Neuromyelitis optica and non organ-specific autoimmunity

BACKGROUND

Neuromyelitis optica (NMO) is often associated with other clinical or serological markers of non-organ-specific autoimmunity.

OBJECTIVE

To evaluate the relationship between NMO spectrum disorders (NMOSDs), including NMO, longitudinally extensive transverse myelitis, and recurrent optic neuritis, and autoimmune disease. We concentrated on the association with systemic lupus erythematosus (SLE), Sjögren syndrome (SS), or serological evidence of these disorders, which commonly is a source of diagnostic confusion.

DESIGN

Retrospective blinded serological survey.

SETTING

Mayo Clinic College of Medicine, Rochester, and Centre Hospitalier Régional Universitaire de Lille.

METHODS

Group 1 included 153 US patients with NMOSDs (78 with NMO and 75 with longitudinally extensive transverse myelitis) and 33 control subjects with SS/SLE. Group 2 included 30 French patients with SS/SLE, 14 with NMOSDs (6 with NMO, 6 with longitudinally extensive transverse myelitis, and 2 with recurrent optic neuritis), 16 without NMOSDs, and 4 with NMO without SS/SLE.

RESULTS

For group 1, NMO-IgG was detected in 66.7%, antinuclear antibodies in 43.8%, and Sjögren syndrome A (SSA) antibodies in 15.7% of patients with NMO and longitudinally extensive transverse myelitis. Five NMO-IgG-seropositive patients with NMOSDs had coexisting SLE, SS, or both. Antinuclear antibodies and SSA antibodies were more frequent in NMO-IgG-seropositive patients than in NMO-IgG-seronegative patients (P= .001). For group 2, NMO-IgG was detected in 5 of 14 patients (35.7%) with NMOSDs and SS/SLE and in 2 of 4 patients (50.0%) with NMO without SS/SLE (P= .59). We detected NMO-IgG only in patients with NMOSDs and not in 49 controls with SS/SLE but without optic neuritis or myelitis from the 2 cohorts (P= .01).

CONCLUSION

Neuromyelitis optica spectrum disorders with seropositive findings for NMO-IgG occurring with SS/SLE or non-organ-specific autoantibodies is an indication of coexisting NMO rather than a vasculopathic or other complication of SS/SLE.

Caffeine for the prevention and treatment of postdural puncture headache: debunking the myth

OBJECTIVE

Is caffeine effective in preventing and treating postdural puncture headache (PDPH)?

METHODS

The question was addressed with a structured evidence-based clinical neurologic practice review via videoconferencing between 3 academic institutions. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarians, and clinical content experts. A critically appraised topic format was employed, starting with a clinical scenario and structured question. Participant groups at each of the 3 institutions independently devised search strategies, located and compiled the best evidence, performed critical appraisals, synthesized the results, summarized the evidence, provided commentary, and declared bottom-line conclusions.

RESULTS

Three directly relevant randomized controlled trial articles were selected as the best available evidence for the clinical questions. Two investigated caffeine [oral and intravenous (IV)] as PDPH prophylaxis and 1 (oral) as PDPH treatment. One additional quasirandomized trial (IV) and 1 open-label trial (IV) of caffeine for PDPH treatment were located by reviewing bibliographies. Articles describing the pharmacological basis for caffeine therapy were also identified. No valid pharmacological rationale for caffeine as an antinociceptive agent for PDPH exists. The clinical trials are few in number, small in sample size, methodologically weak or flawed, and either demonstrate no effectiveness, contradictory and conflicting results, or invalid answers.

CONCLUSIONS

The wide endorsement for caffeine to prevent and treat PDPH found in textbooks and review articles appears to be unwarranted and insufficiently supported by the available pharmacological and clinical evidence.

The spectrum of neuromyelitis optica

Neuromyelitis optica (also known as Devic's disease) is an idiopathic, severe, demyelinating disease of the central nervous system that preferentially affects the optic nerve and spinal cord. Neuromyelitis optica has a worldwide distribution, poor prognosis, and has long been thought of as a variant of multiple sclerosis; however, clinical, laboratory, immunological, and pathological characteristics that distinguish it from multiple sclerosis are now recognised. The presence of a highly specific serum autoantibody marker (NMO-IgG) further differentiates neuromyelitis optica from multiple sclerosis and has helped to define a neuromyelitis optica spectrum of disorders. NMO-IgG reacts with the water channel aquaporin 4. Data suggest that autoantibodies to aquaporin 4 derived from peripheral B cells cause the activation of complement, inflammatory demyelination, and necrosis that is seen in neuromyelitis optica. The knowledge gained from further assessment of the exact role of NMO-IgG in the pathogenesis of neuromyelitis optica will provide a foundation for rational therapeutic trials for this rapidly disabling disease.

The MERITs of evidence-based clinical practice in neurology

We examine the relevance of evidence-based clinical practice (EBCP) in the field of clinical neurosciences, emphasize feasible methods for neurologists to incorporate EBCP into their practice, draw attention to available EBCP resources for the neurosciences, highlight how EBCP has been incorporated into clinical neuroscience training programs, present other EBCP initiatives in neurology, and describe the Mayo Clinic Evidence-Based Clinical Practice, Research, Informatics, and Training (MERIT) Center EBCP programs.

Alpha-lipoic acid may improve symptomatic diabetic polyneuropathy

OBJECTIVE

In patients with symptomatic diabetic polyneuropathy, is oral alpha-lipoic acid (ALA) effective in improving neuropathic symptoms compared with placebo?

METHODS

The question was addressed with a structured evidence-based clinical neurologic practice review via videoconferencing between 3 academic institutions. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarians, and clinical content experts. A critically appraised topic format was employed, with a clinical scenario, structured question, search strategy, appraisal, results, summary of evidence, commentary, and bottom-line conclusions.

RESULTS

A single modestly valid randomized controlled trial demonstrated that oral ALA in doses of 600 mg, 1200 mg, and 1800 mg was effective in reducing neuropathic symptoms of diabetic distal symmetric polyneuropathy (DSP) at 5 weeks, as assessed by the Total Symptom Score (>or=50% reduction), with number needed to treat (NNT) (95% CI) of 2.7 (1.8 to 5.8), 4.1 (2.3 to 20.2), and 3.2 (2.0 to 8.6), respectively. Adverse events, including nausea, vomiting, and vertigo, were identified but occurred most frequently with ALA doses of 1200 mg and 1800 mg. Overall, treatment emergent adverse events for ALA 600 mg were not significantly different than placebo, but ALA 1200 mg and 1800 mg had number needed to harm (95% CI) of 4.5 (2.4 to 31.0) and 3.0 (1.9 to 7.1), respectively.

CONCLUSION

Oral ALA may improve neuropathic symptoms in diabetic DSP. A single modestly valid RCT demonstrated that 600 mg was an effective and well-tolerated dose, with NNT 2.7 to significantly reduce neuropathic pain symptoms over a 5-week period. ALA's role and place in an algorithm among other commonly prescribed oral treatments for symptomatic relief of neuropathic pain in diabetic DSP remains unclear.

