Brief Communication: Lambert-Eaton Myasthenic Paraneoplastic Syndrome Associated With Merkel Cell Carcinoma Successfully Treated by Immune Checkpoint Inhibitors: 2 Cases.

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cutaneous tumor with high metastatic potential. In rare cases, it can be associated with paraneoplastic syndromes (PNS), which result from an antitumor immunity against antigens produced by the tumor itself. Lambert-Eaton Myasthenic Syndrome (LEMS) is a neurological autoimmune PNS characterized by an impairment of the neuromuscular junction, leading to proximal muscle weakness and fatigability. Although the development of immune checkpoint inhibitors (ICI) is a breakthrough in the management of many cancers, onset or worsen of immune diseases has been described. Thereby, in patients with previous neurological PNS like LEMS, the ICI therapy for cancer may aggravate neurological symptoms and lead to irreversible impairment. We report here 2 cases of patients with metastatic MCC associated with a LEMS at the diagnosis. Both successfully received ICI therapies (anti-PDL1 avelumab and anti-PD1 pembrolizumab) without worsening of LEMS and any major immune-related adverse effects. Their neurological condition improved and disappeared concomitantly with the efficacy of immunotherapy, and we did not observe relapse of both MCC and LEMS after treatment discontinuation. Finally, we performed a complete review of the literature, which confirmed that ICI treatment could be discussed for patients with paraneoplastic LEMS, and emphasized the need for multidisciplinary management.

Acute peripheral neuropathy following animal envenomation: A case report and systematic review.

Animal envenomation in humans is usually accidental or for defensive purposes. Depending on the venom composition and administration, different reactions can be observed. After reporting the first case of acute polyradiculitis in a 57-year-old healthy male after red lionfish envenomation, we propose to analyze rare similar cases of acute neuritis after animal envenomation published in the medical literature. Including our case, we found 54 patients who developed acute peripheral neuropathy after having been stung or bitten by various animals, mainly hymenoptera (in half of the cases) but also jellyfishes, snakes, corals or nonhooked arthropods. We observed two distinct patterns of peripheral neuropathy: more than half of them were polyneuropathy while the others were focal neuropathy. The prognosis was favorable in most cases. The pathophysiological mechanism associated with these rare complications remain unknown, although some hypotheses may be proposed. A direct action of certain components of the venom, such as phospholipase-A2, could explain the focal forms of peripheral neuropathy trough toxic reactions and/or vasculitis processes. The more diffuse clinical situations could be due to an allergy-triggered immune-mediated reaction (possibly linked to a molecular mimicry mechanism between venom proteins and some myelin proteins of the peripheral nervous system), or to the action of some venom components on membrane ionic channels particularly at the node of Ranvier. Even if acute peripheral neuropathies are rare after envenomation, they may occur after envenomation from various animals, and their usually favorable prognoses should be known by neurologists.

Usefulness of subcutaneous immunoglobulin therapy in the management of myasthenia gravis: a retrospective cohort study.

INTRODUCTION: To describe the efficacy of subcutaneous immunoglobulin (SCIg) in patients with myasthenia gravis (MG). METHODS: This was a retrospective study conducted in the neuromuscular referral center of Bordeaux (between January 1, 2014 and March 31, 2021) with MG patients treated with SCIg. The main outcome was SCIg efficacy assessed by the before and after SCIg Myasthenia Gravis Foundation of America (MGFA) clinical classification, the duration of hospitalization and the number of days of orotracheal intubation (OTI). RESULTS: Sixteen patients were included in the study (11 females; 5 males). Nine patients were still treated with SCIg at the end of the study (March 31, 2021) and then underwent prospective follow-up. The average age of the patients was 56.1 (19-83) years. The median duration of MG at onset of SCIg was 37.4 months. Eight patients (50%) remained stable (4 in stage MGFA-IV and 4 in MGFA-III). Eight patients (50%) improved: 3 from MGFA-IV to MGFA-III, 1 from MGFA-IV to MGFA-II, 1 from MGFA-IV to MGFA-I, 2 from MGFA-III to MGFA-II and 1 from MGFA-III to MGFA-I (no patient worsened). The duration of disease progression did not appear to affect the response to SCIg therapy. The number of hospital days per month was significantly reduced after SCIg compared to before, and the number of days in intensive care unit and the number of days of OTI were also reduced. Only minor adverse effects were noted, and 80% of patients were in favor of continuing SCIg. CONCLUSIONS: SCIg is a well-tolerated and useful treatment in MG, offering interesting perspectives in the management of MG patients. However, further large-scale prospective studies are needed to confirm these results.

Neurologic manifestations of giant cell arteritis.

