Chronic inflammatory demyelinating polyneuropathy (CIDP) is a well-described, acquired, immune-mediated polyneuropathy. It is characterized by motor and sensory deficits in various combinations, presenting with a relapsing-remitting or progressive course. The spectrum of CIDP includes typical CIDP and atypical CIDP variants, such as distal acquired symmetric neuropathy (DADS), multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), focal CIDP forms, pure sensory and pure motor CIDP and chronic immune sensory polyradiculopathy (CISP). In addition, CIDP can occur in association with other auto-immune diseases, together with central nervous system demyelination, or it may overlap with hereditary or diabetic neuropathy. Standard clinical and neurophysiological criteria establish the diagnosis in the typical idiopathic CIDP. However, although a general consensus is currently formed for the different CIDP subtypes, diagnostic criteria are not well defined. The correct diagnosis in such cases may therefore be delayed, and patients with atypical CIDP are often excluded from clinical trials and deprived of potentially successful treatments. On the other hand, patients with a neuropathy not clearly classified could be at risk for potential side-effects of an undue medication. Moreover, the evolution of the disease is indeterminate, and these patients often meet the criteria for typical CIDP at a later stage.
The two main reasons for the uncertainty in atypical CIDP are the rarity of this neuropathy and the wide variety of clinical phenotypes, neurophysiological and immunological profiles. As a result, a change of an initial diagnosis along the course of the disease can be expected, when new manifestations, electrophysiological findings or immunological data become apparent. Over the last decade, the presence of several auto-antibodies against peripheral nerve targets has been reported in a minority of patients with CIDP. Some of them, such as Neurofascin 155 /186, or Contactin 1 antibodies have been associated with distinct clinical presentations and response to treatment. In cohorts of CIDP patients, the detection of different anti-nerve antibodies, and their clinical syndromes, are currently under study. Neurophysiology plays a pivotal role in the diagnostic process of CIDP and variants, since it provides evidence of specific conduction abnormalities i.e. diffuse versus focal slowing and block, it assesses the severity and the distribution of lesions and unravels subclinical nerve dysfunction. Atypical CIDP cases demonstrate certain electrophysiological findings but no structural criteria for these conditions have been established. Not uncommonly, electrophysiological abnormalities are minimal or equivocal, requiring supplementation with more specialized techniques. Neuro-imaging, including ultrasound and MRI techniques, is a relatively novel diagnostic tool for CIDP and variants, being particularly useful to study proximal neural parts i.e. plexus or roots and individual nerves. However, the distinction by imaging between hereditary and acquired demyelinating neuropathies is difficult. Moreover, specific neuro-imaging signs suitable for the identification and follow-up of different sub-types of CIDP have not yet been suggested. Limited information is available in regards to management, clinical course and outcome of atypical CIDP. There are reports suggesting that not all CIDP sub-types responded equally well to first-line treatment. Novel immunomodulatory strategies have not been designed for CIDP variants. The same applies for CIDP patients with additional medical conditions such as malignancy, other autoimmune diseases, or diabetes mellitus.
The aim of this Research Topic is to provide an outline of the current knowledge on all different aspects of atypical CIDP. We expect that the Reader could benefit from gaining access to comprehensive data on pathophysiology, neurophysiology, and neuroimaging of these conditions, which may have a positive impact on the clinical decision process and optimal management of patients. Submission of Reviews and Original Research focusing on, but not limited to, the following themes are welcome:
1. Appropriate neurophysiological techniques to enhance the sensitivity of diagnosis in atypical CIDP cases;
2. The role of neuroimaging in distinguishing and monitoring atypical CIDP cases;
3. Association between immunological profile and clinical phenotype;
4. Treatment approaches matching the clinical CIDP variant;
5. The significance of combined peripheral and central nervous system demyelination;
6. Differences/similarities between idiopathic CIDP and CIDP as part of a systemic disease, complicating malignancy, or in conjunction with hereditary neuropathy;
