Anti-aquaporin-4 antibody-positive neuromyelitis optica presenting with syndrome of inappropriate antidiuretic hormone secretion as an initial manifestation

Case report: Hyponatremia is an initial presentation of Neuromyelitis optica spectrum disorder

OBJECTIVE

Neuromyelitis optica spectrum disorders (NMOSD) is often misdiagnosed or delayed because of the complex and diverse clinical manifestations, especially the atypical initial presentation. Hyponatremia can be an infrequently isolated initial presentation of NMOSD and is associated with hypothalamus involvement. Awareness of this mechanism will help clinicians to identify NMOSD early, treat it in time and improve the prognosis.

METHODS

We describe a 36-year-old woman who developed repeated hyponatremia and then experienced diplopia. Serum AQP4, MOG, MBP and GFAP antibody were detected, and NMOSD was finally diagnosed.

RESULTS

She responded well to high-dose glucocorticoids. Sequential treatment with mycophenolate mofetil (MMF) was prescribed. Two-month follow-up revealed full recovery. So far, after 10 months, the patient still has no recurrence.

CONCLUSION

For young patients, repeated hyponatremia, with or without slight fever, and no evidence of obvious infection, brain magnetic resonance imaging (MRI) and serum AQP4/MOG antibody detection may be useful to determine whether there is a possibility of NMOSD.

Pearls & Oy-sters: Syndrome of Inappropriate Antidiuretic Hormone Secretion Presenting as Neuromyelitis Optica Spectrum Disorder Flare

While it was previously believed that neuromyelitis optic spectrum disorder (NMOSD) mostly affected the optic nerves and the spinal cord, it is increasingly recognized that NMOSD can involve any area of the CNS where aquaporin-4 is highly expressed. These other areas can include the hypothalamus and the circumventricular organs that surround the third and fourth ventricles, serving as osmoregulators. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia and has been associated with NMOSD due to these lesions. In this report, we present a case of a patient with known NMOSD, who presented with dizziness, fatigue, and generalized weakness and whose workup revealed hyponatremia in the setting of SIADH and hypothalamic demyelinating lesions. This case illustrates an atypical presentation of NMOSD and the importance of looking for syndromes, such as SIADH. This can guide diagnostic testing, such as getting thin MRI cuts through the hypothalamus and brainstem, as well as advanced management techniques such as immunotherapy.

Neuromyelitis Optica Spectrum Disorder With Hyponatremia as an Initial Presentation: A Case Report

The diagnosis of neuromyelitis optica spectrum disorder (NMOSD) is easily missed or delayed because of its multiple clinical features, especially at initial presentation. Hyponatremia is an infrequent complication of NMOSD and can present as an initial sign. Hyponatremia in a patient with NMOSD might be caused by autoimmune-related antibodies that attack the hypothalamus, causing inappropriate antidiuretic hormone secretion. Awareness of this pathophysiologic mechanism will help clinicians in the early diagnosis of NMOSD. We report a case of NMOSD with hyponatremia as the initial presentation.

MRI Patterns Distinguish AQP4 Antibody Positive Neuromyelitis Optica Spectrum Disorder From Multiple Sclerosis

Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) are inflammatory diseases of the CNS. Overlap in the clinical and MRI features of NMOSD and MS means that distinguishing these conditions can be difficult. With the aim of evaluating the diagnostic utility of MRI features in distinguishing NMOSD from MS, we have conducted a cross-sectional analysis of imaging data and developed predictive models to distinguish the two conditions. NMOSD and MS MRI lesions were identified and defined through a literature search. Aquaporin-4 (AQP4) antibody positive NMOSD cases and age- and sex-matched MS cases were collected. MRI of orbits, brain and spine were reported by at least two blinded reviewers. MRI brain or spine was available for 166/168 (99%) of cases. Longitudinally extensive (OR = 203), "bright spotty" (OR = 93.8), whole (axial; OR = 57.8) or gadolinium (Gd) enhancing (OR = 28.6) spinal cord lesions, bilateral (OR = 31.3) or Gd-enhancing (OR = 15.4) optic nerve lesions, and nucleus tractus solitarius (OR = 19.2), periaqueductal (OR = 16.8) or hypothalamic (OR = 7.2) brain lesions were associated with NMOSD. Ovoid (OR = 0.029), Dawson's fingers (OR = 0.031), pyramidal corpus callosum (OR = 0.058), periventricular (OR = 0.136), temporal lobe (OR = 0.137) and T1 black holes (OR = 0.154) brain lesions were associated with MS. A score-based algorithm and a decision tree determined by machine learning accurately predicted more than 85% of both diagnoses using first available imaging alone. We have confirmed NMOSD and MS specific MRI features and combined these in predictive models that can accurately identify more than 85% of cases as either AQP4 seropositive NMOSD or MS.

