Diagnosis of chronic inflammatory demyelinating polyneuropathy

Jeffrey A. Allen, Richard A. Lewis

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a chronic immune-mediated peripheral form of polyneuropathy. No reliable diagnostic biomarkers are available by which to make the diagnosis of CIDP. As a result, diagnosis of the condition can be challenging. Many patients are not recognized early in the disease course, and on the other end of the spectrum both establishing early and accurate diagnosis as well as avoiding misdiagnosis and overtreatment. Identification of the hallmark clinical, electrophysiological, and laboratory features of the disease are critical to facilitate rapid diagnosis, while an understanding of diagnostic pitfalls can help prevent misdiagnosis. Since the original description of CIDP in the 1970s, over 15 sets of diagnostic criteria have been proposed. The criteria published in 2021 by the European Academy of Neurology / Peripheral Nerve Society (EAN/PNS) were developed for use during routine clinical care and are available in the public domain. These criteria provide clinicians with an invaluable resource by which the data collected during the evaluation of the patient with possible CIDP can be interpreted. One point of importance that bridges diagnosis to treatment is objectification of the treatment response. Interpretation of how patients respond to treatment drives both long-term treatment paradigms and the diagnosis at which these treatments are aimed. Although no approach is perfect, utilization of strength impairment and disability outcomes in clinical practice can help unravel the difficulties in interpreting response to treatment. Just as improvement in these outcomes is considered diagnostically supportive, the absence of objective benefit argues against it and should prompt reconsideration of a CIDP diagnosis.

Original languageEnglish (US)
Pages (from-to)545-551
Number of pages7
JournalMuscle and Nerve
Volume66
Issue number5
DOIs
StatePublished - Nov 2022

Bibliographical note

Funding Information:
Throughout the 20th century the cardinal clinical, electrodiagnostic, histopathological, and laboratory features of what we now call CIDP were described, culminating in the naming of the disorder by Peter Dyck in 1975.11 Although much has been learned about CIDP since it was named, the processes of how a diagnosis is reached are largely unchanged. CIDP remains a clinical and electrophysiological diagnosis that can be supported by laboratory, imaging, and treatment data. The challenge is in how to integrate these features accurately and rapidly. At its core, CIDP is a clinical diagnosis. The disease is defined by numbness and weakness that evolves over 2 months or more in a progressive or relapsing pattern, with muscle stretch reflexes invariably reduced or absent on examination.12,13 Although patients with “typical” CIDP have relatively symmetric proximal and distal motor and sensory symptoms, the heterogeneous clinical features of the disease have been well described. Recognized variants that still fall under the CIDP syndromic umbrella include distal CIDP (sometimes referred to as distal acquired demyelinating symmetric [DADS] type), multifocal CIDP (also called Lewis-Sumner syndrome, or multifocal acquired demyelinating sensory and motor [MADSAM]), sensory CIDP, and motor CIDP. Although CIDP variants differ with respect to the modality that predominates or the part of the body that is preferentially affected, all variants have in common weakness and/or numbness as the defining clinical features. Since the disease was described in the 1970s, more than 15 sets of CIDP diagnostic criteria have been developed, a fact that points to the difficulties in defining a disorder without a reliable diagnostic biologic marker. Although many early criteria were developed with clinical trials in mind, modern criteria are meant to be used during routine clinical care. Over the last decade, the European Federation of Neurologic Society / Peripheral Nerve Society (EFNS/PNS) diagnostic criteria have been the most widely used guideline in clinical practice and in clinical trials.12 These guidelines, first published in 2006 and updated in 2010, have been shown to have a sensitivity of 73% to 91% and a specificity of 66% to 88%.13 In 2021, the criteria underwent a second revision, and now are called the European Academy of Neurology and Peripheral Nerve Society (EAN/PNS) criteria.13 The updated criteria more directly recognize that, although the diagnosis of typical CIDP with symmetric proximal and distal weakness is not overly challenging, the variants can be tricky and are difficult to define by a simple or standard diagnostic guideline. EAN/PNS 2021 criteria highlight unique features, which should be explored in patients suspected to have one of the CIDP variants, and they provide useful advice on alternative diagnostic considerations specific to each of the variants. Nerve conduction studies (NCS) play an instrumental role in the diagnosis of CIDP. Electrophysiological findings that support peripheral nerve demyelination include the presence of motor distal latency prolongation, slowed motor conduction velocity, motor conduction block, temporal dispersion, and prolonged or absent F waves. Sensory responses are often absent or attenuated in the upper and lower limbs. When abnormalities on NCS are uncovered in clinical practice it can be challenging to identify whether any given “demyelinating” finding is abnormal to the extent that it unequivocally supports peripheral nerve demyelination. We have found electrodiagnostic guidelines to be an invaluable resource when working through ambiguous electrophysiological findings during routine clinical care (Table 1).12,14 The absence of electrophysiological evidence of demyelination should prompt exploration for an alternative diagnosis. Note: Adopted from European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and management of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint task force---second revision.14 In the event that the clinical and electrophysiological components of the disease are well-defined, a diagnosis of CIDP can confidently be made provided there is no better explanation. Consideration of alternative explanations is important in all patients with suspected CIDP, especially when the clinical or electrophysiological data are equivocal or if there are unique circumstances that pertain to a particular patient. In cases where the diagnosis is uncertain, the collection of supportive data can be helpful to increase diagnostic confidence. Diagnostic data considered supportive of CIDP includes cerebrospinal fluid (CSF) albuminocytological dissociation, characteristic imaging findings on magnetic resonance imaging (MRI) or ultrasound, or histopathological hallmarks on nerve biopsy. We have also found testing for nodal and paranodal antibodies as well as screening for genetically determined neuropathies of high yield in selected clinical settings. Ancillary testing data are presented in Table 2, with a focus on when collection of the data is helpful and when it is not helpful. CIDP clinically suspected but only meet “possible” criteria If infectious or malignant etiology (rather than CIDP) possible or suspected If diagnostic criteria are already met If institutional experience and expertise in nerve imaging is unavailable Clinically mild or moderate cases If surgical and pathological experience and expertise is unavailable Abbreviations: CIDP, chronic inflammatory demyelinating polyneuropathy; CSF, cerebrospinal fluid; CMT, Charcot-Marie-Tooth disease; CNTN1, contactin 1; IVIg, intravenous immunoglobulin; hTTR, hereditary transthyretin; IgM, immunoglobulin M; MRI, magnetic resonance imaging; MGUS, monoclonal gammopathy of undetermined significance; MAG, myelin-associated glycoprotein; MMN, multifocal motor neuropathy; NCS, nerve conduction studies; NF, neurofascin; POEMS, polyneuropathy, organomegaly, endocrinopathy, monoclonal protein skin changes; SPEP, serum protein electrophoresis; WBC, white blood cell.

Publisher Copyright:
© 2022 Wiley Periodicals LLC.

Keywords

  • Autoimmune
  • CIDP
  • Diagnosis
  • Guidelines
  • Misdiagnosis
  • Neuropathy

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't

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