Anti-disialosyl-immunoglobulin M chronic autoimmune neuropathies: a nationwide multicenter retrospective study.

BACKGROUND AND PURPOSE: In this retrospective study involving 14 university hospitals from France and Switzerland, the aim was to define the clinicopathological features of chronic neuropathies with anti-disialosyl ganglioside immunoglobulin M (IgM) antibodies (CNDA). RESULTS: Fifty-five patients with a polyneuropathy evolving for more than 2 months and with at least one anti-disialosyl ganglioside IgM antibody, that is, anti-GD1b, -GT1b, -GQ1b, -GT1a, -GD2 and -GD3, were identified. Seventy-eight percent of patients were male, mean age at disease onset was 55 years (30-76) and disease onset was progressive (82%) or acute (18%). Patients presented with limb sensory symptoms (94% of cases), sensory ataxia (85%), oculomotor weakness (36%), limb motor symptoms (31%) and bulbar muscle weakness (18%). Sixty-five percent of patients had a demyelinating polyradiculoneuropathy electrodiagnostic profile and 24% a sensory neuronopathy profile. Anti-GD1b antibodies were found in 78% of cases, whilst other anti-disialosyl antibodies were each observed in less than 51% of patients. Other features included nerve biopsy demyelination (100% of cases), increased cerebrospinal fluid protein content (75%), IgM paraprotein (50%) and malignant hemopathy (8%). Eighty-six percent of CNDA patients were intravenous immunoglobulins-responsive, and rituximab was successfully used as second-line treatment in 50% of cases. Fifteen percent of patients had mild symptoms and were not treated. CNDA course was progressive (55%) or relapsing (45%), and 93% of patients still walked after a mean disease duration of 11 years. CONCLUSION: Chronic neuropathies with anti-disialosyl ganglioside IgM antibodies have a recognizable phenotype, are mostly intravenous immunoglobulins-responsive and present with a good outcome in a majority of cases.

Sensory neuronopathies: new genes, new antibodies and new concepts.

Degeneration of dorsal root ganglia (DRG) and its central and peripheral projections provokes sensory neuronopathy (SN), a rare disorder with multiple genetic and acquired causes. Clinically, patients with SN usually present with proprioceptive ataxia, patchy and asymmetric sensory abnormalities, widespread areflexia and no weakness. Classic causes of SN include cancer, Sjögren's syndrome, vitamin deficiency, chemotherapy, mitochondrial disorders and Friedreich ataxia. More recently, new genetic and dysimmune disorders associated with SN have been described, including RFC1 gene-linked cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) and anti-FGFR3 antibodies. In this review, we detail the pathophysiology of DRG degeneration, and the genetic and acquired causes of SN, with a special focus on the recently described CANVAS and anti-FGFR3 antibodies. We also propose a user-friendly and easily implemented SN diagnostic strategy.

Charcot-Marie-Tooth disease misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy: An international multicentric retrospective study.

BACKGROUND AND PURPOSE: Charcot-Marie-Tooth (CMT) disease, an untreatable hereditary polyneuropathy, may mimic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), a treatable neuropathy. METHODS: In this retrospective study, we analyzed the characteristics of CMT patients misdiagnosed as CIDP at 16 university hospitals in three countries, compared these patients with a reference group of CIDP patients, and estimated the cost of misdiagnosis. RESULTS: Among 1104 CIDP cases, we identified 35 CMT patients misdiagnosed as CIDP (3.2%). All were initially diagnosed with definite or probable CIDP (European Federation of Neurological Societies/Peripheral Nerve Society criteria), and mutations in PMP22, MPZ, and 10 other CMT genes were found in 34%, 31%, and 35% of cases, respectively. In comparison with a reference group of 35 CIDP patients, CMT patients were younger (median age at disease onset = 39 vs. 56 years) and more frequently had motor weakness at disease onset (80% vs. 29%), hearing loss (14% vs. 0%), normal brachial plexus imaging (70% vs. 40%), lower cerebrospinal fluid protein content (median = 0.5 vs. 0.8 g/L), and lower treatment response (20% vs. 69%). Treatment cost in these 35 misdiagnosed patients was estimated at 4.6 million euros (M€), whereas the cost of CMT genetic analysis in 1104 patients was estimated at 2.7 M€. CONCLUSIONS: In this study, 35 of 1104 (3.2%) patients initially diagnosed with CIDP had CMT. Importantly, the cost of treating these 35 misdiagnosed patients was significantly higher than the cost of performing CMT genetic analysis in 1104 patients (4.6 M€ vs. 2.7 M€), suggesting that CMT genetic investigations should be more widely used before diagnosing CIDP.

