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Dive into the research topics where B. Mark Keegan is active.

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Featured researches published by B. Mark Keegan.


JAMA Neurology | 2009

Treatment of neuromyelitis optica with mycophenolate mofetil: Retrospective analysis of 24 patients

Anu Jacob; Marcelo Matiello; Brian G. Weinshenker; Dean M. Wingerchuk; Claudia F. Lucchinetti; Elizabeth A. Shuster; Jonathan Carter; B. Mark Keegan; Sean J. Pittock

BACKGROUND Neuromyelitis optica (NMO) is the first inflammatory autoimmune demyelinating disease of the central nervous system for which a specific antigenic target has been identified; the marker autoantibody NMO-IgG specifically recognizes the astrocytic water channel aquaporin 4. Current evidence strongly suggests that NMO-IgG may be pathogenic. Since disability accrues incrementally related to attacks, attack prevention with immunosuppressive therapy is the mainstay of preventing disability. OBJECTIVE To evaluate the efficacy and safety of mycophenolate mofetil therapy in NMO spectrum disorders. DESIGN Retrospective case series with prospective telephone follow-up. SETTING Mayo Clinic Health System. Patients Twenty-four patients with NMO spectrum disorders (7 treatment-naive). Intervention Mycophenolate mofetil (median dose of 2000 mg per day). MAIN OUTCOME MEASURES Annualized relapse rates and disability (Expanded Disability Status Scale). RESULTS At a median follow-up of 28 months (range, 18-89 months), 19 patients (79%) were continuing treatment. The median duration of treatment was 27 months (range, 1-89 months). The median annualized posttreatment relapse rate was lower than the pretreatment rate (0.09; range, 0-1.5; and 1.3; range, 0.23-11.8, respectively; P < .001). Disability stabilized or decreased in 22 of 24 patients (91%). One patient died of disease complications during follow-up. Six patients (25%) noted adverse effects during treatment with mycophenolate. CONCLUSION Mycophenolate is associated with reduction in relapse frequency and stable or reduced disability in patients with NMO spectrum disorders.


PLOS ONE | 2014

Radiologically Isolated Syndrome: 5-Year Risk for an Initial Clinical Event

Darin T. Okuda; Aksel Siva; Matilde Inglese; Ilana Katz; Melih Tutuncu; B. Mark Keegan; Stacy L. Donlon; Le H. Hua; Angela Vidal-Jordana; Xavier Montalban; Alex Rovira; Mar Tintoré; Maria Pia Amato; Bruno Brochet; Jérôme De Seze; David Brassat; Patrick Vermersch; Nicola De Stefano; Maria Pia Sormani; Daniel Pelletier; Christine Lebrun; Club Francophone de la Sclérose en Plaques

Objective To report the 5-year risk and to identify risk factors for the development of a seminal acute or progressive clinical event in a multi-national cohort of asymptomatic subjects meeting 2009 RIS Criteria. Methods Retrospectively identified RIS subjects from 22 databases within 5 countries were evaluated. Time to the first clinical event related to demyelination (acute or 12-month progression of neurological deficits) was compared across different groups by univariate and multivariate analyses utilizing a Cox regression model. Results Data were available in 451 RIS subjects (F: 354 (78.5%)). The mean age at from the time of the first brain MRI revealing anomalies suggestive of MS was 37.2 years (y) (median: 37.1 y, range: 11–74 y) with mean clinical follow-up time of 4.4 y (median: 2.8 y, range: 0.01–21.1 y). Clinical events were identified in 34% (standard error = 3%) of individuals within a 5-year period from the first brain MRI study. Of those who developed symptoms, 9.6% fulfilled criteria for primary progressive MS. In the multivariate model, age [hazard ratio (HR): 0.98 (95% CI: 0.96–0.99); p = 0.03], sex (male) [HR: 1.93 (1.24–2.99); p = 0.004], and lesions within the cervical or thoracic spinal cord [HR: 3.08 (2.06–4.62); p = <0.001] were identified as significant predictors for the development of a first clinical event. Interpretation These data provide supportive evidence that a meaningful number of RIS subjects evolve to a first clinical symptom. An age <37 y, male sex, and spinal cord involvement appear to be the most important independent predictors of symptom onset.


