Nerve size in chronic inflammatory demyelinating neuropathy varies with disease activity and therapy response over time: A retrospective ultrasound study

Introduction: Nerves are often enlarged in chronic inflammatory demyelinating polyneuropathy (CIDP). In this investigation we studied changes with treatment over time. Methods: We retrospectively compared serial ultrasound measurements of median and ulnar nerve size with clinical and electrodiagnostic evaluations in 23 CIDP subjects. We defined remission as stable clinical improvement on low or decreasing amounts of medication. Results: Nerves were normal at last follow-up more often in subjects who achieved remission than in those who did not (10 of 13 vs. 0 of 10, P=0.0001). Nerves were normal or smaller (>30% reduction) more often in subjects whose grip strength improved or remained strong compared those whose grip strength weakened (12 of 16 vs. 0 of 3, P=0.04), and in subjects whose demyelinating electrodiagnostic features resolved compared with those whose demyelination persisted (7 of 7 vs. 6 of 12, P=0.04). Over time, nerve size decreased more in subjects with baseline nerve enlargement who achieved remission than in those who did not (-41% vs. 7%, P=0.04). Conclusion: In CIDP, enlarged nerves normalized or decreased with remission.