Central nervous system Aquaporin4 autoimmunity revealed by a single pseudotumoral encephalic lesion.

The radiological spectrum of neuromyelitis optica has become broader since the detection of aquaporin4 antibodies. We report a case of neuromyelitis optica patient with pseudotumoral encephalic lesion. A 66 year-old woman presented with sudden left lateral homonymous hemianopsia. A brain MRI showed an isolated and extensive right temporo-parieto-occipital lesion, involving periventricular white matter and the corpus callosum, with strong enhancement on post-gadolinium T1 weighted images, highly suggestive of lymphoma. Spinal cord MRI and body CT scan were unremarkable. Lumbar puncture showed pleocytosis, raised total protein level without abnormal cells or oligoclonal bands. A brain biopsy demonstrated non-specific demyelination. Serum aquaporin4 antibodies were positive, which was consistent with the diagnosis of neuromyelitis optica. Cases of central nervous system aquaporin4 autoimmunity presenting with an isolated brain lesion without optic neuritis or myelitis are extremely rare: this is the second case so far and the first one with advanced magnetic resonance characterization. Pseudotumoral encephalic lesions should include a large differential diagnosis, and testing aquaporin4 antibodies must be considered in order to avoid brain biopsy.

Association between Ischemic Stroke and Erdheim-Chester Disease: A Case Report and Review of Literature.

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis characterized by a xanthogranulomatous infiltration of tissues by spumous histiocytes. Neurological involvement is frequent, but ischemic strokes have been exceptionally described. We report the case of a 68-year-old woman who presented with an acute ischemic stroke associated with a multisystemic disorder including insipidus diabetes, infiltration of the aorta and the carotid arteries, perirenal infiltration, aortitis, and lytic bone lesions. The surgical biopsy of a lumbar vertebra revealed an infiltration of spumous macrophages consistent with ECD. Many ischemic symptoms can occur in ECD. Ischemic strokes, infrequently reported, might be caused by perivascular infiltration and adventitial fibrosis of the supra-aortic trunks or intracranial arteries.

Hereditary transthyretin amyloidosis in middle-aged and elderly patients with idiopathic polyneuropathy: a nationwide prospective study.

BACKGROUND: Hereditary transthyretin amyloidosis (ATTRv) is an adult-onset autosomal dominant disease resulting from TTR gene pathogenic variants. ATTRv often presents as a progressive polyneuropathy, and effective ATTRv treatments are available. METHODS: In this 5 year-long (2017-2021) nationwide prospective study, we systematically analysed the TTR gene in French patients with age >50 years with a progressive idiopathic polyneuropathy. RESULTS: 553 patients (70% males) with a mean age of 70 years were included. A TTR gene pathogenic variant was found in 15 patients (2.7%), including the Val30Met TTR variation in 10 cases. In comparison with patients with no TTR gene pathogenic variants (n = 538), patients with TTR pathogenic variants more often presented with orthostatic hypotension (53 vs. 21%, p = .007), significant weight loss (33 vs 11%, p = .024) and rapidly deteriorating nerve conduction studies (26 vs. 8%, p = .03). ATTRv diagnosis led to amyloid cardiomyopathy diagnosis in 11 cases, ATTRv specific treatment in all cases and identification of 15 additional ATTRv cases among relatives. CONCLUSION: In this nationwide prospective study, we found ATTRv in 2.7% of patients with age >50 years with a progressive polyneuropathy. These results are highly important for the early identification of patients in need of disease-modifying treatments.

Clinical, paraclinical and outcome features of 166 patients with acute anti-GQ1b antibody syndrome.

BACKGROUND & PURPOSE: In this retrospective study, we aimed at defining the clinical, paraclinical and outcome features of acute neurological syndromes associated with anti-GQ1b antibodies. RESULTS: We identified 166 patients with neurological symptoms appearing in less than 1 month and anti-GQ1b antibodies in serum between 2012 and 2022. Half were female (51%), mean age was 50 years (4-90), and the most frequent clinical features were areflexia (80% of patients), distal upper and lower limbs sensory symptoms (78%), ophthalmoplegia (68%), sensory ataxia (67%), limb muscle weakness (45%) and bulbar weakness (45%). Fifty-three patients (32%) presented with complete (21%) and incomplete (11%) Miller Fisher syndrome (MFS), thirty-six (22%) with Guillain-Barre syndrome (GBS), one (0.6%) with Bickerstaff encephalitis (BE), and seventy-three (44%) with mixed MFS, GBS & BE clinical features. Nerve conduction studies were normal in 46% of cases, showed demyelination in 28%, and axonal loss in 23%. Anti-GT1a antibodies were found in 56% of cases, increased cerebrospinal fluid protein content in 24%, and Campylobacter jejuni infection in 7%. Most patients (83%) were treated with intravenous immunoglobulins, and neurological recovery was complete in 69% of cases at 1 year follow-up. One patient died, and 15% of patients relapsed. Age > 70 years, initial Intensive Care Unit (ICU) admission, and absent anti-GQ1b IgG antibodies were predictors of incomplete recovery at 12 months. No predictors of relapse were identified. CONCLUSION: This study from Western Europe shows acute anti-GQ1b antibody syndrome presents with a large clinical phenotype, a good outcome in 2/3 of cases, and frequent relapses.