JAMA Neurology | 2011

Beneficial Plasma Exchange Response in Central Nervous System Inflammatory Demyelination

Setty M. Magaña; B. Mark Keegan; Brian G. Weinshenker; Bradley J. Erickson; Sean J. Pittock; Vanda A. Lennon; Moses Rodriguez; Kristine M. Thomsen; Stephen D. Weigand; Jay Mandrekar; Linda Linbo; Claudia F. Lucchinetti

BACKGROUND Plasma exchange (PLEX) is a beneficial rescue therapy for acute, steroid-refractory central nervous system inflammatory demyelinating disease (CNS-IDD). Despite the approximately 45% PLEX response rate reported among patients with CNS-IDD, determinants of interindividual differences in PLEX response are not well characterized. OBJECTIVE To perform an exploratory analysis of clinical, radiographic, and serological features associated with beneficial PLEX response. DESIGN Historical cohort study. SETTING Neurology practice, Mayo Clinic College of Medicine, Rochester, Minnesota. Patients All Mayo Clinic patients treated with PLEX between January 5, 1999, and November 12, 2007, for a steroid-refractory CNS-IDD attack. MAIN OUTCOME MEASURE The PLEX response in attack-related, targeted neurological deficit(s) assessed within the 6-month period following PLEX. RESULTS We identified 153 patients treated with PLEX for a steroid-refractory CNS-IDD, of whom 90 (59%) exhibited moderate to marked functional neurological improvement within 6 months following treatment. Pre-PLEX clinical features associated with a beneficial PLEX response were shorter disease duration (P = .02) and preserved deep tendon reflexes (P = .001); post-PLEX variables included a diagnosis of relapsing-remitting multiple sclerosis (P = .008) and a lower Expanded Disability Status Scale score (P < .001) at last follow-up. Plasma exchange was less effective for patients with multiple sclerosis who subsequently developed a progressive disease course (P = .046). Radiographic features associated with a beneficial PLEX response were presence of ring-enhancing lesions (odds ratio = 4.00; P = .03) and/or mass effect (odds ratio = 3.00; P = .02). No association was found between neuromyelitis optica-IgG serostatus and PLEX response. CONCLUSIONS We have identified clinical and radiographic features that may aid in identifying patients with fulminant, steroid-refractory CNS-IDD attacks who are more likely to respond to PLEX.


Neurology | 2006

REM sleep behavior disorder initiated by acute brainstem multiple sclerosis

Maja Tippmann-Peikert; Bradley F. Boeve; B. Mark Keegan

REM sleep behavior disorder (RBD) is defined by loss of normal skeletal muscle atonia during REM sleep, resulting in excessive, often violent motor activity, frequently associated with dreaming.1 RBD is typically a chronic disorder occurring idiopathically or accompanying neurologic disease, particularly the neurodegenerative synucleinopathies of Parkinson disease, multiple-system atrophy, and dementia with Lewy bodies.2 Acute RBD may be associated with alcohol and psychoactive substance intoxication or withdrawal and structural brain lesions. The anatomic lesion site and time course of acute RBD are not well known. We report RBD arising following a severe attack of dorsal pontine demyelination from multiple sclerosis (MS). A 51-year-old woman with MS developed acute vertigo, ataxia, diplopia, dysarthria, and bifacial weakness. She had been in clinical remission for 24 years without immunomodulatory therapy. Following repeated courses of IV corticosteroids and therapeutic plasma exchange (TPE), her symptoms improved markedly, and subcutaneous interferon β-1a was initiated. One week later, the patient’s husband of 28 years described that she exhibited nightly sleep-related groaning, screaming, limb jerking, flailing, and violent thrashing, punching her husband’s jaw once. She did not recall these events or any associated dream content. There were no prior parasomnias or spousal reports of …


Multiple Sclerosis Journal | 2013

Onset of progressive phase is an age-dependent clinical milestone in multiple sclerosis

Melih Tutuncu; Junger Tang; Nuhad Abou Zeid; Nilufer Kale; Daniel J. Crusan; Elizabeth J. Atkinson; Aksel Siva; Sean J. Pittock; Istvan Pirko; B. Mark Keegan; Claudia F. Lucchinetti; John H. Noseworthy; Moses Rodriguez; Brian G. Weinshenker

