Antibiomania: clarithromycin-induced neurotoxicity mimicking autoimmune limbic encephalitis.

We describe a 64-year-old woman with relapsing encephalopathy. She initially presented with 5 days of psychomotor agitation, progressing to mania, psychosis and seizures that mimicked autoimmune limbic encephalitis. During her first hospital admission, extensive investigation failed to establish the underlying cause, and she improved with antiseizure medication alone. After a month at home, she relapsed with identical symptoms, and only then did we recognise that both episodes had been provoked by clarithromycin, prescribed for Helicobacter pylori eradication. Clarithromycin-induced neurotoxicity is rarely reported but likely to be under-recognised. It usually manifests within days of starting treatment, with delirium, mania, psychosis or visual hallucinations, sometimes termed 'antibiomania'. Seizures and status epilepticus appear to be less frequent. A full recovery is expected on stopping the medication.

Myeloperoxidase-positive ANCA-associated vasculitis presenting as myalgia, proximal weakness and a normal CK.

We describe an unusual presentation of myeloperoxidase positive antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis managed by a multidisciplinary approach. A 75-year-old man gave a 3-week history of proximal lower limb weakness and exertional myalgia. His serum creatine kinase was normal and many of his non-specific symptoms suggested small vessel vasculitis. His investigations for common causes of muscle weakness were normal, and renal biopsy was normal despite haemoproteinuria. CT scan of the chest identified a pulmonary nodule of uncertain significance, not amenable to biopsy. MR scan of the thighs showed muscle oedema, and muscle biopsy confirmed typical features of vasculitis. Following high-dose corticosteroids his exertional myalgia quickly resolved and his normal mobility returned. Early immunosuppression is essential to improving clinical outcomes in ANCA-associated vasculitis, but diagnostic investigations often lack sensitivity.

Progressive myelin oligodendrocyte glycoprotein-associated demyelination mimicking leukodystrophy.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may be associated with relapsing disease, but clinical progression independent of relapse activity is rare. OBJECTIVES: To report progressive disease in a patient with MOGAD. METHODS: A single retrospective case report. RESULTS: At 4 years of age, the patient had a single episode of acute disseminated encephalomyelitis. She remained well until age 17 years but over the next 9 years developed progressive spastic quadriparesis, cognitive and bulbar dysfunction. Brain imaging showed a leukodystrophy-like pattern of white matter abnormality with contrast enhancement at different time points. Myelin oligodendrocyte glycoprotein (MOG)-IgG was repeatedly positive by live cell-based assay. CONCLUSION: Secondary progression may be a rare presentation of MOG-IgG-associated disease.

Rituximab abrogates aquaporin-4-specific germinal center activity in patients with neuromyelitis optica spectrum disorders.

Neuromyelitis optica spectrum disorders (NMOSDs) are caused by immunoglobulin G (IgG) autoantibodies directed against the water channel aquaporin-4 (AQP4). In NMOSDs, discrete clinical relapses lead to disability and are robustly prevented by the anti-CD20 therapeutic rituximab; however, its mechanism of action in autoantibody-mediated disorders remains poorly understood. We hypothesized that AQP4-IgG production in germinal centers (GCs) was a core feature of NMOSDs and could be terminated by rituximab. To investigate this directly, deep cervical lymph node (dCLN) aspirates (n = 36) and blood (n = 406) were studied in a total of 63 NMOSD patients. Clinical relapses were associated with AQP4-IgM generation or shifts in AQP4-IgG subclasses (odds ratio = 6.0; range of 3.3 to 10.8; P < 0.0001), features consistent with GC activity. From seven dCLN aspirates of patients not administered rituximab, AQP4-IgGs were detected alongside specific intranodal synthesis of AQP4-IgG. AQP4-reactive B cells were isolated from unmutated naive and mutated memory populations in both blood and dCLNs. After rituximab administration, fewer clinical relapses (annual relapse rate of 0.79 to 0; P < 0.001) were accompanied by marked reductions in both AQP4-IgG (fourfold; P = 0.004) and intranodal B cells (430-fold; P < 0.0001) from 11 dCLNs. Our findings implicate ongoing GC activity as a rituximab-sensitive driver of AQP4 antibody production. They may explain rituximab's clinical efficacy in several autoantibody-mediated diseases and highlight the potential value of direct GC measurements across autoimmune conditions.

Interleukin-6 Receptor Blockade in Treatment-Refractory MOG-IgG-Associated Disease and Neuromyelitis Optica Spectrum Disorders.

