Pain as a First Manifestation of Paraneoplastic Neuropathies: A Systematic Review and Meta-Analysis.

INTRODUCTION: Paraneoplastic neurological syndromes (PNS) consist of a heterogeneous group of neurological disorders triggered by cancer. The aim of this systematic review is to estimate the reported prevalence of pain in patients with paraneoplastic peripheral neuropathy (PPN). METHODS: A systematic computer-based literature search was conducted on PubMed database. RESULTS: Our search strategy resulted in the identification of 126 articles. After the eligibility assessment, 45 papers met the inclusion criteria. Full clinical and neurophysiological data were further extracted and involved 92 patients with PPN (54.5% males, mean age 60.0 ± 12.2 years). The commonest first manifestation of PPN is sensory loss (67.4%), followed by pain (41.3%), weakness (22.8%), and sensory ataxia (20.7%). In 13.0% of the cases, pain was the sole first manifestation of the PPN. During the course of the PPN, 57.6% of the patients may experience pain secondary to the neuropathy. CONCLUSIONS: Pain is very prevalent within PPN. Pain specialists should be aware of this. Detailed history-taking, full clinical examination, and requesting nerve conduction studies might lead to an earlier diagnosis of an underlying malignancy

Electrodiagnostic subtyping in Guillain–Barr\ue9 syndrome patients in the International Guillain–Barr\ue9 Outcome Study

\ua9 2024 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.Background and purpose: Various electrodiagnostic criteria have been developed in Guillain–Barr\ue9 syndrome (GBS). Their performance in a broad representation of GBS patients has not been evaluated. Motor conduction data from the International GBS Outcome Study (IGOS) cohort were used to compare two widely used criterion sets and relate these to diagnostic amyotrophic lateral sclerosis criteria. Methods: From the first 1500 patients in IGOS, nerve conduction studies from 1137 (75.8%) were available for the current study. These patients were classified according to nerve conduction studies criteria proposed by Hadden and Rajabally. Results: Of the 1137 studies, 68.3% (N = 777) were classified identically according to criteria by Hadden and Rajabally: 111 (9.8%) axonal, 366 (32.2%) demyelinating, 195 (17.2%) equivocal, 35 (3.1%) inexcitable and 70 (6.2%) normal. Thus, 360 studies (31.7%) were classified differently. The areas of differences were as follows: 155 studies (13.6%) classified as demyelinating by Hadden and axonal by Rajabally; 122 studies (10.7%) classified as demyelinating by Hadden and equivocal by Rajabally; and 75 studies (6.6%) classified as equivocal by Hadden and axonal by Rajabally. Due to more strictly defined cutoffs fewer patients fulfilled demyelinating criteria by Rajabally than by Hadden, making more patients eligible for axonal or equivocal classification by Rajabally. In 234 (68.6%) axonal studies by Rajabally the revised El Escorial (amyotrophic lateral sclerosis) criteria were fulfilled; in axonal cases by Hadden this was 1.8%. Conclusions and discussion: This study shows that electrodiagnosis in GBS is dependent on the criterion set utilized, both of which are based on expert opinion. Reappraisal of electrodiagnostic subtyping in GBS is warranted

Chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common autoimmune neuropathy. The diagnosis depends on the clinical presentation with a progressive or relapsing course over at least 2 months and electrophysiological evidence of primary demyelination. Whereas typical CIDP is quite easily recognizable because virtually no other neuropathies present with both distal and proximal motor and sensory deficit, atypical CIDP, focal and multifocal variants in particular, may represent a difficult diagnostic challenge. CIDP very likely is an underdiagnosed condition as suggested also by a positive correlation between prevalence rates and sensitivity of electrophysiological criteria. Since no 'gold standard' diagnostic marker exists, electrophysiological criteria have been optimized to be at the same time as sensitive and as specific as possible. Additional supportive laboratory features, such as increased spinal fluid protein, MRI abnormalities of nerve segments, and in selected cases nerve biopsy lead to the correct diagnosis in the large majority of the cases. Objective clinical improvement following immune therapy is also a useful parameter to confirm the diagnosis. The pathogenesis and pathophysiology of CIDP remain poorly understood, but the available evidence for an inflammatory origin is quite convincing. Steroids, intravenous immunoglobulin (IVIG), and plasma exchange (PE) have been proven to be effective treatments. IVIG usually leads to rapid improvement, which is useful in severely disabled patients. Repeat treatment over regular time intervals for many years is often necessary. The effect of steroids is slower and the side-effect profile may be problematic, but they may induce disease remission more frequently than IVIG. An important and as of yet uncompletely resolved issue is the evaluation of long-term outcome to determine whether the disease is still active and responsive to treatment

Validity of diagnostic criteria for chronic inflammatory demyelinating polyneuropathy: a multicentre European study

Background: Diagnostic criteria for chronic inflammatory demyelinating polyneuropathy ( CIDP) have variable sensitivity and specificity. Newly published criteria by Koski et al combine clinical and electrophysiological components, either of which suffices to establish the diagnosis. European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria require mandatory electrophysiology, as do other sets of criteria. Methods: The value of the two above-mentioned sets of criteria, on 151 patients with CIDP, and 162 controls with axonal neuropathy, from four European centres was assessed. Results were compared with Van den Bergh and Pieret's criteria and those of the American Academy of Neurology (AAN). The utility of more extensive nerve-conduction studies was ascertained. Results: Koski et al's criteria had a sensitivity of 63% and specificity of 99.3%. With unilateral, right-sided, forearm/foreleg, four-nerve studies, EFNS/PNS criteria offered a sensitivity of 81.3% and specificity of 96.2% for "definite/probable'' CIDP. Van den Bergh and Pieret's criteria had a sensitivity of 79.5% and specificity of 96.9%. AAN criteria were poorly sensitive (45.7%) but highly specific (100%). "Possible'' electrophysiological CIDP as per EFNS/PNS criteria were poorly specific (69.2%). More extensive studies increased the diagnostic sensitivity of EFNS/PNS criteria (96.7%) but reduced the specificity (79.3%). Conclusions: In our patient populations, the EFNS/PNS criteria were the most sensitive and allowed identification of a highly significantly greater number of patients than Koski et al's criteria. The latter were comparable in specificity with the "definite/probable'' EFNS/PNS electrodiagnostic subcategories. More extensive nerve-conduction studies improved diagnostic yield but resulted in loss of specificity