Background: It is unclear if all patients with relapsing–remitting multiple sclerosis (RRMS) ultimately develop progressive MS. Onset of progressive disease course seems to be age- rather than disease duration-dependent. Some forms of progressive MS (e.g. primary progressive MS (PPMS)) are uncommon in population-based studies. Ascertainment of patients with PPMS from clinic-based populations can facilitate a powerful comparison of age at progression onset between secondary progressive MS (SPMS) and PPMS but may introduce unclear biases. Objective: Our aim is to confirm that onset of progressive disease course is more relevant to the patient’s age than the presence or duration of a pre-progression relapsing disease course in MS. Methods: We studied a population-based MS cohort (n=210, RRMS n=109, progressive MS n=101) and a clinic-based progressive MS cohort (n=754). Progressive course was classified as primary (PPMS; n=322), single attack (SAPMS; n=112) and secondary progressive (SPMS; n=421). We studied demographics (chi2 or t-test), age-of-progression-onset (t-test) and time to Expanded Disability Status Scale of 6 (EDSS6) (Kaplan–Meier analyses). Results: Sex ratio (p=0.58), age at progression onset (p=0.37) and time to EDSS6 (p=0.16) did not differ between the cohorts. Progression had developed before age 75 in 99% of patients with known progressive disease course; 38% with RRMS did not develop progression by age 75. Age at progression onset did not differ between SPMS (44.9±9.6), SAPMS (45.5±9.6) and PPMS (45.7±10.8). In either cohort, only 2% of patients had reached EDSS6 before onset of progression. Conclusions: Patients with RRMS do not inevitably develop a progressive disease course. Onset of progression is more dependent on age than the presence or duration of a pre-progression symptomatic disease course. Moderate disability is sustained predominantly after the onset of a progressive disease course in MS.


JAMA Neurology | 2009

Multiple Sclerosis With Predominant, Severe Cognitive Impairment

Nathan P. Staff; Claudia F. Lucchinetti; B. Mark Keegan

OBJECTIVE To describe the characteristics of multiple sclerosis (MS) presenting with severe cognitive impairment as its primary disabling manifestation. DESIGN Retrospective case series. SETTING Tertiary referral center. Patients Patients were identified through the Mayo Clinic data retrieval system (1996-2008) with definite MS (McDonald criteria) and severe cognitive impairment as their primary neurological symptom without accompanying significant MS-related impairment or alternative diagnosis for cognitive dysfunction. Twenty-three patients meeting inclusion criteria were compared regarding demographics, clinical course, and radiological features. MAIN OUTCOME MEASURES Demographic, clinical, and radiological characteristics of the disease. RESULTS Twelve patients were men. The median age of the first clinical symptom suggestive of central nervous system demyelination was 33 years, and severe MS-related cognitive impairment developed at a median age of 39 years. Cognitive impairment could be dichotomized as subacute fulminant (n = 9) or chronic progressive (n = 14) in presentation, which corresponded to subsequent relapsing or progressive MS courses. Study patients commonly exhibited psychiatric (65%), mild cerebellar (57%), and cortical symptoms and signs (eg, seizure, aphasia, apraxia) (39%). Fourteen of 21 (67%), where documented, smoked cigarettes. Brain magnetic resonance imaging demonstrated diffuse cerebral atrophy in 16 and gadolinium-enhancing lesions in 11. Asymptomatic spinal cord magnetic resonance imaging lesions were present in 12 of 16 patients (75%). Immunomodulatory therapies were generally ineffective in improving these patients. CONCLUSIONS We describe patients with MS whose clinical phenotype is characterized by severe cognitive dysfunction and prominent cortical and psychiatric signs presenting as a subacute fulminant or chronic progressive clinical course. Cigarette smokers may be overrepresented in this phenotype.


Neurology | 2016

The contemporary spectrum of multiple sclerosis misdiagnosis: A multicenter study

Andrew J. Solomon; Dennis Bourdette; Anne H. Cross; Angela Applebee; Philip Skidd; Diantha B. Howard; Rebecca Spain; Michelle Cameron; Edward Kim; Michele Mass; Vijayshree Yadav; Ruth H. Whitham; Erin E. Longbrake; Robert T. Naismith; Gregory F. Wu; Becky J. Parks; Dean M. Wingerchuk; Brian Rabin; Michel Toledano; W. Oliver Tobin; Jonathan L. Carter; B. Mark Keegan; Brian G. Weinshenker