Frequency of diencephalic syndrome in NMOSD

BACKGROUND

Diencephalic region of the brain harbors sites with a considerable amount of aquaporin-4 expression. Neuromyelitis optica spectrum disorder (NMOSD) primarily involves autoimmune processes against this molecule. However, little is known about the frequency of symptoms of diencephalic involvement in NMOSD patients.

OBJECTIVE

To investigate the frequency of symptoms of diencephalic involvement in NMOSD patients and describe the associated characteristics in patients presenting such symptoms.

MATERIALS AND METHODS

This retrospective cohort included 145 NMOSD patients (39 males and 106 females) who visited Isfahan Multiple Sclerosis Center from January 2013 to February 2020 for approximately 61 months. Demographic and clinical information of patients and findings from radiological and serological investigations were retrieved.

RESULTS

The frequency of diencephalic involvement in NMOSD patients was 3.4% (five cases). Diencephalic syndrome-associated symptoms observed in this cohort consisted of narcolepsy (n = 2; 40%), hypotension (n = 1; 20%), amenorrhea (n = 1; 20%), and syndrome of inappropriate antidiuretic hormone secretion (n = 1; 20%). These manifestations responded well to NMOSD-associated treatments, i.e., rituximab and azathioprine.

CONCLUSION

Although rarely manifested through symptoms suggestive of diencephalic involvement, NMOSD should be considered when encountering patients with the diencephalic syndrome to identify the primary cause of these manifestations.

Neuromyelitis optica, aquaporin-4 antibodies, and neuroendocrine disorders

Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system that preferentially affects the optic nerve and the spinal cord. In around 80% of NMO patients, autoantibodies binding to aquaporin-4 (AQP4) are detected. AQP4-IgG unifies a spectrum of disorders (NMOSD) that include not only optic neuritis, longitudinally extensive transverse myelitis but also syndromes caused by lesion of the diencephalic region and the circumventricular organs (CVOs). The distinctive immunopathological characteristics of NMOSD lesions, occurring in regions where AQP4 is highly expressed, supports a central role for AQP4-IgG in disease pathogenesis. AQP4 expression is concentrated in CVOs and in the hypothalamus, mainly in the dorsal hypothalamic area, dorsomedial hypothalamic nucleus and suprachiasmatic nucleus. Several neuroendocrine disorders caused by inflammatory lesions involving the diencephalic region have been described in patients with NMOSD, including syndrome of inappropriate antidiuresis, sleep disorders, and other endocrinopathies caused by hypothalamic injury. Focus of this chapter is the involvement of hypothalamus and CVOs in AQP4 autoimmunity.

Optic Neuritis Presented as Syndrome of Inappropriate Antidiuretic Hormone Secretion in an 8 Year Old

Optic neuritis is a rare demyelinating disorder, which involves the optic nerve. It can be a monophasic self-limiting illness due to postinfectious or postvaccination etiology. It can also be an initial presentation of a relapsing demyelinating disorder such as multiple sclerosis or neuromyelitis optica spectrum of disorders. It is characterized to aquaporin-4 antibody-rich areas in the brain, optic nerve, and spinal cord. The hypothalamus and periventricular area are also rich in specific antibodies and may lead to dysfunction in the hypothalamic-pituitary axis. Antidiuretic hormone (ADH) is synthesized in the hypothalamus and stored in the posterior pituitary and may secrete inappropriately due to this disturbance. This will impair water excretion from the kidney, leading to hyponatremia. When hyponatremia is significant, the patient will present with confusion, agitation, and convulsions. This case report discusses acute symptomatic hyponatremia as the initial presentation of optic neuritis due to syndrome of inappropriate ADH secretion (SIADH).

