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To address practical issues in measuring autoantibodies to neuronal cell-surface antigens (NSAs) in various autoimmune neurological disorders (ANDs).We retrospectively reviewed the clinical information of 221 patients with clinically suspected ANDs who underwent antibody testing for NSAs between January 2007 and September 2017. 31 were excluded. In 190 patients, antibody-detection rate (ADR) and antibody-phenotype association were assessed.Fifty-four patients had NSA-antibodies: NMDA receptor (NMDAR) (n = 39), AMPA receptor (n = 3), leucine-rich glioma inactivated 1 (LGI1) (n = 3), glycine receptor (GlyR) (n = 3), GABA(A) receptor (n = 2), GABA(B) receptor (n = 1), metabotrophic glutamate receptor 5 (n = 1), or unknown (n = 6); 3 had multiple NSA-antibodies. ADR in patients with diagnostic criteria for "possible autoimmune encephalitis (AE)", "probable anti-NMDAR encephalitis", "definite autoimmune limbic encephalitis (ALE)", and "stiff-person spectrum disorder (SPSD)", was 34% (46/134), 85% (34/40), 46% (11/24), and 22% (4/18), respectively, but NSA-antibodies were not identified in 11 patients with systemic autoimmune disorders (SADs). Among 134 patients with "possible AE" criteria, NMDAR-antibodies were more frequently identified in patients with typical anti-NMDAR encephalitis than those without (34/40 [85%] vs. 4/94 [4%], p 0.0001). LGI1-antibodies were identified in patients with ALE but not in the others (3/24 [13%] vs. 0/110 [0%], p = 0.005). GlyR-antibodies were identified in those with stiff-person syndrome plus (2/8, 25%) or stiff-limb syndrome (1/6, 17%).NSA-antibodies were most frequently identified in "probable anti-NMDAR encephalitis", followed by "definite ALE", "possible AE", and "SPSD", but not identified in SADs. NMDAR, LGI1 and GlyR were associated with clinical phenotype. Cell-surface antigens should be determined based on individual phenotype.

Background Asymptomatic acute ischemic lesions (AIL) may be coincidentally found on brain magnetic resonance imaging (MRI) obtained during the acute phase of intracerebral hemorrhage, but its clinical significance has yet to be determined. The objective of this study is to determine the frequency of asymptomatic AIL, its characteristic features of brain MRI and risk factors in patients with acute intracerebral hemorrhage. Methods We retrospectively reviewed the clinical information of 108 patients with intracerebral hemorrhage who underwent brain MRIs within 30 days of hospitalization between April 2013 and January 2018. We determined the frequency of asymptomatic AIL, its brain MRI features, and risk factors. Results AIL was found in 26 of 108 patients; symptomatic in 2 and asymptomatic in 24 (22.2%). Asymptomatic AIL were small, multiple, mainly distributed to the white matter in the anterior circulation (22/24, 91.7%), and occasionally seen in deep watershed areas (15/24, 62.5%). Only 2 patients had severe major vessel stenosis. Asymptomatic AIL was associated with high mean blood pressure (BP) on admission (> 145 mmHg), excessive drug-induced reduction in mean BP (≥ 55 mmHg), and large hemorrhage (> 31 mL in volume). Conclusions Asymptomatic AIL were found in 22.2% of patients with intracerebral hemorrhage within 30 days of hospitalization. Asymptomatic AIL were often small, multiple and occasionally developed in deep watershed areas despite the absence of major vessel stenosis. High mean BP on admission, excessive drug-induced BP reduction, and larger hemorrhage may be a risk factor for development of asymptomatic AIL.

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a distinct clinical syndrome caused by mutations in the mitochondrial DNA. The pathogenesis of stroke-like episodes remains unknown but major vessels stenosis is not a cause of stroke-like episodes. We describe a novel heteroplasmic G617A transition in the mitochondrial transfer RNA phenylalanine gene in a patient with encephalomyopathy who presented with recurrent embolic ischemic strokes accompanied by transient occlusion of middle cerebral, anterior cerebral and internal carotid arteries. These ischemic strokes were presumed to be artery-to artery embolisms associated with carotid artery stenosis. Single muscle fiber analysis revealed the pathogenicity of the mutation although its causative role on carotid artery stenosis remains to be elucidated. This case expands phenotypic spectrum of mitochondrial disorders in terms of macroangiopathy, but macroangiopathy-related ischemic strokes should be distinguished from classic stroke-like episodes of MELAS that are speculated to be microangioapthy-related or non-ischemic neurovascular events.

Background: Ischemic vascular hypothesis as a causative role in the pathogenesis of stroke-like episodes in MELAS remains to be debated. Methods: This study consisted of two parts. Part 1 is a clinicoradiological study during acute stage of 18 consecutive stroke-like episodes in six patients with MELAS. Part 2 is a SPECT study to assess the regional cerebrovascular reactivity (rCVR) to acetazolamide during chronic stage in five patients with MELAS. Results: Headache and epileptic seizure were the most common presenting symptoms. Unique features of acute stroke-like lesions included progressive spread of cortical lesions with vasogenic edema, focal periodic epileptiform discharges, focal hyperperfusion, and cortical laminar necrosis during subacute stage. During chronic stage, SPECTshowed hypoperfusion in non-affected occipital cortex in three patients as well as in previously affected regions in four. The rCVR was preserved in three patients, focally impaired in one, and extensively impaired in one, but relatively preserved in the occipital cortex in all patients. Conclusions: Stroke-like episodes could be non-ischemic neurovascular events initiated by neuronal hyperexcitability. Once neuronal hyperexcitability develops in a focal brain region, epileptic activities depolarize adjacent neurons, leading to a propagation of epileptic activities into the surrounding cortex, and resulting in energy imbalance. The mechanisms for neuronal hyperexcitability remain to be elucidated.