Clinical features and maternal and fetal outcomes in women with Guillain-Barré syndrome in pregnancy.

BACKGROUND: Guillain-Barre syndrome (GBS) is an acute inflammatory polyradiculoneuropathy rarely observed during pregnancy. METHODS: In this retrospective study, we analyzed the characteristics of pregnant women with GBS (pGBS) diagnosed in French University Hospitals in the 2002-2022 period and compared them with a reference group of same-age non-pregnant women with GBS (npGBS) identified in the same institutions & timeframe. RESULTS: We identified 16 pGBS cases. Median age was 31 years (28-36), and GBS developed in the 1st, 2nd, and 3rd trimester in 31%, 31% and 38% of cases respectively. A previous infection was identified in six cases (37%), GBS was demyelinating in nine cases (56%), and four patients (25%) needed respiratory assistance. Fifteen patients (94%) were treated with intravenous immunoglobulins, and neurological recovery was complete in all cases (100%). Unscheduled caesarean section was needed in five cases (31%), and two fetuses (12.5%) died because of cytomegalovirus (CMV) infection (1 case) and HELLP (Hemolysis, Elevated Liver enzymes and Low Platelets) syndrome (1 case). In comparison with a reference group of 18 npGBS women with a median age of 30 years (27-33), pGBS patients more frequently had CMV infection (31% vs 11%), had a prolonged delay between GBS onset and hospital admission (delay > 7 days: 57% vs 12%), more often needed ICU admission (56% vs 33%) and respiratory assistance (25% vs 11%), and more often presented with treatment-related fluctuations (37% vs 0%). CONCLUSIONS: This study shows GBS during pregnancy is a severe maternal condition with significant fetal mortality.

Nitrous oxide-induced predominantly motor neuropathies: a follow-up study.

OBJECTIVES: Recreational nitrous oxide (N2O) abuse is increasingly popular among youth. We report a systematic clinical, electrophysiological and biological follow-up of patients with neuropathy caused by N2O. METHODS: We retrospectively report seven patients with neuropathy attributed to N2O abuse and their comprehensive follow-up. Demographic, toxicological, clinical, biological and electrophysiological data were collected at first and second examination. Functional data were collected at the last evaluation. RESULTS: Seven patients aged 18-30, consuming more than 140 gas-filled balloons (one balloon is filled with approximately 8 g of N2O) per week for over a month, developed a severe, predominantly motor, length-dependent, progressive neuropathy over 3 to 6 weeks. Two-thirds presented associated signs of myelopathy. Distal lower limbs motor deficit and ataxia led to moderate disability. Spinal cord imaging was frequently normal. Nerve conduction studies disclosed an almost exclusively motor axonal neuropathy affecting the lower limbs with active denervation. Homocysteine plasma level was systematically elevated, whereas cobalamin plasma levels were normal in almost all patients. At short-term follow-up after intoxication discontinuation, ataxia and motor deficit only partially resolved despite vitamin B12 supplementation, while active denervation and homocysteinemia decreased. At last follow-up (median 9.2 months, IQR 7.5-10.75), mean ONLS was 2.0 (IQR 2.0-2.0). DISCUSSION: Young patients, with induced N2O motor neuropathy remain disabled after 5 to 14.5 months of gas withdrawal, despite vitamin B12 supplementation. A longer follow-up is needed to fully appraise the severity of these toxic neuropathies.

A juvenile ALS-like phenotype dramatically improved after high-dose riboflavin treatment.

Riboflavin transporter deficiency (RTD) was recently characterized as a cause of genetic recessive childhood-onset motor neuron disease (MND) with hearing loss, formerly described as Brown-Vialetto-Van-Lear syndrome. We describe a 18-year-old woman with probable RTD mimicking juvenile Amyotrophic Lateral Sclerosis (ALS) who presented with an inaugural respiratory failure and moderate distal four limbs weakness. Only one heterozygous SLC52A3 mutation was detected, but presence of a sub-clinical auditory neuropathy and dramatic improvement under high dose riboflavin argued for a RTD. As RTD probably has a larger phenotypic spectrum than expected, a high dose riboflavin trial should be discussed in young-onset MND.