Relapse Patterns in NMOSD: Evidence for Earlier Occurrence of Optic Neuritis and Possible Seasonal Variation

Neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) show overlap in their clinical features. We performed an analysis of relapses with the aim of determining differences between the two conditions. Cases of NMOSD and age- and sex-matched MS controls were collected from across Australia and New Zealand. Demographic and clinical information, including relapse histories, were recorded using a standard questionnaire. There were 75 cases of NMOSD and 101 MS controls. There were 328 relapses in the NMOSD cases and 375 in MS controls. Spinal cord and optic neuritis attacks were the most common relapses in both NMOSD and MS. Optic neuritis (p < 0.001) and area postrema relapses (P = 0.002) were more common in NMOSD and other brainstem attacks were more common in MS (p < 0.001). Prior to age 30 years, attacks of optic neuritis were more common in NMOSD than transverse myelitis. After 30 this pattern was reversed. Relapses in NMOSD were more likely to be treated with acute immunotherapies and were less likely to recover completely. Analysis by month of relapse in NMOSD showed a trend toward reduced risk of relapse in February to April compared to a peak in November to January (P = 0.065). Optic neuritis and transverse myelitis are the most common types of relapse in NMOSD and MS. Optic neuritis tends to occur more frequently in NMOSD prior to the age of 30, with transverse myelitis being more common thereafter. Relapses in NMOSD were more severe. A seasonal bias for relapses in spring-summer may exist in NMOSD.

[A case of suspected neuromyelitis optica spectrum disorder preceded by aseptic meningitis-like symptoms]

A 20-year-old woman was hospitalized after experiencing headaches, high fever, and nausea for 1 week. She was conscious and had no abnormal neurological findings or neck stiffness. Examination of her cerebrospinal fluid showed a pronounced elevation of mononuclear cells. She was admitted to our hospital with the diagnosis of meningitis and had hypersomnia 3 days later. Brain MRI (FLAIR) demonstrated high-intensity lesions at the dorsal pons, and bilateral hypothalamus and spinal MRI demonstrated longitudinal T₂ high-intensity lesions extending from C2 to C4 and from C6 to Th6. We suspected neuromyelitis optica spectrum disorder (NMOSD) and administered intravenous methylprednisolone after which her symptoms and MRI abnormalities improved immediately. Serum anti-aquaporin-4 antibody and anti-myelin oligodendrocyte glycoprotein antibody were negative. Thus, it is important to perform MRI imaging early in the onset of aseptic meningitis due to numerous case reports of patients diagnosed with neuromyelitis optica or NMOSD with initial meningitis-like symptoms.

Subcortical structural abnormalities in female neuromyelitis optica patients with neuropathic pain

Neuromyelitis optica (NMO) is a disease characterised by severe relapses of optic neuritis and longitudinally extensive transverse myelitis and it has a strong female predilection. Pain is one of the most typical symptom in NMO. However, few studies have been conducted to examine the neuropathic pain mechanism of NMO patients or gender-specific effects using magnetic resonance imaging technique. A total of 38 female patients with NMO, 28 with pain (NMOWP) and 10 without pain (NMOWoP), were classified using the Brief Pain Inventory (BPI); 22 healthy females were also recruited. We used the FSL Image Registration and Segmentation Toolbox (FIRST) for subcortical region volumes quantifications, and voxel-based morphometry analysis for cortical gray matter (GM) volume, to examine the brain morphology in NMOWP patients. In addition, correlation test between structural measurements of NMO patients and clinical indexes was also performed. The results showed: 1) no significant differences in cortical GM density between the NMOWP and NMOWoP groups; 2) significantly smaller hippocampus and pallidum volumes in the NMOWP group compared with the NMOWoP group; 3) significant negative correlation between the average BPI and volumes of the accumbens nucleus and thalamus in NMO patients. These results revealed that structural abnormality exists in NMO female patients who have pain, with significant implications for our understanding of the brain morphology in NMO patients with pain.

