PracticeUpdate Neurology June 2019

EDITOR’S PICKS 14

Atypical CIDP: Diagnostic Criteria, Progression, and Treatment Response Journal of Neurology, Neurosurgery, and Psychiatry Take-home message • There are atypical variants of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) that lack well-established diagnostic criteria and sufficient data on natural history and response to therapy. The authors propose a set of diagnostic criteria for atypical CIDP, which include distal acquired demyelinating symmetric neuropathy (DADS), purely motor or sensory CIDP, Lew- is-Sumner syndrome (LSS), and focal CIDP. In the Italian database utilized, 18% of patients had an atypical form of CIDP. Patients with DADS and LSS tended to have a lower rate of response to therapy (64% and 67%, respectively) compared with patients who have typical CIDP (87%). • DADS and LSS may have a different underlying mech- anism than typical CIDP since they respond less well to IVIG therapy. Codrin Lungu MD Abstract OBJECTIVES A few variants of chronic inflammatory demyelinating polyra- diculoneuropathy (CIDP) have been described, but their frequency and evolution to typical CIDP remain unclear. To determine the frequency and characteristics of the CIDP variants, their possible evolution to typ- ical CIDP, and treatment response. METHODS We applied a set of diagnostic criteria to 460 patients included in a database of Italian patients with CIDP. Clinical characteristics and treatment response were reviewed for each patient. The Kaplan-Meier curve was used to estimate the progression rate from atypical to typ- ical CIDP. RESULTS At the time of inclusion, 376 (82%) patients had a diagnosis of typical CIDP while 84 (18%) had atypical CIDP, including 34 (7%) with dis- tal acquired demyelinating symmetric neuropathy (DADS), 17 (4%) with purely motor, 17 (4%) with Lewis-Sumner syndrome (LSS) and 16 (3.5%) with purely sensory CIDP. Based on retrospective review of the symp- toms and signs present at onset and for at least 1year, 180 (39%) patients had an initial diagnosis compatible with atypical CIDP that in 96 (53%) patients evolved to typical CIDP. Mean disease duration was longer in patients evolving to typical CIDP than in those not evolving (p=0.0016). Patients with DADS and LSS had a less frequent response to immuno- globulin than those with typical CIDP, while patients with purely motor and sensory CIDP had a similar treatment response. CONCLUSIONS The proportion of patients with atypical CIDP varies dur- ing the disease course. DADS and LSS have a less frequent response to intravenous immunoglobulin compared with typical CIDP, raising the possibility of a different underlying pathogenetic mechanism. Atypical CIDP: Diagnostic Criteria, Progression and Treatment Response. Data From the Italian CIDP Database. J Neurol Neurosurg Psychiatr 2019 Feb 01;90(2)125-132, PE Doneddu, D Cocito, F Manga- nelli, et al. www.practiceupdate.com/c/79218

MRI or CT Before Treatment in Acute Ischemic Stroke Stroke: A Journal of Cerebral Circulation Take-home message • The authors of this study evaluated data from ischemic stroke patients recruited to the THRACE randomized trial of mechan- ical thrombectomy after intravenous tPA. Patients were adults presenting within 4.5 hours of stroke symptom onset, NIHSS score of 10 to 25, with a proximal cerebral artery occlusion identified on imaging. Site investigators could choose their imaging screening modality of CT or MRI. The authors sought to compare workflow, times to treatment, and functional out- come between modalities. Of the randomized patients, 401 were included in the analysis; 299 in the MRI group and 102 in the CT group. Median scan duration in the MRI and CT groups were 13 minutes and 9 minutes, respectively. Despite longer scanning time in the MRI group, the time from scan to tPA was slightly less in the MRI cohort. • Functional outcomes were no different between image groups. The use of MRI should be promoted given its imaging advantages over CT. Mona Bahouth MD Abstract BACKGROUND AND PURPOSE The acute management of stroke patients requires a fast and efficient screening imaging modality. We compared workflow and functional outcome in acute ischemic stroke patients screened by magnetic resonance imaging (MRI) or computed tomogra- phy (CT) before treatment in the THRACE trial (Thrombectomie des Artères Cérébrales), with the emphasis on the duration of the imaging step. METHODS The THRACE randomized trial (June 2010 to February 2015) evaluated the efficacy of mechanical thrombectomy after intravenous tPA (tissue-type plasminogen activator) in ischemic stroke patients with proxi- mal occlusion. The choice of screening imaging modality was left to each enrolling center. Differences between MRI and CT groups were assessed using univariable analysis and the impact of imaging modality on favora- ble 3-month functional outcome (modified Rankin Scale score of ≤2) was tested using multivariable logistic regression. RESULTS Four hundred one patients were included (25 centers), compris- ing 299 MRI-selected and 102 CT-selected patients. Median baseline National Institutes of Health Stroke Scale score was 18 in both groups. MRI scan duration (median [interquartile range]) was longer than CT (MRI: 13 minutes [10-16]; CT: 9 minutes [7-12]; P<0.001). Stroke-onset-to-imaging time (MRI: median 114 minutes [interquartile range, 89-138]; CT: 107 minutes [88-139]; P=0.19), onset-to-intravenous tPA time (MRI: 150 minutes [124-179]; CT: 150 minutes [123-180]; P=0.38) and onset-to-angiography-suite time (MRI: 200 minutes [170-250]; CT: 213 minutes [180-246]; P=0.57) did not differ between groups. Imaging modality was not significantly associated with functional outcome in the multivariable analysis. CONCLUSIONS Although MRI scan duration is slightly longer than CT, MRI- based selection for acute ischemic stroke patients is accomplished within a timeframe similar to CT-based selection, without delaying treatment or impacting functional outcome. This should help to promote wider use of MRI, which has inherent imaging advantages over CT. Magnetic Resonance Imaging or Computed Tomography Before Treat- ment in Acute Ischemic Stroke. Stroke 2019 Mar 01;50(3)659-664, C Provost, M Soudant, L Legrand, et al. www.practiceupdate.com/c/80606

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