Nerve ultrasound improves detection of treatment-responsive chronic inflammatory neuropathies

Objective To examine the diagnostic accuracy of nerve ultrasound in a
prospective cohort of consecutive patients with a clinical suspicion of
chronic inflammatory neuropathies, including chronic inflammatory
demyelinating polyneuropathy, Lewis Sumner syndrome and multifocal motor
neuropathy, and to determine the added value in the detection of
treatment-responsive patients. Methods Between February 2015 and July
2018, we included 100 consecutive incident patients with a clinical
suspicion of chronic inflammatory neuropathy. All patients underwent nerve
ultrasound, extensive standardized nerve conduction studies (NCS) and
other relevant diagnostic investigations. We evaluated treatment response
using predefined criteria. A diagnosis of chronic inflammatory neuropathy
was established when NCS were abnormal (fulfilling criteria of
demyelination of the EFNS/PNS) or when the degree of nerve enlargement
detected by sonography was compatible with chronic inflammatory neuropathy
and there was response to treatment. Results A diagnosis of chronic
inflammatory neuropathy was established in 38 patients. Sensitivity and
specificity of nerve ultrasound and NCS were 97.4% and 69.4%, and 78.9%
and 93.5%, respectively. The added value of nerve ultrasound in detection
of treatment-responsive chronic inflammatory neuropathy patients was 21.1%
compared to NCS alone. Conclusions Nerve ultrasound and NCS are
complementary techniques with superior sensitivity in the former and
specificity in the latter. Addition of nerve ultrasound significantly
improves the detection of chronic inflammatory neuropathies. Therefore, it
deserves a prominent place in the diagnostic workup of chronic
inflammatory neuropathies. Classification of Evidence This study provides
Class I evidence that nerve ultrasound is an accurate diagnostic tool to
detect chronic inflammatory neuropathies.