BACKGROUND AND OBJECTIVES: To evaluate the long-term safety and efficacy of tocilizumab (TCZ), a humanized anti-interleukin-6 receptor antibody in myelin oligodendrocyte glycoprotein-IgG-associated disease (MOGAD) and neuromyelitis optica spectrum disorders (NMOSD). METHODS: Annualized relapse rate (ARR), Expanded Disability Status Scale score, MRI, autoantibody titers, pain, and adverse events were retrospectively evaluated in 57 patients with MOGAD (n = 14), aquaporin-4 (AQP4)-IgG seropositive (n = 36), and seronegative NMOSD (n = 7; 12%), switched to TCZ from previous immunotherapies, particularly rituximab. RESULTS: Patients received TCZ for 23.8 months (median; interquartile range 13.0-51.1 months), with an IV dose of 8.0 mg/kg (median; range 6-12 mg/kg) every 31.6 days (mean; range 26-44 days). For MOGAD, the median ARR decreased from 1.75 (range 0.5-5) to 0 (range 0-0.9; p = 0.0011) under TCZ. A similar effect was seen for AQP4-IgG+ (ARR reduction from 1.5 [range 0-5] to 0 [range 0-4.2]; p < 0.001) and for seronegative NMOSD (from 3.0 [range 1.0-3.0] to 0.2 [range 0-2.0]; p = 0.031). During TCZ, 60% of all patients were relapse free (79% for MOGAD, 56% for AQP4-IgG+, and 43% for seronegative NMOSD). Disability follow-up indicated stabilization. MRI inflammatory activity decreased in MOGAD (p = 0.04; for the brain) and in AQP4-IgG+ NMOSD (p < 0.001; for the spinal cord). Chronic pain was unchanged. Regarding only patients treated with TCZ for at least 12 months (n = 44), ARR reductions were confirmed, including the subgroups of MOGAD (n = 11) and AQP4-IgG+ patients (n = 28). Similarly, in the group of patients treated with TCZ for at least 12 months, 59% of them were relapse free, with 73% for MOGAD, 57% for AQP4-IgG+, and 40% for patients with seronegative NMOSD. No severe or unexpected safety signals were observed. Add-on therapy showed no advantage compared with TCZ monotherapy. DISCUSSION: This study provides Class III evidence that long-term TCZ therapy is safe and reduces relapse probability in MOGAD and AQP4-IgG+ NMOSD.

Images of the month 1: Trident sign and neurosarcoidosis.

A 36-year-old woman presented with a subacute, relapsing myelitis, manifesting as bilateral ascending lower limb paraesthesia, partially responsive to steroids. Imaging demonstrated a longitudinal spinal cord lesion, with a unique and characteristic sign (the 'trident sign') on axial views, which is specific to a diagnosis of neurosarcoidosis. This case highlights the importance of using this feature to distinguish a longitudinal cord lesion of sarcoidosis from other differentials.

Predictors of relapse in MOG antibody associated disease: a cohort study.

OBJECTIVE: To identify factors predictive of relapse risk and disability in myelin oligodendrocyte glycoprotein associated disease (MOGAD). SETTING: Patients were seen by the neuromyelitis optica spectrum disorders (NMOSD) service in Liverpool, UK, a national referral centre for adult patients with MOGAD, NMOSD and related conditions. PARTICIPANTS: Patients with MOGAD=76 from England, Northern Ireland and Scotland were included in this cohort study. RESULTS: Relapsing disease was observed in 55% (42/76) of cases. Steroid treatment >1 month (OR 0.2, 95% CI 0.05 to 0.80; p=0.022), transverse myelitis (TM) at first attack (OR 0.03, 95% CI 0.004 to 0.23; p=0.001) and male sex (OR 0.16, 95% CI 0.04 to 0.68; p=0.014) were associated with monophasic disease (area under the curve=0.85). Male sex (HR 0.46, 95% CI 0.24 to 0.89; p=0.011) and TM at disease onset (HR 0.42, 95% CI 0.22 to 0.82; p=0.011) were also associated with an increased latency to first relapse. 45% (32/71) of patients became MOG-antibody negative and in relapsing patients negative seroconversion was associated with a lower relapse risk (relative risk 0.11 95% CI 0.05 to 0.26; p<0.001). No specific factors were predictive of visual or overall disability. CONCLUSIONS: Male patients with spinal cord involvement at disease onset have a lower risk of relapsing disease and longer latency to first relapse. Steroid treatment for at least 1 month at first attack was also associated with a monophasic disease course. MOG-antibody negative seroconversion was associated with a lower risk of relapse and may help inform treatment decisions and duration.