Giant cell arteritis, the most frequent form of vasculitis in persons over 50 years of age, is a granulomatous chronic vasculitis involving large and medium-sized vessels, most commonly the temporal and other cranial arteries. This common, treatable condition is associated with various clinical symptoms, including neurological ones, affecting both the central and peripheral nervous systems. In this review, we discuss the cranial and extra cranial neurological complications of giant cell arteritis, to help avoid the many pitfalls in the diagnosis of giant cell arteritis.

Peripheral neuropathy and livedoid vasculopathy.

BACKGROUND: Livedoid vasculopathy (LV) is a chronic dermatosis associated with micro-thrombosis of the vessels of the dermis, leading to ischemic lesions and painful skin ulcerations of the lower limbs. This thrombosing occlusive vasculopathy, clearly distinct from 'classical vasculitis' (not related to alteration of vessel walls), may lead to peripheral neuropathy. OBJECTIVE: To clarify the main clinical, electrophysiological and pathological characteristics of peripheral neuropathy linked to LV. METHOD: We presented a series of personal cases of peripheral neuropathy due to LV. We also conducted a review of the literature (since the first description of LV in 1974) using multiple combinations of keywords from 'PubMed', 'Google Scholar' and 'ScienceDirect' databases according to the 'Preferred Reporting Items for Systematic reviews and Meta-Analyses' guidelines. RESULTS: We identified 16 patients (6 personal cases and 10 cases from the medical literature). Our personal cases were five females and one male, with a median age (at the onset of cutaneous signs of LV) of 38 (range 25-62). Several types of skin lesions of the lower limbs were observed. Median age at the onset of peripheral neuropathy symptoms was 48 years (range 29-66), with a main clinical and electrophysiological pattern of mononeuropathy multiplex. DISCUSSION: We observed a typical pattern of peripheral neuropathy, mostly mononeuropathy multiplex, whose pathophysiology might be related to occlusions of the small vessels of the nerves, as seen in the dermis. Moreover, LV may also be associated with other types of peripheral neuropathies (sometimes of autoimmune etiology) not directly related to the skin lesions. CONCLUSION: The 'ischemic form' of peripheral neuropathy linked to LV is mainly responsible for sensory disturbances (with multifocal distribution), sometimes for motor disturbances. This type of peripheral neuropathy has to be distinguished from 'classical vasculitic neuropathies' which are usually treated with antithrombotic therapies.

Esophageal Achalasia Induced by Ipilimumab and Nivolumab Combination: A Rare Neurological Manifestation of Immune-related Autonomic Neuropathy.

Immunotherapy with immune checkpoint inhibitors (ICIs) has improved the prognosis of many cancers; a combination of nivolumab (anti-programmed cell death protein 1) and ipilimumab (anti-cytotoxic T-lymphocyte-associated protein 4) is approved as first-line therapy for advanced melanoma, with objective responses obtained in more than half of patients. However, this combination is associated with a high rate of immune-related adverse events, which are often severe and multiple. Neurological immune-related adverse events are rare but feared because they can be life-threatening, their diagnosis and management are challenging, and patients can have irreversible sequelae. We reported a case of a young patient treated by nivolumab and ipilimumab combination for metastatic melanoma. Severe dysphagia with regurgitations, major weight loss, uveitis, and vitiligo occurred after 3 infusions of nivolumab and ipilimumab. Magnetic resonance imaging and positron emission tomography scan showed complete remission of melanoma. The endoscopic examination did not find any digestive toxicity. Esophageal manometry revealed achalasia. This was associated with mydriasis, pathologic deep breath test, and alteration of the cutaneous sympathetic response on electromyogram, which was consistent with autonomic neuropathy. This rare etiology of atypical vomiting under ICI should be known by prescribers, as ICI prescription is widening in many new cancers.

Olfaction and anosmia: From ancient times to COVID-19.

Olfaction, one of our five main qualitative sensory abilities, is the action of smelling or the capacity to smell. Olfactory impairment can be a sign of a medical problem, from a benign nasal/sinus problem up to a potentially serious brain injury. However, although clinicians (neurologists or not) usually test the olfactory nerves in specific clinical situations (for example, when a neurodegenerative disorder is suspected), they may omit such tests in many other situations. With the recent COVID-19 pandemic, the resurgence of anosmia has reminded us of the importance of testing this sensorineural function. We retrace here the main historical steps and discoveries concerning olfaction and anosmia.

Impact of Coronavirus Disease 2019 in a French Cohort of Myasthenia Gravis.