NEUROMYELITIS OPTICA SPECTRUM DISORDERS: DIAGNOSIS AND TREATMENT, THE EXPERIENCE OF CLINICAL OBSERVATIONS

Neuromyelitis optica spectrum disorder (NMOSD) is an aggregate of inflammatory and autoimmune disorders of the central nervous system characterized by recurrent, disabling clinical course and damages predominantly targeting optic nerves, brain stem and spinal cord. NMOSD is stratified into two types: seropositive for aquaporin-4 antibodies (AQP4-IgG) and seronegative, which is reported in 25 % of cases. This article presents modern conceptualizations of NMOSD and describes authors’ own experience of clinical observation of patients.

Hyponatremia in neuromyelitis optica spectrum disorders: Literature review

Hyponatremia is a potentially serious electrolyte abnormality observed in neuromyelitis optica spectrum disorders (NMOSDs), and its most common cause is syndrome of inappropriate antidiuretic hormone secretion (SIADH). Another potential cause of hyponatremia is cerebral salt-wasting syndrome (CSWS), although CSWS has not previously been reported in NMOSDs. Accurate and early differentiation between SIADH and CSWS is difficult. However, the two conditions have important implications for the selection of therapy. Here, we describe two patients with aquaporin-4 antibody (AQP4-Ab)-positive NMOSDs who developed hyponatremia as a result of CSWS and SIADH, respectively. Additionally, we review all previously reported studies of hyponatremia in patients with NMOSDs and propose several potential pathophysiological mechanisms of hyponatremia. In conclusion, NMOSDs accompanied by hyponatremia are not actually rare, but have previously been given little attention. Furthermore, SIADH should not be the only consideration, before the exclusion of rare but significant CSWS.

Neuromyelitis Optica Spectrum Disorders

PURPOSE OF REVIEW

This article provides a practical approach for providers caring for patients with neuromyelitis optica (NMO) spectrum disorders. Clinical and imaging features, diagnostic criteria, treatment of acute exacerbations, chronic preventive therapy, and symptom management in NMO spectrum disorders are discussed.

RECENT FINDINGS

The rapid pace of research in NMO spectrum disorders has led to many recent advances. A broader understanding of the clinical spectrum of the disease as well as improvements in anti-aquaporin-4 antibody assays have led to recent revision of the diagnostic criteria. Several recent studies have expanded the knowledge base regarding the efficacy and safety of current therapies for NMO spectrum disorders.

SUMMARY

An NMO spectrum disorder is an inflammatory disorder affecting the central nervous system, previously thought to be closely related to multiple sclerosis but more recently demonstrated to represent a distinct clinical and pathophysiologic entity. As NMO spectrum disorders carry significant morbidity and, at times, mortality, prompt and accurate diagnosis followed by swift initiation of therapy for both treatment of acute exacerbations and prevention of further relapses is critical. This article provides a practical approach to the diagnosis and management of NMO spectrum disorders.

Common and Rare Manifestations of Neuromyelitis Optica Spectrum Disorder

The discovery of a highly specific biomarker of neuromyelitis optica (NMO)-the anti-aquaporin-4 (AQP4) antibody-has opened new paths to understanding disease pathogenesis and afforded a way to confirm the diagnosis in clinical practice. An important consequence of the discovery is the broadening of the spectrum of syndromes seen in the context of AQP4 autoimmunity. These syndromes have been subsumed under the rubric of NMO spectrum disorder (NMOSD). The current classification recognizes not only optic neuritis and myelitis as core syndromes of NMOSD but also cerebral, diencephalic, brainstem, and area postrema syndromes. These neurologic syndromes are the focus of our review. AQP4 is also expressed in many organs outside of the central nervous system, and this may explain some of the unusual, non-neurologic features that have been occasionally reported in NMOSD. Our review catalogues non-neurologic manifestations seen in NMOSD and concludes with a discussion of frequently associated autoimmune and neoplastic comorbidities of NMOSD.