Migraine With Aura Is a Risk Factor for Cardiovascular and Cerebrovascular Disease

OBJECTIVE

To determine whether migraine with aura and migraine without aura are independent risk factors for symptomatic cardiovascular and cerebrovascular disease.

METHODS

We addressed the objective through development of a structured critically appraised topic that included a clinical scenario, structured question, search strategy, critical appraisal, results, summary of best evidence, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarians, and clinical content experts.

RESULTS

A prospective cohort study of 27,840 participants in the Women's Health Study determined that, compared with women lacking a migraine history, women who reported active migraine with aura had adjusted hazard ratios of 2.15 (95% confidence interval [CI], 1.58-2.92) for major cardiovascular disease, 1.91 (95% CI, 1.17-3.10) for ischemic stroke, 1.74 (95% CI, 1.23-2.46) for coronary revascularization, 1.71 (95% CI, 1.16-2.53) for angina, and 2.33 (95% CI, 1.21-4.51) for ischemic cardiovascular disease death. Active migraine without aura was not associated with increased risk of any of the vascular event categories.

CONCLUSION

In women, active migraine with aura increases the risk of major CVD and ischemic stroke by approximately 2-fold compared with women without migraine. Active migraine without aura was not a risk factor for major CVD and stroke outcomes in this study. Additional emphasis on identification and treatment of modifiable vascular disease risk factors for women with active migraine with aura is warranted.

Neuromyelitis optica: Changing concepts

Neuromyelitis optica (NMO; Devic's disease) and the NMO spectrum disorders are idiopathic inflammatory demyelinating disorders that affect the central nervous system and have a predilection for optic nerves and spinal cord. The identification of NMO-IgG as a disease-specific marker and aquaporin 4 as the target antigen has renewed interest in NMO. Based on current data, we suspect that autoantibodies arising from peripheral B cells bind to aquaporin 4 expressed on astrocyte foot processes on the abluminal surface of microvessels, activate complement and initiate inflammatory demyelination and necrosis. The development of animal models and further analysis of the association of NMO-IgG with disease severity and treatment response will elucidate the pathobiology of NMO.

Comparative immunopathogenesis of acute disseminated encephalomyelitis, neuromyelitis optica, and multiple sclerosis

PURPOSE OF REVIEW

Advanced immunopathological techniques hold promise for more precise diagnosis of idiopathic demyelinating diseases of the central nervous system. We review recent progress in differentiating and understanding the disease mechanisms of acute disseminated encephalomyelitis, neuromyelitis optica, and classical multiple sclerosis.

RECENT FINDINGS

Four distinct immunopathological patterns have been described in multiple sclerosis patients, potentially implicating different inflammatory, demyelinating, and apoptotic mechanisms. A specific serum biomarker, neuromyelitis optica immunoglobulin G, is strongly associated with neuromyelitis optica and identifies patients with severe optic nerve and spinal cord lesions with specific pathological features such as eosinophilic and neutrophilic inflammatory infiltrates, necrosis, vascular hyalinization, and extensive vasculocentric immunoglobulin and complement deposition. This biomarker targets the water channel aquaporin-4, which is lost in neuromyelitis optica lesions. Acute disseminated encephalomyelitis still has no validated clinical diagnostic criteria but its perivenous pathological findings distinguish it from multiple sclerosis and neuromyelitis optica.

SUMMARY

The clinically heterogeneous group of idiopathic inflammatory demyelinating diseases of the central nervous system is characterized by several immunopathological patterns that suggest the involvement of diverse pathogenic effector mechanisms. Future advances in experimental pathology, immunology, molecular genetics, and neuroimaging, as well as the discovery of specific biomarkers, will more precisely define these disorders and lead to better targeted therapies.

Neuromyelitis optica

PURPOSE OF REVIEW

We review recent advances in neuromyelitis optica, an idiopathic inflammatory demyelinating disease of the central nervous system predominantly affecting optic nerves and spinal cord. We concentrate on a recently identified serum antibody biomarker, neuromyelitis optica immunoglobulin G (NMO-IgG), which distinguishes neuromyelitis optica from multiple sclerosis.

RECENT FINDINGS

NMO-IgG is detected by indirect immunofluorescence. Its presence and specificity for neuromyelitis optica was confirmed in diverse populations. Seropositivity is now incorporated into new diagnostic criteria for neuromyelitis optica. Testing for this biomarker has suggested that the neuromyelitis optica spectrum is broader than previously recognized. Recently, the molecular target of NMO-IgG was identified as aquaporin-4. Immunopathologic studies suggest that loss of aquaporin-4 immunostaining is detectable in early lesions of neuromyelitis optica. A B-cell-specific monoclonal antibody, rituximab, may be an effective treatment even in patients not responding to other treatments.

SUMMARY

Clinical, radiologic, and immunologic features distinguish neuromyelitis optica from other severe cases of multiple sclerosis. NMO-IgG is the first specific marker for a central nervous system demyelinating disease. The discovery of aquaporin-4 as the putative target of NMO-IgG, and recent data suggesting that aquaporin-4-specific antibodies are pathogenic may enhance our understanding of idiopathic inflammatory demyelinating diseases and their treatment.

“Idiopathic” Rapid-Eye-Movement (REM) Sleep Behavior Disorder Is Associated With Future Development of Neurodegenerative Diseases

OBJECTIVE

To determine whether a diagnosis of idiopathic rapid-eye-movement sleep behavior disorder (RBD) is associated with a future risk of development of neurodegenerative diseases.

METHODS

We addressed the objective through development of a structured critically appraised topic that included a clinical scenario, structured question, search strategy, critical appraisal, results, summary of best evidence, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarians, and clinical content experts.

RESULTS

A retrospective study of 44 consecutive patients diagnosed with idiopathic RBD demonstrated that 20 patients (45%) developed a neurologic disorder, most commonly Parkinson disease or Lewy body dementia, after a mean of 11.5 years from reported symptom onset and 5.1 years after RBD diagnosis.

CONCLUSION

Currently available evidence is limited to cross-sectional and retrospective analyses of patients with RBD. Although ascertainment biases and the retrospective nature of the available evidence limits quantitative analyses, the diagnosis of idiopathic RBD portends a risk of greater than 45% for future development of a clinically defined neurodegenerative disease. This finding has significant implications for clinical neurologic and sleep disorder practice and neurodegenerative disease research.

A secondary progressive clinical course is uncommon in neuromyelitis optica

We compared the clinical course of 96 patients with neuromyelitis optica (NMO) to multiple sclerosis (MS) natural history data. Based on the distribution of follow-up data (median 6.1 year), we estimated that 21 NMO patients would convert to a secondary progressive course, but we observed only two conversions (p = 0.00002; relative risk = 0.08). The disparate natural histories of MS and NMO suggest dissociation between relapses and clinical progression in CNS demyelinating diseases.

