意識障害の患者において代謝性脳症は比較的よく遭遇する病態であり，脳波はその診断と病勢の把握に有用である。代謝性脳症の脳波所見は，意識障害の程度と関係して，基礎律動・後頭部優位律動の徐波化や消失，間欠的律動性または持続性高振幅の全般性デルタ活動，三相波（Triphasic wave）を呈する場合もある。三相波は，陰−陽−陰の三相性からなる特徴的な波形で，肝性脳症を含む代謝性脳症で認めることが多い。中毒の脳波所見の中に両側同期性の全般性周期性放電（Generalized Periodic Discharges（GPDs））を呈するものがある。薬物関連では，炭酸リチウム，テオフィリンなどが挙げられ，セフェピム脳症によるものも知られる。三相波/GPDs においては，非けいれん性てんかん重積（NCSE）の可能性についても常に念頭に置く必要がある。代謝性・中毒性脳症の脳波は原因検索に必ずしも特異的な所見を示すわけではないが，特徴的な脳波所見を示す場合があり，また非侵襲的に早期から病態の客観的な評価が可能であり，積極的に活用すべきである。

意識障害患者の診療において脳波は非常に有用な臨床検査である。一方で，誤って解釈すると診断や治療に大きな影響を及ぼしうる。本稿では，特に高齢者を対象に，意識障害患者における脳波の有用性と注意点を，①客観的な脳機能評価，②非けいれん性てんかん重積状態（NCSE）の診断，③三相波の解釈の3 点に関して概説する。すなわち，高齢者は詳細な神経学的診察が難しいことも多く，脳波は意識障害時の経時的な客観的脳機能評価に有用である。また，高齢者はNCSE の頻度が高いが，その診断には脳波が必須であり，近年ザルツブルグ基準が診断基準としてよく用いられている。最後に，三相波は従来代謝性脳症と関連する波形と考えられてきたが，近年ictal-interictal continuum としての意味合いもあることが分かり，その解釈には注意を要する。神経救急・集中治療の分野で脳波が益々有効かつ適切に活用されることが期待される。

救急・ICU管理において脳波モニタリングが有用な疾患として，感染などを契機に発症する急性脳症がある。「二相性発作と遅発性拡散能低下を示す急性脳症（AESD）」と呼ばれる急性脳症は，発症時は熱性けいれん重積と鑑別が困難で，数日後に二相目の発作群発が起こるとともに高度の大脳白質の浮腫が出現する。発症時のMRIでは異常がみられないため，早期の熱性けいれんとの鑑別のために脳波が重要である。またICUで鎮静下に治療を行うため臨床観察のみでは発作の診断が困難で，脳波モニタリングが治療の指標になる。近年は急性脳症に対して低体温療法を試みることが増えており，低体温療法中の脳波所見も知っておく必要がある。これらのICU脳波モニタリングにはamplitude-integrated EEGやdense spectral arrayなどのトレンドグラムが有用である。

〔背景〕神経救急・集中治療におけるモニタリングである脳波を，時間外あるいは休日に意識障害患者が来院しても医師あるいは看護師により容易に施行することを可能とする簡易的脳波測定デバイスの開発を，2013年より日本臨床救急医学会ACEC委員会と日本光電社との共同研究により開始した。〔経過および現況〕開発に際して，ERにおける意識障害患者に対して脳波測定に不慣れな医療従事者においても簡単かつ迅速に脳波測定ができることを目標とした。これらをみたすデバイスを作製して脳波データをBluetooth^Ⓡでモニターに電送してモニタリングすることが可能となった。〔今後の展望〕現在当施設において完成機が導入されているが，脳波の評価の難しさなどにより脳波に不慣れな医療従事者が十分使いこなしている状況ではない。しかし，このデバイスを用いて脳波測定中に脳波室に院内LANを用いて遠隔監視できるシステムを構築して問題点に対する対応を行っている。

To evaluate the role of a comprehensive stroke center in community medicine, the achievements of a stroke emergency care system at our institute and the Yokohama City Bureau were reviewed. The Yokohama-shi Cerebrovascular Disease Emergency Care System was developed in 2008 in cooperation with the City Medical Bureau, emergency services, and thirty participating medical institutions. This system specialized in stroke care and treated the patients suspected of having acute stroke based on assessments made by emergency services. After being transferred to participating hospitals, 3-400 patients in the whole city area per year were diagnosed as having an acute brain infarct and were treated with alteplase for thrombolysis. From April 2016 to March 2017, our institute treated 22 patients with thrombolysis out of 127 hospitalized stroke patients through stroke hot line from emergency service. Our stroke hot line is connected to the Yokohama-shi Cerebro-vascular Disease Emergency Care System and is clinically informative, particularly for intensive therapy of acute brain infarcts. However, many non-stroke patients have been encountered through the stroke hot line, and some true stroke patients have conditions mimicking general emergency diseases. To avoid clinical errors which are pitfall so-called, neuro-emergency specialists must have a broad unbiased diagnostic perspective.