Syndrome of inappropriate antidiuretic hormone accompanied by bilateral hypothalamic and anterior thalamic lesions with serum antiaquaporin 4 antibody

We described a rare case of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and severe unconsciousness accompanied by bilateral hypothalamic and anterior thalamic lesions with positive serum antiaquaporin 4 (AQP4) antibody. A 29-year-old man was admitted to our hospital due to the subacute progression of an unconscious state. He was observed to be hyponatraemic secondary to SIADH. Brain MRI showed bilateral hypothalamic and anterior thalamic lesions. Anti-AQP4 antibody was detected in his serum. After the administration of intravenous methylprednisolone pulse therapy, his symptoms improved with complete recovery from SIADH and regression of the hypothalamic and anterior thalamic lesions. The patient was transferred to another hospital for rehabilitation with 20 mg/day of oral prednisolone 127 days after admission. This case highlights the importance of testing for anti-AQP4 antibody in patients with unexplainable SIADH, subacute progressive unconsciousness and bilateral hypothalamic and anterior thalamic lesions.

Syndrome of inappropriate antidiuretic hormone secretion associated with seronegative neuromyelitis optica spectrum disorder

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a potential cause of hyponatremia of the central nervous system (CNS). Although SIADH has been reported to be associated with many other central nervous disorders, its association with neuromyelitis optica (NMO) or NMO spectrum disorders are rare. NMO is a demyelinating disorder characterized by optic neuritis and transverse myelitis. Aquaporin-4 (AQP4), which is the target antigen for a NMO autoantibody, is the predominant CNS water channel. However, some NMO patients show seronegative AQP4 antibody results. The spectrum of NMO has been changed, and new findings about the disease have been reported. Here, we report a case of seronegative NMO spectrum disorder associated with SIADH.

MOG-IgG in NMO and related disorders: a multicenter study of 50 patients. Part 2: Epidemiology, clinical presentation, radiological and laboratory features, treatment responses, and long-term outcome

BACKGROUND

A subset of patients with neuromyelitis optica spectrum disorders (NMOSD) has been shown to be seropositive for myelin oligodendrocyte glycoprotein antibodies (MOG-IgG).

OBJECTIVE

To describe the epidemiological, clinical, radiological, cerebrospinal fluid (CSF), and electrophysiological features of a large cohort of MOG-IgG-positive patients with optic neuritis (ON) and/or myelitis (n = 50) as well as attack and long-term treatment outcomes.

METHODS

Retrospective multicenter study.

RESULTS

The sex ratio was 1:2.8 (m:f). Median age at onset was 31 years (range 6-70). The disease followed a multiphasic course in 80 % (median time-to-first-relapse 5 months; annualized relapse rate 0.92) and resulted in significant disability in 40 % (mean follow-up 75 ± 46.5 months), with severe visual impairment or functional blindness (36 %) and markedly impaired ambulation due to paresis or ataxia (25 %) as the most common long-term sequelae. Functional blindess in one or both eyes was noted during at least one ON attack in around 70 %. Perioptic enhancement was present in several patients. Besides acute tetra-/paraparesis, dysesthesia and pain were common in acute myelitis (70 %). Longitudinally extensive spinal cord lesions were frequent, but short lesions occurred at least once in 44 %. Fourty-one percent had a history of simultaneous ON and myelitis. Clinical or radiological involvement of the brain, brainstem, or cerebellum was present in 50 %; extra-opticospinal symptoms included intractable nausea and vomiting and respiratory insufficiency (fatal in one). CSF pleocytosis (partly neutrophilic) was present in 70 %, oligoclonal bands in only 13 %, and blood-CSF-barrier dysfunction in 32 %. Intravenous methylprednisolone (IVMP) and long-term immunosuppression were often effective; however, treatment failure leading to rapid accumulation of disability was noted in many patients as well as flare-ups after steroid withdrawal. Full recovery was achieved by plasma exchange in some cases, including after IVMP failure. Breakthrough attacks under azathioprine were linked to the drug-specific latency period and a lack of cotreatment with oral steroids. Methotrexate was effective in 5/6 patients. Interferon-beta was associated with ongoing or increasing disease activity. Rituximab and ofatumumab were effective in some patients. However, treatment with rituximab was followed by early relapses in several cases; end-of-dose relapses occurred 9-12 months after the first infusion. Coexisting autoimmunity was rare (9 %). Wingerchuk's 2006 and 2015 criteria for NMO(SD) and Barkhof and McDonald criteria for multiple sclerosis (MS) were met by 28 %, 32 %, 15 %, 33 %, respectively; MS had been suspected in 36 %. Disease onset or relapses were preceded by infection, vaccination, or pregnancy/delivery in several cases.