Asian and African/Caribbean AQP4-NMOSD patient outcomes according to self-identified race and place of residence.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy characterized by aquaporin-4 antibodies, whose prognosis is influenced by onset age, race, environmental exposures and immunosuppression. Distinguishing the contribution of environment from genetics is challenging. We aimed to compare neuromyelitis optica spectrum disorder (NMOSD) patient outcomes according to self-identified racial group and place of residence. METHODS: This retrospective analysis of prospectively collected data included non-white anti-aquaporin-4 antibody positive NMOSD patients under follow-up from 15 centers [United Kingdom, France, Germany, Denmark, Martinique, United States of America, Japan, South Korea, Singapore, Thailand, China (including Hong Kong) and India]. Racial groups were designated: African/Caribbean; South Asian; East Asian (including Southeast Asia). Patients from these racial groups residing outside Africa/Caribbean or Asia were compared with those living in the Caribbean or the Asian areas. Kaplan-Meier survival curves and Cox models were generated using time to sustained Expanded Disability Status Scale≥6.0 or death; time to sustained Kurtzke Visual Function Score≥3.0 or a composite endpoint of all three. RESULTS: Among 821 patients, African/Caribbean patients (n = 206) had the shortest time to immunosuppression and higher visual disability at onset. South Asian patients (n = 65) were younger, had lower visual disability at onset and higher mortality rate. East Asians (n = 550) had the lowest relapse rate and lowest accrued motor disability. Survival analysis of African/Caribbean outside Africa/Caribbean vs those in the Caribbean showed a significant difference in the composite endpoint (p = 0.024,log-rank test), not apparently related to treatment differences. No significant differences between native and those residing outside Asia were found for other racial groups. CONCLUSION: This NMOSD study reports the effects of place of residence on the outcomes in different races. Place of residence may not be a significant driver of disability among Asian patients, while it may influence African/Caribbean patient outcomes. Validating these findings could help distinguish between genetic causes and potentially modifiable environmental factors.

A case series of intracranial dural arteriovenous fistulae mimicking cervical myelitis: a diagnosis not to be missed.

OBJECTIVE: To describe the diagnostic features of intracranial dural arteriovenous fistulae (DAVF) presenting with cervical cord or brainstem swelling. METHODS: Retrospective case note and neuroimaging review of patients with angiographically confirmed DAVF diagnosed during January 2015-June 2020 at a tertiary neuroscience centre (Walton Centre NHS Foundation Trust, Liverpool, UK). RESULTS: Six intracranial DAVF causing cervical cord or brainstem oedema (all males aged 60-69 years) and 27 spinal DAVF (88% thoracolumbar) were detected over a 5.5-year period. Significantly more patients with intracranial DAVF received steroids for presumed inflammatory myelitis than those with spinal DAVF (5/6 vs 1/27, p = 0.0001, Fisher's exact test). Several factors misled the treating clinicians: atypical rostral location of cord oedema (6/6); acute clinical deterioration (4/6); absence (3/6) or failure to recognise (3/6) subtle dilated perimedullary veins on MRI; intramedullary gadolinium enhancement (2/6); and elevated CSF protein (4/5). Acute deterioration followed steroid treatment in 4/5 patients. The following features may suggest DAVF rather than myelitis: older male patients (6/6), symptomatic progression over 4 or more weeks (6/6) and acellular CSF (5/5). CONCLUSION: Intracranial DAVF are uncommon but often misdiagnosed and treated as myelitis, which can cause life-threatening deterioration. Neurologists must recognise suggestive features and consider angiography, especially in older male patients. Dilated perimedullary veins are an important clue to underlying DAVF, but may be invisible or easily missed on routine MRI sequences.

Role of complement and potential of complement inhibitors in myasthenia gravis and neuromyelitis optica spectrum disorders: a brief review.

The complement system is a powerful member of the innate immune system. It is highly adept at protecting against pathogens, but exists in a delicate balance between its protective functions and overactivity, which can result in autoimmune disease. A cascade of complement proteins that requires sequential activation, and numerous complement regulators, exists to regulate a proportionate response to pathogens. In spite of these mechanisms there is significant evidence for involvement of the complement system in driving the pathogenesis of variety of diseases including neuromyelitis optica spectrum disorders (NMOSD) and myasthenia gravis (MG). As an amplification cascade, there are an abundance of molecular targets that could be utilized for therapeutic intervention. Clinical trials assessing complement pathway inhibition in both these conditions have recently been completed and include the first randomized placebo-controlled trial in NMOSD showing positive results. This review aims to review and update the reader on the complement system and the evolution of complement-based therapeutics in these two disorders.

