To Rule Out Nodopathy as the Cause of Lewis-Sumner Syndrome, Neurofascin and Contactin Antibodies Should be Determined

We read with interest the article by Shaik et al.[1] about a 24-year-old woman with chronic inflammatory demyelinating polyneuropathy (CIDP) of the multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) subtype (multifocal CIDP, Lewis-Sumner syndrome), which was diagnosed following recurrent episodes of bilateral asymmetric sensorimotor deficits in the upper and lower limbs, nerve conduction studies (NCS) suggestive of possible CIDP according to EAN guidelines, and elevated CSF protein. MADSAM was treated with intravenous immunoglobulins (IVIG) and glucocorticoids, with a particularly good response to bimonthly IVIG.[1] The patient suffered a total of ten relapses.[1] Some points should be discussed. The first point is that a nodopathy due to antibodies against neurofascin-186, neurofascin-155, contactin-1, or contactin-associated protein could not be excluded. As nodopathies represent a growing spectrum of autoimmune diseases[2] that can present as CIDP, it would have been imperative to exclude this etiology as well. The second point relates to NCS and the lack of follow-up NCS results.[1] Since MADSAM is characterized by multifocal conduction blocks that tend to persist,[3] we should know at which sites conduction blocks were found and whether conduction blocks and other initially abnormal NCS parameters have resolved within the follow-up period. Third, no explanation was given as to why the patient only partially recovered after the initial administration of IVIG but fully recovered after the 2-month administration of IVIG at a lower dose. How can this phenomenon be explained? Fourth, SARS-CoV-2 infection or vaccination (SC2I, SC2V) has not been ruled out as a trigger for at least some of the ten reported episodes. Since SC2I[4] or SC2V can be complicated by CIDP, we should know whether the medical history was positive for SC2I or SC2V and whether these events were temporally associated with one of the relapses. The fifth point is that the appearance of the relapses was not described in detail. Did the relapses affect only the motor system or the sensory system or both? Were only the upper limbs affected or also the lower limbs? The sixth point is the discrepancy between the case description, which mentions eight relapses, and the discussion, which mentions ten relapses. This discrepancy should be clarified. In patients with MADSAM, not only close clinical but also close electrophysiologic follow-up is required, especially whether IVIG was also beneficial for the NCS abnormalities. It is also important that all possible causes of CIDP, including antibodies to nodes of Ranvier, are determined to rule out or confirm nodopathy. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.