Objective: To characterize patients misdiagnosed with multiple sclerosis (MS). Methods: Neurologists at 4 academic MS centers submitted data on patients determined to have been misdiagnosed with MS. Results: Of 110 misdiagnosed patients, 51 (46%) were classified as “definite” and 59 (54%) “probable” misdiagnoses according to study definitions. Alternate diagnoses included migraine alone or in combination with other diagnoses 24 (22%), fibromyalgia 16 (15%), nonspecific or nonlocalizing neurologic symptoms with abnormal MRI 13 (12%), conversion or psychogenic disorders 12 (11%), and neuromyelitis optica spectrum disorder 7 (6%). Duration of misdiagnosis was 10 years or longer in 36 (33%) and an earlier opportunity to make a correct diagnosis was identified for 79 patients (72%). Seventy-seven (70%) received disease-modifying therapy and 34 (31%) experienced unnecessary morbidity because of misdiagnosis. Four (4%) participated in a research study of an MS therapy. Leading factors contributing to misdiagnosis were consideration of symptoms atypical for demyelinating disease, lack of corroborative objective evidence of a CNS lesion as satisfying criteria for MS attacks, and overreliance on MRI abnormalities in patients with nonspecific neurologic symptoms. Conclusions: Misdiagnosis of MS leads to unnecessary and potentially harmful risks to patients. Misinterpretation and misapplication of MS clinical and radiographic diagnostic criteria are important contemporary contributors to misdiagnosis.


Annals of Neurology | 2008

Autoimmune myelopathy associated with collapsin response-mediator protein-5 immunoglobulin G

B. Mark Keegan; Sean J. Pittock; Vanda A. Lennon

Several autoimmune myelopathies are recognized clinically. We describe 57 patients in whom serological evaluation for myelopathy of uncertain cause demonstrated collapsin response‐mediator protein 5 IgG. Most had spinal imaging and cerebrospinal fluid abnormalities and insidiously progressive presentation; some had acute monophasic or relapsing myelopathy. Initial diagnoses included multiple sclerosis, transverse myelitis, and unspecified neurodegenerative myelopathy. Most were smokers; neoplasia was discovered in 68% (most commonly small‐cell lung carcinoma and after collapsin response‐mediator protein‐5 IgG detection). Collapsin response‐mediator protein‐5 autoimmune myelopathy and occult neoplasia are important considerations in patients with insidiously progressive myelopathy, especially with known cancer risk. Ann Neurol 2008


Annals of Neurology | 2016

Discriminating long myelitis of neuromyelitis optica from sarcoidosis

Eoin P. Flanagan; Timothy J. Kaufmann; Karl N. Krecke; Allen J. Aksamit; Sean J. Pittock; B. Mark Keegan; Caterina Giannini; Brian G. Weinshenker

To compare longitudinally extensive myelitis in neuromyelitis optica spectrum disorders (NMOSD) and spinal cord sarcoidosis (SCS).


Neurology | 2015

Relapses and disability accumulation in progressive multiple sclerosis

M. Mateo Paz Soldán; Martina Novotna; Nuhad Abou Zeid; Nilufer Kale; Melih Tutuncu; Daniel J. Crusan; Elizabeth J. Atkinson; Aksel Siva; B. Mark Keegan; Istvan Pirko; Sean J. Pittock; Claudia F. Lucchinetti; Brian G. Weinshenker; Moses Rodriguez

Objective: We examined the effect of relapses—before and after progression onset—on the rate of postprogression disability accrual in a progressive multiple sclerosis (MS) cohort. Methods: We studied patients with primary progressive MS (n = 322) and bout-onset progressive MS (BOPMS) including single-attack progressive MS (n = 112) and secondary progressive MS (n = 421). The effect of relapses on time to Expanded Disability Status Scale (EDSS) score of 6 was studied using multivariate Cox regression analysis (sex, age at progression, and immunomodulation modeled as covariates). Kaplan-Meier analysis was performed using EDSS 6 as endpoint. Results: Preprogression relapses (hazard ratio [HR]: 1.63; 95% confidence interval [CI]: 1.34–1.98), postprogression relapses (HR: 1.37; 95% CI: 1.11–1.70), female sex (HR: 1.19; 95% CI: 1.00–1.43), and progression onset after age 50 years (HR: 1.47; 95% CI: 1.21–1.78) were associated with shorter time to EDSS 6. Postprogression relapses occurred in 29.5% of secondary progressive MS, 10.7% of single-attack progressive MS, and 3.1% of primary progressive MS. Most occurred within 5 years (91.6%) after progressive disease onset and/or before age 55 (95.2%). Immunomodulation after onset of progressive disease course (HR: 0.64; 95% CI: 0.52–0.78) seemingly lengthened time to EDSS 6 (for BOPMS with ongoing relapses) when analyzed as a dichotomous variable, but not as a time-dependent variable. Conclusions: Pre- and postprogression relapses accelerate time to severe disability in progressive MS. Continuing immunomodulation for 5 years after the onset of progressive disease or until 55 years of age may be reasonable to consider in patients with BOPMS who have ongoing relapses.

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