Treatment of MOG-IgG-associated disorder with rituximab: An international study of 121 patients.

OBJECTIVE: To assess the effect of anti-CD20 B-cell depletion with rituximab (RTX) on relapse rates in myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD). METHODS: Retrospective review of RTX-treated MOGAD patients from 29 centres in 13 countries. The primary outcome measure was change in relapse rate after starting rituximab (Poisson regression model). RESULTS: Data on 121 patients were analysed, including 30 (24.8%) children. Twenty/121 (16.5%) were treated after one attack, of whom 14/20 (70.0%) remained relapse-free after median (IQR) 11.2 (6.3-14.1) months. The remainder (101/121, 83.5%) were treated after two or more attacks, of whom 53/101 (52.5%) remained relapse-free after median 12.1 (6.3-24.9) months. In this 'relapsing group', relapse rate declined by 37% (95%CI=19-52%, p<0.001) overall, 63% (95%CI=35-79%, p = 0.001) when RTX was used first line (n = 47), and 26% (95%CI=2-44%, p = 0.038) when used after other steroid-sparing immunotherapies (n = 54). Predicted 1-year and 2-year relapse-free survival was 79% and 55% for first-line RTX therapy, and 38% and 18% for second-/third-line therapy. Circulating CD19+B-cells were suppressed to <1% of total circulating lymphocyte population at the time of 45/57 (78.9%) relapses. CONCLUSION: RTX reduced relapse rates in MOGAD. However, many patients continued to relapse despite apparent B-cell depletion. Prospective controlled studies are needed to validate these results.

Outcome prediction models in AQP4-IgG positive neuromyelitis optica spectrum disorders.

Pathogenic antibodies targeting the aquaporin-4 water channel on astrocytes are associated with relapsing inflammatory neuromyelitis optica spectrum disorders. The clinical phenotype is characterized by recurrent episodes of optic neuritis, longitudinally extensive transverse myelitis, area postrema attacks and less common brainstem and cerebral events. Patients often develop major residual disability from these attacks, so early diagnosis and initiation of attackpreventing medications is important. Accurate prediction of relapse would assist physicians in counselling patients, planning treatment and designing clinical trials. We used a large multicentre dataset of 441 patients from the UK, USA, Japan and Martinique who collectively experienced 1976 attacks, and applied sophisticated mathematical modelling to predict likelihood of relapse and disability at different time points. We found that Japanese patients had a lower risk of subsequent attacks except for brainstem and cerebral events, with an overall relative relapse risk of 0.681 (P = 0.001) compared to Caucasians and African patients, who had a higher likelihood of cerebral attacks, with a relative relapse risk of 3.309 (P = 0.009) compared to Caucasians. Female patients had a higher chance of relapse than male patients (P = 0.009), and patients with younger age of onset were more likely to have optic neuritis relapses (P < 0.001). Immunosuppressant drugs reduced and multiple sclerosis disease-modifying agents increased the likelihood of relapse (P < 0.001). Patients with optic neuritis at onset were more likely to develop blindness (P < 0.001), and those with older age of onset were more likely to develop ambulatory disability. Only 25% of long-term disability was related to initial onset attack, indicating the importance of early attack prevention. With respect to selection of patients for clinical trial design, there would be no gain in power by selecting recent onset patients and only a small gain by selecting patients with recent high disease activity. We provide risk estimates of relapse and disability for patients diagnosed and treated with immunosuppressive treatments over the subsequent 2, 3, 5 and 10 years according to type of attack at onset or the first 2-year course, ethnicity, sex and onset age. This study supports significant effects of onset age, onset phenotype and ethnicity on neuromyelitis optica spectrum disorders outcomes. Our results suggest that powering clinical treatment trials based upon relapse activity in the preceding 2 years may offer little benefit in the way of attack risk yet severely hamper clinical trial success.

Rituximab in neurological disease: principles, evidence and practice.