Pattern-specific loss of aquaporin-4 immunoreactivity distinguishes neuromyelitis optica from multiple sclerosis

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease that typically affects optic nerves and spinal cord. Its pathogenic relationship to multiple sclerosis (MS) is uncertain. Unlike MS, NMO lesions are characterized by deposits of IgG and IgM co-localizing with products of complement activation in a vasculocentric pattern around thickened hyalinized blood vessels, suggesting a pathogenic role for humoral immunity targeting an antigen in the perivascular space. A recently identified specific serum autoantibody biomarker, NMO-IgG, targets aquaporin-4 (AQP4), the most abundant water channel protein in the CNS, which is highly concentrated in astrocytic foot processes. We analysed and compared patterns of AQP4 immunoreactivity in CNS tissues of nine patients with NMO, 13 with MS, nine with infarcts and five normal controls. In normal brain, optic nerve and spinal cord, the distribution of AQP4 expression resembles the vasculocentric pattern of immune complex deposition observed in NMO lesions. In contrast to MS lesions, which exhibit stage-dependent loss of AQP4, all NMO lesions demonstrate a striking loss of AQP4 regardless of the stage of demyelinating activity, extent of tissue necrosis, or site of CNS involvement. We identified a novel NMO lesion in the spinal cord and medullary tegmentum extending into the area postrema, characterized by AQP4 loss in foci that were inflammatory and oedematous, but neither demyelinated nor necrotic. Foci of AQP4 loss coincided with sites of intense vasculocentric immune complex deposition. These findings strongly support a role for a complement activating AQP4-specific autoantibody as the initiator of the NMO lesion, and further distinguish NMO from MS.

NMO-IgG: a specific biomarker for neuromyelitis optica

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease that principally targets the optic nerves and spinal cord and often leads to severe disability and occasionally life threatening respiratory failure. Although its clinical manifestations overlap with those of multiple sclerosis (MS), in established cases these two conditions can be distinguished on the basis of clinical, radiological, and routine spinal fluid studies. The diagnosis in early cases or limited forms of NMO is difficult. We recently discovered a unique IgG autoantibody (NMO-IgG) that is highly specific to patients with NMO and thus a valuable diagnostic aid. Its antigen, aquaporin-4 (AQP4), is the central nervous system’s predominant water channel protein. This antibody has not yet been proven to be pathogenic, but several facts suggest that it might be, including the similarity of the immunohistochemical pattern of NMO-(AQP4) IgG binding to mouse CNS tissues to the pattern of immune complex deposition in autopsied patients’ spinal cord tissue. The spectrum of diseases identified by NMO-IgG is broader than has previously been recognized clinically and includes incomplete forms of NMO, such as recurrent transverse myelitis without optic neuritis and recurrent optic neuritis without myelitis.

Second-generation antiepileptic drugs' impact on balance: a meta-analysis

OBJECTIVE

To systematically review available evidence regarding whether second-generation antiepileptic drugs (AEDs) contribute to the risk of balance disorders.

METHODS

We systematically evaluated data from randomized controlled trials that compared adjunctive therapy with a second-generation AED (gabapentin, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, tiagabine, topIramate, or zonisamide) vs placebo for partial epilepsy and that reported dose-specific rates of ataxia or Imbalance for each group. Random-effects meta-analysis was used to pool ratios (risk ratio [RR]) and associated 95% confidence Intervals to determine whether there was evidence of an overall AED class effect or a dose-response effect and whether there were differences between Individual AEDs.

RESULTS

Sixteen studies met inclusion criteria, representing 4279 individuals randomized to a second-generation AED and 1830 patients to placebo. Pooled analyses of all AEDs demonstrated that they Increase imbalance risk at any dose (RR, 2.73; 95% confidence interval, 2.07-3.61) and at lowest dose (RR, 1.76; 95% confidence interval, 1.26-2.46). The highest dose analysis showed heterogeneity; evaluation of individual AEDs revealed that oxcarbamazepine and topiramate increased imbalance risk at all doses, whereas gabapentin and levetiracetam did not increase imbalance risk at any dose. A dose-response effect was observed for most AEDs.

CONCLUSION

Second-generation AEDs at standard dosages, except for gabapentin and levetiracetam, increase the imbalance risk, and evidence exists for a dose-response effect. The mechanisms, risk factors, and consequences of this risk for individual AEDs warrant further study.

Neuromyelitis Optica: New Findings on Pathogenesis

Neuromyelitis optica (NMO) is an idiopathic CNS demyelinating disorder that preferentially involves the optic nerve and spinal cord. Diverse sources of evidence support the hypothesis that NMO is distinct from classical multiple sclerosis (MS) and that the pathogenesis of NMO is dominated by humoral mechanisms. Such evidence includes clinical observations that systemic autoimmune diseases often coexist with NMO and that therapeutic plasmapheresis may provide meaningful rescue therapy for severe clinical attacks, immunopathologic studies that demonstrate prominent complement activation and immunoglobulin deposition, and the discovery of the serum autoantibody NMO-IgG, a potential NMO biomarker that targets aquaporin-4 (AQP4). The NMO-IgG marker is present in a majority of patients with "NMO-spectrum disorders," including isolated or recurrent longitudinally extensive transverse myelitis, recurrent optic neuritis with negative brain imaging, and the Asian optic-spinal form of MS. Preliminary experiments demonstrate that NMO-IgG can modulate AQP4 function and fix complement, characteristics that suggest it has the potential to be pathogenic in NMO. Other immunologic differences among NMO, NMO-spectrum disorders, and classical MS are reviewed.

Treatment of Vascular Dementia and Vascular Cognitive Impairment

OBJECTIVE

In patients with vascular dementia and vascular cognitive impairment, are acetylcholinesterase inhibitors (donepezil, galantamine, and rivastigmine) and N-methyl-d-aspartate (NMDA) receptor antagonists (memantine) effective in improving cognitive function over placebo?

METHODS

The question was addressed with a structured, evidence-based, clinical, neurologic practice review. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarians, and clinical content experts. A critically appraised topic format was employed, with a clinical scenario, structured question, search strategy, appraisal, results, summary of evidence, commentary, and bottom-line conclusions.

RESULTS

Eight relevant systematic reviews and randomized controlled trials were identified and served as the principal sources of information. The best evidence to date revealed that donepezil 5 mg/d [number needed to treat (NNT) = 10] was the most effective and best tolerated [number needed to harm (NNH) = 50] of the available agents. Galantamine 24 mg/d (NNT = 7) was also effective but less well tolerated (NNH = 7). Due to insufficient evidence, rivastigmine could not yet be recommended for the treatment of vascular dementia. Memantine appeared to be safe and well tolerated but did not demonstrate effectiveness across all cognitive outcomes and clinical global measures.

