definite and probable findings as positive for vasculitis.

Of the 91 patients who underwent SNB, 45 percent were female, and 44 percent had histological evidence of vasculitis (14 definite and 26 probable). A concomitant muscle biopsy done in 10 patients did not contribute to the diagnostic yield.

A positive biopsy is significantly associated with positive antineutrophil cytoplasmic antibody test, organ involvement other than the nervous system, and a longer biopsy sample. Of note, the reported surgical complication rate was 15 percent.

“SNB of sufficient length is a useful procedure to confirm a diagnosis of vasculitis,” researchers said.