Nerve ultrasound score in distinguishing chronic from acute inflammatory demyelinating polyneuropathy
Introduction
The acute inflammatory demyelinating polyneuropathy (AIDP) is defined as a monophasic polyradiculoneuropathy causing a rapidly progressive bilateral and relatively symmetric weakness of the limbs, with or without involvement of respiratory or cranial nerve-innervated muscles and albuminocytologic dissociation in cerebrospinal fluid (Asbury and Cornblath, 1990, van der Meché et al., 2001). The annual incidence of this disease is reported to be 1.2–2.3 per 100.000 (Hughes and Cornblath, 2005, Hahn, 1998). On the other hand, the typical chronic inflammatory demyelinating polyneuropathy (CIDP) arises between the ages of 30 and 60 years and is characterised by a progressive, symmetric, proximal and distal muscle weakness, paresthesis, sensory dysfunction and impaired balance, which may evolve slowly over at least 2 months (Koller et al., 2005, Vallat et al., 2010). Although CIDP symptoms do not usually reach their most severe until at least 2 months from disease onset (Dalakas, 2011), about 16% of the patients may have a subacute onset with a monophasic course (Vallat et al., 2010, Said, 2006, Hughes et al., 2006, Odaka et al., 2003).
The diagnostic challenge of distinguishing these two immune-mediated polyradiculoneuropathies remains high, as in case of CIDP convincing data from randomised controlled trials indicate, that corticosteroids, intravenous immunoglobulines (IVIg) and plasmapheresis exert short term or long term clinical improvement in about two-third of patients (Hughes et al., 2008, Vanhoutte et al., 2013, Latov et al., 2010, Joint Task Force of the EFNS and the PNS, 2010). Recent clinical criteria have been proposed in order to distinguish subacute onset CIDP from AIDP, among which are: a new clinical deterioration 8 weeks after first manifestation of the disease, no signs of cranial nerve involvement or autonomic symptoms and treatment-related fluctuations (Ruts et al., 2010). In cases of polyradiculoneuropathies with (sub-) acute onset, rash distinction between these two entities consecutively leading to an early and accurate immunotherapy might be of great help for clinical outcome. Both, CIDP and AIDP respond to IVIg and/or plasma exchange, but only CIDP improves by steroids. Nerve conduction studies with respect to sural nerve sparing pattern, sensory ratio >1, or the presence of A-waves (Dionne et al., 2010) may also not be helpful in distinguishing (sub-) acute CIDP from AIDP.
The role of neuromuscular ultrasound in the diagnostic workup of immune-mediated polyneuropathies remains less well defined. Only a few studies have used ultrasound to examine the pathological changes, highlighting mainly pathological changes of the cross sectional area of peripheral nerves and their correlation with electrophysiological findings (Padua et al., 2012, Kerasnoudis, 2013b, Kerasnoudis, in press, Smith et al., 2008, Zaidman et al., 2009). Although cross sectional area reference values for peripheral nerves and brachial plexus have been reported in previous studies (Cartwright et al., 2008, Haun et al., 2010, Kerasnoudis and Klasing, 2013a, Kerasnoudis et al., 2013d, Kerasnoudis and Pitarokoili, 2013e) the difficulty to quantify pathological changes remains an important limitation of neuromuscular ultrasound in clinical practice.
It still remains unknown, whether neuromuscular ultrasound could be a useful diagnostic method in distinguishing CIDP from AIDP. We aimed to develop and evaluate a new ultrasound score to differentiate these two immune-mediated polyradiculoneuropathies, with emphasis in the distinction of the subacute CIDP from AIDP.
Section snippets
Patients
The local university ethics committee approved our study protocol and all CIDP, AIDP patients signed informed consent. For the diagnosis of definite CIDP we used the diagnostic criteria proposed from the Joint Task Force of the European Federation of Neurological Societies and the Peripheral Nerve Society (Van den Bergh et al., 2010, Table 1). According to these criteria, for a definite CIDP the clinical criterion and at least one of the electrodiagnostic criteria should be fulfilled.
For the
Phase 1
In order to develop a new ultrasound score for distinguishing CIDP from AIDP, 20 patients with known CIDP (mean age 56.7, SD ± 13.5, 6 women) and 20 post-AIDP patients (mean age 58.3, SD ± 13.8, 10 women) were enrolled in the study. The CIDP group underwent sonographic evaluation a mean of 4.55 years (SD ± 3.5) and the post-AIDP group a mean of 3.4 years (SD ± 2.91) after the onset of the disease.
Table 3 summarizes the statistically significant differences between the two patient groups. The two groups
Discussion
In the present study we present a new ultrasound score for distinguishing CIDP from AIDP and try to highlight possible distribution patterns of pathological ultrasound changes in these 2 polyradiculoneuropathies.
Conclusions
In this study, we present the applicability of the “Bochum ultrasound score” in distinguishing CIDP from AIDP. Our results demonstrate, that the “Bochum ultrasound score” seems to be a very promising, easily applicable and safe method with emphasis in distinguishing subacute CIDP from AIDP.
Some shortcomings have also to be addressed. The development of the above score was based in a retrospective evaluation of the ultrasound data of already diagnosed CIDP and AIDP patients. Although, the
Acknowledgements
Antonios Kerasnoudis, Kalliopi Pitarokoili, and Volker Behrendt report no disclosures.
R. Gold has received consultation fees and speakers honoraria from BayerSchering, BiogenIdec, MerckSerono, Novartis, Sanofi-Aventis and TEVA. He also acknowledges grant support from BayerSchering, BiogenIdec, MerckSerono, Sanofi-Aventis and TEVA, all not related to this manuscript.
Min-Suk Yoon has received speakers honoraria from CSL Behring, all not related to this manuscript.
The study was not
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