CONCLUSION

Our findings from a predominantly Caucasian cohort strongly argue against the concept of MOG-IgG denoting a mild and usually monophasic variant of NMOSD. The predominantly relapsing and often severe disease course and the short median time to second attack support the use of prophylactic long-term treatments in patients with MOG-IgG-positive ON and/or myelitis.

Syndrome of Inappropriate Antidiuretic Hormone Associated with Eosinophilic Granulomatosis with Polyangiitis

A 78-year-old woman with a history of bronchial asthma presented with distal dominant sensory disturbance and weakness in the upper and lower extremities. A biopsy of the left peroneus brevis muscle showed active vasculitis with inflammation extending into muscle fascicles and fibrinoid necrosis of the vessel wall, consistent with eosinophilic granulomatosis with polyangiitis (EGPA). Despite her decreased serum osmolarity, her serum antidiuretic hormone level was not reduced, consistent with the syndrome of inappropriate antidiuretic hormone (SIADH). Intravenous and oral steroid therapy improved her neurological symptoms. Clinicians should consider EGPA as a concurrent, and potentially causative, disorder in cases of SIADH.

Syndrome of inappropriate antidiuretic hormone secretion in patients with aquaporin-4 antibody

The objective of this study was to analyze the frequency of syndrome of inappropriate antidiuretic hormone secretion (SIADH) in patients with positive aquaporin-4 (AQP4) antibodies and evaluate the relationship between SIADH and hypothalamic lesions in patients with NMO and NMO spectrum disorder (NMOSD). AQP4 antibodies were tested by an indirect immunofluorescence assay employing HEK-293 cells transfected with recombinant human AQP4. Clinical data of patients were analyzed retrospectively. In total, 192 patients with AQP4 antibodies were certified, of which 41 patients (21.4 %) were included in the present study. Six patients (14.6 %, 6/41) met the criteria of SIADH, of which hyponatremia was mild in one patient, and severe in five. Five patients experienced confusion or decreased consciousness. Four patients were diagnosed with NMO and two were diagnosed with recurrent optic neuritis. Magnetic resonance imaging showed 11 of 41 patients (26.8 %) had hypothalamic lesions. All patients with SIADH had hypothalamic abnormalities. Hyponatremia resolved in all patients after intravenous methylprednisolone and intravenous immunoglobulin therapy. SIADH is not rare in patients with NMO/NMOSD, especially in patients with lesions close to the hypothalamus.

[Case of neuromyelitis optica spectrum disorder associated with central pontine and extrapontine myelinolysis preceded by syndrome of inappropriate antidiuretic hormone secretion]

A 36-year-old woman complained of general malaise. She presented with hyponatremia and plasma osmotic pressure was lower than urinary osmotic pressure. In addition, serum antidiuretic hormone level was higher than the measurement sensitivity. She was diagnosed with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). She fell into a coma despite correction of serum sodium level. Brain magnetic resonance imaging (MRI) revealed high signal intensities in the cerebral cortex, striatum, thalamus, hypothalamus, midbrain, and pons in fluid-attenuated inversion recovery images. Spinal MRI revealed a longitudinally extending lesion in the cervical cord. Serum sample was positive for anti-aquaporin-4 antibody, supporting the diagnosis of neuromyelitis optica spectrum disorder (NMOSD) combined with central pontine and extrapontine myelinolysis. In patients with NMOSD, the immune reaction can gradually cause destructive changes of the hypothalamus and lead to unstable ADH secretion in the absence of immunomodulatory treatment.