CONCLUSION

Acetylcholinesterase inhibitors and NMDA receptor antagonists, in general, displayed promise as treatments for patients with vascular dementia and vascular cognitive impairment. The most effective, evidence-based treatments were donepezil and galantamine.

Diagnosis and Treatment of Neuromyelitis Optica

BACKGROUND

Neuromyelitis optica (NMO) is an uncommon CNS demyelinating syndrome often mistaken for severe multiple sclerosis (MS). Several clinical, laboratory, and neuroimaging characteristics may accurately distinguish NMO from MS early in the disease course.

REVIEW SUMMARY

NMO is usually a relapsing disorder associated with early, severe, attack-related residual disability. It is associated with a highly specific antibody marker, NMO-IgG, which targets the water channel aquaporin-4. Revised NMO diagnostic criteria require optic neuritis, acute myelitis, and 2 of the following 3 characteristics: disease-onset brain magnetic resonance imaging (MRI) that is nondiagnostic for MS, contiguous spinal cord MRI lesion extending over 3 or more vertebral segments, and NMO-IgG seropositive status. Symptoms referable to central nervous system regions other than the optic nerve and spinal cord do not necessarily exclude the diagnosis of NMO, nor does the presence of brain MRI lesions. NMO-IgG has facilitated an appreciation that the spectrum of NMO is wider than previously recognized, and includes a proportion of patients with each of recurrent longitudinally extensive myelitis, recurrent isolated optic neuritis, and Japanese opticospinal MS. In contrast to typical MS, clinical experience and case series suggest that NMO requires long-term immunosuppressive therapy.

CONCLUSIONS

NMO can be reliably differentiated from MS at an early stage using validated diagnostic criteria. The spectrum of NMO is wider than previously appreciated. Accurate, early diagnosis is critical to facilitate initiation of immunosuppressive therapy for attack prevention.

Spinal cord astrocytoma presenting as “idiopathic” intracranial hypertension

Increased intracranial pressure is rarely seen in association with spinal tumors. We describe a young, non-obese man who presented with increased intracranial pressure, papilledema and visual obscuration. Multiple cerebrospinal fluid (CSF) examinations with normal or minimally elevated CSF protein lead to the initial diagnosis of idiopathic intracranial hypertension. After a lumboperitoneal shunt placement a progressive thoracic myelopathy developed 7 months after onset of symptoms. The spinal MRI showed a low cervical-upper thoracic intramedullary tumor. Open biopsy confirmed a grade 3 fibrillary astrocytoma. The suspected mechanisms of spinal tumors causing increased intracranial pressure are reviewed as well as three other cases of spinal astrocytomas previously reported in the literature that presented with papilledema and increased intracranial pressure without hydrocephalus. This case illustrates that increased intracranial pressure may in exceptional cases of spinal tumors precede the more typical myelopathic presentation by months and mimic idiopathic intracranial hypertension.

Neuromyelitis optica brain lesions localized at sites of high aquaporin 4 expression

BACKGROUND

Neuromyelitis optica (NMO)-IgG is a specific autoantibody marker for NMO. It binds selectively to aquaporin 4 (AQP4), which is highly concentrated in astrocytic foot processes at the blood-brain barrier and is not restricted to optic nerve and spinal cord. Although it is conventionally believed that the brain is spared, brain imaging abnormalities are not uncommon in patients with NMO.

OBJECTIVE

To investigate the location of brain lesions that are distinctive for NMO with respect to the localization of AQP4 in mammalian brain.

DESIGN

Observational, retrospective case series.

SETTING

Clinical serologic cohort of patients tested for NMO-IgG for whom brain MRI images were available.

PATIENTS

We identified 120 patients seropositive for NMO-IgG for whom brain magnetic resonance images were available.

MAIN OUTCOME MEASURE

Magnetic resonance imaging abnormalities.

RESULTS

In 8 patients we observed recurring and distinctive magnetic resonance imaging abnormalities in the hypothalamic and periventricular areas that corresponded to brain regions of high AQP4 expression.

CONCLUSION

The distribution of NMO-characteristic brain lesions corresponds to sites of high AQP4 expression.

The clinical course of acute disseminated encephalomyelitis

The objective of this review is to describe recent advances in understanding the clinical course of pediatric and adult acute disseminated encephalomyelitis (ADEM), especially the risk of relapse and conversion to multiple sclerosis (MS). The diagnosis of ADEM is reached on clinical grounds, typically in the setting of a post-infectious meningoencephalitic syndrome associated with multifocal neurological symptoms and signs, magnetic resonance imaging (MRI) evidence of white matter lesions and exclusion of other causes. Although typically monophasic, several case series demonstrate 'multiphasic' or 'recurrent' forms of ADEM with clinical relapses occurring within a short interval of disease onset. Furthermore, the estimated risk of developing MS is substantial for both children (0-33%) and adults (approximately 35%). Advances in neuroimaging have identified some MRI features that have predictive value for a relapsing course but they are not accurate enough for therapeutic decision-making; a diagnosis of monophasic ADEM should be made with caution in all cases, especially those presenting in adulthood. Research in ADEM and related disorders remains hampered by lack of prospective studies, specific and reproducible clinical case definitions and variable follow-up methods. Standardization of these variables would facilitate identification of more accurate diagnostic and prognostic variables, discovery and testing of potential objective biomarkers that would, in turn, allow early prediction of a relapsing course and appropriate therapeutic interventions.

Premenstrual Multiple Sclerosis Pseudoexacerbations

BACKGROUND

Many women with multiple sclerosis (MS) experience transient neurologic symptom worsening and fatigue in conjunction with the menstrual cycle. Aspirin reduces MS fatigue in some patients.

OBJECTIVE

To describe 3 women with MS who experienced stereotypic, temperature-independent neurologic symptoms and diurnal fatigue in the mid-to-late luteal phase of the menstrual cycle. Aspirin treatment prevented the symptoms.

DESIGN AND SETTING

Case series at the Mayo Clinic outpatient MS clinics, Scottsdale, Ariz, and Rochester, Minn.

PATIENTS

Three women with relapsing-remitting MS.

INTERVENTIONS

Body temperature measurement, symptom diary, and oral aspirin.

MAIN OUTCOME MEASURES

Body temperature, Modified Fatigue Impact Scale, and evaluation of neurologic symptoms and signs.

RESULTS

Morning oral body temperature did not differ during symptomatic vs asymptomatic portions of the luteal phase (P = .55). Aspirin (650 mg twice daily) prevented symptoms but did not significantly alter the luteal phase body temperature.

CONCLUSIONS

Aspirin prophylaxis may prevent luteal phase-associated MS pseudoexacerbations. However, the observed relationship between the luteal menstrual phase and MS symptom worsening is not fully explained by thermoregulation, which implicates other hormonal or immunologic mechanisms.