Acute stroke is the leading cause of morbidity and mortality. The emergency medical technicians (EMTs) must confirm acute stroke rapidly at the scene and transport these patients to the applicable medical facilities for treatment. Acute stroke presents with neurologic deficits, and many conditions may present with stroke-like symptoms, known as stroke mimics. This study aims to analyze the characteristics of stroke mimics affecting prehospital identification transported to Wakayama Medical University by helicopter emergency medical service during 7.5 years. Totally 349 patients were identified as potential strokes by EMTs, of which 284 (81.4%) had a definitive diagnosis of acute stroke, and 65 (18.6%) were stroke mimics. Epileptic Seizure was the most likely to be misdiagnosed as acute stroke. While all cases of acute stroke required admission to hospital, 10 patients of stroke mimics needed no hospitalization due to dramatic symptomatic recovery. The major symptoms of stroke mimics judged as acute stroke by EMTs were consciousness disturbance, hemiparesis, eye deviation. In these cases, there were 5 cases of the ipsilateral hemiparesis with eye deviation following seizure. Overtriage for potential strokes by EMTs should be acceptable. However, follow-up medical inspection is educationally important for EMTs to improve the quality of prehospital emergency care.

Guillain-Barré syndrome (GBS) is an autoimmunological demyelinating polyneuropathy that may occur after a traumatic event. We describe a case of suspected GBS following a traumatic brain injury. A 49-year-old man was transferred to our hospital after a motor cycle accident. On arrival, his consciousness level was GCS 14 and he had no motor weakness. Head CT revealed left acute subdural hematoma, cerebral contusion and traumatic subarachnoid hemorrhage. Conservative treatment was chosen, but right upper and lower limb weakness developed and his consciousness level worsened. Hematoma removal and craniotomy were performed 2 days after the trauma. The postoperative course was uneventful and the patient was extubated 3 days after the operation. However, respiratory failure, hypoxemia and circulatory disorder developed 3 days after the extubation, with accompanying loss of the deep tendon reflex and bilateral limb weakness. Neuromuscular disorder was suspected, and a spinal tap and motor conduction test revealed cyto-albuminological dissociation and axonal peripheral polyneuropathy. GBS was diagnosed and intravenous immunoglobulin was started 20 days after the trauma. The patient was weaned from the ventilator on the next day, and cerebrospinal fluid findings and clinical symptoms recovered gradually. He was discharged 6 months after the accident. The correct diagnosis of GBS in this case contributed to recovery of the patient.

Simultaneous onset of ruptured intracranial and intra-abdominal aneurysms are rare. We report the case of a patient who suffered from a subarachnoid hemorrhage (SAH), coexisting intra-abdominal hematoma. A 51-year-old man was transferred from another hospital for consciousness disturbance with hemodynamic instability. The contrast computed tomography (CT) showed SAH caused by the left ruptured vertebral artery dissecting aneurysm and intraabdominal hematoma caused by the ruptured posterior superior pancreaticoduodenal artery aneurysm. On CT examination of abdomen with contrast, another finding of the compression of celiac artery by midline arcuate ligament in were revealed. He was diagnosised with median arcuate ligament syndrome. Transcatheter arterial embolization (TAE) of the ruptured posterior superior pancreaticoduodenal artery was first attempted to control the bleeding. After successful of abdominal hemostasis was achieved by TAE, a coil embolization with stent combination was performed for the left ruptured vertebral artery dissecting aneurysm. He was transferred to a rehabilitation hospital at modified rankin scale 1 after treatment. We should be considered the possible of the coexisting of intra-abdominal hematoma for severe SAH with hemodynamic instability.

