Nerve Ultrasound Distinguishes Non-Inflammatory Axonal Polyneuropathy From Inflammatory Polyneuropathy With Secondary Axonal Damage

Abstract

IntroductionChronic inflammatory demyelinating polyneuropathy (CIDP) may have a similar clinical and electrophysiological presentation to non-inflammatory axonal polyneuropathies (NIAPs) when secondary axonal damage occurs. We aimed to investigate if nerve ultrasound can help to differentiate CIDP with additional secondary axonal damage from NIAP.MethodsIn a retrospective analysis, the cross-sectional area (CSA) of the peripheral nerves measured by ultrasound at six suitable nerve sites was compared in 95 patients with CIDP and 82 patients with NIAP. We developed the adjusted Bochum ultrasound score (aBUS) ranging from 0 to 6 resulting from the number of sites with enlarged CSA (median, ulnar, radial, and sural nerve).ResultsThe mean CSA of patients with CIDP was enlarged at all six nerve sites compared with the mean CSA of patients with NIAP. A total of 21 patients with CIDP did not meet 2010 electrophysiological diagnostic criteria (European Academy of Neurology/Peripheral Nerve Society Guideline, EFNS/PNS criteria) for CIDP at examination timepoint but only in further follow-up, while 25 patients with NIAP fulfilled electrophysiological EFNS/PNS criteria for CIDP as “possible” or “probable” CIDP. To increase diagnostic power, we included aBUS measured by ultrasound in patients classified as “possible” or “probable” resulting in an improved specificity of 94% and a sensitivity of 59%, compared to a specificity of the EFNS/PNS criteria alone of 60% and sensitivity of 78%.ConclusionUsing nerve ultrasound and the aBUS as a complementary method to distinguish CIDP from NIAP in case of secondary axonal damage can facilitate the diagnosis of CIDP.

Nerve ultrasound for the diagnosis and follow-up of peripheral neuropathies

“…According to the novel recommendations of the EAN/PNS, enlargements of median nerve and/or the cervical nerve roots indicate a CIDP [7 ▪ ,8 ▪▪ ,9 ▪▪ ]. Various other scoring systems have been introduced to further improve the sensitivity and specificity of the method, for example, the Bochum Ultrasound Score for distinguishing Guillain-Barré Syndrome (GBS) and CIDP [10], the inclusion of vagus nerve for the GBS diagnosis [11], the axonal Bochum ultrasound score for distinguishing noninflammatory from inflammatory polyneuropathies with axonal damage [12]. In Table 1, the different scoring systems are presented with the mean values for healthy individuals from different study groups as well as the mean values from the existing meta-analysis [13 ▪ –15 ▪ ].…”

Diagnostic accuracy of nerve ultrasonography for the detection of peripheral neuropathy in type 2 diabetes

“…If clinical review suggests discrepancy between ultrasound measures and clinical features of neuropathy, then an alternative aetiology such as a demyelinating process should be considered. Additional investigations may include serum assessment of B12 levels, paraproteins, and thyroid function, nerve conduction studies, and possibly lumbar puncture to assess cerebrospinal fluid protein concentration [ 21 , 22 , 23 ].…”

“…If clinical review suggests discrepancy between ultrasound measures and clinical features of neuropathy, then an alternative aetiology such as a demyelinating process should be considered. Additional investigations may include serum assessment of B12 levels, paraproteins, and thyroid function, nerve conduction studies, and possibly lumbar puncture to assess cerebrospinal fluid protein concentration[21][22][23].Measurement of CSA is the most sensitive of ultrasound markers for peripheral neuropathy, compared to loss in fascicular pattern or nerve echogenicity[5]. Previous studies have demonstrated evidence of enlarged peripheral nerves in type 2 diabetes[6,[24][25][26].…”

Electrodiagnostic studies and new diagnostic modalities for evaluation of peripheral nerve disorders

“…169 There have been several ultrasound protocols developed to standardize the assessment of patients with CIDP. [169][170][171] MRI of the plexus was retrospectively evaluated in patients with suspected but atypical CIDP and revealed abnormalities in about 50% of cases. 172 In a small prospective study, plexus MRI found abnormalities in 36% of patients eventually diagnosed as CIDP.…”

“…In another study, adding ultrasound identified 25% more treatment‐responsive patients than NCS alone, although 11% of the cohort studied was diagnosed with multifocal motor neuropathy and not CIDP 169 . There have been several ultrasound protocols developed to standardize the assessment of patients with CIDP 169–171 . MRI of the plexus was retrospectively evaluated in patients with suspected but atypical CIDP and revealed abnormalities in about 50% of cases 172 .…”