Revised diagnostic criteria for neuromyelitis optica

BACKGROUND

The authors previously proposed diagnostic criteria for neuromyelitis optica (NMO) that facilitate its distinction from prototypic multiple sclerosis (MS). However, some patients with otherwise typical NMO have additional symptoms not attributable to optic nerve or spinal cord inflammation or have MS-like brain MRI lesions. Furthermore, some patients are misclassified as NMO by the authors' earlier proposed criteria despite having a subsequent course indistinguishable from prototypic MS. A serum autoantibody marker, NMO-IgG, is highly specific for NMO. The authors propose revised NMO diagnostic criteria that incorporate NMO-IgG status.

METHODS

Using final clinical diagnosis (NMO or MS) as the reference standard, the authors calculated sensitivity and specificity for each criterion and various combinations using a sample of 96 patients with NMO and 33 with MS. The authors used likelihood ratios and logistic regression analysis to develop the most practical and informative diagnostic model.

RESULTS

Fourteen patients with NMO (14.6%) had extra-optic-spinal CNS symptoms. NMO-IgG seropositivity was 76% sensitive and 94% specific for NMO. The best diagnostic combination was 99% sensitive and 90% specific for NMO and consisted of at least two of three elements: longitudinally extensive cord lesion, onset brain MRI nondiagnostic for MS, or NMO-IgG seropositivity.

CONCLUSIONS

The authors propose revised diagnostic criteria for definite neuromyelitis optica (NMO) that require optic neuritis, myelitis, and at least two of three supportive criteria: MRI evidence of a contiguous spinal cord lesion 3 or more segments in length, onset brain MRI nondiagnostic for multiple sclerosis, or NMO-IgG seropositivity. CNS involvement beyond the optic nerves and spinal cord is compatible with NMO.

Neuromyelitis optica

Neuromyelitis optica (NMO), otherwise known as Devic's disease, is an idiopathic, severe, inflammatory disorder that preferentially affects the optic nerves and spinal cord. Clinical, laboratory and immunopathological evidence suggests that NMO is a humorally mediated disease distinct from MS. A spinal cord lesion extending contiguously over three or more vertebral segments is characteristic of NMO and, in combination with a cranial magnetic resonance imaging scan that does not meet radiological criteria for MS, is over 94% sensitive and 96% specific for NMO diagnosis. The serum autoantibody marker, neuromyelitis optica-immunoglobulin G (NMO-IgG), appears specific for NMO and suggests that the disease spectrum includes cases of recurrent longitudinally extensive transverse myelitis and Japanese opticospinal MS. Its target antigen is the water channel aquaporin-4, suggesting that NMO may represent a novel autoimmune channelopathy. Relapsing NMO has a poor prognosis; therapy, typically with immunosuppression, is necessary as early as possible in the disease course to prevent attack-related disability.

Brain abnormalities in neuromyelitis optica

BACKGROUND

Neuromyelitis optica (NMO) is a severe demyelinating disease defined principally by its tendency to selectively affect optic nerves and the spinal cord causing recurrent attacks of blindness and paralysis. Contemporary diagnostic criteria require absence of clinical disease outside the optic nerve or spinal cord. We have, however, frequently encountered patients with a well-established diagnosis of NMO in whom either asymptomatic or symptomatic brain lesions develop suggesting that the diagnostic criteria for NMO should be revised.

OBJECTIVE

To describe the magnetic resonance image (MRI) brain findings in NMO.

DESIGN

Observational, retrospective case series. Patients We ascertained patients through a clinical biospecimens database of individuals with definite or suspected NMO. We included patients who (1) satisfied the 1999 criteria of Wingerchuk et al for NMO except for the absolute criterion of lacking symptoms beyond the optic nerve and spinal cord and the supportive criterion of having a normal brain MRI at onset; (2) had MRI evidence of a spinal cord lesion extending 3 vertebral segments or more (the most specific nonserological feature to differentiate NMO from MS); and (3) were evaluated neurologically and by brain MRI at the Mayo Clinic.

MAIN OUTCOME MEASURES

Magnetic resonance images were classified as normal or as abnormal with either nonspecific, multiple sclerosis-like or atypical abnormalities. We evaluated whether brain lesions were symptomatic and analyzed the neuropathologic features of a single brain biopsy specimen.

RESULTS

Sixty patients (53 women [88%]) fulfilled these inclusion criteria. The mean +/- SD age at onset was 37.2 +/- 18.4 years and the mean +/- SD duration of follow-up was 6.0 +/- 5.6 years. Neuromyelitis optica-IgG was detected in 41 patients (68%). Brain MRI lesions were detected in 36 patients (60%). Most were nonspecific, but 6 patients (10%) had multiple sclerosis-like lesions, usually asymptomatic. Another 5 patients (8%), mostly children, had diencephalic, brainstem or cerebral lesions, atypical for multiple sclerosis. When present, symptoms of brain involvement were subtle, except in 1 patient who was comatose and had large cerebral lesions.

CONCLUSIONS

Asymptomatic brain lesions are common in NMO, and symptomatic brain lesions do not exclude the diagnosis of NMO. These observations justify revision of diagnostic criteria for NMO to allow for brain involvement.

Neuromyelitis optica IgG predicts relapse after longitudinally extensive transverse myelitis

OBJECTIVE

We investigated whether neuromyelitis optica (NMO) IgG seropositivity at the initial presentation of longitudinally extensive transverse myelitis (LETM) predicts relapse of myelitis or development of optic neuritis.

METHODS

Prospective study of patients with initial LETM who were tested for the presence of NMO-IgG.

RESULTS

Eleven of 29 patients (37.9%) were seropositive after a first attack of LETM spanning three or more vertebral segments on magnetic resonance imaging. Of 23 patients followed up for 1 year, none of 14 who were seronegative experienced a relapse or developed optic neuritis. Of 9 seropositive patients, 5 developed a second event: 4 of 9 (44%) developed recurrent transverse myelitis and 1 of 9 (11%) developed optic neuritis (p = 0.004).

INTERPRETATION

LETM represents an inaugural or limited form of NMO in a high proportion of patients. The 40% of patients who are seropositive for NMO-IgG are at high risk for relapse.