7. Promising novel diagnostic and therapeutic markers for disease progress and outcome.
Chronic inflammatory demyelinating polyneuropathy (CIDP) is a well-described, acquired, immune-mediated polyneuropathy. It is characterized by motor and sensory deficits in various combinations, presenting with a relapsing-remitting or progressive course. The spectrum of CIDP includes typical CIDP and atypical CIDP variants, such as distal acquired symmetric neuropathy (DADS), multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), focal CIDP forms, pure sensory and pure motor CIDP and chronic immune sensory polyradiculopathy (CISP). In addition, CIDP can occur in association with other auto-immune diseases, together with central nervous system demyelination, or it may overlap with hereditary or diabetic neuropathy. Standard clinical and neurophysiological criteria establish the diagnosis in the typical idiopathic CIDP. However, although a general consensus is currently formed for the different CIDP subtypes, diagnostic criteria are not well defined. The correct diagnosis in such cases may therefore be delayed, and patients with atypical CIDP are often excluded from clinical trials and deprived of potentially successful treatments. On the other hand, patients with a neuropathy not clearly classified could be at risk for potential side-effects of an undue medication. Moreover, the evolution of the disease is indeterminate, and these patients often meet the criteria for typical CIDP at a later stage.
The two main reasons for the uncertainty in atypical CIDP are the rarity of this neuropathy and the wide variety of clinical phenotypes, neurophysiological and immunological profiles. As a result, a change of an initial diagnosis along the course of the disease can be expected, when new manifestations, electrophysiological findings or immunological data become apparent. Over the last decade, the presence of several auto-antibodies against peripheral nerve targets has been reported in a minority of patients with CIDP. Some of them, such as Neurofascin 155 /186, or Contactin 1 antibodies have been associated with distinct clinical presentations and response to treatment. In cohorts of CIDP patients, the detection of different anti-nerve antibodies, and their clinical syndromes, are currently under study. Neurophysiology plays a pivotal role in the diagnostic process of CIDP and variants, since it provides evidence of specific conduction abnormalities i.e. diffuse versus focal slowing and block, it assesses the severity and the distribution of lesions and unravels subclinical nerve dysfunction. Atypical CIDP cases demonstrate certain electrophysiological findings but no structural criteria for these conditions have been established. Not uncommonly, electrophysiological abnormalities are minimal or equivocal, requiring supplementation with more specialized techniques. Neuro-imaging, including ultrasound and MRI techniques, is a relatively novel diagnostic tool for CIDP and variants, being particularly useful to study proximal neural parts i.e. plexus or roots and individual nerves. However, the distinction by imaging between hereditary and acquired demyelinating neuropathies is difficult. Moreover, specific neuro-imaging signs suitable for the identification and follow-up of different sub-types of CIDP have not yet been suggested. Limited information is available in regards to management, clinical course and outcome of atypical CIDP. There are reports suggesting that not all CIDP sub-types responded equally well to first-line treatment. Novel immunomodulatory strategies have not been designed for CIDP variants. The same applies for CIDP patients with additional medical conditions such as malignancy, other autoimmune diseases, or diabetes mellitus.
The aim of this Research Topic is to provide an outline of the current knowledge on all different aspects of atypical CIDP. We expect that the Reader could benefit from gaining access to comprehensive data on pathophysiology, neurophysiology, and neuroimaging of these conditions, which may have a positive impact on the clinical decision process and optimal management of patients. Submission of Reviews and Original Research focusing on, but not limited to, the following themes are welcome:
1. Appropriate neurophysiological techniques to enhance the sensitivity of diagnosis in atypical CIDP cases;
2. The role of neuroimaging in distinguishing and monitoring atypical CIDP cases;
3. Association between immunological profile and clinical phenotype;
4. Treatment approaches matching the clinical CIDP variant;
5. The significance of combined peripheral and central nervous system demyelination;
6. Differences/similarities between idiopathic CIDP and CIDP as part of a systemic disease, complicating malignancy, or in conjunction with hereditary neuropathy;
7. Promising novel diagnostic and therapeutic markers for disease progress and outcome.
