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Dive into the research topics where Hiromichi Miyazaki is active.

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Featured researches published by Hiromichi Miyazaki.


PLOS ONE | 2017

Histamine H2-Blocker and Proton Pump Inhibitor Use and the Risk of Pneumonia in Acute Stroke: A Retrospective Analysis on Susceptible Patients

Nobuhiko Arai; Tomoki Nakamizo; Hikaru Ihara; Takashi Koide; Akiyoshi Nakamura; Masanao Tabuse; Hiromichi Miyazaki

Background Although histamine H2-blockers (H2B) and proton pump inhibitors (PPI) are used commonly to prevent gastrointestinal bleeding in acute stroke, they are implicated in the increased risk of pneumonia in other disease populations. In acute stroke, the presence of distinctive risk factors of pneumonia, including dysphagia and impaired consciousness, makes inclusive analysis vulnerable to confounding. Our aim was to assess whether acid-suppressive drugs increase pneumonia in acute stroke in a population controlled for confounding. Methods We analyzed acute stroke patients admitted to a tertiary care hospital. To minimize confounding, we only included subjects who could not feed orally during 14 days of hospitalization. Exposure was defined as H2B or PPI, given in days; the outcome was development of pneumonia within this period. The incidence was calculated from the total number of pneumonias divided by the sum of person-days at risk. We additionally performed multivariate Poisson regression and propensity score analyses, although the restriction largely eliminated the need for multivariate adjustment. Results A total of 132 pneumonias occurred in 3582 person-days. The incidence was 3.69%/person-day (95% confidence interval (CI); 3.03–4.37%/day). All subjects had dysphagia. Stroke severity and consciousness disturbances were well-balanced between the groups exposed to H2B, PPI, or none. The relative risk (RR) compared with the unexposed was 1.22 in H2B (95%CI; 0.83–1.81) and 2.07 in PPI (95% CI; 1.13–3.62). The RR of PPI compared with H2B was 1.69 (95%CI; 0.95–2.89). In multivariate regression analysis, the RRs of H2B and PPI were 1.24 (95% CI; 0.85–1.81) and 2.00 (95% CI; 1.12–3.57), respectively; in propensity score analyses they were 1.17 (95% CI; 0.89–1.54) and 2.13 (95% CI; 1.60–2.84). Conclusions The results of this study suggested that prophylactic acid-suppressive therapy with PPI may have to be avoided in acute stroke patients susceptible to pneumonia.


NMC Case Report Journal | 2017

Late-Onset Massive Epistaxis due to a Ruptured Traumatic Internal Carotid Artery Aneurysm: A Case Report

Nobuhiko Arai; Akiyoshi Nakamura; Masanao Tabuse; Hiromichi Miyazaki

A traumatic internal carotid artery (ICA) aneurysm is rare and difficult to treat. Trapping of ICA is commonly performed owing to the difficulty of directly approaching ICA aneurysms. Recently, coiling the aneurysm itself was recommended if possible. However, it is controversial which of methods are best to completely treat aneurysm. We present the case of a 74-year-old man, who had experienced a head injury 8 years previously, with recurrent severe epistaxis. An ICA aneurysm was detected on computed tomography. The trapping and bypass was planned. However, sudden epistaxis occurred, we performed trapping to stop the bleeding and save his life. After the operation, no right ICA or aneurysm was detected. However, severe epistaxis recurred two months after the operation. In the second operation, a ligation of the common -/- external carotid artery and a severance of an ICA portion between the ophthalmic artery and the aneurysm were insufficient to stop the bleeding. This case indicates ICA trapping, even if a trapping portion is below an ophthalmic artery, is insufficient to treat an ICA aneurysm. ICA aneurysms should be suspected when a patient present with recurrent -/- massive epistaxis, who has a head injury history, even if it is far past.


Journal of Stroke & Cerebrovascular Diseases | 2018

Severe Reversible Cerebral Vasoconstriction Syndrome with Large Posterior Cerebral Infarction

Hiroki Yamada; Ryogo Kikuchi; Akiyoshi Nakamura; Hiromichi Miyazaki

Reversible cerebral vasoconstriction syndrome is characterized by thunderclap headache and multifocal cerebral vasoconstriction. Cerebral vasoconstriction is reversible, and most cases have good prognosis. However, clinical outcome is possibly severe when it is complicated by stroke, yet detailed reports on such a case are few. We experienced a case of severe reversible cerebral vasoconstriction syndrome in a 32-year-old woman with medical history of preeclampsia 3years prior. She presented with sudden sharp headache followed by altered mental status and vasoconstriction of the bilateral posterior cerebral arteries. She was treated with intravenous and oral calcium channel blockers, edaravone, and glycerol. However, the cerebral infarction in the posterior circulation subsequently remained, and her impaired consciousness did not recover. Furthermore, although imaging findings of vasoconstriction showed improvement a day after the occurrence of symptom, the same vessels showed poor visualization 7 weeks later, which indicated the recurrence of vasoconstriction, without additional symptom due to the fixed infarction. Although most cases of reversible cerebral vasoconstriction syndrome show good prognosis, neurologists must monitor the possibility of worse clinical course and permanent neurological deficit when associated with stroke, such as cerebral infarction. Strict management and treatment are needed in these cases.