The natural history of multiple sclerosis: a geographically based study 9: observations on the progressive phase of the disease

The clinical features of relapses and progression largely define multiple sclerosis phenotypes. A relapsing course is followed by chronic progression in some 80% of cases within 2 decades. The relationship between these phases and long-term outcome remains uncertain. We have analysed these clinical features within a well-studied natural history cohort with mean follow-up of 25 years. For the entire cohort, median times to reach Disability Status Scale (DSS) 6, 8 and 10 were 12.7, 20.6 and 43.9 years, respectively. Among 824 attack-onset patients, the great majority entered a progressive phase with a mean time to progression of 10.4 years. The effects of relapses often cloud the clinical onset of progression. However, there are circumstances where onset of progression is early, relatively discrete and identifiable at DSS of 2 or less. Three subgroups allow for clarity of outcome comparison and they are (i) cases of primary progressive (PP) disease, (ii) attack-onset disease where only a single attack has occurred before onset of progression (SAP) and (iii) secondary progressive (SP) disease where recovery from relapses allows recognition of the earliest clinical stages when progression begins. Here we compare survival curves in these three groups. Among cohorts of SAP (n = 140), PP (n = 219) and SP (n = 146) where progression was stratified by DSS at its onset, there was no difference in time to DSS 6, 8 and 10. These findings demonstrate that the progressive course is independent of relapses either preceding the onset of relapse-free progression or subsequent to it. Among SAP patients, the degree of recovery from the single defining exacerbation had no significant effect on outcome. The site of the original attack was not usually where progression began. The relatively stereotyped nature of the progressive phase seen in all progressive phenotypes suggests regional and/or functional differential susceptibility to a process that appears degenerative in nature. The highly prevalent distal corticospinal tract dysfunction in progressive disease and the pathologically demonstrated selective axonal loss seen in this tract raises the possibility of a dying back central axonopathy, at least in part independent of plaque location or burden. Despite considerable individual variation, the progressive course of disability seen in groups of PP, SAP and SP-DSS2 is similarly stereotyped in quality and pace and may entail mechanisms common to all forms of progressive multiple sclerosis. The possibility that this is the primary process in some cases must be considered.

A pilot study of oral calcitriol (1,25-dihydroxyvitamin D3) for relapsing-remitting multiple sclerosis

BACKGROUND

Epidemiological and ecological studies suggest links between vitamin D deficiency and increased multiple sclerosis (MS) prevalence.

OBJECTIVE

To evaluate the safety and tolerability of oral calcitriol therapy in an open label pilot study.

METHODS

15 ambulatory patients with relapsing-remitting MS and at least one clinical relapse within the previous 12 months received oral calcitriol (target dose: 2.5 microg/d) for 48 weeks. Dietary calcium was restricted to 800 mg/d. Patients were monitored using frequent clinical and laboratory examinations, the expanded disability status scale (EDSS), and brain magnetic resonance imaging (MRI).

RESULTS

Two patients withdrew because of symptomatic hypercalcaemia (serum calcium >3.35 mmol/l in each case) resulting from persistent dietary indiscretion. Two diet compliant patients required temporary dose adjustments for mild asymptomatic hypercalcaemia. Diet compliant patients experienced mild adverse effects. The on-study exacerbation rate (27%) was less than baseline. Four patients experienced five clinical relapses but only one patient worsened by >1 EDSS point. Brain MRI revealed enhancing lesions in five patients at baseline (33%) and in four (29%) at both 24 and 48 weeks.

CONCLUSIONS

Oral calcitriol is safe and well tolerated for up to one year by diet compliant relapsing-remitting MS patients. Further study of vitamin D related mechanisms is warranted in MS.

Neuromyelitis optica

Neuromyelitis optica (Devic's syndrome) is an uncommon, idiopathic, demyelinating syndrome of the central nervous system that preferentially affects the optic nerves and spinal cord. It frequently is misdiagnosed as severe multiple sclerosis, but usually is readily distinguished from multiple sclerosis in fully developed cases because of its severity, typical magnetic resonance imaging (MRI) findings (normal brain MRI; longitudinally extensive lesions on spinal cord MRI), and cerebrospinal fluid analysis (polymorphonuclear pleocytosis and absence of oligoclonal banding). A serum autoantibody marker, NMO-IgG, is highly specific for the disorder. Most patients have relapsing disease, and natural history studies confirm early and severe disability. We treat acute myelitis and optic neuritis exacerbations with parenteral corticosteroids and use rescue plasmapheresis for severe, refractory attacks. Immunomodulatory drugs used for typical multiple sclerosis seem ineffective for relapse prevention. We recommend systemic immunosuppression, usually with azathioprine and oral corticosteroids, for most patients. Fulminant disease and breakthrough disease may respond to other forms of humoral immunotherapy such as rituximab.

A randomized controlled crossover trial of aspirin for fatigue in multiple sclerosis

Pharmacotherapeutic options for multiple sclerosis (MS)-related fatigue are limited. Thirty patients were randomly assigned to aspirin (ASA) 1,300 mg/day or placebo in a double-blind crossover study. Results favored ASA for the main clinical outcomes: Modified Fatigue Impact Scale scores (p = 0.043) and treatment preference (p = 0.012). There were no significant adverse effects. The results warrant further study and support a role for ASA-influenced mechanisms, perhaps immunologic, in the generation of MS-related chronic fatigue.

A serum autoantibody marker of neuromyelitis optica: distinction from multiple sclerosis

BACKGROUND

Neuromyelitis optica is an inflammatory demyelinating disease with generally poor prognosis that selectively targets optic nerves and spinal cord. It is commonly misdiagnosed as multiple sclerosis. Neither disease has a distinguishing biomarker, but optimum treatments differ. The relation of neuromyelitis optica to optic-spinal multiple sclerosis in Asia is uncertain. We assessed the capacity of a putative marker for neuromyelitis optica (NMO-IgG) to distinguish neuromyelitis optica and related disorders from multiple sclerosis.

METHODS

Indirect immunofluorescence with a composite substrate of mouse tissues identified a distinctive NMO-IgG staining pattern, which we characterised further by dual immunostaining. We tested masked serum samples from 102 North American patients with neuromyelitis optica or with syndromes that suggest high risk of the disorder, and 12 Japanese patients with optic-spinal multiple sclerosis. Control patients had multiple sclerosis, other myelopathies, optic neuropathies, and miscellaneous disorders. We also established clinical diagnoses for 14 patients incidentally shown to have NMO-IgG among 85000 tested for suspected paraneoplastic autoimmunity.

FINDINGS

NMO-IgG outlines CNS microvessels, pia, subpia, and Virchow-Robin space. It partly colocalises with laminin. Sensitivity and specificity were 73% (95% CI 60-86) and 91% (79-100) for neuromyelitis optica and 58% (30-86) and 100% (66-100) for optic-spinal multiple sclerosis. NMO-IgG was detected in half of patients with high-risk syndromes. Of 14 seropositive cases identified incidentally, 12 had neuromyelitis optica or a high-risk syndrome for the disease.

INTERPRETATION

NMO-IgG is a specific marker autoantibody of neuromyelitis optica and binds at or near the blood-brain barrier. It distinguishes neuromyelitis optica from multiple sclerosis. Asian optic-spinal multiple sclerosis seems to be the same as neuromyelitis optica.

Seizure prophylaxis in patients with brain tumors: a meta-analysis

OBJECTIVE

To assess whether antiepileptic drugs (AEDs) should be prescribed to patients with brain tumors who have no history of seizures.