Conventional and advanced imaging in neuromyelitis optica

Myelitis and optic neuritis are prototypic clinical presentations of both multiple sclerosis and neuromyelitis optica. Once considered a subtype of multiple sclerosis, neuromyelitis optica, is now known to have a discrete pathogenesis in which antibodies to the water channel, aquaporin 4, play a critical role. Timely differentiation of neuromyelitis optica from MS is imperative, determining both prognosis and treatment strategy. Early, aggressive immunosuppression is required to prevent the accrual of severe disability in neuromyelitis optica; conversely, MS-specific therapies may exacerbate the disease. The diagnosis of neuromyelitis optica requires the integration of clinical, MR imaging, and laboratory data, but current criteria are insensitive and exclude patients with limited clinical syndromes. Failure to recognize the expanding spectrum of cerebral MR imaging patterns associated with aquaporin 4 antibody seropositivity adds to diagnostic uncertainty in some patients. We present the state of the art in conventional and nonconventional MR imaging in neuromyelitis optica and review the place of neuroimaging in the diagnosis, management, and research of the condition.

Relapsing inappropriate antidiuretic hormone secretion in an anti-aquaporin-4 antibody positive paediatric patient

Paediatric patients with the syndrome of an inappropriate antidiuretic hormone secretion (SIADH), as a manifestation of inflammatory demyelinating disorders of the central nervous system, have been rarely described until now, in only a few cases of neuromyelitis optica spectrum disorders (NMOSDs). We present a case of relapsing SIADH associated with NMOSD, in an anti-aquaporin-4 antibody positive 14-year-old girl, who is, to our best knowledge, the first reported paediatric patient with relapsing SIADH and NMOSD. Additionally, our case further supports the notion that paediatric encephalomyelitis associated with SIADH should suggest the diagnosis of NMOSD.

A review of the current literature and a guide to the early diagnosis of autoimmune disorders associated with neuromyelitis optica

Neuromyelitis optica (NMO) is an immune-mediated neurological disorder characterised by recurrent episodes of optic neuritis and longitudinally extensive transverse myelitis. A serum biomarker, aquaporin-4 IgG, the autoantibody against aquaporin-4 water channel, has been specifically associated with NMO and has assisted early recognition and prediction of relapses. Less commonly, a monophasic course, associated with antibodies to myelin oligodendrocyte glycoprotein has been reported. Specific diagnostic criteria have been defined; however, some cases that do not fulfil these criteria (but are nevertheless associated with aquaporin-4 IgG) are classified as NMO spectrum disorder and follow the same relapsing course. An ever-growing list of autoimmune disorders, both organ-specific and non-organ-specific, have been associated in up to 20-30% of patients with NMO. These disorders, which may become symptomatic before or after the development of NMO, are often diagnosed long after the diagnosis of NMO, as symptoms may be wrongly attributed to NMO, its residual effects or medication side effects. In addition, autoantibodies can be found in patients with NMO without coexisting disease (up to 40% in some series) and maybe suggestive of a heightened humoral immune response. We present a comprehensive review of the current literature on autoimmune disorders co-existing with NMO and identified 22 autoimmune conditions (myasthenia gravis, coeliac disease, ulcerative colitis, sclerosing cholangitis, systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid antibody syndrome, Sjogren's syndrome, autoimmune hypothyroidism, immune thrombocytopenic purpura, pernicious anaemia, narcolepsy, pemphigus foliaceus, alopecia areata, psoriasis, scleroderma, dermatitis herpetiformis, polymyositis, chronic inflammatory demyelinating polyneuropathy, paraneoplastic disorders, insulin dependent diabetes mellitus and autoimmune encephalitis).