Journal of Stroke & Cerebrovascular Diseases | 2018

Paroxysmal Sympathetic Hyperactivity after Surgery for Cerebral Hemorrhagic Arteriovenous Malformation: A Case Report

Hiroki Yamada; Ryogo Kikuchi; Jumpei Katayama; Akiyoshi Nakamura; Hiromichi Miyazaki

Paroxysmal sympathetic hyperactivity is a condition involving a sudden increase in body temperature, heart rate, blood pressure, respiratory rate, sweating, and posturing followed by severe brain injury. Most of the reported preceding disorders involve head trauma, followed by anoxic brain injury, and stroke. Here, we report an extremely rare case of 17-year-old man diagnosed with hemorrhagic arteriovenous malformation, underwent emergent surgery, was on prolonged sedation due to postoperative complications, and subsequently developed paroxysmal sympathetic hyperactivity. We recommend monitoring for paroxysmal sympathetic hyperactivity occurrence with severe brain injury patients, even when sedating.


Journal of Craniofacial Surgery | 2017

Spontaneous Intraventricular Pneumocephalus.

Nobuhiko Arai; Masanao Tabuse; Akiyoshi Nakamura; Hiromichi Miyazaki

Backgroud: Pneumocephalus without a known underlying cause is defined as spontaneous pneumocephalus. Few patients of intraventricular pneumocephalus have been reported. Patient Presentation: An 84-year-old man presented with dysarthria and incontinence. Computed tomography revealed an intraventricular pneumocephalus, thinning in the petrous bone, fluid in the air cells, and cleft in temporal lobe. A right subtemporal extradural approach was taken to detect bone-/-dural defects, and a reconstruction was performed using a musculo-pericranial flap. Conclusion: This is the first patient of an isolated intraventricular spontaneous pneumocephalus without any other site air involved. Surgical approaches to repair such bone and dura defects should be considered an appropriate option.


Journal of Craniofacial Surgery | 2016

Delayed Acute Subdural Hematoma Associated With Percutaneous Coronary Intervention.

Nobuhiko Arai; Akiyoshi Nakamura; Masanao Tabuse; Hiromichi Miyazaki

Background:Delayed acute subdural hematoma (DASH) is a subdural hematoma which is detected later. An initial computed tomography (CT) does not reveal any intracranial hemorrhage at all. Few patients of DASH after mild traumatic brain injury associated with percutaneous coronary intervention (PCI) have been published. Patient Presentation:A 63-year-old woman presented with cardiac pulmonary arrest due to acute myocardial infarction and lethal arrhythmia. She had hit her head on the road. The initial CT did not reveal any hemorrhage in the intra-cranium. She fully recovered after PCI. However, 1 hour after PCI, she lost consciousness and immediate CT showed acute subdural hematoma and subarachnoid hemorrhage. The period from losing consciousness to brain herniation presenting as anisocoria was very short—only 30 minutes in our patient. Although emergent evacuation of hematoma and external decompression were performed, the patient died 1 day after the operation. Conclusion:The authors encountered a patient of DASH after PCI that resulted in death. Clinicians should be aware that subdural hemorrhage can occur after PCI if no hemorrhage is noted in the initial head CT, and the operation should be performed as soon as possible when the consciousness level decreases.


Archive | 1993

Development and Treatment of Chronic Subdural Hematoma

Hiromichi Miyazaki; Ishiyama N; Kiyotaka Tamura; Hiroshi Kagami

One hundred eleven adult patients with chronic subdural hematoma (SDH) were reviewed. In 28% of the cases it was observed that traumatic subdural fluid collection (SFC) developed into chronic SDH in successive computed tomographic (CT) scans after the initial head injury. In 43% of the cases which had not been followed up after their head injury, it was assumed that there was also traumatic SFC initially which later developed into chronic SDH, considering the similarity in temporal course with the former group. It was proposed that traumatic SFC played an important role in the development of chronic SDH. As for treatment, 99 cases were operated upon; 31 patients underwent craniotomy and evacuation with membranectomy and later 68 patients had burr-hole and continuous drainage (simple drainage). Both methods produced comparable good results, clinically and radiographically. The advantages of simple drainage, i.e., gradual decompression and simplicity of the procedure make this method a first operative procedure. A theoretical basis supporting simple drainage is discussed.


Neurologia Medico-chirurgica | 1988

Intraoperative monitoring of brainstem auditory evoked potentials

Takayuki Ohira; Shigeo Toya; Moriichirou Takase; Yoshiki Nakamura; Hiromichi Miyazaki; Masashi Nakatsukasa; Yukio Ibata


No shinkei geka. Neurological surgery | 2000

[The stenoses at the terminal portion of the internal carotid artery improved after initiation of antithyroid therapy: a case report].

Wakamoto H; Ishiyama N; Hiromichi Miyazaki; Shinoda A; Tomita H


No shinkei geka. Neurological surgery | 2002

[A dissecting aneurysm of the posterior inferior cerebellar artery was reduced spontaneously during conservative therapy: case report].

Wakamoto H; Maaya Orii; Hiromichi Miyazaki; Ishiyama N

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