Goedee HS, van der Pol, L, van Asseldonk J-TH, et al. Diagnostic Value of Sonography in Treatment-naïve Chronic Inflammatory Neuropathies.
Neurology 88:143-151; 2017
Submitted by David B. Rosenfield, MD, News Science Editorial Board
Nerve conduction studies (NCSs) often provide demyelinating diagnostic criteria for these diagnoses. In the absence of NCS abnormalities, high-resolution ultrasound (HRUS) is an emerging alternative that allows sonographic evaluation of multiple peripheral nerves in a short time window. Inflammatory demyelinating and axonal neuropathies can have distinctive sonographic patterns of nerve enlargement and are altered by treatment.
Goedee and colleagues studied 75 patients who had not had treatment for their chronic inflammatory neuropathies and 70 disease controls. The authors performed extensive nerve conduction and standardized HRUS studies bilaterally of large arm and leg nerves, as well as the brachial plexus. They determined optimal sonographic cutoff values of nerve size and used multiple parameters to identify nerves.
The authors determined that enlargement of median nerve at the forearm >10 mm2
, upper arm >13mm2
and any trunk of the brachial plexus >8 mm2
provided information that was 99% specific for chronic inflammatory neuropathies. They then provide a shortened HRUS protocol for detecting these abnormal nerve enlargements, providing high sensitivity (83-95%), a positive predictive value (100%) and negative predictive value (98%) for discriminating CIDP, LSS and MMN from clinical mimics.
The authors conclude sonographic enlargement of proximal median nerve segments in the arms and brachial plexus is a key feature of chronic inflammatory neuropathies, which helps to reliably distinguish them from axonal neuropathies and amyotrophic lateral sclerosis.
: Physicians often need to distinguish inflammatory neuropathies [e.g., chronic inflammatory demyelinating polyneuropathy (CIDP); Lewis-Summer syndrome (LSS); multifocal motor neuropathy (MMN)] from other neuropathies and motor neuron disorders since the former respond to immune-modulating treatment and the latter (pretty much) do not.
Many of us attend or think about attending workshops pertaining to ultrasound investigations. There are issues of clinical viability and importance, as well as remuneration. Previously, some have believed that ultrasound provided meaning mainly for carpal tunnel syndrome and picking up cysts near the peroneal nerve at the fibula. However, these authors provide a different filter for this procedure and underline that testing has robust merit.
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