Introduction: We reported a case of primary central nervous system lymphoma after craniotomy for organized chronic subdural hematoma. Case: A 62-year-old man. History: The patient was diagnosed with chronic subdural hematoma in a neurosurgical clinic 10 years ago. Six years ago, head magnetic resonance imaging (MRI) was performed in our hospital and he was diagnosed with organized chronic subdural hematoma, but there was no intervention. He presented with right paralysis and was transported to our hospital. On physical examination, consciousness was clear and right upper and lower limb was mildly paralyzed. Based on head computed tomography (CT) and MRI results, he was diagnosed with organized chronic subdural hematoma. Because his symptoms were mild and not representative of acute onset hematoma, he was started on tranexamic acid and had scheduled follow-ups in the outpatient clinic. Two months later, he experienced a seizure and was transported to our hospital. Course: The cause of seizure was judged to be organized chronic subdural hematoma; craniotomy was performed. Size of the organized hematoma decreased, and pathological examination did not show any malignant findings. He was transferred for rehabilitation 2 months after craniotomy. He continued rehabilitation but his consciousness level declined; thus head MRI was performed 6 months after craniotomy. A tumor mass lesion in the cerebral hemisphere was suspected; he was admitted to our hospital. We suspected a primary brain tumor and performed craniotomy. Pathological examination showed malignant lymphoma diffuse large B-cell type. We started chemotherapy, but he died after 4 months. Conclusions: Organized chronic subdural hematoma with long term hematoma can cause malignant lymphoma and requires caution.

Background: Cervical level posterior spinal artery infarction is very rare among spinal cord infarcts. Case: The patient was a 69-year-old male with paroxysmal atrial fibrillation and high blood pressure under treatment with oral apixaban, pilsicainide and azilsartan. He became aware of numbness and movement disorder of the left arm, and visited our hospital. He presented with Horner syndrome; hypoesthesia of the left anterior chest, left face and left upper limb; mild motor paralysis; and deep sensory disturbance of the left upper limb. Diffusionweighted MRI showed a high signal on the dorsal medial side at the first cervical level. The diagnosis was cervical posterior spinal artery syndrome. A cerebral angiogram showed no abnormality in surrounding blood vessels, including the posterior spinal artery. Paralysis improved relatively quickly, and sensory disorders improved with a delay. His only risk factor was paroxysmal atrial fibrillation. Discussion: Posterior spinal artery syndrome causes symptoms such as deep sensory disorder, total sensory depletion at the medullary level, and motor paralysis. In this case, we speculate that Horner syndrome manifested due to an effect on the posterior lateral cord. Thus, cerebral infarction in the posterior spinal artery region can have various symptoms and care is needed for diagnosis.

A 42-year-old male patient was admitted to our hospital because of generalized convulsive status epilepticus (GCSE), disturbance of consciousness, and shock. He had cardiopulmonary arrest after arrival our hospital, but he was return of spontaneous circulation as soon as cardiopulmonary resuscitation. He had disseminated intravascular coagulation (DIC) and multiple organ dysfunction. From the time of admission, we managed about the patient's breathing, circulation, body temperature. We also administrated sodium valproate 400mg, levetiracetam 1,000mg daily, and continuous use of midazolam to status epilepticus. In addition, he underwent continuous renal replacement therapy because of acute renal failure. The electroencephalogram showed scattered delta waves. Brain MR images showed hyper-intense lesions at bilateral pallidum and thalami, which led to a diagnosis of hypoxic encephalopathy associated with long-term GCSE. On day 13, he started tracking our fingers with his eyes. On day 34, he was able to obey commands and he was transferred to the general ward. GCSE is known to exhibit various organ dysfunctions. In this case, there was a history of epilepsy and had developed on GCSE, but as a result of the clinical examination, it was considered epilepsy-related organ dysfunction because the cause of multiple organ dysfunction was not clear.

In recent years, brain-dead organ donation has been increasing in Japan, but the number is still extremely low compared to Western countries. To date, we have encountered 8 brain-dead organ donation cases at Hamamatsu Medical Center. To enhance brain-dead organ donation, it is important to develop a sustainable system for the organ donation process rather than employ a temporary approach for an individual case. From this point of view, we intended to share many roles with many doctors and staffs in order to escape excess burden to particular persons. Additionally, we adjusted the schedule of brain death determination and organ donations in order not to disturb routine hospital functions. However, some staffs still took on the heavy burden during these processes. And some problems related to privacy protection appeared. These efforts clarified the importance to share the knowledge accumulated through such experiences.