METHODS

We performed a meta-analysis of randomized controlled trials (1966-2004) that evaluated the efficacy of AED prophylaxis vs no treatment or placebo to prevent seizures in patients with brain tumors who had no history of epilepsy. Summary odds ratios (ORs) were calculated using a random-effects model. Three subanalyses were performed to assess pooled ORs of seizures in patients with primary glial tumors, cerebral metastases, and meningiomas.

RESULTS

Of 474 articles found in the initial search, 17 were identified as primary studies. Five trials met inclusion criteria: patients with a neoplasm (primary glial tumors, cerebral metastases, and meningiomas) but no history of epilepsy who were randomized to either an AED or placebo. The 3 AEDs studied were phenobarbital, phenytoin, and valproic acid. Of the 5 trials, 4 showed no statistical benefit of seizure prophylaxis with an AED. Meta-analysis confirmed the lack of AED benefit at 1 week (OR, 0.91; 95% confidence interval [CI], 0.45-1.83) and at 6 months (OR, 1.01; 95% CI, 0.51-1.98) of follow-up. The AEDs had no effect on seizure prevention for specific tumor pathology, including primary glial tumors (OR, 3.46; 95% CI, 0.32-37.47), cerebral metastases (OR, 2.50; 95% CI, 0.25-24.72), and meningiomas (OR, 0.62; 95% CI, 0.10-3.85).

CONCLUSIONS

No evidence supports AED prophylaxis with phenobarbital, phenytoin, or valproic acid in patients with brain tumors and no history of seizures, regardless of neoplastic type. Subspecialists who treat patients with brain tumors need more education on this issue. Future randomized controlled trials should address whether any of the newer AEDs are useful for seizure prophylaxis.

Practical consultations: multiple sclerosis

People with multiple sclerosis (MS) are increasingly referred for specialty care to tertiary centers, particularly for advice regarding initiation and monitoring of immunomodulatory therapies. However, the generalist must still be able to apply appropriate skills and technology to diagnose the disease and its complications, provide basic counseling of patients, and be aware of potential treatment options at the time of diagnosis and when therapeutic regimens fail. A general approach, supported by evidence where possible, to common and contemporary clinical issues in MS care is provided in a case-based narrative.

Neuromyelitis optica: current concepts

Neuromyelitis optica (NMO; Devic's syndrome or Devic's disease) is a clinically defined disorder consisting of optic neuritis (ON) in combination with myelitis. Its nosological relationship to other central nervous system demyelinating diseases remains uncertain. Advances in understanding of its natural history and pathophysiology may eventually allow determination of whether idiopathic NMO represents a specific disease. This article summarizes recent progress in these areas of NMO research.

Postinfectious encephalomyelitis

Postinfectious forms of encephalomyelitis, also termed acute disseminated encephalomyelitis (ADEM), form one of several categories of inflammatory demyelinating disorders of the central nervous system (CNS). Recent large, retrospective case series have refined our understanding of the clinical, laboratory, and neuroimaging characteristics of ADEM. The differences between childhood and adult ADEM, risks of development of multiple sclerosis, and the contributions of recent studies to refining the nosology of CNS demyelinating syndromes are discussed.

Neuromyelitis optica: clinical predictors of a relapsing course and survival

BACKGROUND

The relapsing form of neuromyelitis optica (NMO) is characterized by recurrent optic neuritis and myelitis, usually leading to severe, permanent, relapse-related neurologic impairment (e.g., blindness, paraplegia) within 5 years. Aggressive therapy aimed at relapse prevention initiated soon after disease onset may be expected to have a relatively greater impact on early relapse-related disability in NMO than in typical MS. Early prediction of a relapsing course and subsequent disease severity would facilitate design and implementation of clinical trials of such therapies.

METHODS

A database of clinical and laboratory features of patients with NMO (n = 80) was used to develop potentially useful models predictive of a relapsing disease course and of subsequent disease severity as measured by survival.

RESULTS

Predictors of a relapsing course were longer interattack interval between the first two clinical events (rate ratio [RR] = 2.16; per month increase), older age at onset (RR = 1.08; per year increase), female sex (RR = 10.0, female vs male), and less severe motor impairment with the sentinel myelitis event (RR = 0.48; per severity scale point increase). A history of other autoimmune disease (RR = 4.15; presence vs absence), higher attack frequency during the first 2 years of disease (RR = 1.21; per attack), and better motor recovery following the index myelitis event (RR = 1.84; per point increase) were associated with mortality due to relapsing NMO.

CONCLUSIONS

These predictive models identify several clinical features, each available at diagnosis or early in the disease course, that predict relapsing disease and survival. These results may be useful to identify patients at high risk for severe, relapsing neuromyelitis optica in order to initiate early therapy for relapse prevention and to design clinical trials to study such interventions.

Is there a neurologist on this flight?

OBJECTIVE

To analyze the frequency of neurologic events during commercial airline flights and to assess whether onboard emergency medical kits are adequate for in-flight neurologic emergencies.

METHODS

Collaboration of the Mayo Clinic's Departments of Emergency Medicine and Medical Transportation Service and the Division of Aerospace Medicine to provide real-time in-flight consultation to a major US airline that flies approximately 10% of all US passengers. We analyzed all medical events reported from 1995 to 2000 in a database that catalogs the air-to-ground medical consultations. All cases with potential neurologic symptoms were reviewed and classified into various neurologic symptom categories. The cost of diversion for each neurologic symptom was calculated and then extrapolated to assess the cost of neurologic symptoms to the US airline industry.

RESULTS

A total of 2,042 medical incidents led to 312 diversions. Neurologic symptoms were the single largest category of medical incidents, prompting 626 air-to-ground medical calls (31%). They caused 34% of all diversions. Dizziness/vertigo was the most common neurologic symptom followed by seizures, headaches, pain, and cerebrovascular symptoms. Whereas seizures and dizziness/vertigo were the most common reasons for diversion, loss of consciousness/syncope was the complaint most likely to lead to a diversion. The estimated annual cost of diversions due to neurologic events is almost 9,000,000 dollars.

CONCLUSION

Neurologic symptoms are the most common medical complaint requiring air-to-ground medical support and are second only to cardiovascular problems for emergency diversions and their resultant costs to the US airline industry. Adding antiepileptic drugs to the onboard medical kit and greater emergency medical training for in-flight personnel could potentially reduce the number of diversions for in-flight neurologic incidents.

Randomized controlled trials to assess therapies for multiple sclerosis

MS poses formidable challenges to clinical investigators. Obstacles to the study of MS therapies include disease chronicity, an unpredictable clinical course, radiologic and pathologic heterogeneity, and limited understanding of the underlying pathophysiology. Randomized controlled trials (RCTs) provide a means to assess therapeutic efficacy while reducing the risks of study bias and confounding factors that influence interpretation of results. RCTs have demonstrated that type 1 interferons and glatiramer acetate alter the short-term natural history of MS and have served as the basis of approval for the marketing of these treatments. Improvements and optimization of trial methodology may hasten the discovery of effective therapies and facilitate better comparisons of the results of individual drug trials. The most urgent need is for improved surrogate end points for clinical outcome with predictive validity for long-term disability. Even if RCT methodology is optimal, however, several limitations inherent to MS trials threaten to impede further progress, including obstacles to long-term studies (e.g., costs), patient withdrawal, and escalating sample size requirements to detect partial therapeutic benefit. There is a crucial need to develop alternative investigative methods, possibly through enhanced collaboration across centers and with industry, and by exploring innovative techniques to use existing RCT and natural history databases to greater advantage.