OBJECTIVE: To describe the clinical characteristics and outcomes of coronavirus disease 2019 (COVID-19) among patients with myasthenia gravis (MG) and identify factors associated with COVID-19 severity in patients with MG. METHODS: The CO-MY-COVID registry was a multicenter, retrospective, observational cohort study conducted in neuromuscular referral centers and general hospitals of the FILNEMUS (Filière Neuromusculaire) network (between March 1, 2020, and June 8, 2020), including patients with MG with a confirmed or highly suspected diagnosis of COVID-19. COVID-19 was diagnosed based on a PCR test from a nasopharyngeal swab or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology, thoracic CT scan, or typical symptoms. The main outcome was COVID-19 severity based on location of treatment/management (home, hospitalized in a medical unit, or in an intensive care unit). We collected information on demographic variables, general history, and risk factors for severe COVID-19. Multivariate ordinal regression models were used to identify factors associated with severe COVID-19 outcomes. RESULTS: Among 3,558 patients with MG registered in the French database for rare disorders, 34 (0.96%) had COVID-19. The mean age at COVID-19 onset was 55.0 ± 19.9 years (mean MG duration: 8.5 ± 8.5 years). By the end of the study period, 28 patients recovered from COVID-19, 1 remained affected, and 5 died. Only high Myasthenia Gravis Foundation of America (MGFA) class (≥IV) before COVID-19 was associated with severe COVID-19 (p = 0.004); factors that were not associated included sex, MG duration, and medium MGFA classes (≤IIIb). The type of MG treatment had no independent effect on COVID-19 severity. CONCLUSIONS: This registry-based cohort study shows that COVID-19 had a limited effect on most patients, and immunosuppressive medications and corticosteroids used for MG management are not risk factors for poorer outcomes. However, the risk of severe COVID-19 is elevated in patients with high MGFA classes (odds ratio, 102.6 [4.4-2,371.9]). These results are important for establishing evidence-based guidelines for the management of patients with MG during the COVID-19 pandemic.

Minimizing the Diagnostic Delay in Amyotrophic Lateral Sclerosis: The Role of Nonneurologist Practitioners.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS), usually fatal in a few years, is a neurodegenerative disorder where the diagnostic delay, although variable according to the studies, remains too long. The main objective of this study was to determine the average time to diagnose ALS and the role of each physician, general practitioner (GP), or specialist (neurologist or not) involved in the management of these patients. The secondary objective was to propose some simple schemes to quickly identify an ALS suspicion with the aim to reduce this delay. Patients and Methods. This retrospective study evaluated the diagnostic delay (and other intermediate delays) of 90 ALS patients registered in the ALS Center of Bordeaux (France) in 2013. The main clinical signs encountered (and their order of appearance) were studied. RESULTS: The average diagnostic delay was 17 months, with a median diagnostic delay of 12 months. The average diagnostic delay was 2.7 months between the first symptoms and the first complaint to GP, followed by an additional 6.5 month delay before the patient's first visit to a neurologist. This period could be shortened, especially if GP performed additional tests quickly (p=0.01), as the time spent consulting various specialists often extends this crucial step. Overall, diagnostic delay accounted for 40% of the total duration of the disease progression. CONCLUSION: In relation to total survival time, the diagnostic delay of ALS appears to be proportionately very long, sometimes longer than that observed in previous studies (because it also included the total delay to diagnostic or treatment initiation). The rapid execution of useful additional tests by the first medical doctor, often GP (with the help of a neurologist), considerably reduces the diagnostic delay. The central role of GP seems to be crucial in the management of patients with ALS. The main objective is, of course, to initiate appropriate treatment and care as soon as possible. Finally, based on our results, we also provide a short practical diagram to help nonneurologist practitioners to quickly discuss the diagnosis of ALS in case of some specific symptoms ("red flags").

Papilledema and Peripheral Neuropathies.

INTRODUCTION: Papilledema is a common sign in ophthalmology and is typically associated with increased intracranial pressure (ICP) in neurological diseases. Since the beginning of the 20th century, some cases of papilledema have been reported in association with acute or chronic inflammatory neuropathies. CASE REPORT: We describe a 42-year-old man with acute-onset inflammatory polyradiculoneuropathy and bilateral papilledema. CONCLUSIONS: Based on a personal case report and from an extensive review of the medical literature, we identify 2 distinct patterns. First, radiculoneuropathy may be a consequence of intracranial pressure (peripheral nerve involvement corresponding to a "false localizing sign"). Second, papilledema may occur after the onset of inflammatory neuropathy. For such cases, the pathophysiological mechanism remains unknown (eg, reactional inflammatory processes or actions of unknown autoantibodies) and requires further elucidation.

Myopathy and scleromyxedema.

Scleromyxedema is a chronic, idiopathic disorder associated with monoclonal gammopathy, and characterized by dermal mucin deposition. However, systemic manifestations are frequent, including neuromuscular symptoms. We herein present a 71-year-old man who developed a vacuolar myopathy in a context of a known scleromyxedema, and we compare our observation with the nineteen other cases found in the medical literature. Such an association (especially with suggestive skin abnormalities) has to be known for two reasons. First, this diagnosis might be quite challenging because the myopathy may precede the typical skin changes. Secondly, conversely to other forms of vacuolar myopathy, some of the symptoms may respond (even partially) to immunomodulatory and/or immunosuppressant therapeutics.