Update on the diagnosis and treatment of neuromyelitis optica: recommendations of the Neuromyelitis Optica Study Group (NEMOS)

Neuromyelitis optica (NMO, Devic’s syndrome), long considered a clinical variant of multiple sclerosis, is now regarded as a distinct disease entity. Major progress has been made in the diagnosis and treatment of NMO since aquaporin-4 antibodies (AQP4-Ab; also termed NMO-IgG) were first described in 2004. In this review, the Neuromyelitis Optica Study Group (NEMOS) summarizes recently obtained knowledge on NMO and highlights new developments in its diagnosis and treatment, based on current guidelines, the published literature and expert discussion at regular NEMOS meetings. Testing of AQP4-Ab is essential and is the most important test in the diagnostic work-up of suspected NMO, and helps to distinguish NMO from other autoimmune diseases. Furthermore, AQP4-Ab testing has expanded our knowledge of the clinical presentation of NMO spectrum disorders (NMOSD). In addition, imaging techniques, particularly magnetic resonance imaging of the brain and spinal cord, are obligatory in the diagnostic workup. It is important to note that brain lesions in NMO and NMOSD are not uncommon, do not rule out the diagnosis, and show characteristic patterns. Other imaging modalities such as optical coherence tomography are proposed as useful tools in the assessment of retinal damage. Therapy of NMO should be initiated early. Azathioprine and rituximab are suggested as first-line treatments, the latter being increasingly regarded as an established therapy with long-term efficacy and an acceptable safety profile in NMO patients. Other immunosuppressive drugs, such as methotrexate, mycophenolate mofetil and mitoxantrone, are recommended as second-line treatments. Promising new therapies are emerging in the form of anti-IL6 receptor, anti-complement or anti-AQP4-Ab biologicals.

Detection of anti-aquaporin-4 autoantibodies in the sera of Chinese neuromyelitis optica patients

In this study, we recruited 10 neuromyelitis optica patients, two multiple sclerosis patients and two myelitis patients. Chinese hamster lung fibroblast (V79) cells transfected with a human aquaporin-4-mCherry fusion protein gene were used to detect anti-aquaporin-4 antibody in neuromyelitis optica patient sera by immunofluorescence. Anti-aquaporin-4 autoantibody was stably detected by immunofluorescence in neuromyelitis optica patient sera exclusively. The sensitivity of the assay for neuromyelitis optica was 90% and the specificity for neuromyelitis optica was 100%. The anti-aquaporin-4 antibody titers in sera were tested with serial dilutions until the signal disappeared. A positive correlation was detected between Expanded Disability Status Scale scores and serum anti-aquaporin-4 antibody titers. The anti-aquaporin-4 antibody assay is highly sensitive and specific in the sera of Chinese neuromyelitis optica patients. Detection of aquaporin-4 autoantibody is important for the diagnosis and treatment of neuromyelitis optica.

Brain abnormalities in neuromyelitis optica spectrum disorder

Neuromyelitis optica (NMO) is an idiopathic inflammatory syndrome of the central nervous system that is characterized by severe attacks of optic neuritis (ON) and myelitis. Until recently, NMO was considered a disease without brain involvement. However, since the discovery of NMO-IgG/antiaqaporin-4 antibody, the concept of NMO was broadened to NMO spectrum disorder (NMOSD), and brain lesions are commonly recognized. Furthermore, some patients present with brain symptoms as their first manifestation and develop recurrent brain symptoms without ON or myelitis. Brain lesions with characteristic locations and configurations can be helpful in the diagnosis of NMOSD. Due to the growing recognition of brain abnormalities in NMOSD, these have been included in the NMO and NMOSD diagnostic criteria or guidelines. Recent technical developments such as diffusion tensor imaging, MR spectroscopy, and voxel-based morphometry reveal new findings related to brain abnormalities in NMOSD that were not identified using conventional MRI. This paper focuses on the incidence and characteristics of the brain lesions found in NMOSD and the symptoms that they cause. Recent studies using advanced imaging techniques are also introduced.