Pediatric nerve biopsy

Cristiane M. Ida, Peter J. Dyck, P. James B. Dyck, Janean K. Engelstad, HT, Wei Wang, Duygu Selcen, John B. Bodensteiner,  Michelle L. Mauermann, , Christopher J. Klein.  Pediatric Nerve Biopsy Diagnostic and Treatment Utility in Tertiary Care Referral.  Pediatric Neurology in press.

Abstract

Objectives

To assess the utility of nerve biopsy in children at a tertiary referral center in light of availability of current genetic testing

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Background

Pediatric neuropathies are both unique and similar to their adult counterparts with genetic varieties thought to be more common.

Methods

We retrospectively reviewed the clinical, nerve biopsy and genetic testing findings of 316 pediatric (≤18 yrs) patients.

Results

Median age at diagnosis was 9.8 yrs (4 days-18 yrs). Nerve biopsy was non-targeted in 198 (182 whole sural, 7 superficial peroneal and 9 other), targeted in 21 (14 fascicular sciatic and 7 brachial plexus) and unknown in 97 cases. Pre-biopsy localizations and diagnoses were diverse, most commonly with length-dependent localizations (n=150). Median follow-up was 6 months (0-480 months). A distinctive histopathologic diagnosis was made in 106 (33%) cases, including inflammatory/immune (n=30); neoplastic (n=19); hereditary (n=41), vasculitis (n=10) and other (n=6). Nerve biopsy confirmed the suspected diagnosis in 91 (29%) cases and changed or refined the initial diagnosis in 182 (58%). Treatment modifications as a result of biopsy occurred in 80 (25%) cases; 59 (19% of the entire cohort) with clinical improvements noted, most commonly by immunotherapy (n=30). Low diagnostic yield occurred in “hypotonic infants” without nerve conduction abnormalities. Pain at the biopsy site beyond 1 month was rare (n=3; 1%). Forty-four patients underwent genetic testing. Among demyelinating varieties, mutations were identified in 5 of 11 (46%) cases compared to only 6 of 33 (18%) cases of axonal varieties.

Conclusion

Pediatric nerve biopsy provides diagnostic information that frequently alters treatment recommendation. Furthermore, it leads to clinical improvements, especially in inflammatory immune neuropathies. For suspected inherited varieties, genetic testing has highest diagnostic yield in demyelinating phenotypes.

Courtesy of:  http://www.mdlinx.com/neurology/medical-news-article/2016/02/26/pediatric-peripheral-nerve-biopsy-neuropathy-diagnosis/6530222/?category=sub-specialty&page_id=3&subspec_id=317