Rituximab is a widely used B-cell-depleting monoclonal antibody. It is unlicensed for use in neurological disorders and there are no treatment guidelines. However, as a rapidly acting, targeted therapy with growing evidence of efficacy and tolerability in several neuroinflammatory disorders, it is an attractive alternative to conventional immunomodulatory medications. This practical review aims to explain the basic principles of B-cell depletion with therapeutic monoclonal antibodies. We present the evidence for using rituximab in neurological diseases, and describe the practical aspects of prescribing, including dosing, monitoring, safety, treatment failure and its use in special circumstances such as coexisting viral hepatitis, pregnancy and lactation. We provide an administration guide, checklist and patient information leaflet, which can be adapted for local use. Finally, we review the safety data of rituximab and ocrelizumab (a newer and recently licensed B-cell-depleting therapy for multiple sclerosis) and suggest monitoring and risk reduction strategies.

Intracranial dural arteriovenous fistula mistaken as cervical transverse myelitis.

We describe a man with an intracranial dural arteriovenous fistula that presented as a subacute longitudinally extensive cervical myelopathy. The uncommon location of the fistula and the absence of specific radiological signs resulted in initial misdiagnosis as longitudinally extensive transverse myelitis. Neurologists should have a high index of suspicion for dural arteriovenous fistula in older men, especially those with subacute or chronic symptoms, acellular cerebrospinal fluid and, particularly, if there is neurological deterioration soon after corticosteroid treatment. Patients need early angiography to identify this treatable cause of myelopathy.

Area postrema syndrome: Frequency, criteria, and severity in AQP4-IgG-positive NMOSD.

OBJECTIVE: To define the frequency, duration, and severity of intractable nausea, vomiting, or hiccups in aquaporin-4-immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD) and propose diagnostic criteria and a severity scale for area postrema syndrome (APS). METHODS: An International NMOSD database was interrogated for frequency of APS. Patients with AQP4-IgG-positive NMOSD completed an APS symptom questionnaire. Nausea and vomiting severity was derived from the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) score. The diagnostic criteria, severity scale, and immunotherapy response was applied to a prospective validation cohort of patients from multiple centers. RESULTS: Analysis of an international database for AQP4-IgG-seropositive NMOSD (n = 430) revealed a high prevalence of isolated APS attacks (onset 7.1%-10.3%; subsequent 9.4%-14.5%) across continents. For 100 patients with 157 episodes of APS, nausea (n = 127, 81%) lasted for a median of 14 days (range 2-365), vomiting (113, 72%) with a median of 5 episodes/d (2-40) lasted 1-20 minutes, and hiccups (102, 65%) lasted a median of 14 days (2-365). Symptoms consistently and completely resolved following immunotherapy. Data were used to propose APS diagnostic criteria and repurpose PUQE score (hiccups severity grade based on symptom duration). The clinical utility was demonstrated in a prospective validation cohort. CONCLUSION: Isolated APS attacks are frequently encountered both at onset and during the NMOSD course. The diagnostic criteria proposed here will assist clinicians in recognizing APS. Diagnosis of an APS attack earlier than 48 hours is possible if a dorsal medulla lesion is detected. Accurate diagnosis and evaluation of APS attack severity will assist in outcome measurement in NMOSD clinical trials.

What proportion of AQP4-IgG-negative NMO spectrum disorder patients are MOG-IgG positive? A cross sectional study of 132 patients.

Antibodies to myelin oligodendrocyte glycoprotein (MOG-IgG) have been described in patients with neuromyelitis optica spectrum disorders (NMOSD) without aquaporin-4 antibodies (AQP4-IgG). We aimed to identify the proportion of AQP4-IgG-negative NMOSD patients who are seropositive for MOG-IgG. In a cross sectional study, we reviewed all patients seen in the National NMO clinic over the last 4 years (after the availability of MOG-IgG testing), including clinical information, MRI, and antibody tests. 261 unique patients were identified. 132 cases satisfied the 2015 NMOSD diagnostic criteria. Of these, 96 (73%) were AQP4-IgG positive and 36 (27%) were AQP4-IgG negative. These 36 patients were tested for MOG-IgG and 15/36 (42%) tested positive. 20% (25/125) of the patients who did not satisfy NMOSD criteria had MOG-IgG. Approximately half of seronegative NMOSD is MOG-Ig seropositive and one in five of non-NMOSD/non-MS demyelination is MOG-IgG positive. Since MOG-associated demyelinating disease is likely different from AQP4-IgG disease in terms of underlying disease mechanisms, relapse risk and possibly treatment, testing for MOG-IgG in patients with AQP4-IgG-negative NMOSD and other non-MS demyelination may have significant implications to management and clinical trials.