A randomized trial of intravenous immunoglobulin in inflammatory demyelinating optic neuritis

OBJECTIVE

To determine whether IV immunoglobulin (IVIg) reverses chronic visual impairment in MS patients with optic neuritis (ON).

METHODS

In this double-blind, placebo-controlled Phase II trial, 55 patients with persistent acuity loss after ON were randomized to receive either IVIg 0.4 g/kg daily for 5 days followed by three single infusions monthly for 3 months, or placebo.

RESULTS

The trial was terminated by the National Eye Institute because of negative results when 55 of the planned 60 patients had been enrolled. Fifty-two patients completed the scheduled infusions, and 53 patients completed 12 months of follow-up. Analysis of this data indicated that a difference between treatment groups was not observed for the primary outcome measure, improvement in logMAR visual scores at 6 months (p = 0.766). Exploratory secondary analyses suggested that IVIg treatment was associated with improvement in visual function (including logMAR visual scores at 6 months and visual fields at 6 and 12 months) in patients with clinically stable MS during the trial.

CONCLUSIONS

IVIg administration does not reverse persistent visual loss from ON to a degree that merits general use.

Multiple sclerosis: current pathophysiological concepts

Multiple sclerosis (MS) is an often disabling disease primarily affecting young adults that exhibits extraordinary clinical, radiological, and pathological heterogeneity. We review the following: (a) known environmental and genetic factors that contribute to MS susceptibility; (b) current knowledge regarding fundamental pathophysiological processes in MS, including immune cell recruitment and entry into the central nervous system (CNS), formation of the plaque, and orchestration of the immune response; (c) descriptive and qualitative distinct pathological patterns in MS and their implications; (d) the evidence supporting the causative role of direct toxins, cell-mediated and humorally mediated immune mechanisms, and the concept of a "primary oligodendrogliopathy" in demyelination and axonal injury; (e) the potential benefits of inflammation; (f) the prospects for remyelination; and (g) therapeutic implications and approaches suggested by putative pathophysiological mechanisms.

Early versus late antiepileptic drug withdrawal for people with epilepsy in remission

BACKGROUND

Antiepileptic drugs ( AEDs) are used to prevent seizures but are associated with both short and long term adverse effects. When epilepsy is in remission, it may be in the patient's best interest to discontinue medication. However, the optimal timing of AED discontinuation is not known.

OBJECTIVES

To quantify seizure relapse risk after early (less than two seizure free years) versus late (more than two seizure free years) AED withdrawal in adult and pediatric epilepsy patients. To assess which variables modify the risk of seizure recurrence.

SEARCH STRATEGY

We searched the Cochrane Epilepsy Group trials register, the Cochrane Controlled trials register (Cochrane Library Issue 4, 2000), MEDLINE (January 1996 to January 2001), EMBASE, Index Medicus, CINAHL, as well as hand-searching of journals.

SELECTION CRITERIA

Randomized controlled trials that evaluate withdrawal of AEDs after varying periods of seizure remission in adult and pediatric epilepsy patients with or without blinding were included. Included studies compared an early versus late AED discontinuation.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. Relative risks with 95% confidence intervals were calculated for each trial. Summary relative risks and 95% confidence intervals for dichotomous data were calculated using a random effects model. A test of statistical heterogeneity was conducted for each pooled relative risk calculation.

MAIN RESULTS

Seven eligible controlled trials were included in the analysis representing 924 randomized pediatric patients. There were no eligible trials evaluating adult seizure free patients. The pooled relative risk for seizure relapse in early versus late AED withdrawal was 1.32 (95% confidence interval 1.02 to 1.70). On the basis of this estimate, the number needed to harm, that is expose an individual to a higher risk of seizure relapse because of early withdrawal of AED, is 10. Early discontinuation was associated with greater relapse rates in patients with partial seizures[pooled RR = 1.52; 95% confidence interval 0.95 to 2.41] or an abnormal EEG [pooled RR=1.67; 95% confidence interval 0.93 to 3.00].

REVIEWER'S CONCLUSIONS

There is evidence to support waiting for at least two or more seizure free years before discontinuing AEDs in children, particularly if individuals have an abnormal EEG and partial seizures. There is insufficient evidence to establish when to withdraw AEDs in pediatric patients with generalized seizures. There is no evidence to guide the timing of withdrawal of AEDs in adult seizure free patients. Further blinded randomized controlled trials are needed to identify the optimal timing of AED withdrawal and risk factors predictive of relapse.

Multiple sclerosis: epidemiology, genetics, classification, natural history, and clinical outcome measures

Advances in MR imaging and randomized controlled-trial methodology have fundamentally altered the diagnosis and investigation of multiple sclerosis (MS). Further progress in epidemiology and classification will provide clues toward identification of the genetic and environmental factors that predispose to MS and dictate its course. More detailed understanding of the descriptive natural (untreated) history of the disease and development of intermediate and surrogate outcome measures, with better validity and reliability, will increase the likelihood that future clinical trials will identify beneficial treatments to reduce disability. This article reviews the current state of knowledge of MS epidemiology, genetics, disease classification, natural history, and outcome measures.

The natural history of multiple sclerosis: a geographically based study: 8: familial multiple sclerosis

We have examined the demographics and long-term outcome of 1044 patients with sporadic and familial multiple sclerosis in a population-based cohort from London, Ontario. The mean follow-up was 25 years in duration, and by this time most patients had reached the unambiguous endpoint scores of the Kurtzke disability status scale (DSS), DSS 6, 8 or 10. An affected family member was identified in 19.8% of the total population, and this subgroup was further divided arbitrarily into the following three groups by the type and number of relatives affected: (i) first degree only; (ii) first degree plus others; (iii) second or third degree. The outcome in these groups was compared with that for those patients who, at a mean 25 year follow-up, had no relatives known to be affected. Familial cases closely resembled those remaining sporadic in both demographics and outcome, although onset in the most heavily loaded families was earlier and male/female ratio was greater. The times to DSS 6, 8 and 10 did not differ significantly when sporadic, familial and familial subgroups were compared. These results provide no clinical support for viewing familial multiple sclerosis as distinct from the sporadic form. The observed recurrence rate for siblings in a strictly defined epidemiological sample was 3.5%, much as projected. These results validate the recurrence risks which have previously been derived from age-corrected data for these first-degree relatives.